Help MK2 QR20 Bombers and Hope C2 Brakes

[Rob H]

Simple problem; IS brake mount plus IS calliper equals a gap:



Any ideas what's up? I've lost track of the number of bikes I've built over the years and I've never seen anything like this, I'm guessing I need a spacer and they're no longer available? Anyone got on going spare?

For those that are interested here's the entire bike:



EDIT: Fixed photo links

 

[old_coyote_pedaller]

Re:

I've built several bikes with IS calipers/discs, mostly Hope, and most of them have required spacers/shims between caliper and mount on frame and/or forks both Lefty on my Cannondales and conventional on my wife and daughters' Marins. Sometimes just washers plus thin shims to line up caliper or I've made spacers out of flat aluminium plate the required thickness. Cut out the number you need in rough round shape then drill hole in middle, mounting bolt sized, mount on long bolt with nut, stick in electric drill then file down till round. Obviously you can buy SS washers the right size and disc caliper shims in various thicknesses off Ebay.
If there was no space between caliper and mounts you wouldn't be able to fine tune the fit of caliper and disc, in both directions from frame/fork mounts.

 

[Rob H]

Re:

I've normally had small gaps in the past that's needed a couple of shims but this one is going to take a dozen for each bolt.

 

[jimo746]

Re:

Look for some spacers and/or shims.
Things that may work... brake caliper/brake booster spacers, chainring bolt spacers, seat bolt spacers?
Maybe try the Avid mounting kit with concave/convex spacers to allow caliper adjustment.

 

[old_coyote_pedaller]

Re: Re:

I've normally had small gaps in the past that's needed a couple of shims but this one is going to take a dozen for each bolt.

Just checked my Cannondale F800, the rear caliper, a Hope Original M4, has a 6.5mm gap between caliper and mounts on frame. It needed 6mm spacers I made plus a couple of thin caliper shims for each bolt to line it up. The front caliper, again an Original M4, fitted to a 2000 Lefty has 2 normal washers plus 2 thin caliper shims per bolt. I know it's a pain having to do this but it would be worse if there was no tolerance at all. As Jimo says try to find Post Mount spacers, caliper shims,

caliper shims
http://www.chainreactioncycles.com/hope ... rp-prod356

Hayes washers
http://www.chainreactioncycles.com/haye ... -prod20174

Avid mount kit
http://www.chainreactioncycles.com/avid ... -prod21475

or make your own like I did.