Slapped a 1×10 on this vintage Cannondale, is this level of chain bend normal or can I do something to help it?
by Foxcookies
Slapped a 1×10 on this vintage Cannondale, is this level of chain bend normal or can I do something to help it?
by Foxcookies
7 Comments
I’m surprised it even stays on with that much bend.
You need to better straighten the chain line out. Either the chainring moves inboard on crank or the BB moves in, if possible.
Narrowide chainring may help too.
Edited for clarity
Yes that chain line is way outta wack.
You need a different BB, probably a 107 or 109. Depends on your cranks, those look inset so you want the narrowest spindle possible.
After that, making sure your cassette is max spaced helps.
And after that, an offset -3 chainring.
Keep an eye on where the chain ring wants to hit the stays. It looks like you’ve got enough room to move everything to the left by several millimeters.
I think the better indicator is to put the chain on the middle cog. That primary line should be straight. Dial that in and you get the extremes—biggest or littlest—sharing the lateral bend on the chain.
You need to either get a shorter bottom bracket to move the cranks in, or a chainring that is offset towards the frame, or most likely both.
You can’t just slap 1x whatever onto a bike that was designed for 2 or 3 chainrings and have it work.
Slapped it on you say?
Remove your crank and measure your bottom bracket spindle. Buy a new one that has a 6-8mm shorter spindle. Make sure you buy a BSA 73mm shell bottom bracket with a JIS square taper.