What size front mech for an On-One Inbred 29er?

hubba

Ok shimano is the choice of manufacture yet i have been a little slow and not looked into it a lot when i purchased the frame.

i have a on one inbred 29'er frame and apparently i checked with on one it has a front mech size of 29.8mm..

my lack of knoledge means i have no idea what to fit on here as i can only find 28.6, 31.4 and 33.6 sizes, do i get larger and put a shim in somewhere or buy smaller and have a gap with longer bolts ??

any help apreciated with this one...

andrewjoseph

I'd go bigger with shims. smaller may put pressure points on the frame from the front edges of the clamp.

cooldad

Have you checked with On One by phone, or just checked the website? If I was a gambler I'd bet it's really 28.6 and the site is wrong. They've just used the seatclamp size.

hubba

yes i checked with on one by phone and customer service tech team, they ahve stated that the seat tube is the same size and it's not reduced at all hence the size matches the seat diameter for seat clamp..

so it' looks like i need to get a 31.6 front shimano mech and shim it up then is my only option.

cooldad

So what do On One do if they build a bike up?

davewalsh

All Inbreds are 28.6 front mech clamp, as clearly stated on thier website:
http://www.on-one.co.uk/i/q/FROO29VD/on ... al_dropout
AFAIK, all shimano front mechs are 34.9 clamp and come with a 31.8 or 28.6 shim, which you should be able to specify when you buy.

cooldad

davewalsh wrote:

All Inbreds are 28.6 front mech clamp, as clearly stated on thier website:
http://www.on-one.co.uk/i/q/FROO29VD/on ... al_dropout

This makes sense - no one is going to build frames for a mech size that doesn't exist. I'd check again - I reckon the customer service person is wrong. Or find someone with a mech that size and check it.
Or the simplest thing - just measure it.
viewtopic.php?f=40073&t=12726337

essexboyupnorth

Just bought a Shimano M510 Band Adapter (28.6mm) 28.6 Black from Wiggle for this very frame to scale down a SRAM 31.8 clamp, might work, might not.

http://www.wiggle.co.uk/shimano-m510-band-adapter-286mm/

davewalsh

I hate to say this but it probably won't, as it'll be for spacing a shimano mech from 34.9 to 28.6, and will come with all the lugs to snap it in place in a shimano mech. You may be able to bodge something by filing the lugs off. Alternatively, return it and buy this:
http://www.chainreactioncycles.com/Mode ... elID=11803

essexboyupnorth

davewalsh wrote:

I hate to say this but it probably won't, as it'll be for spacing a shimano mech from 34.9 to 28.6, and will come with all the lugs to snap it in place in a shimano mech. You may be able to bodge something by filing the lugs off. Alternatively, return it and buy this:
http://www.chainreactioncycles.com/Mode ... elID=11803

You were right Dave, it's an old style front mech and doesn't have the jubilee style fixing.

Decided to buy a new 2012 X9 31.8 high clamp front mech and the the shim mentioned in the post above. CRC doesn't mention any compatibilty issues but it didn't fit, clamp would not do up around the shim. I don't know whether I should have bought the 34.9 front mech but what has worked is using half the original Shimano shim I bought, so the front mech is on.

Update: I thought a low clamp X9 front mech might offer better clearnce so I ordered one. The additional bulk at the rear of this device hit the 2.35 tyres (I know they're a bit big but I got a mountain to climb) but I think you'd still be struggling with 2.2.

The bottom line is when it comes to SRAM X9 and the 18" Inbred frame you need to go 31.8 high clamp with half a Shimano shim. A 34.9 high clamp would probably work with SRAM shim but I can't be bothered to order another front derailleur.