Genesis Day One chain line question

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  • I'm setting up my day one.

    Was hoping to run my SRAM gxp chainset.
    Chain line looks to be 42mm

    At the rear the stock hub is 135. I have a dished surly fixed cog which gives (135/2=67.5mm. 67.5mm-23mm=44.5

    Is 2.5mm difference acceptable or should I be switching cranks to get it closer?

    This is going to be fixed gear off road.

  • I reckon it’ll work but be a bit noisy.

  • Thanks that's what I'd thought. It's a track chaonset, think a road crank would be better as I'd have more options

  • I guess the cog arrived safe and sound?

  • Yes! Arrived and fitted thankyou!

  • I remember I had spacers between my (track) crankset and chainring when I was running a Day One fixed.

    Think I bodged some out of large washers but velosolo and the like sell proper ones.

  • Thanks @M_V !
    Not an option unfortunately. My Sram cranks only allow the chainring to be mounted on the inside. I need to push the chainring out further. Can’t adjust the bb so I think I’ll source another Sram chainset to match the levers.

  • Worth riding and seeing what it’s like, I had chainline out by 2mm on a steel frame and could barely notice - same on aluminium frame and whole bike vibrated like a chainsaw.

  • Thanks @TM I really appreciate your advice.

  • If you're running a 3/32 chainring and sprocket, you can use a 3/32 chain designed for use with a derailleur which will be more tolerant of running at an angle.

  • Can you move some axle spacers about to shift the hub across towards the non drive side?

  • @cupcakes @Alexnharvey thanks

    I think I've found the answer. This is all new to me I've never set up chainline before.

    I'm running a 3/32 setup. Surly dished rear cog, surly ring and tester approved wipperman chain.

    With the dished surly hub flipped closest to the spokes and a road double chainset with the cajonringnon the outside I should be at around 45mm front and back give or take 0.5mm.

    Im not sure how these come set up as stock as without the dished cog, if I wanted to run single speed for example, then the rear chainline would be about 52mm which seems nuts. I guess they use a wide square taper BB but the q factor must be huge. I'd be tempted to cold set the rear down to something with more options in future if I change setup.

  • Another option is a Shimano hub converted to bolt on sprocket on the disc mount, as sold/promoted by velo solo. Built without dish it gives a chainline which matches a road double outer. With the standard dish for a disc front wheel it gives a chainline of 41 which can be spaced out to match a track crank or a road double inner.

  • That's a really good shout @cupcakes I'd forgotten about those.

  • No probs. They're good, it's a setup I ran on the pomp for a while and will have on my upcoming fat tyre fixed.

  • Second top recommendation is the spa cycles cranks. Seem decent, plenty chainring options available e.g. velosolo, adjustable chainline as they're square taper.

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Genesis Day One chain line question

Posted by Avatar for sacredhart @sacredhart