Fixed gear - what length cranks???

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  • I usually ride 165 chainsets on my fixed gear bikes but I've inherited a bike that belonged (and was built) for my Uncle. I know it started out fixed gear but had a SA 4 speed when I got it. I have had a fixed rear wheel built using the same type of hub and rim and want to keep the bike as like it was as possible but it has 170 cranks. Does anyone ride with the longer cranks or is 165 as long as sensible?

  • 170 will be absolutely fine

  • DoUrace? Nope! live with it, it doesn’t matter what length as long as its compy to ride

  • Your knees will explode and the chiropractor will send you huge bills, you will also be mocked by purists. I use 172.5 on all 3 of my fixed bikes and haven't died yet after 40 years of doing so.

  • Crank length should, in theory, relate to your thigh length, but seeing as you generally only get four crank lengths, it’s not very scientific. Track bikes usually have a lower bottom bracket height and so shorter cranks were fitted to give clearance on the track, and 165mm became the norm.
    Personally I’ve always used 170’s on my road and fixed gear bikes, just to keep it simple.

  • 165mm. Next question?

  • 175 on most of my bikes.
    Only had one unclipping incident when my pedal hit a rock when cornering and popped the cleat out.
    That would have happened with a shorter crank though.

  • I don't think ideal crank length depends on whether you ride fixed or free, but on what suits you personally.

    At times in the past, for various reasons, I have used 165, 170 and 175 (naturally, I would say 6 and a half, six and threequarters and seven inch) but I have found that I am only really happy with 170. I prefer to be adaptable and not to be fussy about equipment, but that small difference in crank length seems to affect me quite a bit. However we're not all the same:-

    A club mate, who is generally an excellent mechanic, long ago believed the theory that
    different crank lengths were suitable for different purposes. Over a bank holiday weekend he had entered a time trial and a road race, and being a rider who went in for meticulous bike preparation, he stripped both road and tt bikes, polished everything and re-assembled them.
    He was really 'pinging' that weekend and won both events.

    It was only after he got home he realised that he had muddled the cranks and the 175 TT lefthand crank had got onto the road bike, and the 170 road crank was on the TT bike.

    Since then, he tells me, he hasn't bothered too much about this theory.

  • Haha, excellent!

  • I'm happy with my 170's on the fixed gear, never felt the need to change it

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Fixed gear - what length cranks???

Posted by Avatar for flash @flash