Originally Posted by
Jerrys88
Mulleady - I'm very interested in this mod. I hope you don't mind a bunch of questions: Can I achieve a gear range between low 20's (and I mean NEAR 20) and 80's? How hard is it to install the Shimano Alfine on the Brompton? Does it require any frame modifications? Is it a do-it-yourself job, or something an experienced bike mechanic needs to do? Is there only one 8 speed Shimano Alfine hub, or do I need to buy a specific model (if so, which one?)? I assume it works with the derailleur my Brompton came with, yes?
Hi Jerry88. Thanks for your PM or I would not have noticed your questions.
I am not sure of my exact ratios but The lowest gear really is fit for steep hills. While I've not done costant gradients much in London, I've sailed over some pretty steep bridge inclines on the Grand Union in London in the lowest gear so I know it's low enough to climb brilliantly.
To install the Alfine the rear triangle needs to be widened to 135mm with proper tooling to accommodate the hub. This small modification does not compromise the frame integrity at all as the Brompton frame is steel. I then recommend Ergon grips at the front with the right one adapted for the Alfine twist grip. this is way better than the 2 cumbersome and rather ugly Brompton shifters. You would need the back wheel rebuilt with shorter spokes. I don't know the exact length but it's a custom job. The wheel I got built is bomb proof though.
The SA hub is narrower for sure but not as good a hub as the Alfine in my experience. It's OK but can tend to slip in 6th gear. That's been my experience with the SA 6 speed and also one other German user who had the SA mod on her Brompton from Kinetics. The Alfine is one of the finest gear hubs outside of the Rohloff speedhub. There is a new 11 speed Alfine hub with even wider gearing coming out (double the price of the 8 speed at £350 ) but I find the Alfine 8 provides a more than adequate range of gearing on the Brommie.
Unless you are a tech whizz with your hands you need a LBS skilled in these sort of mods. They are well beyond the average bike mechanic. Some people on this forum are technically skilled way beyond that but not me lol! Mind you I had lots of ideas of what I wanted in my head but don't trust the hands. A confidence thing I guess! In the UK I only know of 3 people who do Brompton mods. Kinetics (limited to SA 6 speed wheel build), Steve Parry (anything goes) and the LBS I used in London; Fudges Cycles. Fudges did a brilliant job on the bike.
Was it worth it?
Absolutely yes! The Brommie is a fine bike anyway for riding but the mods make this a bike capable of cycling much further and with a beautifully smooth transmission. I can ask Andrew Fudge what chainwheel and sprocket teeth ratios he used. I fear most of the Brompton mod experts reside in the UK and one woman in Germany I believe.
Where are you based Jerry88?