14 November 2012

14 November 2012

Making good progress on Scott’s bike. The chainstays took a while to get just right – trying to maximise tire clearance for 29″x2.4″, whilst allowing for the beltring at the relatively inboard beltline of an Alfine hub – all with short chainstays…. But the whole frame is now all brazed up and the brake mount has been added to the fork (really liking the Anvil post mount tool). Next up is the stem/steerer and the custom front rack.




  1. I’m intreguided by this build – I’m wanting something similar built but didn’t think anyone could get an Alfine to work with a belt and a fat tyre (2.4 or bigger) because of the chain line needed on the Alfine and cog sizes available for belt drive systems.
    Are you modifying the Alfine to push out its chain line or building bespoke belt cogs?

    • Yes it is very tight! Scott and I considered doing an offset rear end to help the beltline, but ultimately decided to keep things symmetrical. Shaping the chainstays just right took a long time, and it wouldn’t have been possible with the original Gates CDX system. The CenterTrack has two advantages – one that the rear cog can be flipped to push the belt out 3mm, and secondly that it can handle a little bit of out-of-alignment. I haven’t yet had a chance to test it to make sure it all runs smoothly; I do have a plan for a custom offset belt cog if it should become necessary, but I’m hopeful of keeping things simple! The other option would be to do an elevated chainstay, so that the beltring/belt can be where they need to be without trying to squeeze the chainstay in.


  1. Custom Rob English MTB - Page 4 - London Fixed-gear and Single-speed - [...] Rob has made great progress on the bike the last couple of days...pretty much the whole frame is done!…

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