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PostPosted: Tue Nov 13, 2012 1:00 pm 
Gold Trader
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I hope someone running avid BB7 mechanical discs can help me out... I have an early model avid mechanical disc caliper, which I finally fitted to my 2012 rebas the other day. The inside part is very close to the spokes though, only 1 or 2mm away - is this normal?

I need to move the caliper even further in, to stop the fixed pad rubbing on the disc, which will mean it almost touches the spokes - too close for comfort, I think.

As I said, this is an early model and I'm not sure it has the same dimensions, or is even designed for a post mount fitting. or maybe it's a rear caliper? I'd like to get it working if possible, but if I can't get it sorted then I'll have to buy a new caliper...

Can anyone with a BB7 front caliper measure the distance from the slot for the disc to the inner most part of the caliper (the part nearest the spokes)?

thanks!


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PostPosted: Tue Nov 13, 2012 3:22 pm 
Old School Grand Master
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Location: Fircombe.
Pics would help...
Are you sure it's a BB7 and not a BB5?
BB7s have an adjuster knob for each pad. BB5s only have one outer one.
If the inner adjuster "piston" is adjusted too far out then the caliper will be closer to the wheel. A couple of mm to the spokes sounds pretty normal though.


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PostPosted: Tue Nov 13, 2012 3:35 pm 
Gold Trader
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well I'm not sure what it is, as it doesn't have a model number. It does have pad adjustment on each side though. Even with the pads adjusted all the way out, they still seem very close to the disc (and rub slightly, as the disc isn't 100% straight), and closing the lever all the way by hand doesn't seem to provide enough stopping power...

I have it mounted to the fork without the adaptor you can see in the pic - just mounted directly to the post mounts. Any history on the different disc brake mounting systems would be useful too!

I took the lever assembly apart the other day, to remove the rubber seal which was cracked and broken. I did want to pull the whole thing apart, but it looks like it's been painted after being put together, as there's no definite separation line between the two halves. I might just give it a go though - not a lot to lose if it's not really working anyway!

I'll head to the LBS tomorrow and check out the disc brakes there, see how much clearance they have. This is the first one I've ever had, so I have no experience to go on!

pic below...

cheers, Andy


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PostPosted: Tue Nov 13, 2012 11:48 pm 
Gold Trader / PoTM Winner / RB Rider
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Postmount wasnt very common when those brakes were made .

you might need a post mount adaptor to space them out a bit better .

I run bb7 with older Rebas , IS , and they are very close to the spokes .


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PostPosted: Tue Nov 13, 2012 11:54 pm 
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Thanks for the info. This one bolted straight to my rebas, without the adaptor shown in the pic. There is some side to side adjustment, but not a lot. I'll get it set up with a cable and see how it works...


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PostPosted: Wed Nov 14, 2012 10:28 pm 
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update: so I fitted the caliper following the avid instructions (more or less like this: fit rotor, fit caliper without fully tightening bolts, adjust both pads so they clamp the rotor firmly, tighten mounting bolts, adjust pads to allow rotor to turn) When I moved the pads out to allow the rotor to turn, I spun the wheel and there was still some rubbing. Squeezed the brake lever to see if anything happened, and it did... :shock:

The actuation arm came flying off, the bolt, spring and adjustment dial are now in a dark corner of the garage somewhere, and I'm left thinking I should never have bothered :(

it's probably my fault for thinking I had the bolt correctly tightened when I obviously didn't... :oops:

Anyone got a new or VGC avid BB7 mountain caliper that they want to offload, before I go out and buy a new set? :lol:


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PostPosted: Sun Nov 18, 2012 1:43 am 
Devout Dirtbag

Joined: Fri Oct 14, 2011 3:54 pm
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Location: Denmark (Vejen)
This is the distance on my bike, around 15mm.

Pictures are not the best, taken in the night and with the cell phone, better can come if you want :-)
Image
Image
Image


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PostPosted: Sun Nov 18, 2012 10:32 am 
Gold Trader / MacRetro rider
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foz wrote:
Anyone got a new or VGC avid BB7 mountain caliper that they want to offload, before I go out and buy a new set? :lol:


Doctor S has a set for sale which seeing as he doesn't come here no more you can get here.


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PostPosted: Mon Nov 19, 2012 7:50 pm 
Gold Trader
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thanks for the help - I've registered on fatbike but still haven't received confirmation... any idea if he still has them? year? price?

thanks!


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PostPosted: Tue Nov 20, 2012 8:47 pm 
Gold Trader / MacRetro rider
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Location: Riding my Woodsie.
foz wrote:
thanks for the help - I've registered on fatbike but still haven't received confirmation... any idea if he still has them? year? price?

thanks!


Doc on ukfatbikes wrote:
Pr Avid BB7 mechanical discs everything you need, calipers, mounts, 160mm rotors, cables, Avid FR-5 levers. BRAND NEWreduced to £70


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