Brompton OM4-1 User manual

OWNERS MANUAL
ISO 4210-2
CITY AND TREKKING BICYCLES
CPSC 16 CFR 1512
NORTH & SOUTH AMERICA
MAINLAND EUROPE
OM4-1

COMPONENT NAMES
SADDLE
PENTACLIP
SEATPOST
SEAT CLAMP
SUSPENSION BLOCK
LOWER STOP DISC
REAR FRAME
CHAIN
REAR WHEEL NON-FOLDING PEDAL
CRANKSET
FRONT WHEEL
FORK
HANDLEBAR CATCH
HANDLEBAR STEM
HANDLEBAR CATCH NIPPLE
GRIP
BRAKE LEVER
HINGE CLAMP
CABLES
HANDLEBAR
FOLDING PEDAL
MAINFRAME HINGE
MAINFRAME

CONTENTS
INTRODUCTION 4
SAFETY 5
UNFOLDING 6
FOLDING 10
USING THE BROMPTON 13
GEARS 14
BRAKES 20
LIGHTING 20
LUGGAGE 21
CLEANING & LUBRICATION 23
ADJUSTING THE SADDLE POSITION 24
SADDLE HEIGHT INSERT FITTING 25
BRAKE LEVER ADJUSTMENT 28
REAR WHEEL REMOVAL AND FITTING 30
ROUTINE REPLACEMENTS 31
WARRANTY 33
OTHER LANGUAGES
FRENCH 35
ITALIAN 69
SPANISH 103
PORTUGESE 137
GERMAN 171
DUTCH 205
3

4
INTRODUCTION
Before using your Brompton, please read this manual noting the
sections on safety and folding in particular. While this manual is
intended as a guide, it is not a comprehensive guide to cycling
or bicycle maintenance.
To activate your 7 year extended warranty you must register your bike in the My Brompton section of our
website to record the details of your bike(s); that way, if your bike is stolen or we have any need to contact
you, we will have a record to refer to. You will be asked to enter your serial and frame numbers: the serial
number is located on a plate at the back of the main frame; the frame number is stamped on the main frame
near the bottom bracket. The information remains on the Brompton database and will not be passed on to
third parties https://www.brompton.com
If you carry out any adjustments or maintenance work yourself, please read the relevant sections of this man-
ual first, as it’s quite easy to get things wrong, and to impair the folding process or damage your bike. This
manual contains some tips and advice for using your Brompton but if you are ever unsure of how to maintain
your bike, visit an authorised Brompton dealer for expert advice. For a list of dealers, please visit our website:
https://www.brompton.com/Find-a-Store
We recommend having your bike inspected and serviced by a Brompton dealer regularly.
This manual conforms to ISO 4210-2
CARRYING & WHEELING THE FOLDED BIKE
• Owners are responsible for assessing the way they use the bike at all times, and should ensure that
they take due care of their safety and welfare when riding, moving or carrying their bike
• Brompton accept no responsibility for any injury caused when lifting and handling a folded bike
• A Brompton bike weighs between 9 and 14kg, depending on the equipment fitted
• Luggage fitted to the front carrier block can also weigh up to 10kg
• Owners must take due consideration of the weight of their bike and any luggage they plan to lift or
carry, and balance this against their particular physical capabilities; the circumstances i.e. route,
under-foot conditions etc, must also be considered before each lift and/or carry of the bike and
luggage
• Owners should always remove luggage from their folded bike so they do not attempt to lift or carry
the combined weight of the bike and luggage
• Whenever you are no longer able to ride your Brompton, inside a train station for example, you should
first push it as far as possible, then fold it up and roll it on the rear rollers before carrying it for the
shortest distance
• It is recommended that the folded bike is carried one-handed, most comfortably with your arm
straight and the bike to your side. The bike should be held either by the saddle, or the main frame
below the saddle, whichever is most suitable for you
• If you have to carry the bike for any distance, then it may be appropriate to swap the bike between
each hand at suitable intervals, depending on your capabilities
• Carrying the folded bike two-handed is only advisable over a very short distance, as it can only be
done by holding the bike at chest/stomach level in order to avoid knocking your legs or knees against
the bike; this requires both arms to be bent with an approx 90degree bend, which will place extra
strain on your arms
The small rollers fitted as standard on a Brompton are useful for pushing the folded bike into tight spaces.
Using the raised handlebar as a handle, the folded bike may also be pulled around on these rollers, though
this only works over short distances on a smooth surface. Remember to raise the seatpost slightly from the
fully-down position so that it does not hinder the bike from rolling along, but not so high that the bike unfolds.
The folded bike is not designed to be used as a stool, do not sit on the bike when folded.

SAFETY
The Brompton is designed for use on roads and well-made paths, carrying a maximum load not exceeding
110kg (rider and luggage weight included). A Brompton is not intended for stunts, cross-country riding or
extreme sports. Your Brompton should be used for its intended purpose. Misuse may lead to failure of some
components and void your Brompton warranty. We do not recommend fitting a child seat or trailer to the
Brompton, doing so will invalidate the Brompton warranty.
Before riding your Brompton for the first time, and periodically thereafter, please pay close attention to the
following:
• We recommend the use of an approved cycling helmet, even in countries where
their use is not mandatory
• Read and follow the national legal requirements of the country where
you are riding, and comply with all applicable traffic laws
• Make sure the wheel rims are clean and undamaged along the braking
surface, and check for excess rim wear. If you doubt the safety of your
rims, have them inspected by an authorised Brompton dealer
• Check brakes, tyres and steering regularly
• Keep brakes and gears properly adjusted and operating cables in good condition
• In rain, the brakes may be less effective and roads more slippery so brake sooner
• Check that all wheel nuts are properly tightened (see torque table, page 13)
• In the UK, the left hand brake lever operates the rear brake and the right hand
lever operates the front brake, but this varies from country to country
• When riding in the dark, wear reflective clothing and use lights (front and rear);
check to ensure that your lights comply with local laws
Before or after each ride, pay close attention to the following:
• Ensure that the quick release seatpost clamp is secured and the saddle is at the
correct height
• The hinge clamps are in place, with levers firmly tightened
• During folding and unfolding, as well as during use and maintenance, avoid putting your hands or
fingers anywhere they may be caught or trapped
• Ensure the bike is correctly folded or unfolded to avoid possible injury
• On an S Type, do not use the T Bag, C Bag or Folding Basket (which may interfere
with steering)
• On a P Type, remember you have no brakes to hand when using the lower grips
• Never try to alter the height of the handlebar stem where it enters the front forks
WARNING
Many components on a bike are highly stressed, and with high mileage, heavy loads or hard riding, will even-
tually reach the end of their design life; in particular, aluminium alloy has a limited fatigue life. Failure in use
can cause injury. You should check all load-bearing parts for any signs of damage, corrosion, or cracking,
and replace if necessary. Please visit an authorised Brompton dealer for expert advice if you are uncertain.
The bike must not be subject to any modification, repair or replacement other than as authorised by Bromp-
ton Bicycle Ltd. The bike must be serviced by an authorised Brompton Dealer.
If the bike has been subject to a crash or impact you should stop using the bike immediately and have the
bike inspected by a Brompton dealer. Damaged components should be replaced before the bike is ridden
again. Any deep scratches or gouges in the aluminium parts can severely weaken the component and cause
premature failure of the part.
Note: We recommend that genuine Brompton parts are used for safety-critical components.
5

6
• To release the handlebar, firmly push down on the end of the grip nearest you
with the flat of your left hand
UNFOLDING THE BIKE
Take some time to look at the bike folded; it helps when you come to fold it again.
Stand on the left (non-driveside) of the bike. Unfold the left-hand pedal by pulling the
toothed metal cage towards you. As you do this note how the black catch operates
as this will help you when folding.
• Swing the handlebar up until the hinge closes, align the clamp plate with
the hinge and tighten the black clamp lever tightly

7
• Undo the seat clamp lever, pull the seatpost up and re-clamp
• Place your right hand on the saddle & hold the handlebar stem with your left
hand, near the hinge
• Look down where the chain runs between the two wheels and you will see the
black hook holding the front wheel to the rest of the bike
• Lift the handlebar stem with your left hand, to lift the hook above the tube it is
resting on

• Swing your left hand away from you in an
arc to push the fork and front wheel away
from you, push until the hinge on the main
frame is closed
• When doing this do not twist your wrist;
make sure to keep the front wheel pointing
in the same direction, the hook must
remain on your side of the bike and the
front wheel pointing forward at a slight
angle, (not parallel with the rear wheel)
The bike is now in its “parked” position – it will stand by itself.
• The hinge on the main frame should now be closed
• Align the hinge clamp plate and tighten the
black clamp lever firmly
8

The bike is now unfolded and ready to ride 9
• To complete the unfold, hold the handlebar with your
left hand, with your right hand lift the bike up swiftly by the
saddle and swing the rear wheel will backwards and into
position • Push down on the saddle to ensure
the suspension block pushes against
the mainframe; there should be a loud
click as it locks into place

• Turn the handlebar slightly to the left so it is not parallel with the rear wheel &
spin the cranks so the right-hand pedal is pointing backwards
FOLDING THE BIKE
• There is a small black lever behind and below the seat clamp. Press it forward,
then lift the back of the bike swiftly so the rear wheel swings under the frame,
then lower the bike so it sits in the ‘parked’ position
• Undo the hinge clamp lever on
the mainframe by 4-6 turns
10

• With your left hand hold the handlebar stem above the plastic nipple,
swing the front wheel away & to the right
• Bring the stem round in a clockwise stirring motion, don’t twist your wrist & keep
the hook facing you, untill the front wheel is alongside the rear; you may need to
lift the front of the bike a little
• Lower the black hook over the rear frame, underneath the top section of the chain
• Undo the hinge clamp lever on the handlebar stem by 4-6 turns and let the
handlebar stem drop down; the nipple on the handlebar stem fits into the clip
which is mounted on the top of the fork, locking it securely to the bike
11

• Undo the seatclamp and lower the saddle fully,
this locks the bike together, so It won’t open up
when carrying; re-tighten the seat clamp lever
• Pull the left hand pedal upwards, the right hand pedal should tuck under the front
wheel
• Fold the left hand pedal, by pressing the central black plate upward, enough that
it can pass over the end of the crank arm & into a vertical position
• If you can’t lift the plate, turn the pedal over & try again
The bike is now folded and ready to be
picked up and carried. Brompton saddles
have a tailored grip plate underneath the
‘nose’ of the saddle.
The left hand pedal should not be
folded when turning the cranks, as it
can catch on parts of the rear frame
and cause damage to your bike.
12

USING THE BROMPTON
TYRE PRESSURES
Tyre pressure is important for both comfort and safety. Please note the following tips for ensuring a safe
and comfortable ride.
It is important to keep your tyres well-inflated; soft tyres increase pedalling effort (which takes the fun out of
riding), wears tyres down quickly and has an adverse effect on handling. Keeping your tyres well-inflated
is highly recommended.
The most appropriate pressure depends on your weight and preference. It’s also worth remembering that
a very hard tyre isn’t always faster. A hard tyre might be faster in the velodrome, on a rough road a lower
pressure will deflect more easily over uneven and rough road surfaces and therefore roll faster and make the
ride more comfortable. Generally a slightly lower pressure in the front wheel and slightly higher in the rear is
recommended, this accounts for the different weight distributions between the two tyres.
Brompton bikes are fitted with Schrader valves, allowing various methods of inflation. The Brompton pump
is installed on the rear frame of all-steel Bromptons with mudguards. When replacing the pump on the bike,
make sure that it has full engagement with the pump locators on the rear frame. You can also use a hand-
pump, or an air-line found at petrol/gas service stations.
The table below shows recommended tyre pressures for tyres supplied on Brompton bicycles.
MARATHON RACER SCHWALBE MARATHON SCHWALBE KOJAK
MIN(psi) MAX(psi) MIN(psi) MAX(psi) MIN(psi) MAX(psi)
FRONT 65 110 65 110 70 115
REAR 65 110 65 110 70 115
13
Part name Torque (Nm)
1-2 speed wheel nuts 15
3-6 speed wheel nuts 18
Brake lever bolts 2
Chain tensioner nut 5
Chainring bolts 10
Crank bolts 30
Dynamo/superlight front wheel axle 8
Front carrier block fixing bolts 4.5
Front wheel hook fixing bolt 3.5
Handle bar support expander bolt* 30
Handlebar catch clip bolt 9
Handlebar clamp bolt 18
Brake caliper nut 8
Brake (caliper) cable clamp bolt 8
Pedals 30
Pentaclip 15
Rear rack stay bolts 3
*Never try to alter the height of the
handlebar stem where it enters the
front forks, it should be fully inserted
into the fork up to stop. If adjusting the
alignment of the handlebar to the front
wheel, ensure the fixing bolt is tightened
correctly before riding the bike.
If the handlebar stem is not fully inserted
or not tightened correctly, it could cause
movement or failure of the part in use.
TORQUE VALUES
A list of torque values for the major
components is shown here.
These parts should be checked
periodically, as well as during routine
maintenance and repair of the bicycle.
If components are not tightened to the
correct torque, it could cause damage
or failure of the part. This could cause
loss of control of the bicycle and result
in a crash.

FEATURES
Improved ergonomics
Intuitive operation, simple to use
Two way self returning lever
The same feel and action across both shifters
Gear indicator window helps you see which gear to select
The shifter mounts directly to the brake lever, taking up less space on the bar
Underbar design gives the bike a more streamlined appearance
2-speed shifter now features a barrel adjuster for tool free tuning
Designed, Tested, Manufactured & Assembled in the UK
Weight saving over previous design
USING THE SHIFTERS
A Brompton can be fitted with either 1, 2, 3 or 6 gears. 2-speed bikes feature a left hand shifter, 3-speed
bikes a right hand shifter and 6-speed bikes use both a left and right hand shifter.
On a 3-speed bike you pick 1, 2 or 3 for a low, medium and high gear. Using a 2-speed bike is as simple as
selecting + or - on the shifter for a higher or lower gear.
To sequentially change gear on a 6 speed, the gear levers must be operated in the correct order; another
way to think about it is that there is a high and low option (left hand shifter) for each of the three hub gears
(right hand shifter). The left hand shifter gives a small change between gears, whereas the right hand will
give a large change.
GEARS
Brompton uses two gearing solutions: a derailleur system (left hand control) and a hub gear system (right
hand control). These systems are used independently on 2 and 3-speed Bromptons. When combined, the
derailleur and hub gear system create a 6-speed gearing system. Whatever your Brompton, if pedalling while
changing gears, take pressure off the pedals as you do so; this will ensure efficient gear changes.

3-SPEED GEAR SHIFTER
3-speed shifters are used on 3 and 6-speed bikes
These shifters were introduced on 2017 bikes
This shifter is not compatible with older brake levers or pre-2017 M/H Type bars
If you are unsure about any fitting or operation instructions please contact a Brompton dealer
USING THE SHIFTER
The 3-speed shifter uses a self-returning lever to change between the three gears. Pushing it down with
your thumb will shift into an easier gear and flicking the lever upwards with the back of the thumb will shift
into a harder gear (fig.1). It is important to stop pedalling or back pedal slightly when changing gear, if you
do not do this it is possible to damage the hub internals. The indicator window (fig. 1, 2) shows you which
gear is selected.
Fig. 1
Fig. 2
SHIFTER
WINDOW
SHIFT LEVER
HIGHER
GEAR
LOWER
GEAR
TORQUE 0.35Nm
SPACER
SHIFTER
BRAKE LEVER
Fig. 3 FITTING THE SHIFTER
The shifter mounts to the right hand brake lever, it
is held in place by two M3 screws, these should be
tightened to 0.35Nm. Do not overtighten the screws
as this can reduce the performance of the shifter and
damage the parts.
As standard a spacer (fig. 3) is fitted between the
shifter and brake lever. This spacer is vital to ensure
clearance between the shift lever and the grip.
On P-Type bikes and also on M, H & S-type bikes using
non-standard grips, the locking collar or grip material
can interfere with the lever operation, if the spacer is
not fitted.
15

FITTING A NEW CABLE
• Select gear 1 then press the shift lever downward so it does not obscure the cable entry hole (fig. 5)
• Feed the gear cable into the shifter and through the cable bush
• If there is resistance pushing the cable through the bush pull the cable back a little and try again
• Once you can feel the cable pass through the bush keep feeding it until you feel slight resistance
• Keep feeding it through so that it follows around the guide inside the shifter and exits through the cable
barrel
DO NOT FORCE THE CABLE AS THIS MAY DAMAGE THE SHIFTER
INDICATOR CHAIN
CABLE ANCHOR
Fig. 4
CLAMP NUT
LOCKNUT
CABLE HOUSING
INNER CABLE
REMOVING THE GEAR CABLE
• Select gear 3 on the shifter, backpedal to engage the hub
• Unscrew the indicator chain locknut (fig. 4)
• Unscrew the indicator chain from the gear cable anchor
• Undo the gear cable anchor clamp nut and
release the inner gear cable
• If there is a cable crimp fitted to the cable end you will
need to remove this, then pull the cable out of the clamp
• Pull the cable housing away from the shifter
• Remove the inner cable from the cable housing
• Select gear 1 and then press the shift lever downward
so it does not obscure the cable entry hole
• Feed the gear cable through the shifter so that the
cable nipple ejects from the cable entry hole
• If there is resistance pushing the cable through the
bush pull the cable back a little and try again
• Keep feeding the cable through until the cable can be
fully removed from the shifter
Fig. 5
GUIDE
CABLE BUSH
CABLE ENTRY HOLE
SHIFT LEVER
CABLE BARREL
CABLE PULLEY
16

REFITTING THE GEAR CABLE
• Thread the inner cable through the housing and around
the cable pulley (fig. 4)
• Thread the cable through the clamp on the cable
anchor and pull through before tightening the clamp nut
• Screw the indicator chain into the gear cable anchor
HUB-GEAR ADJUSTMENT
Adjustment must be carried out with the bike fully unfolded and with
the indicator rod screwed into the hub (backed off not more than
half a turn to align with the cable). The aim is to make sure that the
indicator rod & chain move to the correct position in response to
moving the trigger. For this the cable has to be running free of kinks
or sharp bends, with the cable pulley rolling freely.
While setting gears, keep the wheel spinning forwards, and pedal back and forwards, to ensure the gear
engages. It’s easiest, when altering the setting, to have the cable slack: select top gear and back and forward
pedal.
Adjustment is carried out by slackening the lock nut, turning the cable anchor barrel (fig. 4) to obtain correct
setting, and relocking the nut.
The indicator chain is correctly adjusted (fig. 6) when the shoulder S on the indicator rod IR is proud of the
axle end by no more than 1mm (this can be seen by looking through the hole in the chain tensioner nut CTN)
when in the middle position on the shifter is selected.
IR
SCTN
AXLE END
Fig. 6
2-SPEED GEAR SHIFTER
2-speed shifters are used on 2 and 6-speed bikes
These shifters were introduced on 2017 bikes
This shifter is not compatible with older brake levers or pre 2017 M/H Type bars
If you are unsure about any fitting or operation instructions please contact a Brompton dealer
USING THE SHIFTER
The 2-speed shifter uses a self-returning lever to change between the two gears. Pushing it down with your
thumb will shift into an easier gear and flicking the lever upwards with the back of the thumb will shift into a
harder gear (fig.7). It is possible to change gear while pedalling or stationary, though the gear will not engage
until the pedals are moving forward. The indicator window (fig. 7, 8) shows you which gear is selected.
Fig. 7
Fig. 8
SHIFTER
WINDOW
SHIFT LEVER
HIGHER
GEAR
LOWER
GEAR
17

TORQUE 0.35Nm
SPACER
SHIFTER
BRAKE LEVER
Fig. 9 FITTING THE SHIFTER
The shifter mounts to the right hand brake lever, it
is held in place by two M3 screws, these should
be tightened to 0.35Nm. Do not overtighten the
screws as this can reduce the performance of the
shifter and damage the parts.
As standard a spacer (fig. 9) is fitted between the
shifter and brake lever. This spacer is vital to ensure
clearance between the shift lever and the grip.
On P-Type bikes and also on M, H & S-type bikes
using non-standard grips, the locking collar or grip
material can interfere with the lever operation, if the
spacer is not fitted.
REMOVING THE GEAR CABLE
• Select the highest gear (+)
• Release the cable from the cable connector (fig. 10) by loosening the grub screw
• Select the lowest gear (-) and then press the shift lever downward so it does not obscure the cable
entry hole
• Seperate the inner cable from the outer housing
• Push the inner cable through the barrel adjuster, until the cable end is fed out from the entry hole (fig. 5)
• Pull the cable from the entry hole until it is seperated from the shifter
GRUB SCREW
CABLE CONNECTOR
CABLE HOUSING
INNER CABLE
Fig. 10
18

FITTING A NEW CABLE
• Screw the barrel adjuster (fig. 11) fully clockwise so that it is at its shortest setting, then unscrew by 2
turns
• Select the lowest gear (-) and then press the shift lever downward so it does not obscure the cable
entry hole
• Feed the gear cable into the shifter in a slightly downward direction and through the cable bush
• If there is resistance pushing the cable through the bush pull the cable back a little and try again
• Once you can feel the cable pass through the bush keep feeding it until you feel slight resistance
• Keep feeding it through so that it follows around the guide inside the shifter and exits through the barrel
adjuster
DO NOT FORCE THE CABLE AS THIS MAY DAMAGE THE SHIFTER
Fig. 11
GUIDE
CABLE BUSH
CABLE ENTRY HOLE
SHIFT LEVER
BARREL
ADJUSTER
SETTING THE GEARS
• Insert the gear cable into the housing
• Thread it all the way through so that it exits through the end of the housing
• Using needle nose pliers or similar pull the cable through the housing and insert fully into the
connector
• Tighten the grub screw to secure the cable in the connector
• Use the barrel adjuster on the shifter to make adjustments to the cable tension as needed (fig. 11)
• Unscrewing the adjuster will add more tension to the cable and improve shifting into the lower gear
• Screwing the adjuster inwards will reduce tension and improve shifting into the high gear
19

BRAKES
You should adjust your brakes on a regular basis as they are critical to your safety. The time between
adjustments will vary depending on how often you use your Brompton; if your brake lever touches the handle
bar when you pull on it, your brakes need urgent adjustment. The brakes should be set so that the brake pads
are as close to the rims as possible without interfering with the rotation of the wheels. Adjustment is carried
out using the threaded cable stop on the brake lever. If you are unsure of how to do this, have it adjusted by
a Brompton dealer or qualified bicycle technician.
• When setting the rear brake, the bicycle should be unfolded
• When setting the front brake, do not set the pads so close that they bind on the rim when the wheel
is turned to the right or left
• Replace your brake pads if the grooves on the brake pad surface are less than 1mm deep
Keeping your rims and brake pads clean will improve your braking performance and increase the lifespan
of the pads and rims. The black residue that accumulates on the rims is a mixture of dirt, pad material and
aluminium powder worn from the braking surface of the rim, this residue is abrasive and will accelerate the
wear of the rim and pads. When cleaning the pads and rims check to ensure they are not worn out and a
worn rim or pads should be replaced immediately.
LIGHTING
Two lighting options are available on Bromptons; a battery-operated front and rear lamp and a hub dynamo
system that generates electricity while you cycle. These Brompton lighting sets can be fitted to any bike
model. Please use these lights in accordance with local laws. For technical information relating to the
operation of the battery lamps and hub dynamo system, please refer to the technical section on our website
https://www.brompton.com
THE REAR FRAME CLIP
The rear frame clip assembly can be set in “latch mode”
or “non-latch mode”.
In “latch mode” the clip automatically engages with the
rear frame when it’s unfolded, so that the rear frame/
wheel doesn’t fold when the bike is lifted.
To release the rear frame press the small lever (fig. 12)
forward and lift the bike so the suspension block moves
away from the latch and the rear wheel swings under the
frame. Lower the bike so it sits in the parked position.
In “non-latch mode” the clip can’t engage leaving the
rear frame free to fold, and allowing easier parking.
To switch between the two modes you simply rotate the
suspension block SB (with the clip disengaged).
To switch between modes, the hook must be disen-
gaged, and you turn the block SB: when the mark M is
on top and central (fig. 13) the clip is set in “latch mode”
(the latch will still engage if M is not exactly central).
If for any reason the clip doesn’t engage with the rear
frame or is stiff to release, try rotating the suspension
block a little. Turning the suspension block a quarter of a
turn or more (with the hook not engaged) moves the re-
cess well away from the hook so that it cannot engage.
MSB
Lever
Fig. 12
Fig. 13
20