Setting the correct chainline - SS

GT-Steve · Aug 20, 2012

Cheers fellas,

The frame doesn't have horiz dropouts, and I'm gonna attempt without a tensioner as well. :shock: I owned a cannondale SS before (but didn't personally build it) and this was the same set-up without any problems of the chain jumping off, even when I was bouncing around at max cadence..

danson67 · Aug 20, 2012

You might be able to get away without a tensioner

Have a look at the Fix Me Up calculator first.

All the best,

suburbanreuben · Aug 20, 2012

A velosolo spacer kit is your chainline friend!

sic_nick · Aug 21, 2012

Check out post #7 for a very neat way to get your chainline spot on:

http://forums.mtbr.com/singlespeed/why-does-happen-736137.html#post8417452

danson67 · Aug 21, 2012

That's a smart method...like it

Just make sure of the rear hub/dropout width and halve it for the length of the 'skewer' indicator.
Should be OK if it's a MTB cassette conversion, but dedicated singlespeed hubs can be different.
It's not always 135mm, could be 120, 126, 130 or 135mm, or even bigger these days. :twisted:

All the best,

JamesM · Aug 21, 2012

sic_nick":3bm2ihhj said:
Check out post #7 for a very neat way to get your chainline spot on:

http://forums.mtbr.com/singlespeed/why-does-happen-736137.html#post8417452

JamesM":3bm2ihhj said:
measure from the centre of the seat tube to the teeth on the chainring and then make sure the rear sprocket is the same distance from the centre of the hub.

danson67 · Aug 22, 2012

measure from the centre of the seat tube to the teeth on the chainring and then make sure the rear sprocket is the same distance from the centre of the hub.

True, James, it is the same thing really, but it's not easy to find the centre of the hubshell, or to measure from it avoiding the flanges and spokes. The method above is extra smart as it uses only one measurement and the dropout face as a fixed and firm reference.

I still prefer a bit of maths, or a straightedge myself

All the best,

Woz · Aug 22, 2012

I measure the front chain line by putting an engineers metal ruler pushed next to the seat-tube over the chain ring, read it off then add half of the seat-tube diameter. It's more precise and less fiddly as you don't need to guess where is the center of the seat-tube.

Then take the above number, subtract it from half of the rear axle OLN distance and you have the required rear matching chain-line measured from the center of rear sprocket to the RH axle / inside drop-out.

Taller sprocket teeth are far more important than a chain line within +/- 1mm.

oldave · Aug 22, 2012

Don't some folk like to make life difficult! A straight edge really does do the job!

JamesM · Aug 23, 2012

If you have a straight edge long enough!!!

Setting the correct chainline - SS

GT-Steve

danson67

suburbanreuben

Old School Grand Master

sic_nick

Senior Retro Guru

danson67

JamesM

Senior Retro Guru

danson67

Woz

Old School Grand Master

oldave

JamesM

Senior Retro Guru

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