Viewed products

Top sellers

Brompton crankset with 50T "spider" chainwheel View larger

Brompton crankset with 50T spider chainwheel



50T Brompton crank set (left and right complete) - the "new" 2013 "spider" Brompton crankset

More details

We have 3 in stock


More info

Brompton crank set - 50 tooth - silver

The Brompton "Spider" crankset was introduced on new Brompton bicycles at the beginning of 2013. In 2015 it was introduced to the after-sales market, allowing us to offer it to you

Colour: Silver (with black chain guard)

It is available in a choice of 44T, 50T and 54T sizes - the 50T is the standard one used on a 3 or 6 speed standard ratio Brompton

This is a replacement 50 tooth crank set complete with left and right hand crank - bottom bracket is NOT included - if you are upgrading from the old fixed crankset then you will also need to change the bottom bracket (the old one was ISO standard and the new one is JIS standard)

This Brompton "spider" crankset has a few advantages over the older fixed crankset:

  • The chainring protector is held on with screws rather than plastic lugs so is less liable to falling off
  • The chainring can be changed without the need to replace the crank as well (making it easier to change gear ratio) 
  • Better protection of folding pedal (a hook on the back of the crank arm stops the pedal folding in too much) to help prevent it from scratching the frame (though the pedal should be unfolded first and folded last in the folding sequence to prevent frame scratches
  • It looks better too - with a modern brushed metallic finish
  • Lighter weight

The box contains the following:
Left hand crank and bolt
Right hand crank with 50T chainring and chainguard and crank bolt (pre-assembled)

Crank length 170mm
Brompton logo on cranks 

A standard 3 or 6 speed Brompton comes with this 50 tooth front chain ring

Brompton 2020 Q part code: Q101395
Brompton Q part code: QCRANKSET-SPI-50
Brompton part number: 9020140

Have a question?

2 Question(s) answered - see below

If your question has not yet been answered here, use the form below to ask something

*(Required - so we can email an answer - we wont show it)
    Answered questions

  • Asked by Stephen Worrall
    on 02/03/2021
    Had a major failure on my Brompton crankset. it’s a 50 tooth 170mm set. My Brompton is a three speed not sure what year but imagine around 2010. If I buy the spider 50t will I need to replace the bottom bracket too? Answer:
    Yes, due to the age of your Brompton you will also need to replace the bottom bracket;
  • Asked by Michael Tully
    on 08/04/2022
    Do you sell the 50 tooth chainring on its own? I already have the spider chainset, but with a 44 tooth which I need to replace Answer:
    It sounds like you are looking for a Brompton chain ring / guard assembly for 50T spider chainwheel, link as follows: You will need to increase the length of your chain by 2 links due to the larger chain ring size

Related items / accessories

Data sheet

Comm Code87149990