Brompton gearing

arse_neck

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

wgwarburton

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?


Cheers,
W.

shinybits

WGWarburton wrote:

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

rampax

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.

Discuss.

rb1956

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.