Page last changed December 19, 2004

Riding issues

• Is it normal for the hub gears to go "tick-tick-tick" when you pedal forward?
• Spotlight on the (hub) gears - Hub gear troubleshooting
• Spotlight on tyres - Preventing punctures
• Spotlight on lights - Slipping tyre-side dynamo
• Spotlight on lights - Auto-engaging bottle dynamo
• Spotlight on lights - Blown tail lights
• Spotlight on the seatpost and saddle - Keeping it up
• Spotlight on wheels (rims, spokes and hubs) - Broken spokes
• Spotlight on the chain - Chain falling off while riding over bumps or while unfolding
• Spotlight on lights - Front light lens falls off
• Spotlight on wheels (rims, spokes and hubs) - Pantour suspension front hub
• If you have problems or worries about a particular part, look it up in the Tinker section...

How can I go faster?

• Riding issues - Changing the Brompton's gearing set-up
• Spotlight on tyres - Alternative tyres
• Spotlight on pedals - Toe clips/clipless pedals
• Adopt a more aerodynamic riding position: Spotlight on handlebars - Rotating the handlebars
• Genetically Modified Bromptons - Electrically powered Bromptons

Rolling resistance tests

• A2B, May 98:
  Here in Castle Cary, we've been using the same test hill for some time. We've found that if you put the same rider on the same bike, and sit him in the same position under the same weather conditions, the results are pretty accurate.
  Measuring average speed in MPH from a standing start, we found that Swallow tyres performed best at 70psi, hitting 13mph, a well-worn set of Raleigh Records performed best at 60psi, achieving 13.6mph, and the Primos gave the best results, managing almost 14mph at just 50psi. We went on to fine tune the pressures and found a performance peak at about 14.3mph with 65psi in the rear tyre and 45psi in the front. 1.3mph best to worst might not sound much, but it's a 10% performance boost for very little outlay.
  Obviously, the weight of the rider has an effect, but we went on to produce a recommended pressure v rider weight chart, which was printed in Folder 18. There's no doubt that Primos give a clear advantage, but you need to set the pressures with care.

Suspension versus efficieny (biopacing?)

• Stein Somers, May 2000:
  A Brompton user recently aired concerns about the suspension block consuming part of his muscular output. Something referred to as biopacing, although an internet search suggests this term was really invented for oval chainrings. Anyway, everyone can see the suspension block squeezed in and out at each pedal stroke; when you try to do the same off the bike, the effort seems huge.
  So, I wondered while stumping up a steep hill the other day, how much is that squeaky little devil costing me? When riding at speed with a standard 6W generator on, it doesn't take long for the generator to start feeling warm. The 6W is the power sent over to the bulbs; more than twice that power is taken from the wheel. Roughly some 10W is wasted heating up the generator.
  The suspension block doesn't seem to become warm at all. Of course rubber doesn't pronounces its temperature as good as metal, but if I've been wasting a sizable amount of energy, shouldn't I feel *something*?
  I gather from literature that during this effort, leaving me out of breath, I might be hammering 400 watts through that poor chain. And it seems the suspension block accounts for at most a mere percent of that? So why bother...
• Matt Hayworth, May 2000:
  Yea, it seems like the point of shock absorption and springy seats is partly to cut down on rider fatigue which results in part from being jarred unnecessarily. So the shock absorber probably does more good than harm.
• David Dodson, May 2000:
  Pure springs do not absorb any energy (but absorb shocks...).
  So-called 'shock absorbers' (in the conventional use of this term) are energy absorbers used to attenuate oscillations in springy position-control systems such as transport suspension systems. Energy-wise they convert motive power (only) to heat. A springy suspension element may be included in the shock aborber unit (as in some car shock absorbers with an outer coil spring element).
  Rubber shock absorbers are (usually) in effect mainly springs, but not pure springs -- the rubber's hysteresis absorbs energy. But if they don't heat up much they are not absorbing much energy.
  But if you have anything at all like a car shock absorber - typically an oil filled cylinder with a piston with holes in it that the oil is forced through - then we are probably in the realms of much greater energy absorbtion than with rubber.

How can I improve comfort?

• Which model is meant for me? - Do I need a longer or telescopic seat post?
• Spotlight on the seatpost and saddle - Comfy saddles
• Spotlight on handlebars - Alternative handlebars
• Spotlight on handlebars - Rotating the handlebars
• Spotlight on handlebars - Bar ends
• Spotlight on handlebars - Handgrips
• Spotlight on pedals - Toe clips/clipless pedals
• Spotlight on handlebars - Twist-grip or other gear changer for the 5 speed hub
• Riding issues - Changing the Brompton's gearing set-up
• Genetically Modified Bromptons - Brompton Recumbent Conversion Kit

Changing the Brompton's gearing set-up

• shift the gearing range to a more suitable level (trade in the highest gears for very low ones or vice versa):
  • Spotlight on the front chainring - Does the Brompton use a special crank, or can I find a suitable replacement at any decent LBS?
  • Spotlight on the rear sprocket - Replacement rear sprockets
• extend the gearing range (add very low or very high gears):
  • Spotlight on the front chainring - Multiple front chainrings
  • Spotlight on the bottom bracket - Geared bottom bracket - the Schlumpf Mountain Drive
• decrease the gearing steps (add gears in between the existing range):
  • Spotlight on the front chainring - Multiple front chainrings
  • Spotlight on the bottom bracket - Geared bottom bracket - the Schlumpf Mountain Drive
  • Spotlight on the (hub) gears - 7 or more speed hub gears

What are gear inches?

• Ian (two Bromptons) Oliver, Sep 2001:
  Excel spreadsheet for working out Brompton gearing
• Bob Gelman, Oct 1999:
  This Gear Calculator should be very helpful! http://www.pagesz.net/~scotty/gear-form.html

Is it normal for the hub gears to go "tick-tick-tick" when you pedal forward?

• Stein Somers, Sep 1997:
  Absolutely, though only in middle (neutral) gear and above.
• Anthony Cartmell, Sep 1997:
  The ticking is coming from a free-wheel ratchet in the hub gear. The hub has a couple of epicyclic gear sets, with dog clutches and ratchets to change gears. If you change gear while free-wheeling you can hear the different ratchets buzzing at different speeds.
• Phil Gough, Sep 1997:
  My older model 5-speed ticks at twice the rate as it has two sets of pawls.

My heels hit those darn castors!

• David Hansen, Sep 1997:
  This was a problem for this male, until I unscrewed the Brompton wheels, turned them round and screwed them back in. As a result it is hard to catch my shoes, as they slide down the slope of the coned part of the wheel.
  This does make the folded bike slightly less stable, but not to any noticeable extent.
• mike, Oct 1998:
  I have big feet and did a lot of damage to my ankles by knocking them on the castors at the front end of the rack in the first couple of weeks - I now have an unstable bromton when folded because I removed the front (large castors) and I have not made my ankles bleed since.
• Mr A Follis, Oct 1998:
  My problem with the castor wheels is that they snag the turn-ups on my good trousers. I've ripped one pair. Then again maybe turn-ups are out of fashion and Brompton are just doing me a favour.
• Another cure: Carrying or rolling issues - Improving the castors

Waggly rear ends

• Rob Cope, Aug 1998:
  Roland & anyone else with waggly rear ends (Brompton, that is),
  You need to get your dealer/agent to have a look ASAP. The main bearing between frame & rear triangle is worn or loose: unlikely to break (substantial piece of silver steel) but it does you & the bike no good to keep using it. Whatever you do, do *not* just tighten up end screws with an allen key: they are Loctited in place & screwing/ unscrewing breaks the seal & makes it likely to loosen up more.
  When this happened to me last year, I ended up back at the factory (live 2 km away lucky me) for a new bearing sleeve: presume your dealer can sort it out locally.
  All done under guarantee: Brompton stand by their products.
• David Henshaw - A to B Magazine, Aug 98:
  Several very important points here.
  ONE Never, ever unscrew the allen-head screws holding the rear triangle to the frame... honestly, there is nothing in there worth looking at. The screws are Locktighted in place at a high preset torque. If you break the Locktight, the screws WILL certainly unfasten in use and the rear triangle could come adrift.
  TWO Because the bearings need to be very accurately reamed to size with a custom-made reaming tool, only Brompton can fit them. So the assembly is neither user or dealer serviceable at present.
  THREE As enthusiastic Brompton users you can do two things: Keep an eye on the screws - any movement may mean one has come loose. If the bike is more than a year or so old, run oil into the bearings on a regular basis. If you commute every day in all weathers, that should really be once a week.
  FOUR Movement in the bearing is not a problem. My six year old bike has quite a bit of play and I barely notice it on the road. Once the rubber suspension is compressed, the triangle is restrained from moving sideways too much.
• Phil Gough, Mar 1999:
  Owners in the London area of ageing and/or high mileage Bromptons which have developed slack rear fork pivots may be interested that Tim Whiity of Cyclecare (30 Blythe Road, London W14 0HA) has got the tool to do this job. He has just rejuvenated my 1988 T5 which no longer shimmies about when carrying a load on the back. Cost was just under £40, but I had partially dismantled the bike before I took it in (to fix another problem). You get new bushes, pivot, nylon washers and Allen-head machine screws.
• Custfold, Mar 1999:
  I have - through breaking about 6 rear frames - had the rear pivot spindle out on many occasions.
  A few comments -
  1. the spindle does wear noticably, and on one quadrant more than the other 3 I fit new spindles if I notice wear.
  2. the ptfe washers collapse - I now use brass ones
  3. the system for the machine screws is not brilliant - I have tried star washers under the coutersink faces, and am trying to locate screws with better quality drive sockets which can be impact driven to tighten them and do away with the unreliable locktite system. A tip is that if your chainring is larger you cut a nick to allow the bolt to be tightened without having to take the transmission apart.
• David Edge, Apr 1999:
  AFAIK the advice against DIY is the need to precision ream the new bushes once you've put them in.
• Custfold, Mar 2000:
  It may be worth checking first that the PTFE washers that take side thrust are not kaput.
  I've replaced mine with brass washers and also looked at impact drive CSK machine screws as both these are sources of slop in rear end usually well before the pivot bush fails - but they do wear, as pins removed but destroyed when changing rear frames have shown.
• If you want to DIY anyway: Maintenance at home - Removing the rear triangle.

Adjusting suspension

• Try the fully adjustable version suggested by the designer - aka a standard Brompton block with a jubilee clip (approx 50p) restraining its, err, fuller figure from bulging too much. [ A jubilee clip or hose clamp (US) is ] a circular band tightened by a screw, often used to hold hosepipes on to water taps. Ironmongers have them. Result: fully adjustable suspension!

Rear mudguard too short (the mud striped back syndrom)

• Bernd Bieker:
  I had the same problem and attached a small 4" flexible plasic strip to the rear fender.
• Jane Thomas:
  Definitely too short! Although when I phoned Brompton they denied there was a problem. I ended up with a super-duper extension made out of a front muguard and castor so the whole thing still rolls under when folding (I found my early experiments caught the ground when flicking the wheel under to fold). The extra length also allowed me to mount a Busch & Muller 4D lite on the mudguard (dynamo driven LED light + capacitor so it stays on when you stop), and I am very happy with the arrangement.
• Malcolm Lyon:
  My only disappointment with the bike has been the silly short mudguard, or fender, fitted to the L model. When riding in the rain, I found I finished up with a skunk stripe up my back. I am pleased to say I have solved the problem by developing a semi rigid mud flap which in no way restricts the folding. Brompton Bicycles did dot think it could work but I have demonstrated it to them at their factory and can assure you it does.
  It is easy to make. Just cut a piece of semi stiff butyl rubber sheet of one eighth inch thickness into a rectangle of 4 inches by 1 and 7/8ths. It can be held in place by 2 pop rivets with rivet washers to sandwich it. Or if you want a really simple fitting drill two 3mm holes about 15mm apart, down the centre line on the mudguards tail and secure the flap with 3mm cable tie.
  I have made up a small stock of these and I am pleased to say that I have recieved a good number of orders from Folding Society members here in UK. I mention the construction details in case any of our Brompton pals in more isolated areas, like the US, want to overcome the problem. I call the device a Damp Patch Eliminator,... DPE ... or Skunky for short!
  For the kits that I produce, I use butyl rubber of about 3.5mm thickness. When this is riveted in place under the mudguard it takes up only about 4mm which is a very small intrusion into the clearance.. the cable tie method is slightly thinner. On the L model to increase the clearance you merely gently squeeze the four mudguard stays together towards the centre plane of the wheel and the clearance is increased. This is needed anyway from time to time with thumping the roller wheel takes when tucking the rear wheel.
  The natural curvature induced by the mudguard to the flap, adds to it rigidity giving it a springyness to resist deformation by the tuck under. It works beautifully. I took it to show the Brompton factory - they were surprised but impressed.. and said they had been considering a solution.
  On the T model there should be enough clearance but I guess one can gain bit more through adjustment.
  You do not need a wide or pear shaped flap the rear as the spray comes straight off the centre of the tyre. On the front a wide flap is needed because your also have to cope with the spray deflected from the road towards the botton bracket and your feet. I doubt if a curved in front flap will over come this problem.

  I am marketing a simple kit which will completely eliminate the problem of your rear damp patch. This has been developed and tested on the L model but I hear from people that it works well on the T model too.
  2 pounds 50 pence including postage.

  Malcolm Lyon 2 The Mill, Turvey, Beds, MK43 8ET

  This is not commercial venture - just a service to fellow Brompton enthusiasts!

• Peter Amey:
  A rear mudflap works wonders. On my T5 I found I could not use any of the commercial mudflaps I found because they all need to go between the mudguard and the tyre; on my bike at least, there simply isn't room. I cut a mudflap out of an old inner tube and used impact adhesive (Evostick) to fasten it to the outside of the (thoroughly cleaned with alcahol) mudguard. The flap is 3 inches long and extends 2 inches below the end of the mudguard. It is pear shaped being the width of the mudguard at the top and about 3 inches across near the bottom. To make it keep its shape I laminated it with a couple more pieces of inner tube using rubber solution. I no longer have a mud stripe up my back so it must work. Being rubber, the midflap doesn't seem to suffer from flicking the ground when I break the bike's back (before wringing its neck to complete the fold :-)) - stiffer materials, such as are being discussed for front mudguard extensions, might well get ripped off during the folding process.
• Stein Somers:
  At the moment a thin plastic patch the width of the mudguard (cut from the cover of a pocket agenda) extends my rear mudguard for exactely 4cm measured at the centre. It is fixed between a stronger plastic strip (cut from a telephone card :) and the inside of the mudguard, with 2 tiny nuts and bolts through the sides of the mudguard, and has been guarding mud without intervention for a pleasant time.
• Mark James:
  I used a strip of reflective fluorescent strip super glued onto my L5 approx 5cm flap and 1.5-2 stck onto the mudguard Had it on for four months and no muddy strip
• Stein Somers, Apr 1998:
  Saw a brand new T5 with a new fancy looking type of mudguards, about a centimetre longer at the rear. Brompton is strangling the mudguard extension business!
• Nico J. de Boer, Oct 1998:
  Tromm (our famous Brommpton dealer in Amsterdam) has a very beautiful _and_ effective rubber extension of the mudguard. You see this type of thing in increasing numbers on "mountain" type of bikes in the Netherlands. Maybe it's a common accessory these days.
• Chris Newport, Nov 1998:
  I took the advice posted in this list (I think) and cut up an old inner tube, cementing 2 layers of the rubber together using standard puncture repair solution to give the right thickness.
  Then loosen the screws that hold the mudguard stay and remove the fixing plate, cut 2 holes through the rubber, and fasten the rubber strip to the mudguard beneath the fixing plate.
  It took about 15 minutes and works just fine.
• Ulric Schollaert, Jun 1999:
  Velodroom (Brussels) also fitted a self-made flap for the back wheel (made out of a strong, flexible sort of gum, fixed with screw and bolt for easy replacement). I've found out that it holds very well and doesn't suffer from regular folding/parking. I wonder how B. have not come up with the brilliant idea themselves!
• Mark James, Jan 2000:
  Add a length of rubber / reflective tape approx 6cm at end of mudguard/fender a smear of superglue after cleaning the fender does the trick wont last for ever but my first effort lastest 2 years of moderate use. Custfolder has fantastic but rather large cordura type flaps that really stop everything ace for the frontalmost reaches the deck.

Loose frame clamp

• Ludger Offerhaus, May 1998:
  I'm surprised to hear you get that, My clamps tend to get stuck more and more, taking increasing force to unscrew them.
• Custfold, Feb 1999:
  If the clamp face bottoms out on the hinge - it has spread out and shoul be changed (a set of spark plug feelers helps here). The clue is usually cracking along the inside faces.

Loose chainguard

• Willi Mindak, Feb 99:
  The chainwheel disk (chainguard) is attached at 5 points to holes in the chainwheel. When starting at a traffic light I accidently kicked 2 of these 5 fixing points out of their holes in the chainwheel. Trying to get them into their holes again prooved difficult. After some banging and cursing I examined the chainguard closer. Turns out that the chainguard has little plugs fitted where it is inserted into the chainwheel. You push the plugs back to the outside, insert the chainguards plastic hooks into the holes in the chainwheel, and push the plugs flush with the rest of the chainguard. Job done. When you try to push the chainguard back on without moving the plugs first you are more than likely to damage the chainguard hooks, and the thing will come off again. No earth- shattering revelation, but I thought I'd let you know.

Undesirable sounds

• Ian Charles, Aug 2000:
  Likewise, we haven't experienced any significant noise on either of our two Bromptons in more than ten years (no idea of mileage), certainly no worse than with our various conventional bikes.
  Don't want to spoil this fascinating string, but surely a product which is at least in part hand built will vary; the type of use it's put to will affect likelihood of rattles, squeaks etc developing; and - this is something which has been alluded to before, I think - what about the weight of the rider and possible load?
  • Mike, Aug 2000:
    Well I'm 13 and a half stone and I've had an additional 3 stone of shopping on it and no odd rattles.

Localising the nosiy culprit

• John R. Bolt, Oct 1999:
  Don't be too sure that the noise is coming from the bottom bracket. I had a similar situation a year ago, and went slightly nuts trying to figure out the source of the noise. I, too, was pretty sure it was from the area of the bottom bracket, and figured it was probably one of the pedals. After a lot of experimentation, I finally established that the source was actually the front wheel. The bearings had apparently not been adequately lubricated in the first place, and were now noisy, but with a sound that I would not have expected.
  So it can be quite difficult to localize a noise, and the "obvious" source may not be the real offender.

Clanking

• Stuart Quick, Aug 2000:
  I had this on my T5 for a while. Everytime I hit a bump there was an almighty 'clang' sound. I originally thought that it was the rear jockey wheels...however, I found out that the back wheel was very slighly loose. i.e. the compression nut on the rear bearings was not done up enough. I found this out by turning the bike upside down and gripping the wheel, and being able to rock it side to side very slightly. I took the wheel off and did up the compression nut just enough to stop the play - but no more than that as the bearings will wear out prematurely if too tight.
• Jonathan Brickley, Aug 2000:
  i have a similar rattle on my 500 mile brompton L5...I assume it is the little plastic wheels rotating and rattling(that's what it sounds like)...I keep forgetting to grease them to see if this damps it out....May try it now as you have reminded me.Will advise if it does the trick after riding to work tomorrow...
  Just been and greased the wheels...they are swines to undo as Brompton have used loctite on them....needed a foot long flat screwdriver with self grip wrench clamped to the shaft of the screwdriver, before they were beaten!Need to rest the bike on a solid surface and really lean on the screwdriver handle to stop it slipping.On a quick roadtest, bike is much quieter(you don't realise how noisy it is until the rattle has gone.....) The little wheel on the back of the mudguard is riveted together, may be worth drilling out so it can be greased,but I sprayed some gooey motorcycle chain lube on it ...seems to have done the trick.See if that's the problem on your bike..... ps don't forget to reloctite the screws
• Nico van Beek, Aug 2000:
  Who knows! Curious. But I don't think that's the problem. It's a metallic rattle.
• Roland Elsenberg, Aug 2000:
  some weeks ago I took my Sprinter 5 apart. I found that a tiny spring from a paw had come loose. After reassembly the hub was much quieter, but has started to rattle again. I don't know if the rattle is the same in all gears or if it depends on the gear I drive. I confess I forget to sort that out every time I enjoy a ride. On my Gazelle with SA 3-speed a noise appeared at 10000 km. In an advertisement by Sachs I found a sentence like: "some hubs are reported to have lasted for 10000 km". Surely 10000 km is nothing Sturmey-Archer would advertise about. The Gazelle is now well above 30000 with the hub still going. It even gets quieter, or perhaps my ears worse :)
• Mindak Dietmar, Aug 2000:
  Yes, the noise is a problem on my bike as well. About a year ago there was a thread in this list about it. I went as far as removing everything on the rear triangle and came to conclude that it originates at the hub. I promised myself to take the hub apart but haven't come round to it yet. One of the list members described how he had ruled out the coasters by riding with his feet on the rear carrier touching the coasters. Don't try this at home was his sound advice.
  I compared the noise to empty cans on a string being pulled behing the bike. Very entertaining on cobblestones. I wouldn`t go as far as advising people against buying a Brompton, but it is definately much less enjoiable on poor surfaces. Now that the brake issue is solved we might get to the bottom of this. Has anybody experiene with other hubs on the Brompton? I know the rear triangle is too narrow to take other hubs unmodifieed, but have heard of several attempts to use the Sachs 3 and 5 Speed and even the Rohloff. Do they clank as well? And what makes that clanking noise in the Sturmey-Archer? Any ideas?
• Stein Somers, Aug 2000:
  Boy, I'm happy my T5's are quiet. I'm very sensitive to noise, sometimes even the ticking in higher gears gets on my nerves. The Sachs 7 speed on my recumbent however rattles annoyingly, although I wouldn't compare it to pulling empty cans. It also has some gear changing problems. The Sachs 5 on my cumbersome are quiet until they implode (which took four months for the first two).
  I read on the Utopia Forum that the Rohloff 14 speed makes a distinct grinding noise in the lowest gears. The Shimano hubs are reported to exhibit not even ticking, but I know someone who complained that the roller brake rattled like hell. I rode one recently and it was very quiet and braking power smoothly controllable. Alas, maximum braking power couldn't match an original Saccon brake on a Brompton in the rain.
• mark james, Aug 2000:
  I have the same loud noise mostly when I freewheel (5 speed 10/96). Not little wheels. My new mk III is fine after approx 1000k.
• mark james, Aug 2000:
  That rattling around the rear wheel has now struck my new Mark 3 whilst freewheeling and its starting to rattle after around 6-700 miles. It is irritating on a less than smooth surface, my older bike is very noisy and rattles a little even when pedalling. Something must be loose as my front cones need substantial tightening too.
  Why should some rattle and others not? Haven't tried to tighten anything yet, keep you posted

Squeaking

• Anthony Cartmell:
  A friend's T5 and mine both did this when they were new. It sounds just like the rubber block, but the squeak is in fact coming from the suspension hinge pin. Try putting some light penetrating oil on the plastic spacers at each end of the hinge, and fold/unfold the bike several times. This eventually fixed my one (I also took the rubber block to pieces, greased it etc. all to no avail). I toyed with the idea of adding a grease nipple, but this might mess up the bearing which I think is oil-impregnated.
• Channell Wasson:
  WD40 took squeek out for me--it never came back
• Peter Amey:
  I have had this occasionally and have always been able to clear it just by rotating the rubber block a quarter turn. No idea why this works or what causes the noise in the first place :-)
• Phil Gough, Sep 1997:
  Also check that it's not slack spokes causing the rim to move in relation to the hub.
• Custfold, Sep 1997:
  As well as the pivot, heavier riders can break up the system used to fix the suspension rubber. This will cause the bolt to 'saw' a neat slot down from its original position through the plate on the rear frame, and at the same time slim down the bolt by wearing away the thread, and then the rest of it. This will give a squeaking noise.
  I have made a system which rigidly fixes the rubber to the frame, and has a 'floating' metal bearer pad which rests on the main frame (and does not crack up with heavy loads). I'm not yet happy enough to say it's a sellable item, and may try out some alternative rubber bushes. It has made an immense improvement to my rear end.
• David Cox, Jun 1999:
  In hot weather the rear suspension elastomer squeaks on mine but that's after years of use. I little grease on the bold cures it but usually the weather changes before I get round to doing it. Also check that the mudguard or the stay is not rubbing on the tyre.

Creaking

• Andrew Holland, Dec 1998:
  I had creaking noise on my Brompton which took some time to trace [...] to the rear suspension block (Shock absorber) The bolt was rubbing with the metal of the rear frame. The metal to metal contact had cut a slot in the rear frame. The reason for the failure appeared to be a stepped bush that the shock absorber bolt passes through.
  The rear frame is about UKP100 and the washer is probable a few pence but has to be bought as part of the rear shock absober UKP 8.
  When I got the part as with brompton parts there was some fitting instructions that told you how to pre compress the shock absorber and thus prevent the bush jumping out of position.
  It would appear that I am not the only one to have had this failure. It would be helpful if this adjustment were in the owners manual.
  I have spen the last 12 months with a slot in the rear frame but with the rear shock absorber pre compressed have had no futher trouble.
• Paul Weeks, Oct 1999:
  Bucket of water over the rubber suspension thingy cured mine...
• Larry Chinn - The Freewheel, Oct 1999:
  The creaking is probably caused by a loose crank arm. If the sound remains after tightening the bolt, then it could be the bottom bracket. Chains do stretch after a while especially after the kind of riding you described.
  A loose bottom bracket might also cause creaking. It's a good idea to overhaul the bottom bracket about once a year, especially if you ride during the winter in the rain.
  A stretched chain also wears down the teeth on your rear cog and more so the chain ring, since it's aluminium. You can tell if you've got a stretched chain if you can see space between the link and teeth when you pull the chain tight. Also the teeth on the chain ring will be sharp and pointed. If your chain is really stretched, it will skip, especially when pedaling hard. In any case, if you see any of these symptons, you need to replace the chain ring along with the chain.
• Deborah Eacock, Oct 1999:
  I suggest that you check your cranks. Disconnect the chain from the front chain-ring and check for wobble or looseness in your cranks. Also, check the rubber block for rear suspension. Also, tighten the screws that hold down the rear rack.
• Stein Somers, Oct 1999:
  Whenever it happens to me, I get off, give a twist to the suspension block and gone is the creaking.
• Graeme Smith, Oct 1999:
  I experienced a creaking sound which I suspected was coming from the bottom bracket or folding pedal. Shortly after this I changed the pedals for SPD pedals and the creaking went away - Could it be your pedals ?
• Mindak, Oct 1999:
  Me too. The creaking started after about a year with approx. 5 miles/day. I suspected loose cranks, and as the proud owner of a torque wrench tightend them up to the right torque. Even though they were quite loose it didn't improve things. I tried a second right hand pedal from another bike and the creaking disappeared.
• Bob Gelman, Oct 1999:
  I've had a squeak in my seat post, where it attached to my seat, on my Birdy. It drove me nuts for a while; very difficult to "listen" while you're riding. I actually thought it came from the FRONT of the bike for quite a while. I finally asked someone jogging if they would allow me to ride along side them so they could "listen" and tell me what part of the bike it was coming from. This was really deceptive since there was no torsional movement when you weren't pedaling and the squeak stopped when you coasted. I suspected something in the bottom bracket, chain area for a long time. Spokes rubbing together can be especially tricky. One just has to be patient with these things and track them down.
• Nico J. de Boer, Oct 1999:
  One more unexpected source of creaks while pedaling can be the frame hinge: after a droplet of oil my creaks disappeared.
• David Edge, Oct 1999:
  In my case, tighten the bottom bracket in its housing. It does need that fancy FAG tool that's also used for low-end Campag BBs. Not much you can do to overhaul it. It's one part of the bike that has given me little trouble.
• Paul Brady, Oct 1999:
  Creaks are usually from the crank arm losing up a little or perhaps the seat post. You can remove the crank and put a little bike grease on there and tighten it back up. That usually takes care of it.
  • Len Rubin, Nov 1999:
    Whoa! Hold on there! Bad advice alarm! Don't grease the tapers of bottom bracket spindles or crank arms! Clean them, check (and retighten the bolts if necessary) on a regular basis, but do not grease them, as they are MEANT to "seize"! Grease will perpetuate loosening and wear, as the softer aluminum will keep traveling up the lubricated slope of the harder steel crank taper. If you ride throughout the winter, more frequent maintenance may be necessary to prevent galvanic corrosion, but greasing them is a bad idea.
• Robert Payne, Nov 1999:
  It ended up being a lot more simple to fix than I thought. I ended up rotating the rubber suspension block and puting oil on the folding points, cranks, and pedals. No creaking anymore.

Cracking

Ticking

• John R. Bolt, Sep 1997:
  I had the same annoying noise coming from my T5, and I worked harder than now seems necessary to isolate the source (lubricating frame clamps, adjusting bottom bracket, etc.). In my case, it turned out to be coming from the right (non-folding) pedal. This cheapie pedal does not seem to be adjustable, so I replaced it with the right pedal from an old Bickerton, which is better quality anyway. Recently, tho, a quieter "tick-tick-tick" has been coming back. I suppose the new pedal is now giving me a problem--but at least this pedal is adjustable, so one of these days I will have a look at it.
• David Henshaw, Sep 97:
  Easy solution to this one. Drill a small hole in the plastic end-cap and inject oil every couple of months. The pedal will stop ticking and last almost indefinitely. Try to avoid fitting better quality pedals - they're all heavier than the nice basic items on the Brompton.

Clicking

• Deborah Eacock, Jun 1999:
  I discovered that the click corresponded to torque on the pedals. No, it was not in the cranks, rather a slight mis-adjustment of indicator spindle into the hub. Check the location of the red spot in 2nd gear. Also, drop a few drops of oil into the hub.

Screaming or scraping

• Hanel, Steven, Jun 1999:
  By alignment I hope you mean toeing them in [Spotlight on brakes - Do the 'toe in'].

Rattles from the rear

I have tried tightening all the screws and so on at the rear but this has made no difference. (I have not tampered with the rear hinge screws since the Brompton owner's manual emphasises that these should be left alone.) At one time I suspected that the mudguard might be vibrating against the luggage rack. I therefore put some pieces of foam rubber between mudguard and rack but still the rattle remained. I have wondered whether the source of the problem might be the castors on the rear rack, but if I try riding with my feet on the castors on the front of the reack (don't try this at home, children), the blasted rattle is still there.

Has anyone else had a similar problem? I so, how did you cure it, or did you just hurl the bike over a cliff, driven into an irrational rage by the rattle?

• Stein Somers, Nov 1997:
  One Dave Holladay, casually passing through Brussels today to deliver my Custom Folder order (and meet some Euro officials along the way), just told me they do come loose. At least when you wheigh 95 kg and tow an even heavier load!
  What about the castor pair at the back? Please, before you indulge in acrobacy, may I suggest temporarily locking them with sticky tape.
• Custfold@aol.com, Nov 1997:
  Have you;
  1. Taken hold of the upper section of the rear triangle and firmly holding this with bike on its wheels, tried to rotate this around the rear pivot in the same plane as its axis of rotation. My rear pivots regularly loosen and there ar 2 key clues - a small discomforting change in handling which becomes more pronounced as the condition worsens, and a wobble when folding the back under. My opinion of important connections secured by Loctite (tm) if a proper mechanical system is a viable option is that a design improvement is desirable. The Brompton design however has a lot of constraints which mitigate against the over engineered belt & braces, and I have cut a slot in the (53/61) chainrings, to allow me to get a Allen keys into the sockets without dismantling the crankset every time (tip here, do this so that the other side is not covered by the l/h crank!). I have however recently painted the bolts, with Hammerite (tm) paint and tightened them into the paint film. I think there might be other action to develop this further but it hasn't been a pressing issue, as I can always tighten the things as needed. The trailer howver does knock 6 bells out of the rear end, especially when you've got around 100Kg on the tail!
  2. Have you checked the suspension system. The original one has a bolt and guide which float in the rear frame, and will obviously be tight when you're not sitting on the bike. As a very heavy (120+Kg with backpack) rider I soon cut the plastic face from the unit, and then proceeded to have the fixing bolt saw its way down through the frame, and rub itself into a waisted, and wasted shadow of its former self. Fortuitously the hole is suitable for an M8 bold which can be fixed to the rear frame, if the suspension rubber has some degree of float (as on the Birdy IIRC), and I may try some Birdy rubbers as an option one of these days.
  3. Check also the folding stop plate, and SA componentry
• Norman Tulloch, Nov 1998:
  [...] my T5 has exactly the symptoms that you describe and has had them for the last year or so. Like you, I have tried and failed to find the cause. If the rattle does suggest the hub is on the way out, mine seems to be taking quite a while to die and otherwise works just fine. (There's a foolishly over-confident statement!)
• Graham S Jones, Nov 1998:
  Maybe it's heresay to mention another make, but hub-geared Moultons have being making rear end rattles since 1962. From the bottom bracket back, Bromptons, Moultons and AMs are very much the same. The rattles have something to do with the amplitude of vibration of small wheels on the road and idle hub gear internals - hence why it stops when you pedal.
  My L5 rattles, but my 1963 Moulton Deluxe (FW S-A hub) has done so since I got it 10 years ago, and it's still going strong.
• David Edge, Dec 1998:
  This sounds to me like a misaligned chain tensioner - the chain is perhaps running with the sideplates on the jockeys. If you can get someone to hold the back of the bike up while you turn the pedals it will be obvious enough.

Noise from the front

Silencing a whiny generator

1. A little oil around rotor
2. Check alignment of rotor to side wall
3. Super glue two o rings on rotor. ( Be sure not to get "s/glue" on rotor shaft area) [or get a regular dynamo cap from any (European?) bike shop]

Why is the Brompton's steering sensitive?

• Jim McLaughlin, Jun 2000:
  I'm not sure what you mean by "trail", I am guessing that is what we call "caster" in the US. Caster does affect the self steering. I believe it is defined something like this:
  Project a line down the axis of the fork to the point where it hits the ground. The tire will hit the ground usually somewhat behind this, and the offset is referred to as caster.
  I'm not versed in the trade offs, though I believe the racing types prefer twitchy steering (less caster?) and the masses perhaps prefer less twitchy steering. I assume the small wheels have much to do with it. For example, every recumbent I have seen has a small wheel in front and it is a given that recumbents do not lend themselves to riding with no hands.
  The Brompton's short wheel base might have something to do with it but I think less so.
  We need a physicist or engineer out there who can enlighten us on the geometry. But rest assured that one quickly becomes accustomed to the Brompton's balance, there is no special danger. Riding with no hands is never a good idea on any bike.
• Ka Lun Tam, Jun 2000:
  I have experienced that too, pushing my bike by the saddle. I had always assumed that part of the reason I can steer from the saddle on a regular bike was because the weight of the front wheel allowed it to "fall" to one side, so I can lean the bike to the left and the wheel would "Fall" left, thus turning itself to the left. With the smaller wheel on the B, I had thought it just wasn't heavy enough.
  By no means a theory with any scientific basis...
• Wei-Yuen Tan, May 2002:
  Self-steer and steering sensitivity are separate qualities, but both are related to head-tube angle. Steering sensitivity decreases as the head-tube angle departs from vertical. Self-steer (identical to the caster effect) increases as trail increases, where trail is the distance between a) the point of contact between the tire and the ground, and b) the intersection of the ground with an imaginary line passing through the centre of rotation of fork (i.e. a line extending from the steering column). The amount of trail is determined by the amount of fork-rake and the head-tube angle.
  To say that the Brompton's steering is due to its small wheels is indirectly true but inaccurate. Small wheels, a low headset placement and a telescopic steering column allow for a compact folded-form but entail that the head-tube angle must be close to vertical, hence the sensitive steering.

Riding on the sidewalk - is a Brompton a children's bike?

• Ka Lun Tam, Feb 2000:
  Well, here in Ontario, you're allowed to ride on the sidewalk so long as your wheels are under 24" in diameter, which the Brompton happens to have.
• Peter O'Reilly, Feb 2000:
  NYC ordinance permits you to ride on the sidewalk only if under age 14 *and* the bicycle has wheels less than 26 inches in diameter.
  NYC Bicycle FAQ: http://www.ci.nyc.ny.us/html/dot/html/get_around/bike/bikesafe.html

Wobbles and top speed

• Custfold, Aug 2000:
  Wobbles occur mainly as steering geometry alters to reduce the trail - with small wheels this is more rapildy changed that with large wheels. Perhaps as you go faster you put weight forward, and thus create what bikers over here know as a tank slapper.
  Sitting back and transferring weight rearwards will increase the trail and a wobble can be enhance or removed - especially if you have a fairly weighty backpack on to make weight transfer of considerable effect.

The Brompton Folding Bicycle FAQ