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Brompton gearing

arse_neckarse_neck Posts: 24
edited December 2008 in The workshop
Hi there everybody.

I commute about 12 miles a day on my two-speed Brompton folder. But my legs are spinning out all too easily on the flat (and potholed) roads of that London.

My S2L has a 54-tooth chainring. Not sure what teeth the two cogs have got at the rear, but it's a derailleur rather than hub set-up.

I've spoken to my LBS about doing something with the gearing so I can overtake more couriers!! They didn't think I could do anything with the drive at the rear, but suggested a Dura Ace chainset (and BB) with 56 teeth. And suggested this was pretty much my only option.

I don't mind spending a bit of cash on this, as it will make a lot of difference. And some Dura Ace would look kinda bling on my Brompy. But before I take the plunge, can anybody suggest another option? The lower tech the better, as I'm hopeless at DIY fixes.

Thanks in advance, Stu


  • wgwarburtonwgwarburton Posts: 1,863
    54 -> 56 teeth is a pretty small jump. I doubt you'll feel much difference.

    I'd be very surprised if this is your only option, but you'll need to find someone who knows much more about Bromptons than I do to get good advice.
    I'm surprised your gearing's low, though- when I used a borrowed Brompton earlier this "summer" I found it overgeared. It had a three speed Sturmey hub and I wondered what the point of the top gear was.. I wouldn't have used it much. Maybe fitting a hub gear would be your best option?

  • 54 -> when I used a borrowed Brompton earlier this "summer" I found it overgeared

    Yeah, I rode one today (gonna buy one) and was amazed at the range of the top gear - would probably only need the thing when caning it downhill! But that was the 3 speed, not the 2 speed. Let us know how you get on :)
  • rampaxrampax Posts: 139
    I have the 2 speed model, and find I rarely use the smaller sprocket.
    When the bigger sprocket finally wore out, I took it to my LBS (brompton dealer) and asked if they could change the ratios.
    They said that Brompton dont make alternate sprocket sizes for the 2 speed model, but that they could "probably" fudge it from BMX sprockets or similar.
    I didnt try it.
    I would like a slightly smaller chanset than the 54, but it appears the next one down is a 48 - which will probably be far too easy to padal.

    The A6 Hazel Grove - "Always the worst part of any ride".
  • rb1956rb1956 Posts: 134
    There are 60-tooth chainrings out there with a 130mm BCD. I think Vuelta makes one, for example. That would probably be your best bet.
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