Folding Bikes - Brompton rear derailleur

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JohnyKwst
06-29-09, 04:26 PM
Is there anything special about Brompton's 2 speed rear derailleur system? Brompton claims that it is a unique system. What are the advantages and disadvantages of their system? Does it still suffer from the problems other derailleur systems face, such as ease of being knocked out of alignment? Also, what is direct drive?

Folder4life
06-29-09, 05:17 PM
I had that system on my Brompton S2L-X and it is okay for occasional riding. To tell you the truth, I sold it because I wanted alittle more gear range. The first gear will get you up small hills standing and the second gear will get you cruising at a reasonable speed, but I always felt the need for another gear to make the bike worthwhile. It just wasn't as fast as my Dahon Mu C9. The chain is straight so when you pedal, the power goes straight to the wheel.
I bought my S2L-X from an authorized dealer in Japan and after riding it for a week, I couldn't switch gears. I assumed this was the cable stretching. But after taking the bike back to the bike shop, they spend a week trying to figure out what was wrong with it. Needless to say, I was alittle disappointed. Not sure what they fixed, but they said that something was stuck......
LWaB
06-30-09, 01:50 AM
Is there anything special about Brompton's 2 speed rear derailleur system? Brompton claims that it is a unique system. What are the advantages and disadvantages of their system? Does it still suffer from the problems other derailleur systems face, such as ease of being knocked out of alignment? Also, what is direct drive?

- It is unique to Bromptons.
- It is quite light, very compact and relatively protected from impacts. Setting the limits is quite easy and it generally needs little maintenance, other than changing the cable and cleaning the mechanism occasionally.
- It is sensitive to cable drag and can only shift a maximum of two cogs with a limited tooth differential. The mechanism can be confusing to bike mechanics only used to standard derailleurs.
- Both derailleur cogs are direct drive, as are all derailleur gears. Only when hub gears are involved do you not have direct drive.