Help with single speed magic gear?

[Brother]

Anyone have an idea how this works or could help explain/simplify?

I have a need to run my bike with SS but wanted know what the magic gear ratio was?
Already seen Harris Cycles but couldn't make out details of obtaining magic gear. Anyone good on this topic?

 

[kaiser]

http://eehouse.org/fixin/formfmu.php


try having a go with this.

 

[Brother]

i see, that figures. so with a 40t 13t ratio,
it would work on a 420mm chain stay. magic gear.

thank-you kaiser

 

[kaiser]

Ideally you measure your chainstay length, input it into the box and and ratios within the blue band should be 'magic' its all done with formula though so real world might be slightly different.

 

[Brother]

Thanks

Is that Axel to BB center? I would think so.

 

[kaiser]

yes

 

[FMJ]

http://eehouse.org/fixin/formfmu.php


try having a go with this.