Brompton 2 speed gearing tweak

ugo.santalucia
ugo.santalucia Posts: 28,312
in Workshop
One for the 16 inch wheel fanatics,

I've got a 2 speed Brompton, which comes with standard gearing 54 T chainring and 12-16 T sprockets. I would like taller and closer gearing, Ideally an 11-14T at the back, but there is no option to replace the sprockets with smaller ones. The 11T is probably impossible to find, as the cassette ones don't work. Any chance to at least find a suitable 14 T?
In the past I have replaced the 16 with a 17 T from a 10 speed cassette but it never worked properly...
What are my options?
left the forum March 2023

Comments

  • mr_mojo
    mr_mojo Posts: 200
    Sorry I can’t advise on the sprockets but is it possible to change the front chainring to a larger size to achieve the 11/14 ratio?
  • ugo.santalucia
    ugo.santalucia Posts: 28,312
    mr_mojo said:

    Sorry I can’t advise on the sprockets but is it possible to change the front chainring to a larger size to achieve the 11/14 ratio?

    There is no official Brompton chainring bigger than 54. You can buy some other brands which are 58 or even 60, but they come without the chain protector, which is a hassle if you are wearing trousers. Also, needs a new chain and not a Brompton one, as those are not long enough for a bigger chainring.
    Might be that the best option is to butcher a cassette for the 12 and the 14 T sprocket and fit a 10 speed chain to make sure everything works together. Dunno...
    left the forum March 2023
  • fenix
    fenix Posts: 5,437
    I think the easiest option is a bigger chainring.

    https://www.cyclechat.net/threads/brompton-higher-gearing-option.232802/page-3
  • ugo.santalucia
    ugo.santalucia Posts: 28,312
    ... as above, a more expensive route and not without issues
    left the forum March 2023

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