Magic Gear Tips for Single Speed?


Naturist Smurf
I know my chainstay length, and want to use this calculator

How much slack do I need to allow for the slight eccentricity that always seems to be present in chain rings and sprockets? Would a calculation showing my chainstays are 1.5mm too short be ok? I don't want it to bind and wreck the wheel or BB bearings. How long can I expect it to last off-road before the chain wears and ruins my magic gear?


Ride It Like You Stole It!
South Manchester
You'll know if the chain is too tight, it will make a grumbling noise. You want just enough slack to move the chain up and down by an inch or so. You'll need a very slight amount of slack, enough to slightly move the cranks without the wheel moving.

You will feel a tight chain as soon as you start to pedal.


Active Member
Suffolk UK
Assuming your magic gear calculation is correct you can get away with a chain stay about 1mm shorter. Don't forget to use a new chain.

Old Plodder

Living at the top of a steep 2 mile climb
For a single speed, as against a fixed, you should have about half an inch of slack in your chain, any more & it may jump off.
Chain stretch will be dependent on how & where you ride, but if it stretches an eigth of an inch over a 12 inch section, it needs replacing.
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