I've managed to completely break the folding left-hand pedal on my Brompton. The bit where it fastens onto the crank* is fine, but the rest of it gone.

What tool(s) do I need to remove the broken pedal and fit a new one?

I'm asking this because I want to compare the price of doing it myself (pedal + tools) to the price of getting my local Brompton dealer to do it (pedal + labor + loss of self-respect).


*Please forgive me if my terminology is terribly wrong! :o

  • Can you add a picture?
    – Jay Bazuzi
    Commented Mar 3, 2011 at 18:04
  • "Crank" is indeed the correct term. Have added an entry for crank to the terminology index. Commented Mar 8, 2011 at 22:16
  • Brompton pedal breaks are increasingly being reported , both on folding and fixed pedals.
    – user3686
    Commented Mar 17, 2012 at 15:17
  • A pedal failure on a cycle is very dangerous unlike other breakages on cycles you are unable to come to a controlled stop, if the pedal suddenly breaks. I think more research needs to be undertaken on the brompton pedal failures and the potential of serious injuries. Interested to hear from others who have had serious problems with brompton pedals and what brompton are planning to do . It would be shame if a great British invention suffers from a pedal failures.
    – user3686
    Commented Mar 17, 2012 at 15:25
  • Self respect is overrated - there's totally no shame in knowing your limits. Pushing your limits a bit is great for personal development, but there are some things I won't touch, like brakes on my car.
    – Criggie
    Commented Dec 20, 2016 at 9:13

5 Answers 5


If it's a pre-2012 non-titanium Brompton, it takes a 24mm socket. If it's a 2012 on-wards, it needs an 8mm Allen key. The 2009 to 2012 titanium Brompton used a 10mm Allen key in a Ti pedal bolt. The official Instructions are available on Brompton's site.

Very important: remember that the left hand pedal is left-threaded -- the reverse of normal.

Note that pedals can get quite tight. A standard 8mm Allen wrench might well not be enough leverage. An 8mm Allen socket combined with a larger socket wrench is a better tool.

  • 1
    @trentp Good edit - thank you. Please have a browse through the tour (found in the help menu) to learn more about SE - you're off to a great start.
    – Criggie
    Commented Dec 20, 2016 at 9:11

As per an email from Brompton:

...the folding pedal needs a 24mm socket to remove unless it is a superlight bike, the titanium folding pedal bolt uses a 10mm hex. The right hand pedal uses a standard 15mm spanner.


It worked with a 24 mm socket on mine. But remember it is left hand thread. So turn the wrench clockwise to loosen! I had an annoying tick with each rotation when this pedal was on top. I noticed a fatigue crack in the titanium casing, but also there was 1 mm play between the black plastic and the vertical plate in locked position, and this could also be the cause of the noise. My Brompton is 4 years old and was used for only 1250 km with great care, so I would consider this failure of the pedal a construction fault!


this should help you. Basically a big allen key should do the trick:

  • 2
    Good find and useful for future searchers. However this question was asked in 2010 so OP will have whatever came before. Do you know how pre-2012 brompton pedals were attached ?
    – Criggie
    Commented Jan 14, 2020 at 19:35
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    What's more, the pedal is long since fixed - and even upgraded to a modern one! :) -OP Commented Jan 23, 2020 at 14:20

Having never seen a folding Brompton pedal, I would assume a standard pedal wrench would do the trick. It's basically a skinny 15mm open end wrench: http://www.parktool.com/product/home-mechanic-pedal-wrench. Keep in mind the left side pedal is reverse threaded, so you'll have to turn it clockwise to loosen.

  • Thanks, I'll take a look at my Brompton tonight and see if it'll work. Commented Mar 3, 2011 at 13:27
  • An alternative mechanism for some pedals is that they use a 6mm allen key on the other side. You can easily see if your pedals have that by just looking at where the pedal comes out the other side of the crank. I too don't know anything specific about the bromptons. Commented Mar 3, 2011 at 13:49
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    According to this thread from 2009, the folding pedals take a 24mm <strike>allen key</strike> socket. (For what its worth, I would have made the same guess and assumed one could use a pedal wrench.) Commented Mar 3, 2011 at 15:30
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    @Neil - it's likely current, saw some folding pedal replacement bolts for sale that have 24mm hex heads.
    – darkcanuck
    Commented Mar 3, 2011 at 16:46
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    @Neil, @Colin, @Moz: the Brompton is standard bicycle in some parts, but unique in other parts. One of the those particular specialities is the right-hand folding pedal; this is quite industrial and folds within cuboid of the folded bike (ie, the pedal folds behind the crank stem). This technique is made possible by a large diameter ball-race, and equally large bolt against it (see google.com/images?q=brompton+folding+pedal). You'll need a socket-set for the standard bolt. In addition, because of the size, it's also available in titanium, for which you'll need an Allen Key. Commented Jul 16, 2011 at 18:53

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