Converting 2speed Brompton to 4speed similar to the new P and T lines

[berlinonaut]

I have to cancel certain roads out of my way home where I live now with certain amount of beers in the bag unless using lower hub gears, or grind to a stand-still, especially if knee accidentally knocks the gear up mid-ramp.

What if in such a situation you drink the beer before tackeling the hill? Makes the bag lighter and rises the motivation. Could be a winner!

 

[mitchibob]

What if in such a situation you drink the beer before tackeling the hill? Makes the bag lighter and rises the motivation. Could be a winner!

It's a good plan, except then I'll have less beers for recovery!

 

[boluser]

There is a company called Brombacher that sells a 4 sped conversion that fits the standard 2 speed wheel. Ive not tried it myself but was considering it as an option:

http://en.brombacher.kr/product/bro...4s-shift-kit/339/?cate_no=106&display_group=1

View attachment 649678

It uses standard shimano cogs which are readily available (so can be changed cheaply), in 11-13-17-21T.

Hello friends I am new here.

Sorry but English is not my first language. I was reading the thread and saw that the conversion kit by Brombacher may not fit a Brompton rear wheel.

So, I just look into the page and found this other kit also by Brombacher
http://en.brombacher.kr/product/bro...-4s-full-set/493/?cate_no=106&display_group=1
which includes conversion peaces for the rear wheel.
Has anyone tried it?

I am planning to buy a Brompton bike. I can't decide whether to buy a P line or a 2 speed Brompton + the 4 speed conversion kit. That second kit which includes modification for rear wheel.

I am from South America. There is no Brompton dealer in my Country. I am travelling to Chile to buy a Brompton. I have two options.

1.- Brompton p line which is around 3100 USD

2.- Brompton 2 speed (1400 USD) + 4 seepd conversion kit with rear wheel parts ( 420 USD including shipping and customs) + 2 scwalbe one tires (160 USD) = 1980 USD

I do not know if it is worth it to buy the 2 speed and trying the conversion, or make the financial effort and acquire a P line. I live in a place with low steep inclination ( or hills). I live in the City of Cochabamba, Bolivia. And from what I saw, it is best for me the bike has no internal hubs, for changing flat tire and finding replace part if it gets damaged.

I saw US or English speaking tourist with Bromptons in my country and I fell in love with them. I want a Brompton.

Do you have any advice? Saving for me around 1000 USD would be great. I am making a great effort to get a Brompton. I know those bikes are expensive even in the developed world, so if the conversion kit is a good idea I would try it.

Thank you.

 

[berlinonaut]

I'd say both ways are valid but personally I'd rather go for the factory P-Line. The Brombacher Kit costs 350$ according to their webpage and if this is US$ this sounds very steep to me for what it does. As with any 3rd-party mod you are pretty much on your own if problems occur and you do have a single source of spare parts which is on the other side of the world and may stop being in business any time.
The resale value of a genuine bike is typically also better in comparison to a tuned one.
The need for those 3rd party conversions has vanished a fair bit in my eyes with the availability of the factory 4-speed option. It uses sprockets of 11-13-17-21T, so a bit more mounain-ready than the P-Line but you could also modify the P-Line this way.

As a last bit: During Eurobike this year Brompton presented a 4*3 speed based on the 4-speed derailleur. Strangely enough there has been barely any media coverage of it and no further details are publically known. In one video the statement was however that the 4*3 will appear for 2024 in P-Line electric, C-Line electric and P-Line. But no real details about the timeline or the spec.

It will no doubt be technically possible to retrofit this to a P-Line bought today if desired, massively extending it's gear range. No so much on today's C-Line.

 

[Kell]

As a last bit: During Eurobike this year Brompton presented a 4*3 speed based on the 4-speed derailleur. Strangely enough there has been barely any media coverage of it and no further details are publically known. In one video the statement was however that the 4*3 will appear for 2024 in P-Line electric, C-Line electric and P-Line. But no real details about the timeline or the spec.

Ooh.

 

[berlinonaut]

Ooh.

Jup. It is a bit weird. This finally addresses the often named issues with the Brompton's limited gear range and it is - for Brompton territory - a massive change with pretty wide impact if you think it through. A lot of open questions, a lot of marketing potential. Still presented silently and mentioned as a side note in the Eurobike video of a huge but not so Brompton-competent bike shop. The cited statements come from a Brompton marketing guy in this video. I have no idea how reliable they are. Really strange that no one followed up on this and that Brompton did not use their marketing power to promote or at least communicate it. Possibly they are in fear of P-Line and Electric sales potnetially dropping when people decide to wait. But then: Why do they present this bike publically if they don't want it to be recognized?

 

[u_i]

So, I just look into the page and found this other kit also by Brombacher
http://en.brombacher.kr/product/bro...-4s-full-set/493/?cate_no=106&display_group=1
which includes conversion peaces for the rear wheel.
Has anyone tried it?

Note that the kit includes parts that wear off and need to be periodically swapped. Will the replacement parts be available for the life of your bike? Will you be willing to pay premium each time? The alu pusher there will wear off quickly.

 

[mitchibob]

All this talk of 4-speed .... just need Classified hub to make it 8... would be fine! Should've been a T/P Line option