Say Wha??? Bolts Don't Fit on BB7's...
06-11-07, 02:57 AM
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Say Wha??? Bolts Don't Fit on BB7's...
A few weeks ago I installed an Avid BB7 disk brake on the front of my bike without any problems...Now I decided to do the rear. I got the brake only to discover that the bolts for holding the caliper are not the same size as the hole in the frame! The hole is too large so they cannot be threaded in and the hole cannot be drilled. I have a Gary Fisher Tassajara btw...but what is up with this? Am I going to have to find some longer bolts and fasten them down with a nut?
06-11-07, 03:57 AM
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No, a larger diameter bolt that fits the frame threading is the 'proper' way to do the job.
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06-11-07, 05:19 AM
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You need the proper IS disc adapter. The brakes don't mount direct to the frame - there is a part that goes between. Most brakes will come with the proper adapter for whatever rotor size, IS or post mount, and front or rear. you order it with or specify. Some you order the brake and the adapter separately. Either you don't have one, or it's missing, or it's the wrong size/format.
The vast majority of newer frames (yes, with a few exceptions) are 51mm IS mount. The bolts that go for the frame/mount don't actually thread into the frame. They go through the hole in the frame, then thread into the adapter. The caliper then bolts to the adapter...
You need a post mount to 51mm IS rear Avid (or hayes -yes, it'll work) adapter for whichever diameter rotor you have. Either 160, 185, or 203mm. Or 165mm if it's an older Avid BB7 caliper.
Read the instructions. Get the right parts. Go to work. If still confused, take it to a shop.
The vast majority of newer frames (yes, with a few exceptions) are 51mm IS mount. The bolts that go for the frame/mount don't actually thread into the frame. They go through the hole in the frame, then thread into the adapter. The caliper then bolts to the adapter...
You need a post mount to 51mm IS rear Avid (or hayes -yes, it'll work) adapter for whichever diameter rotor you have. Either 160, 185, or 203mm. Or 165mm if it's an older Avid BB7 caliper.
Read the instructions. Get the right parts. Go to work. If still confused, take it to a shop.
