Brompton 3 or 6 gears

[T4tomo]

Unless you aren't doing any hills at all the 2spd is quite limited (but a good option for a flat town commute) which is why Berlinonaut is recommending it I guess.

3 spd is most robust for minimal maintenence, As the 2spd and 6spd rely on the rear derailleur, which as mentioned further up thread, can be temperamental if not kept clean.

I Have had several years on 3 spd standard and then several on 3spd - 12%, I favour the latter. Better to run out of gears at the top end than the bottom. You won't use 1st in London on either set up though!

 

[Ming the Merciless]

I have a three speed and have got used to riding out if saddle when steep stuff turns up. Keeps you fit and is good fun.

 

[oldwheels]

I use a 6 speed with a 40 tooth chainring and use all 6 gears. On the flat I spin out at about 18 mph in top but that was only for test purposes and never get near that speed in everyday use.

 

[TheDoctor]

I think I've twice had to get the rear mech off and take it to bits.
For context, I've had the bike about a decade, and worn the transmission out in that time. And I'm toying with the idea of replacing the Marathon tyres after a mere seven years.

 

[kais01]

2 or 6. i really fail to see why accepting the weight penalty of a hub, and not keeping the derailer with almost no weight penalty at all.

but.

the 2x3 bwr have too big steps for a multigeared bike. really!!

so the option i highly recommend newcomers is buying a bsr 3-speed and have the shop add the 2-speed derailer kit with 13 + 15 cogs, thereafter pick chainring according to taste and leg strength. get 6 reasonably close-ratio gears. much better than the bwr out on open road.

of course for the technically skilled all kinds of other options are open. in our family we have 2sp with a 50t for my wife, with 69t for me, a 5sp with 305/44 tyres for winter, a 2x5 oldie with 13+14 cogs giving really close ratios, and my 2x10 dura-ace/schlumph with about 14 unique super close ratio gears about the same as a tdf racer.

but the 2x3 bsr is a good start for anyone.

 

[berlinonaut]

so the option i highly recommend newcomers is buying a bsr 3-speed and have the shop add the 2-speed derailer kit with 13 + 15 cogs, thereafter pick chainring according to taste and leg strength. get 6 reasonably close-ratio gears. much better than the bwr out on open road.

There's a simple and very good reason why one would not do that: It does not work. The derailleur upgrade from a 3-speed only works with the SRAM Hubs that were replaced with the SRF-3 (later renamed to BSR) already back in 2005 - 15 years ago. It does NOT work with the BSR. You can however modify a 3-speed BSR-hub by using parts of the BWR and adding the freewheel parts of this hub to the BSR and thus making it able to deal with 2 sprockets and the derailleur, but this is a rarely made modification, nothing for total beginners and finding out which parts one exactly needs, then getting hold of those parts and finally putting the things together appropriately and may be a bit of a showstopper for most people. The more as the gain in spread from the 3-speed is just from 178% to 214% - not too impressive and probably only for very few people not worth the hassle.
My modification of the BWR to 9-speed ist way easier and cheaper and adds spread as well as small gear-steps to the BWR. However: For most people this would possibly be overengineering, too.

but the 2x3 bsr is a good start for anyone.

I don't think so, for the reasons outlined above. And furthermore I always have my doubts when someone says something would be "good for anyone". People are different as are their needs and desires and in most cases the person giving such advice just thinks what he considers to be good for himself must be good for anyone, thus showing a bit of a limited imagination and overestimating himself...

 

[kais01]

sorry berlinonaut, exchanging cogs in the 2x3 kit is hardly expert work...

making the 3speed derailer is, as you are likely to be aware of. fiddly is its middle name

 

[berlinonaut]

sorry berlinonaut, exchanging cogs in the 2x3 kit is hardly expert work...

Exchanging cogs is definitively not hard work. Making two cogs fit onto a BSR hub is. Because without that the 2*3 obviously does not work and the BSR is not prepared to take two cogs from the factory. Did you do it? Or do you confuse it with the former SRAM hub (which could easily be upgraded from 3 to 2*3 spreed but is - as I wrote - gone for a very long time already). If you know an out-of-the-box way of upgrading the BSR I would love to learn about it!

 

[kais01]

well as far as i know the bsr has the same 3 tagged fastening originally meant for a single cog as the torpedo/sachs/sram. but the kit works regardless, because the cogs in the kit are narrower, and if i remember correctly the fastening spring is also slightly narrower.

i recommend this setup for the novice because they dont have to anything themselves. the conversion can be performed by any authorised brompton workshop. there is a ready-made all inclusive kit sold by brompton. even the chain is in the package

the 3sp derailer is off limits there, and better suited for you and me

have made this conversion on at least three brommies and still have one or two kits in my garage.

 

[berlinonaut]

well as far as i know the bsr has the same 3 tagged fastening originally meant for a single cog as the torpedo/sachs/sram.

It uses the same style of sprockes (with three "noses") but as far as I know the conversion to two sprockets still does not work on the BSR (it did on some of the Sprinter hubs). Would be good to know if it is different.

but the kit works regardless, because the cogs in the kit are narrower, and if i remember correctly the fastening spring is also slightly narrower.
(...)
I have made this conversion on at least three brommies and still have one or two kits in my garage.

So we talking about part number
QDRRETSET3SR->6SR as outlined here?
UPGRADEKIT SRAM-3V NAAR SRAM-6V
http://www.vlerickfietsen.be/brompton/spareparts/versnelling_buiten/upgradekits/index.html

So did you really apply this conversion to a BSR hub or do you just believe that it will fit due to the sprockets having the same shape and have only applied it to Sram hubs?

 

[kais01]

i just believed

if someone says it does not work that is something we both have heard in in the past. if you have specific info of why it most surpricingly would not work it really would be nice to know

ot; in a somewhat related example i heard something similar from expert mechanics when back in the days i wanted to add a third cog to the torpedo/sram hub. went without any problems on with that anyway, and later did not stop until i reached six.

later came similar hybrids on the market.

 

[kais01]

so here are the two hubs in question...

 

[berlinonaut]

I am not very interested in this mod anyway but I still have a Brompton SRF-3 rear wheel collecting dust in my workshop but unfortunately no SRAM 6-speed. So if I do not forget it I might just order a sprocket set for the Sram 6-speed the next time I need parts and try it out for the sake of science. Should not be too expensive, just not sure if those sprockets are still available as a Kit from Brompton - looks as if they were discontinued.

 

[kais01]

you should be ok. my guess you need to keep the bsr fascia, and maybe this is what any compatibility issue is about.

of course to make the conversion you, or our ts does not need the kit, the friendly brompton store is likely to have the necessary parts on hand, for example when buying a bike.

my experience is they change out freely on new bikes after customer's demand.

 

[u_i]

So to understand, one speed-doubling BSR conversion goes through adopting hardware from BWR that then allows mounting Shimano cassette cogs. The more straightforward conversion utilizes cogs that directly fit BSR. Would the latter cogs basically be 3-spline Sturmey-Archer cogs widely available from different vendors?