Brompton 2 speed Gearing

rampax

Hi
I have a Brommie S2L with the 2 speed rear derallieur, and the 54 tooth Chainring.
In the 2.5 years I have owned it, I have allmost never used the smaller sprocket, as you have to be really cruising before its useable.
The bigger sprocket wore out, and some teeth broke off it.
When I took it to get repaired I asked if they could replace the smaller (rarely used) sprocket with a bigger one.
They said that to change the ratios on these machines, you have to replace the chainset.
I have had a look on the webbe, and the next size down from the 54 tooth, appears to be a 50 tooth.

Will this be TOO bigger jump, I am cautious as you are looking at the best part of £50 for the chainset!

Cheers.

jc4lab

...

brompting

Oh dear, oh dear, oh dear,

I have and still owned some 3 and 5 speed Bromptons and fixed all my (other) bikes.

I think Brompton uses a 2 speed freewheel for their 2 speed. That is to say you cannot change the sprockets (please somebody prove me wrong!). That is why your dealer suggest an other chain set. If you look closely to their options you will see that you can choose for two lower gearings. Your NEW higher gear will end up somewhere in-between your present gears. Actually you will create a down shift in both your gears.

The thing you should realize is: In using your present lower gear, are there situations where you wished you still can shift down? Is this quite often. If so go for the lowest option. The present jump from one gear to the other is 100% to 133%. If you look at it from the other way it is 100% to 75%. So with the lowest option Brompton offered you are still in between.

IMHO the present jump between gears is to big for (an old man) me. It is the same jump as the 3-speed. That's why I prefer the 5-speed. Alas the 5-speed is no longered offered and it does not have even jumps like the present 6-speed. Since nothing is perfect, the 6-speed is a liitle ackward to shift. But this is for an other thread/topic.

I hope I could be of any help in helping you make up your mind.

Keep cycling, Brompting

rampax

Thanks for the reply Brompting,
I use the bigger sprocket more than 98% of the time, and there are many times I wished it was easier still, like when starting on an incline.
I have considered selling my current S type and getting a new M type, so that I have the 3 speed hub, and the slightly higher riding position, though I have heard some bad things about the new SRAM hub gears that are in use.
I probably will buy the 50 tooth chainset at some point.

Cheers.

gma

I've got an M6 (from late 2006), but find it neither difficult to shift, or unreliable in the three speed hub department. Once you've spent a few days riding it the shifting becomes second nature, and really shouldn't put you off getting a six speed...

brompting

Rampax,
What do you want your Brompton for. May be it is time to rephrase that question. And remeber there is no such thing as a "Jack-of-all-trades". Do you need a folder or is it time to have a folder AND a regular bike?
Notice I said folder, there are more folders than the Brompton. Is it the compactness when folded or is it the lightness? Have you considered the Tikit from Bike-Friday. Folds fast and a little bird told me there will be a 8-speed hub option very very soon.

I am suprised to hear about hub problems with the 3-speed. These S-Ram hubs are still made in Germany, Schweinfurth I believe. They are as good (may be better) than the SA.

About the Brompton 6-speed. They have nice even steps, BUT, but TWO levers are not as easy as ONE lever. Of course you get use to it but there will allways be a slight delay.

Good luck Rampax and a lot of wisdom in choosing a new/other bike.

rampax

Yes, I have got another folder - a Dahon Jack, which I use sometimes to "spice up" the commute. Its much nicer to ride than the Brommie, but is a pain to fold, and is still big when folded.
The Brompton is SO handy when it comes to the train though, and when I need to nip in a shop on the way home.
I know there is no such thing as a jack of all trades, thats why I (currently) have four bikes.
Just had a quick look at the Tikit from Bike Friday. Its certainly a fast fold, but it seems like its still in Brompton territory to me, ie, tiny wheels = poor ride. Great if you are on smooth Tarmac, but bad if you are on the highly potholed streets of "Gun"chester.

cakewalk

I thought the SRAM was only fitted on the six speed?

rootes1

Old thread resurrection... as note in case anyone else comes across this, but the 2 speed is based on a bespoke freehub and not a freewheel. It is splined in the standard shimano freehub pattern so you can make use of different sprockets to alter ratios.