Aargh! Chainring touching the chainstay!

[My_Teenage_Self]

how far is the none drive side out and what bottom bracket is it.
You could drop to a 44 or 46 outer if you are up at 48 say.

Right, It's a Hope Ti BB. The non drive side crank arm is around 7-8mm from the chainstay, as I shifted the BB to the drive side a little to se if it would help. With the BB centred, there's 9-10mm each side.

I will say the 50mm chainline was there for fat tubes, 73mm shells and often would be using the widest band size front mech.

Aye, 73mm shell, 34.9 front mech (and the seat tube narrows to that!). The chainstays are actually 20mm wide, which surprised me - seems pretty wide?

Brilliant links, thanks Guys.

 

[gibbleking]

i have a campy 128 on mine as the front ring on thye mavic is huge....i have to turn the bottem bracket round today as its fitted the wrong way round and the front mech catches the swingarm and wont drop to the bottem ring

 

[Anthony]

Right, It's a Hope Ti BB. The non drive side crank arm is around 7-8mm from the chainstay, as I shifted the BB to the drive side a little to se if it would help. With the BB centred, there's 9-10mm each side.

You need a chainline of 50mm, 45 is no good for any bike. As it's a Hope bb, you can simply adjust it until it's 50mm and provided you still have sufficient clearance on the non-drive side you should be fine.

It has nothing to do with chainring sizes - the frame was designed for standard drive and 50mm chainline.

 

[We_are_Stevo]

Trek still went over to compact drive Deore LX-C the following year, which would suggest that the frame was designed for the compact drive but fitted with the standard on a longer spindle until the compact was released??

http://vintage-trek.com/images/trek/94/Trek94.pdf

Surely the middle ring should line up with the middle of the block to get the optimum chain run on the big/granny rings?? Looking at the photo's at the top of the thread that's not going to happen...

 

[FluffyChicken]

Trek still went over to compact drive Deore LX-C the following year, which would suggest that the frame was designed for the compact drive but fitted with the standard on a longer spindle until the compact was released??

http://vintage-trek.com/images/trek/94/Trek94.pdf

Surely the middle ring should line up with the middle of the block to get the optimum chain run on the big/granny rings?? Looking at the photo's at the top of the thread that's not going to happen...

It was just designed for MicroDrive, that settles it
Shimano just paid them off and they had to bodge it.

 

[Anthony]

Trek still went over to compact drive Deore LX-C the following year, which would suggest that the frame was designed for the compact drive but fitted with the standard on a longer spindle until the compact was released??

http://vintage-trek.com/images/trek/94/Trek94.pdf

Surely the middle ring should line up with the middle of the block to get the optimum chain run on the big/granny rings?? Looking at the photo's at the top of the thread that's not going to happen...

No, the chain line has to be 50mm and that's so that the front mech will work properly.

Nobody is going to bring out a bike that doesn't work with current components, even if different components are due to come out the following year.

 

[legrandefromage]

without this descending into a technical slanging match, old cranks, wide stays, equals wide axles whether you want it or not.

 

[We_are_Stevo]

I'd still rather believe the evidence of my own eyes from the middle photo

 

[bm0p700f]

I hope you find the BB you are after. There are several new options still.

 

[Anthony]

I'd still rather believe the evidence of my own eyes from the middle photo

His problem is that he has an untenable 45mm chainline - a CD ring wouldn't make much difference to that, it would still be far too close. If he had a 50mm chainline, there would be no problem.

XTR stayed on standard drive until 2003. According to you, Trek designed a frame that couldn't have XTR fitted to it with a standard chainline?