no drop outs?

ok i have bought a frame and it is a modern alimunium frame with no drop-outs… i have seen it done where by using 1/2 link chain and a certain ratio
my Q’s are

  1. how do i calculate the ratio?
  2. do i have to use a rounded ratio eg. 65, 70 etc etc.

Maybe save yourself the trouble and get a tensioner:

forgot about that option… does it affect running brakeless? eg hard to skid

Wouldn’t recomend a chain tensioner for fixed, try hunt down an eccentric rear hub, white industries make a good one

I’ve never used one. But yes I imagine it would be a bit sketchy brakeless. But, honestly, I would be wary of riding brakeless on these sorts of dropouts full stop.

Tensioner & fixed is not an option. Brakeless or not.

As soon as you backpedal you’ll lose chain tension.

Your options are:

Eccentric hub
Eccentric BB
Magic ratio (dropout length / ring & sprocket combo
New frame
Not fixed.


My friend has an aluminium Formigli with vertical drop outs he’s managed to get the correct chain tension with the chain ring / sprocket combo. He is just using a KMC chain. I think. He also rides brakeless. It’s been like this for the last 9 or so months with no problems.