Anyone tried 2 speed to 3 speed conversion on Brompton

[Fastpedaller]

As per title. I've seen a video about using sprockets from an 11 speed cassette, with an 11 speed chain and a friction lever to convert to 3 speed.
As the 11 speed parts appear to have dropped a lot in price, I'm considering it - has anyone here got 1st hand knowledge?

 

[Schwinnsta]

I did that a few years back with 10 speed components and chain. It works well. Maybe the best mod I have done to date. I did 12t 14t and 19t.

 

[Fastpedaller]

I did that a few years back with 10 speed components and chain. It works well. Maybe the best mod I have done to date. I did 12t 14t and 19t.

any clearance issues? Did you need to move spacers on the hub and redish the wheel, and a thinner clip -in ring or was it straightforward?

 

[berlinonaut]

Done this, no issues. Needed so add a small spacer between chain tensioner and rear frame. If you use the forum search you'll find plenty of information in detail from various people including a write up from 2014 (!) from the guy who probably invented this hack als a linked pdf and some in detail reports. No need to once more write up what has already been written up and discussed countless times.

 

[Schwinnsta]

I did need to use a thin washer as a spacer, too.

 

[Fastpedaller]

Done this, no issues. Needed so add a small spacer between chain tensioner and rear frame. If you use the forum search you'll find plenty of information in detail from various people including a write up from 2014 (!) from the guy who probably invented this hack als a linked pdf and some in detail reports. No need to once more write up what has already been written up and discussed countless times.

Thanks, I forgot to try the search feature

 

[Fastpedaller]

Wow! that took some searching - I guess the 3speed derailleur for BWR hub is the thread I was looking for?

 

[berlinonaut]

Wow! that took some searching - I guess the 3speed derailleur for BWR hub is the thread I was looking for?

Possibly, don't know. Would be easier to tell if you actually linked to the thread you found. Think linking thing is what the WorldWideWeb is all about, isn't it? Would it also make easier for others to find the correct route later if they happen to end up in this thread....
In the recommendations below there's also a link to
https://www.cyclechat.net/threads/brommieplus-3-speed-derailleur-upgrade.286950/
which is not the real thing but tackels the topic from a different angle.

 

[Fastpedaller]

Here's the thread I found earlier:-
https://www.cyclechat.net/threads/anybody-installed-a-modified-3rd-gear-to-a-bwr-hub.243473/page-3

 

[berlinonaut]

Yeah, that's it. There's also this post and a couple before and after it that deal with the topic: https://www.cyclechat.net/threads/lets-see-your-folding-bike.239213/page-22#post-6521434

 

[Fastpedaller]

My B is a 2017 superlight, and after carefully perusing all the above (thanks berlinonaut!) I've drawn a few conclusions:-
1)I would have liked Brompton to have fitted a 130 width to accept a standard shimano freehub. their 2) The option of a front derailleur appeals to me, however, a 38mm mount isn't available, although it appears a 40mm could be used with the addition of some shims - this would in all probability only give 5 useful gears with 3 on the rear because of close duplicate unless the chainrings have such a difference the front changer won't cope.
3) And this may be the one that 'kills' even the change to 3 on the rear (cost-wise)........ I think my standard 54T chainring (non-removable) is too wide for a 11 speed chain!

 

[berlinonaut]

My B is a 2017 superlight (...)
3) And this may be the one that 'kills' even the change to 3 on the rear (cost-wise)........ I think my standard 54T chainring (non-removable) is too wide for a 11 speed chain!

With a 2017 clearly the chainring should be removable as with any Brompton since 2013. Also, for 3 sprockets you don't need an 11 speed chain. Just a bunch of sprockets (10 speed), an according chain, a new shifter or you modify your existing one. All in way less than 50$ if you shop carefully.
I used the 3-speed mod on my BWR with a 44t fixed chainring btw. with the bike dating from 2011.

 

[Fastpedaller]

With a 2017 clearly the chainring should be removable as with any Brompton since 2013. Also, for 3 sprockets you don't need an 11 speed chain. Just a bunch of sprockets (10 speed), an according chain, a new shifter or you modify your existing one. All in way less than 50$ if you shop carefully.
I used the 3-speed mod on my BWR with a 44t fixed chainring btw. with the bike dating from 2011.

Oops, my error - bike is 2007

 

[Fastpedaller]

Berlinonaut - do you agree an 11-speed chain will not fir my chainring?

 

[berlinonaut]

It will probably not but I wouldn't bet my life on it. Possibly there are some that do and others that don't. Still don't get why you think you'd need an 11-speed chain.