Hey guys

I've been puzzling over this and I need some advice. I did a fixed conversion on an old Brian Rourke racer (circa some time round 1990 I guess, with 126mm rear spacing). I'm running a 16t cog on a 120mm dura ace hub with a 42t chain ring. The chain ring is mounted on the inside of the spindle.

The problem is that the chainline clearly isnt straight - the chain ring sits further from the centre of the frame than the cog. Its gotta be 5mm or even more. The problem is that the teeth of the chain ring are only a couple of mm from the chainstay - so it doesnt seem as if moving the chain ring in is an option ... which I guess means that, in order to get a straight chainline, the rear cog has gotta move out?

My question is then - what options do I have to achieve that?

Do I have to have the rear wheel redished (I'd prefer not to have to do that)? Or are there other options I'm not considering?

Would I be better off with a 126mm hub (I saw that Phil Wood makes one)?

Any advice greatfully received.

Thanks, Simon

first guess is that when you squeezed your frame down you did it assymetrically.
check that 1st and re squeeze.

what size chainring are you using?

if you're out by 5mm and a shorter BB (giving the correct chainline) means the ring hits the chainstay then yes, you need to use up some of the dropout width, and you'll probably need to redish too by the sounds of it, 5mm is quite a lot..

you need to get the sprocket outward, and the only way to do this and keep the rim central is red-dish

TBH, most road frames with 126 don't have too many problems, it seems odd, unless you've got flared stays and a 52 tooth chainring

Could you please post some photos looking down the chain from the hub and the cranks plus a photo of your chain ring clearance.

but tommy, there's no challenge then

It seems strange that a road frame can not take a 42 chain ring at a 42 mm chain line.

:)

Thanks for the replies fellas. I've come home and fiddled a bit more and I dont think the problem was as bad as first thought. I busted out the tape measure and the figures dont lie. Chainline appears to be approx 41mm front and back.

Think the problem was (a) my chain was a bit tight, (b) i squeezed the frame down a bit assymetrically and (c) my eyes.

Hopefully a chain clean/lube should take care of the remainder of the noise.

Thanks, Simon