INTRODUCTION:
Before using your Brompton, we recommend you read the sections on safety and folding. You
should also be aware how important it is to keep your tyres well pumped-up: soft tyres make for a
lot more pedalling effort (which takes much of the fun out of riding), wear out quickly, and also
have an adverse effect on handling. We cannot overemphasise the need to keep tyres well
inflated.
If you carry out any adjustments or maintenance work yourself, do read the relevant section of this
manual first, as it’s quite easy to get things wrong, and to impair the folding process or damage
the machine. If you take your bike to a dealer for any servicing work, wherever possible use an
authorised Brompton stockist.
Serial and Frame Numbers. The label at the back of the seat tube on the main frame carries the
serial number. The frame number is stamped on the main frame just forward of the rear
suspension pivot: it’s a good idea to keep a record of both numbers. The serial number will be
useful if you have any maintenance or technical queries.
CONTENTS
Section A Safety
Section B Folding and unfolding
Section C Using the Brompton
(tyres, gears, luggage, lights, etc.)
Section D Saddle position
Section E Handlebar and control positions
Section F Wheels, removing and refitting
Section G Running adjustments and checks
Maintenance diagram
Section H Other design points to do with folding
(front hook, handlebar catch,
lower stop disc, cables)
Section J Lubrication and diagram
Section K Routine replacements
Section L Specification of spares
Section M Options and accessories
SECTION A: SAFETY.
1. Before riding, see that the seat pillar clamp is properly secured, and that the hinge clamp
levers are firmly screwed up.
2. Carrying the Brompton: it is obviously less critical that the bike is correctly folded than
assembled, but bear in mind that, if the machine has not been properly locked together,
unexpected unfolding of the folded package, for instance on a staircase or lifting it off a luggage
rack, could cause injury.
3. Do NOT try to alter the height of the handlebar stem where it enters the front forks.
4. Keep the gears properly adjusted, and brakes and control cables in good condition. Running
adjustments should be carried out as described in section G.
5. During folding and unfolding, avoid putting your hands anywhere that they may be trapped.
6. High mileage and hard riding: aluminium alloy is used on the Brompton and this has a limited
fatigue life. Failure in use can cause injury, so follow the recommendations in section K
regarding routine replacements of ALLOY components of the bike.
7. The Brompton is for use on roads and well made paths. It is not designed for cross country
riding: this can overstress the frame, and anyway the tyres and wheels are quite unsuitable.
8. When riding on fine grit, or on wet surfaces, the 16″ tyres
have less grip: wet metal (such as a man-hole cover) is
particularly slippery. Also, in rain the brakes may be less
effective. Take due care.
9. Use lights, front and rear, when riding after dark.
SECTION B: FOLDING AND UNFOLDING.
If you have not had the Brompton demonstrated or explained to you, read this section before
trying to unfold or fold the bike. For those who are already familiar with the Brompton, part 3 may
be a useful source of tips.
Part 1: ORDER OF UNFOLDING & FOLDING – OVERVIEW.
a) UNFOLDING:
Stage 1: raise saddle & handlebar and (if a folding pedal is fitted) unfold pedal: these items can
be dealt with in any order, but they must be unfolded before moving on to stage 2.
Stage 2: unfold front wheel. The bicycle is now in its “parked” position and ready for use.
b) FOLDING:
Always “park” the bike by swinging the rear wheel under before folding:
Stage 1: fold back front wheel (right hand pedal should be moved out of the way if necessary).
Stage 2: lower handlebar & saddle and, if fitted, stow folding pedal; again, these items can be
dealt with in any order once the front wheel has been folded back and latched onto the rear frame.
Part 2: OTHER POINTS TO REMEMBER.
1. The seat pillar, when folded, is what locks the folded package together: it projects down from
the main frame, so preventing the rear frame from rotating. So, if the seat pillar is projecting
below the main frame, DON’T try to park or unpark the Brompton: also DON’T try to latch or
unlatch the front wheel from the rear frame, as this requires that the rear frame rotates relative the
main frame. Also if the saddle is not fully down, the folded package may fall apart when you pick
the bike up.
2. The folded bicycle can be carried by the main tube. Alternatively grip the front of the saddle,
but to do this a) re-clamp the seat pillar after folding (best with the saddle pointing slightly
rightwards, over the centre of gravity), and b) avoid pulling the padding away from the saddle
frame.
3. Turning the cranks/pedals when the bicycle is parked:
a) the left hand pedal should not be folded when turning the cranks, as it can catch on parts of the
rear frame;
b) during folding, the right hand pedal may have to be moved: to do this, the cranks can be
rotated forwards or backwards. However, when new, particularly in top gear, turning the cranks
quickly backwards can cause the chain to go slack or even come off. If this happens, turn the
pedals forward instead, or alternatively keep the bike in middle gear when folding.
Part 3: UNFOLDING AND FOLDING EXPLAINED IN DETAIL.
If you have not seen the Brompton being folded, you may get the impression on reading this
section that the process is difficult: it involves in practice only a few easy movements.
UNFOLDING, stage 1 – Saddle & Handlebars
(and folding pedal):
Saddle, fig FS1. Undo the quick release lever,
QR, under the saddle (swing it outwards and
backwards). Grip the saddle at the rear end,
and, resting one hand on the main frame tube
near M, draw the saddle upwards until it comes
to a stop: get the saddle pointing straight ahead,
and do up the lever QR (it should lie alongside
the main frame). In order to obtain a smooth
action when moving the saddle up or down, you
should pull or push along the line of the seat
pillar itself. If you need a saddle height higher
than normal, see section D.
fig. FS1
fig. FS2
Handlebar, fig FS2. The handlebar
assembly is kept folded by the nipple,
HBNIP, being trapped in the clip, HBC.
To release, pull the handlebar outwards
and forwards and swing it round and up.
To secure, make sure that the hinge
clamp plate, HCPL, straddles both
hinge plates, and screw up the lever at
HH, firmly.
Left Hand pedal, fig FS3. If this is
fitted, unfold it by swinging the pedal
body, PB, outwards. The latch plate,
LP, will snap into position to lock the
pedal in place.
fig. FS3
UNFOLDING stage 2 – Front wheel, figures FS4 & 5:
Do not attempt to unfold the front wheel assembly if either the saddle or the handlebar is still
folded.
Unfolding or folding the front wheel requires only
a single action, described below: however, it’s
a help to understand what goes on. The front
wheel/fork is held in place when folded by
means of the hook, H, passing over the tube,
CHS, on the rear frame. To release, the whole
bicycle must be tipped slightly back relative to
the rear wheel underneath it, so that the hook
clears the tube, fig FS4. The front wheel is then
moved out and forward into position:
during this action there is no need to turn the
front wheel – it should be kept pointing forward
(and slightly leftwards), fig FS5. Also you should
note that during this action the top of the
handlebar assembly remains roughly in the
same position, with the bottom moving round a
small half circle. fig. FS4
fig. FS5
You will find that there is a variety of methods
for carrying out this action, but to begin with
try the following: grasp the handlebar support,
HBS, lift it slightly (maybe lifting the main
frame or pushing back on the saddle at the
same time), and then, using a “stirring” action
move the front wheel out and round to its
unfolded position. No strength is needed for
this, but if you find the action awkward to
begin with, take hold of the front mudguard
with your other hand and help the wheel round
and forward. Finally, do up the hinge clamp
on the main frame at MH, securing the lever
firmly (leaning the bike to the right helps keep
the locking plate in place whilst doing this).
The bicycle is now parked, in
effect ready for use: to unpark
(fig FS6), lift the bike by the
saddle (keeping the front
wheel turned slightly
leftwards) and allow the rear
frame/wheel to rotate down
and back into its unfolded
position. By controlling the
way in which you raise and
lower the saddle, this can be
done in a single smooth
movement: if to begin with you
find the wheel hanging in the
halfway position, help the
wheel round by hand or with
your foot. There is no need to
lock the rear wheel assembly,
as your weight, when you are
on the bike, keeps it in
place.
fig. FS6
FOLDING: stage 1 – Front wheel, fig FS5:
Always start by parking the bike, fig FS6: to do this, turn the front wheel slightly leftwards (if you
don’t, no harm would result, but the rear wheel would clash with the front wheel) and then raise the
bike by the saddle, so allowing the rear wheel to swing down and forward to lie under the main
frame. The bike is now parked, and providing it is on reasonably level ground will stand up
unsupported.
It is tempting to start folding with the “easy” items, the seat or handlebars. The bike cannot be
folded properly if you do start with these: you must fold back the front wheel/fork FIRST.
Have the right hand pedal out of the way of the front wheel: best if the right hand pedal ends up
pointing backwards and downwards.
Unscrew the hinge clamp at MH on the main frame (three or four turns of the handle normally
suffice). Grip the handlebar support, HBS, lift slightly (maybe pushing back on the saddle at the
same time) and, keeping the front wheel pointing forwards, use a “stirring” action to move it out
and back round till it lies alongside the rear wheel (again no strength is needed for
this, but if it helps, take hold of the front mudguard with your other hand and guide the wheel
round). Make sure that the hook, H, has passed over the tube, CHS, on the rear frame, and allow
the front wheel assembly to drop (the whole bike actually rotating relative the rear frame). With
the front wheel now folded, you can move on to the other parts.
FOLDING stage 2 – Handlebars and Saddle (and folding pedal):
Handlebar, fig FS2. Undo the hinge clamp at HH (handlebar stem). Swing the handlebars down
to lie alongside the front wheel, and push home so that the nipple, HBNIP, engages in the clip,
HBC: alternatively, simply let the handlebars drop into position on their own.
Saddle, fig FS1. Undo the lever, QR, push the
saddle right down, and re-clamp the lever. During
this action, the lower end of the seat pillar passes
behind the plastic disc, LSD, on the rear frame: it is
because of this that the rear frame remains folded,
in turn retaining the front wheel in its folded
position. So if you do not push the saddle fully
down, it is possible for the folded package to come
apart when you pick the bike up.Folding pedal, fig
FS3. It is best to fold this with the left hand crank as
high as possible (i.e. with the cranks turned so that
the right hand pedal touches the front wheel): also,
the ridged side of the nylon latch plate on the pedal
should face upwards. Press the outer part of the
latch plate downwards, so that the inner part clears
the top of the bearing housing, BH, and stow the
pedal PB.
Front wheel assembly, other methods for folding and unfolding: the method described above,
viz. holding the handlebar support and using a stirring action to move the front wheel assembly, is
perfectly satisfactory. However, if you frequently fold and unfold your Brompton, you’ll become
aware of other, easier, techniques for this stage of folding.
SECTION C: USING THE BROMPTON.
1. Tyre pressures:
BROMPTON high-pressure: Record (C-type, see note):
Recommended Maximum Recommended Maximum
FRONT 60 – 80 psi 100 psi 50 – 70 psi 75 psi
REAR 70 – 90 psi 100 psi 60 – 70 psi 75 psi
(Note: on the Raleigh Record tyres it is safe, because of the rim profile on the Brompton, to use
75 psi max. instead of the 55 psi marked on the tyre.)
The most appropriate pressure depends on your weight and
preference. On rough roads, it’s obviously more comfortable if
you keep the pressures near the lower end of the ranges.
However, for minimum pedalling effort, use the higher
pressures.
With lower tyre pressures, the pedalling effort rapidly increases,
and the risk of punctures is higher: KEEP YOUR TYRES WELL
INFLATED.
A car-type valve is used, allowing various methods of inflation.
The Brompton HP pump is well suited, and can be kept on the
rear frame. You can also use a standard car foot- or hand-pump,
or an air line: with compressed air, say at a garage, the
pressure in the tyre will rise very quickly: so let the air enter in
short bursts, checking the pressure all the time. If you use a
standard bike pump with a flexible connector, you have to
unscrew the connector very swiftly to avoid air loss.
2. Gears:
Two gear systems are used on Bromptons, derailleur (left hand trigger) and hub gears (right hand
trigger). To keep things simple, follow two rules for changing gear:
a) when moving, keep pedalling, but take the pressure off the pedals while making the change,
and
b) when stationary, avoid using the left hand trigger, and for the right hand trigger, back pedal a
little to allow the new ratio to engage (if, when pulling
the lever on the RH control down, you encounter unusual resistance, do not force the control:
instead, back pedal and try again).
Always make sure that the hub gear-control lever clicks positively into place (and is not left in an
“in-between” position). And if your bike has a derailleur, do not neglect to use it: if you use only
one sprocket all the time, the wear will be uneven.
If transmission is not smooth in any gear, take action to remedy this, as damage could result.
Adjustments of the gear control(s) will be needed from time to time, particularly during early use:
see section G.
3. Operating the dynamo on the T-type.
To engage the dynamo against the tyre, either, if the dynamo is fitted with a lever, depress the
lever, or, if there is no lever, push the body of the dynamo down relative to its bracket. To release
the dynamo, pull the body of the dynamo away from the tyre, and the dynamo will latch off
4. Fitting luggage to the front carrier block.
The front carrier frame has an integral tapered
latch plate. To attach the frame, slide this plate
down onto the front of the carrier block: you will
hear a distinct click as the frame approaches
its rest position, an indication that the sprung
latch lever in the carrier block has engaged. To
remove luggage, pull the bottom of the latch
lever backwards (this projects underneath the
carrier block, just above the front brake), and
then draw the frame upwards and off: a slight
side to side rocking action may be needed to
free the luggage from the block
5. Parking the Brompton.
When you first start using the Brompton, you may be put off by the way the rear wheel falls away
whenever you pick the bike up. However, this feature allows you to park the bike instantly, a great
convenience.
When wheeling the bike up on to a curb, the rear wheel assembly may tend to start folding,
particularly when you have a load on the bike. You can normally prevent this by lightly applying the
rear brake.
If you wish to do without the Brompton’s parking feature, preferring the rear wheel assembly to
stay put, tie an elasticated cord round the base of the seat pillar: it is often worth doing this when
carrying loads on the rear rack.
6. Carrying the unfolded bike.
Now and again, for instance to climb a set of steps, you may wish to carry the Brompton without
folding it up. To prevent the rear frame from folding, you need to use two hands, one holding the
rear end: but without luggage at the rear, you can pick the bike up with one hand by the main
frame and let the rear end hang down.
7. Wheeling the folded bike around.
The folded Brompton can be pushed into tight spaces on its rollers. You can also pull it around
with you, using the raised handlebar as a handle: this is useful over relatively short distances, for
instance along a station platform, but it isn’t practical for longer distances or on uneven ground
(when it pays to unfold the machine).
8. Using the cover.
The cover comes with a saddlebag for
storage when it’s not in use. If you don’t use
the saddlebag for the cover, you may find it
useful as a container for other small
items.
The zip on the cover helps fitting, and
allows access at the top for carrying the
bike. If you wish to make a neater package
and also partially to cover the base of the
bike, pull the lower edge of the cover right
down, and then draw the pull cord tight.
SECTION D: SADDLE POSITION.
If folded size is critical (and you are happy with the saddle nearer to the handlebars) then, for
maximum compactness, fit a saddle adaptor pin, pointing “downwards”.
With the saddle mounted in any other way, it ends up projecting somewhat from the minimum
folded envelope.
BASIC ADJUSTMENTS:
Height of the saddle: for the maximum height, draw the seat pillar up until it reaches a positive
stop (and for lower positions slide it down). If you wish to select a very low position, take care, as
the bottom of the seat pillar may project below the main frame and prevent the rear frame from
swinging between parked and un-parked positions.
Saddle angle is adjusted in the normal way (slacken the nut securing the mounting clip, choose a
suitable angle and re-tighten the nut: torque 13NM).
The saddle can be moved 30mm back by reversing its clip so that the seat pillar passes forward
of the bolt.
ADDITIONAL HEIGHT:
Riding with a saddle even slightly too low
is no fun. You can win around 15mm of
extra height by moving the saddle-clamp
up the seat pillar itself, and this might be
sufficient. If not, there are three Brompton
options which allow more height,
extended seat pillar, telescopic seat
pillar, or saddle adaptor pin pointing “up”:
see Section M for details. Alternatively,
use another design of saddle, with
greater depth.
Note: if you do opt for a saddle adaptor
pin, don’t mount it pointing backwards as
this could produce stresses for which the
bicycle is not designed.
SECTION E: HANDLEBAR & CONTROL POSITIONS.
The handlebars and control levers on the Brompton are factory set to provide a compromise
between compactness and riding comfort: for most users the riding position should be fine.
There is no vertical adjustment (see below), but there is some adjustment available in the fore/aft
direction. You should be aware that if you do choose to make such an adjustment, then the folded
handlebar will not lie as close to the front wheel as normal.
Handlebars or levers moved FORWARD: these will hit against the front wheel on folding, and so
prevent the handlebar catch from functioning properly: adjust the handlebar nipple as described in
section H.
UNDER NO CIRCUMSTANCES should you attempt to set the handlebar at a higher position by
withdrawing the lower part of the handlebar stem from the steerer tube on the front forks.
If the handlebar stem assembly has to be moved for any reason, then, on reassembly, a) leave a
gap of 0.5mm-1.5mm between the top of the steering locknut and the step in the stem under the
hinge, b) use a tightening torque of 20NM for the expander bolt (whose 6mm AF socket head is
visible when the handlebar is folded), and c) check the alignment of the handlebar catch (section
H).
SECTION F: WHEELS, REMOVING AND REFITTING.
If the brakes are properly adjusted and the tyre is well inflated when removing or fitting a wheel,
you won’t be able to move the tyre past the brake pads. One way round this is to deflate the tyre:
alternatively, loosen the cable adjustor (if it’s possible) or remove a brake pad.
Front wheel.
To remove, undo and remove the nut and washer on the left hand end of the axle, move the hook
(and mudguard stay) out of the way, and detach the special LH tab washer. Slacken the RH nut,
disengage the tab washer and remove the wheel (see note below).
To replace, follow the above in reverse, making sure that each tab washer engages the hole near
the fork end, and that the axle remains seated against the end of each slot while you tighten the
wheel nuts: torque 15NM.
Notes:
1. If the front wheel has not been removed for some time, you may find, on undoing the second of
the two nuts that the axle starts to turn with the nut so that the nut cannot be slackened off. If this
happens, re-tighten both nuts, then slacken and retighten the right hand nut a few times till it turns
easily on the axle; partially re-tighten this nut and then slacken the left hand nut, and finally undo
the RH nut again.
2. The LH tab washer is special: do not swap it with the RH tab washer.
Rear wheel.
Move the gear trigger(s) up to high gear and, in order to engage the high gear(s), move the
pedals forward and backwards. Park the bike.
Removing the chain tensioner, fig AR3.
For a hub gear, the control has to be disconnected: press the spring clip C on the adjustor A, and
withdraw it from the end B of the gear indicator; the indicator chain GICH will be left hanging
loose from the end of the axle and should be unscrewed from the hub and withdrawn.
Move the sprung arm, CTARM, anti-clockwise and lift the chain off: allow the CTARM to move
back clockwise until it comes to a stop; undo the securing nut CTN and remove it together with its
washer. The chain tensioner assembly may now be removed by drawing it sideways, off the end
of the axle (if a derailleur is fitted, it has to be tilted to clear the changer).
Removing the wheel, fig AR4.
Slacken the axle mounting nuts. For hub gears at least 4 or 5 turns are needed, so that the
tab-washers TA can disengage from their slots, SL2: you may need to prise these tab-washers
out with a small screw-driver.
Fitting the wheel.
Make sure that the chain passes round the rear sprocket. Drop the axle into the slots, with any
tab-washers TA the correct way round (i.e. tabs aligned with slots SL2). Make sure that the axle
is seated, at each end, against the end of the slot, SL1, and do up the wheel nuts, torque 22NM.
Fitting the chain tensioner:
First arrange the chain so that it is running true over both chainwheel and rear sprocket (for a
derailleur, the outer sprocket); next note that the chain tensioner body has two flanges on its inner
face – these should pass either side of the axle plate when fitting the chain tensioner.
For a non-derailleur bike, address the chain tensioner to the axle plate and press home, making
sure that the chain passes between the fixed idler sprocket CTIDL and the rear sprocket.
For a derailleur bike, the chain and the fixed idler
on the chain-tensioner-base, CTIDLB, have to lie
between the “uprights” of the chain-pusher-plate.
So, with the LH trigger up and the chain-tensioner
inclined slightly outwards as in fig DR14 (chain
not shown in this figure), feed the idler CTIDLB
between these uprights, and then feed the
chain-tensioner base onto the rear axle plate till it
abuts squarely.
Next secure the chain tensioner using the chain tensioner nut CTN and its washer CTW. This nut
should not be done up too tightly: somewhat more than hand tight suffices, max torque 8NM.
Now draw up the slack in the chain and feed it over the idler wheel on the sprung arm CTARM -
check that the chain is flowing correctly by turning the cranks.
For a hub gear, the control has to be reconnected. Screw the indicator chain GICH into the hub,
and make sure it is fully screwed home, then unwind through not more than half a turn so that it
points towards the gear cable. Next connect the adjustor A to the indicator chain and, with the
bike unfolded, make sure that it is correctly adjusted (see section G).
SECTION G: RUNNING ADJUSTMENTS & CHECKS.
It is important that certain of the jobs listed here are carried out at least once, if not two or three
times, during the first few hundred miles of use when parts are bedding in (see chart on centre
page). Thereafter, except for brake adjustment, they need to be carried out less and less
frequently. If you are not confident about carrying out these jobs yourself, your dealer can help.
Hub Gear adjustment:
The aim is to make sure that the indicator chain down at the end of the rear axle moves to the
correct position in response to moving the trigger. For this the cable has to be running well: it
must be free of kinks or sharp radii, with the cable pulley rolling freely.
Adjustment of gears must be carried out with the bike FULLY UNFOLDED (i.e. NOT parked).
Also (fig AR5), if the indic- ator chain GICH has
been detached from the adjustor, A, for any
reason (say for wheel removal), make sure the
indicator rod is screwed fully home inside the
hub (and backed off not more than half a turn),
before connecting to the adjustor.
While setting hub gears, always back and
forward pedal a bit before checking a setting,
and back pedal while changing gear. The cable
is made tighter by pushing the adjustor further
onto the grooved end B of the indicator chain: to
obtain a looser setting, the spring clip C has to
be depressed.
You can usually get things right first time by moving the trigger into the top gear, pulling on the
adjustor (away from the pulley housing CPULA), and then feeding the grooved end B of the
indicator chain into the adjustor until it is just not loose, i.e. WITHOUT pulling the indicator chain
out of the axle at all.
The setting is correct when
a) with the trigger in top (”3″), the cable is just slack, in other words neither flopping around at all
nor taut (if, when you try pulling the adjustor away from the CPULA, you can see any movement of
the indicator chain back into the axle where it enters it, then the setting is too tight).
b) with the trigger in low (”1″), the indicator chain (where it enters the end of the axle) should either
move not at all, or perhaps up to 1mm, when you pull the adjustor towards the CPULA (if it moves
more than this, then the setting is probably too loose: on the other hand, if, while back-pedalling
and moving the trigger slowly from position 2 to 1, you see that the indicator chain stops moving
out of the end of the axle before the trigger has clicked into position 1, then the setting is too
tight), and
c) when pedalling forwards (under no load) and changing through the 3 gears both up and down,
all three gears are positively selected.
If you need to make any further adjustment, always select top gear and back and forward pedal a
bit first. If you cannot obtain a satisfactory setting, then the most likely cause is either the cable
not running freely, or damage to the indicator chain itself, where it runs into the axle end.
Otherwise, the fault may be with the hub internals.
Derailleur maintenance and adjustment.
For satisfactory gear changes and smooth running, two stops need correct setting, and two key
elements of the system have to move freely: the actuator (or “chain-pusher”), and both idlers on
the chain tensioner
Chain pusher adjustment.
Use the stop screws, fig DR9, on the
chain pusher. The idea is that, in high
gear, the inner face of the inner upright
IU, fig DR16, shall be as close as
possible to the idler wheel, without any
rubbing pressure while the idler rotates
(to give the slickest change with
minimum wear): when the setting is
right, you should just be able to see
daylight between the two while turning
the cranks forwards, perhaps with
occasional contact. Use a 2mm hex key
in the forward stop screw H for
adjustment.
The same principle applies for the lower
gear setting, only this time, fig DR17, the
inner face of the outer upright OU has to
just not rub on the idler, and the rear
stop screw L is used for adjustment.
Cable adjustment should seldom be necessary, as the trigger moves the cable twice as far as
the movement of the chain-pusher (an over-ride spring inside the dogleg DL absorbs this
movement).
Derailleur trouble shooting.
If the derailleur still malfunctions after adjustment, or if turning the adjustor screws has no useful
effect, and there is no obvious sign of dirt obstructing free movement, then the procedure for
diagnosis is as follows. Step 1, remove the chain tensioner: this allows you to identify whether the
problem lies with the idlers on the chain tensioner (they should be free to move in an
out 7mm) or with the chain-pusher. If the chain-pusher does not move freely, and the cause is not
obvious, try slackening the M3 screw slightly (there is supposed to be clearance). Step 2, remove
this M3 screw completely: this allows you to identify whether there is a problem with the cable and
the dogleg link DL (e.g. dirt on the spring, misalignment of cable and cable stops, etc.), or with
the chain-pusher (e.g. hidden dirt, seized bearing: you may need to remove the chain pusher from
the frame).
Crank axle bolts and pedals:
The crank axle bolts should be torqued down (32NM, use a 14mm AF socket) after the first few
hours of use, with occasional checks thereafter. Check also that the pedals are secure (torque
30NM): note that the LH pedal has a LH thread.
Seat clamp:
The quick release clamp (QR, fig FS1) should be kept adjusted so that the lever closes firmly
when doing the clamp up; if the movement is slack and easy, with little resistance, the seat pillar
will not be properly secured. As a guide, with the seat clamp lever forward (i.e. done up), the
adjustor nut AN should be tightened with a torque in the range 5-8NM and the maximum closing
force needed at the end of the lever while securing the clamp should lie in the range 80-120N.
The correct setting will depend on the weight and strength of the user.
Do not over-tighten, as this can cause damage. For normal tightening during the life of the
machine, a sixth of a turn or less of the adjustor nut will normally be quite sufficient.
If, after adjusting the clamp, the seat pillar slips in use, then the cause is almost certainly oil or
grease. Remove the seat pillar from the bike, and using soapy water, thoroughly clean both the
seat pillar and the sleeve in the main frame.
Spokes:
These tend to bed in during early use, and to lose some of their initial tension. which can cause
spoke failure (particularly for heavier riders). See that these are re-tensioned correctly after initial
use, and check thereafter.
Saddle clip bolt:
Because this passes through the body of the saddle, which is moulded nylon, some settling of this
nylon during early use may reduce the clamping force in the clip bolt: you ought now and again to
check that the nut on this clip bolt is firmly secured (torque 13NM).
Handlebar clip bolt:
Check that this is properly secured, torque 15NM. If it is loose, the handlebars may slip without
warning.
Brakes:
The brakes should be set so that the pads are as close to the rim as practical without actually
interfering with the free running of the wheel. When setting the rear brakes, the bicycle should be
in its un-parked position. Adjustment is carried out using the threaded cable stop on the brake
lever (or, on a C-type, at the caliper).
Dual-pivot calipers, centering. These are not self-balancing, and need to be trimmed so as
not to exert any side force on the rim. Apply the brake and watch for any trace of sideways motion
of the rim or tyre as the pads engage: adjust the M5 set-screw (visible on top of the caliper – use
a 2.5mm hex key) in order to get the caliper properly balanced. (If after doing this, the caliper
appears “lop-sided”, with one arm lower relative the rim than the other, then the whole caliper
assembly needs to be re-positioned in the frame. Slacken off the main nut (10 AF) holding the
brake spindle, adjust the M5 set-screw to get rid of the uneven look of the brake, and do up the
main nut again while pulling on the brake lever. Finally, re-trim the caliper so as to centre the
pads using the M5 set-screw.)
Dual-pivot calipers, pad position. As these wear down, or after any adjustment as above, the
pads may no longer bear centrally against the braking surface on the rim: re-position as needed.
Cup and cone bearings:
If these are set over-tight, damage is likely, and in the case of a geared rear hub, the freewheel
will tighten up as well (in turn causing chain problems during folding). Always ensure that the
relevant locknut is secure after adjustment:
a) wheel hubs: set so that very slight play is just discernible at the wheel rim. On the rear geared
hub, do not use the RH cone for bearing adjustment. Instead use the two nuts (22AF) at the LH
end: the bearing cone here is unthreaded, and its position on the axle is set by the inner of these
two nuts, which is in turn locked in position with the outer.
b) steering head: set so that no play is discernible, and so that (after tightening the lock-nut) the
steering is still free, and without tight spots.
SECTION H: OTHER DESIGN POINTS TO DO WITH FOLDING
Hook:
Correct function of the hook is important for
satisfactory folding: it retains the front wheel in
place when the bike is folded. It is attached to
the front mudguard stay (or, if there are no
mudguards, to a special wire form, not
illustrated). If it is knocked out of position, the
design allows it tobe bent back. For the function
to be correct:-1. The chainwheel mustn’t be too
far out. Part of the stay, B (fig HK1), acts as a
buffer against the chain wheel during folding,
and steadies the folded front
1. The chainwheel mustn’t be too far out. Part of
the stay, B (fig HK1), acts as a buffer against the
chain wheel during folding, and steadies the
folded front wheel. If the chainwheel lies too far
out (the gap G (fig HK4) between inside of chain
and hinge plate RHPL when the bike is parked,
should be 0-3mm, not more), then the hook will
be a tight fit over the chainstay CHS, and may
stick when trying to unfold the front wheel.
2. The hook must not be bent wrong (fig HK3): if
it is bent up too far, then a) it may catch on the
rear spokes, and b) it may slide off the tube
CHS, causing the bike to unfold inadvertently. If
it is bent down too far, then the hook will contact
the tube CHS at C before the front wheel (and
the rest of the bike) has dropped to its fully
folded position. If it is bent fore/aft it may strike
the chainwheel or (if fitted) the derailleur
changer, and if the stay is “crushed” in, the front
wheel spokes will clash with the chain tensioner
nut as the bike is folded.
If the hook is ineffective, and/or sticks during
unfolding, then, bearing the above in mind,
judicious bending of the wire stay (say by pulling
on the hook) should cure the problem.
fig. H3
Handlebar catch and nipple:
The “body” of the handlebar catch acts as a stop to align the front wheel correctly during folding.
The correct torque for the securing screw is 9NM.
Operation of catch and nipple: keep these correctly set, for, if wrong, the handlebar catch will
loose its spring effect, with the irritating result that the handlebars unlatch too easily from the
folded package.
Alignment of the catch, HBC: the catch itself
must be aligned so that the nipple enters centrally
(fig HB3 rather than HB4)
.Alignment of the nipple, HBNIP: this should be
in line with the catch HBC as it enters it during
folding (fig HB5 rather than HB6). Bear this in
mind if making adjustments as described
below.
Offset of the nipple, HBNIP: if the handlebar
itself, or the control levers/cables, are set too far
forward, they may, on folding, foul against the
front wheel and so prevent the nipple from fully
entering the catch (i.e. as per fig HB8). To
remedy, either reset the handlebar or levers
further back (i.e. further out when folded), or
unscrew the nipple so that it is further from the
support tube, HBS: the nipple must be able to
enter the catch HBC fully, as per fig HB7.
If the set up is correct and the catch remains
ineffective, either replace the h’bar catch, or you
may obtain a temporary cure by twisting the
nipple slightly (i.e. as not normally recommended,
fig HB6).
Lower stop disc:
When you pick up the folded bike, the rear
frame cannot unfold because the lower
stop disc, LSD, butts against the “folded”
seat pillar, SP. The LSD can be adjusted
to give the correct gap between itself and
the SP: if the gap is too small, then the SP
may foul, irritatingly, against the LSD
during folding. If the gap is too large, then
the rear wheel will drop away too far when
the bike is picked up, so that the hook
retaining the front wheel slips off the tube
CHS on the rear frame. The correct gap
is 1-2mm (fig LS1).
To set the lower stop correctly, you need a 15AF and a 19AF spanner. Do not over-tighten the
lock-nut, correct torque 8NM.
Cable routing, fig CR1:
The routing of the cables is carefully worked out,
and when replacing cables, correct routing is
vital if these are not to be damaged during
folding. Also the outers should be exactly the
same length (+/- 2mm) as the original cables,
and also have same ferrules (if fitted): always
use lined outers, and PTFE coated inner
cables.
All cables MUST pass in front of the handlebar,
to the left of the handlebar stem and to the right
of the main frame tube. The FRONT brake cable
must pass through the forward cable guide
CGF. The REAR cables must pass through the
cable gatherer CABGATH on the front brake
cable, the centre cable guide CGC and the rear
cable guide CGR as shown: they should also
pass inside the tube TT and the tube SS. The
gear cable GCAB should lie below the brake
cable BRCABR (if the bike has both derailleur
and hub gears, the derailleur cable should be
lowest).
Rear hinge screws:
These are factory set with a torque of 10NM, using thread-locking fluid, and (unless there is a
problem) should NEVER be checked or moved.
SECTION J: LUBRICATION.
When lubricating your Brompton, avoid getting oil or grease on the seat pillar or the wheel rims.
Grease is the right lubricant for all wearing parts (oil does not last as well), and where it is
practical to dismantle an assembly and apply grease, it’s best to do so. However, this is often
inconvenient or impossible, and oil can be used instead, but note that applying oil to a greased
assembly can cause the remaining grease to be washed away fairly quickly, and frequent
re-lubrication is needed thereafter (unless you re-grease).
Choice of lubricant: any good quality general purpose grease is satisfactory, especially lithium
based. For the chain, proprietary chain lubricants with good penetrating properties give the best
results. As for oil, some spray-on products are convenient to use, otherwise employ an ordinary
light mineral oil. For the rear hub, Sram recommends:
a) for the bearings and gears, Sram grease “Fett type A”: Brompton can advise where to
obtain this.
b) for the pawls, light mineral oil.
The chart on p.25 shows what to lubricate. For medium frequency items (marked “3″), a sensible
guide for the interval between lubrication is a year, or 5,000 miles.
Notes:
a) Chain: for smooth pedalling the chain HAS to be well lubricated: if the bike is used in the wet,
this should be done frequently. The easiest way to cover the whole chain is to turn the pedals
backwards while applying oil: make sure that the oil flows both onto the rollers and between the
side plates: turn the pedals a few more times to allow the oil to work in, and then wipe off excess
oil.
b) Hinge clamps: a thin smear of grease on the inside faces of the clamp plates ensure that
these release OK: the thread of the clamp bolt, and its washer, should also be greased.
c) Folding pedal: the pivot spindle on which it folds likes greasing from time to time. The main
bearing, which is grease packed, should not be oiled: however, if the bearing is not running freely,
some oil fed in past the seal will extend its useful life.
d) Rear hinge: this comprises a stainless steel shaft running in pre-greased bushes and these
will normally give a very long maintenance free life; however, after the first say 10,000 miles or 2
years, an occasional application of oil is recommended.
e) Hub gears: the gears and bearings are sealed; greasing need only be carried out during major
service.
SECTION K: ROUTINE REPLACEMENTS.
Planned replacement is advised to ensure both safety and good performance. The suggested
intervals between replacements are for bicycles subjected to normal use: the most appropriate
timing depends on the conditions of use and your riding style.
1. ALUMINIUM COMPONENTS: as on other lightweight machines, aluminium alloy is used in
the construction of the Brompton, and this material has a finite life before failure. In normal use,
the risk of aluminium fatigue failure is remote, even after many thousands of miles. However, the
risk of failure increases with use, especially with hard riding or other severe loading: as such a
failure could cause injury, the hinge clamp plates, handlebar and chainset should for safety be
replaced every 5,000 miles (more frequently on any machine subjected to hard use), and we
recommend that these items are anyway checked regularly. For the handlebar, an alternative is to
fit a cross bar (see Section M).
2. Transmission: if the chain is allowed to stretch unduly, through lack of lubrication or long term
wear, power transmission will be inefficient and rough and the sprockets will also wear quickly. A
new chain is not expensive: so replace every 2 – 3,000 miles (or sooner if it has lacked lubrication
or been used in harsh conditions). If you have allowed the chain you are replacing to stretch
unduly, you will almost certainly have damaged the rear sprocket(s), and possibly the chainwheel
too: these should be checked when fitting a new chain and if worn should be replaced at the
same time as fitting the new chain.
3. Brake cables: these do not have an indefinite life, and to reduce the risk of brake cable failure,
replace the inner cables at intervals of 4,000 miles or less. If there is any doubt about the free
running of the cables, the outer cables should also be replaced. New outers should be exactly the
same length as the original cables, with the correct terminating ferrules.
4. Gear cables: though less safety critical than brake cables, the hub-gear inner control cables
should be replaced at the same interval as brake cables.
5. Tyres: the risk of punctures increases with the mileage covered, as the tyre accumulates small
sharp particles in its tread. You should reckon on replacing the rear tyre every 3 – 4,000 miles and
the front tyre every 6,000 miles.
6. Lighting on the T-type: a) repeated flexing of the wires around the rear hinge when folding
eventually causes failure – replace the wiring loom connecting the dynamo to the front light at
intervals of 7,500 miles: b) front bulb and dynamo: these can have a very long life between failure,
but performance deteriorates – replace after 250 hours.
8. Suspension bush (flanged bush under the suspension block): 10-15,000 miles.
SECTION L: SPECIFICATION OF SPARES.
Chain: this must have the correct number of links for a given sprocket combination, as noted
below. Also traditional joining links are usually unsuitable because the pin is too long: so instead
the joint should be made by pressing in the rivet pin. We recommend Sram PC1 (1/8″) and PC10
(3/32″) chain.
· for non-derailleur, size ½” x 1/8″: max. pin length 8.7mm: number of links 50T/13T/98L,
44T/13T/96L, and 44T/14T/96L
· for derailleur, size ½” x 3/32″: max. pin length length 7.4mm: number of links 54T/16T/104L,
50T/15T/100L, and 44T/15T/98L (the rear sprocket size given is that of the larger, inner
sprocket).
Rear sprockets for geared hub (to ISO 10230): non-derailleur, ½” x 13T x 3mm thick (but for
lower gearing, use a 14T or 15T sprocket): derailleur, special Brompton sprockets, 13T and 15T
only.
Chainset. Best to use the Stronglight set specified for the Brompton. If you use an alternative,
make sure that it suits the BB axle (ISO 6695), that it gives the correct chainline (fig HK4), and
that the end of the crank does not clash with any part of the rear frame when the bicycle is parked.
BB cartridge. ISO 6695. For C-type, Ritmo S x 127mm. For other models, FAG 119mm.
Chain tensioner idler sprockets: non-derailleur, 10 tooth x 3/32″ wide at the teeth, x 1/2″ wide at
the centre, mounting hole to receive M5 bolt: derailleur, special flanged Brompton idlers.
Brake pads: Alhonga HJ 454-11.
Tyres: size 16″ x 1.3/8″, ETRTO 37-349. Inner tube with Schrader valve. Best to use the
special high-pressure Brompton tyres (see Section M). But if you cannot obtain these, choose
another reputable make: take care, as some tyres lose shape on inflating, and/or offer a lot of
rolling resistance, and some tubes lose pressure fast.
Control cables: The cable routing and terminations are critical. For outer cables the length, and
ferrule diameter should be identical to that of the cable originally fitted: for the front brake cable,
the outer must be in two parts of the correct length, so that the cable gathering ring occupies the
right position in the cable system. You are best advised to use cables supplied by BROMPTON. If
you have to use cables from another source, specify low friction cables (PTFE coated inner
cable, lined outer cable).
Dynamo: AXA IQ right hand fitting. Other 6v dynamos are also suitable, but you may need to fit a
special slotted stay (available from Brompton).
Front lamp bulb: 6 volt x 2.4 watt halogen. Do not touch the glass when fitting.
SECTION M: OPTIONS AND ACCESSORIES.
LUGGAGE, the front carrier system.
The Brompton system provides a highly convenient method for taking luggage on the bike as it
only takes a moment to attach or release it. As the load is effectively attached rigidly to the main
bike frame, it has little effect on steering. The system is a delight to use, especially if you
regularly need to take luggage or shopping with you.
At the heart of the system are a tapered block and a special frame which latches onto it. Then is
then a choice of 3 soft-luggage options that fit over this frame: all are badged for safety with a
reflective mark. A shoulder strap (not shown) is available for the panniers
Front carrier block and clip (100 gms). A mounting kit is
provided, and with this the block is made fast to the bicycle.
The block has a sprung clip to ensure that luggage remains in
place when riding. The block does not project from the folded
package.
Cloth pannier (1380 gms), a handy and
practical holdall made from tough waterproof
polyester fabric. The main compartment has a
divider for keeping papers separated from other
articles. At the back, there are two pockets for
items such as tools, maps etc. Total capacity is
22 litres. All the compartments have zip
fasteners.
Touring pannier (1670 gms). With considerably
more capacity than the cloth pannier, this has,
instead of zips, a roll-top system, with nylon clips, for
closing. Like the cloth pannier, there are two
pockets at the back, and a divider inside: in addition
there are three elasticated net pockets around the
outside, where you can stuff things which you may
want during your ride. Total internal capacity approx
28 litres.
Folding basket (1340 gms). Using the same material as the panniers, this
provides a large, open-top
container, ideal for shopping.
Mounted on the bike, the shape
is maintained by virtue of a
simple bracing frame, which
folds flat for storage. Drainage
holes are provided in case of
rain. When used as a basket
off the bike, it has the character
part bag/part basket, and you
have to take a little care when
stowing goods if you want it to
stand up properly. Capacity is
24 litres
Rainproof cover (55 gms, not shown). Though the material on the Brompton luggage items is
PVC coated, leakage is possible during prolonged rain through zips or seams. The Brompton
rainproof cover gives complete protection against rain, with an elasticated hem to keep it in
place. It’s colour is a highly visible, bright yellow: when not in use, it takes up next to no space.
Front carrier frame (690 gms), a brazed, tubular steel
frame, with a plated finish. The top member provides a
carrying handle and the base gives support for the load.
Its principal use is as backbone for the cloth items, but it
may also be used on its own to carry other luggage tied
to it.
COVER & SADDLE BAG (240 gms). In many
situations, say on trains, or when the bike is dirty,
a cover is useful. The Brompton cover is quick to
fit or remove, and it can be drawn tight around the
base of the bike by using its draw-cord. The
saddle bag is a home for the cover when it’s not in
use.
BROOKS LEATHER SADDLE for the
Brompton: If you are thinking of a change of
saddle, you should consider the special Brooks
leather saddle made for Brompton (extra 420
gms). This beautifully made traditional saddle
will give years of comfortable riding. For real
refinement, you can specify a titanium frame,
obviously light (extra weight only 185 gms), but
also with more spring.
LIGHTING
L-type battery lighting system. The relatively lightweight
rear lamp stays permanently on the rear frame, out of harm’s
way, while the heavier front lamp is removed for folding.
Rear lamp: Basta extra bright 6LED type, with integral
reflector: 2 or 4 AA batteries give approx. 20 or 40 hours’
use. Front lamp: Cat Eye lamp with very easy quick
release system: 2 size C batteries give up to 17 hours’ use.
The set includes batteries and the special mounting
brackets needed front and rear for attaching the lamps.
Weight with front lamp removed 140 gms (complete 350
gms).
T-type dynamo: “standlights”. A rear light which stays on when you’re
stationary is a great safety feature: the Basta 6LED rear standlight
stays lit for 4 full minutes after you have stopped (with a button for
turning it off sooner if you want, say at the end of a ride). For the front,
the Cat Eye lamp (as above) can be used: its large switch is very handy
for frequent operation.
T-type: special dynamo stay. If you wish to use a dynamo different
from the normal Brompton dynamo, it may, with luck, fit directly onto the
standard stay. However, if not, we offer a stay where the bracket is
SLOTTED, which allows nearly any type of bottle-dynamo to be fitted.
HANDLEBAR CROSSBAR.
If you ride hard or regularly (and particularly if you
jump over kerbs), your handlebar may not last for
ever: as failure can cause injury, we recommend
that handlebars are replaced at regular intervals.
But for greatest safety, you can fit the crossbar
(suitable for normal Brompton bars).
REPLACEMENT TYRES.
Our high performance tyres, compared to ordinary road tyres, make a really noticeable difference
to the performance of the bike: more expensive, but well worth it. Whatever happens, avoid using
any old tyre: on a small-wheeled bike, a good tyre is essential, and certain cheap makes can
completely spoil the fun by making pedalling far more effort.
Brompton standard tyres, 42FL, “yellow”.
Standard on L-types and T-types, these are
exceptionally free-running, durable and
lightweight.
Brompton Kevlar tyres, 42FT, “green”, with
the same skin-wall build as the 42FL, except for
the inclusion, under the tread, of a Kevlar belt.
This much reduces the risk of punctures, and it
barely has any effect on the attractive
free-running qualities of the 42FL.
Schwalbe Marathon. Though heavier (110
gms per pair) than the 42FL, and not as free
running, its advantage is its robust construction.
Like the 42FT it has a Kevlar belt included, but it
differs in having a) a deeper unidirectional tread
(with improved grip off tarmac) and b) a heavier
side-wall to reduce the risk of “pinch-punctures”.
Raleigh Record: an inexpensive, hard wearing, good quality, conventional road tyre, fitted as
standard on the C-type.
SADDLE POSITION. If you need a higher saddle and
you can live with its projecting slightly from the folded
package, fit a longer seat pillar and/or a saddle adaptor
pin (pointing up). Note: additional height is also
possible by fitting other types of saddle.
1. Longer seat pillars:
EXTENDED SEAT PILLAR (extra 150 gms), 60mm
longer than the standard seat pillar.
TELESCOPIC SEAT PILLAR: permits a saddle height
up to 175mm higher than normal, yet when lowered, the
saddle projects only 30mm from the folded package
(extra 295 gms).
2. Saddle adaptor pin (125 gms)
a) mounted “pointing down”, it allows the saddle to be moved up
to 40mm forward (which also makes the folded package the
most compact)
b) mounted “pointing up”, it allows the saddle to be moved up to
30mm higher, albeit slightly further forward.
GEARING.
Suitable rear sprockets and Stronglight/Brompton chainwheels are available to give gearing 12%
lower or 18% lower. If you want to use our chainwheels to change the gearing on a C-type, then
the FAG 119mm bottom bracket cartridge must be fitted instead of the Ritmo 127mm cartridge.
OPTIONS FOR THE C-TYPE ONLY:
FOLDING LEFT HAND PEDAL: The Brompton folding pedal has an ingenious design, using a
precision industrial bearing. It allows you safely to use both sides of the pedal in the normal way,
and yet to fold it at a touch, leaving a projection of only 20mm.
MUDGUARDS: Complete set with all stays, mud-flaps and fastenings, for retrofitting to the
C-type (365 gms).
PUMP: high pressure pump with thumb-lock connection, made specially for Brompton by Zefal. If
required this can be kept permanently to hand, on the rear frame.
BROMPTON BICYCLE LTD
Kew Bridge Distribution Centre, Lionel Road, Brentford, Middlesex TW8 9QR.
(and at www.bromptonbicycle.co.uk) April 2002
