Disc Brake upgrade


May 12, 2014, 09:53 AM

I'm thinking about upgrading the brakes on my 09 GT avalanche 2.0. They are the stock tektro disc brakes. I was thinking about some avid BB7's and was wondering if I should also upgrade the rotor to the one in the kit, or if it would be ok to save some money and just replace the caliper. Its about a $30 difference for each wheel to have the rotor.

Thanks Guys

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XXX

May 12, 2014, 07:22 PM

I'm not a mechanic by any means - so grain of salt here... in my experience, you'll need to at least rough up the old rotors with coarse sandpaper and clean them with alcohol before installing the new calipers. This will help the pads/rotors 'break in' together and you'll have less squealing...

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XXX

May 13, 2014, 09:33 AM

I'm not a mechanic by any means - so grain of salt here... in my experience, you'll need to at least rough up the old rotors with coarse sandpaper and clean them with alcohol before installing the new calipers. This will help the pads/rotors 'break in' together and you'll have less squealing...

I'm also not a mechanic, but sanding them sounds weird to me. I think the OP would be okay just leaving the stock rotors as is.

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Bmoha7311
Specialized Jeremy

May 13, 2014, 12:11 PM

I see no problem with upgrading. As long as the wear on the old rotors isn't too severe. Not all calipers bolt up exactly the same so you need to pay close attention to where the new pads fall on the rotor.

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XXX

May 13, 2014, 12:21 PM

In my experience, mismatched rotors and calipers tend to play just fine together. I got my first full brakeset with all components bearing the same name this year and it does feel nice. In my opinion, I don't think you'd see any benefit switching from one mechanical brakeset to another. You could save your pennies and find a deal on eBay for a set of hydraulic brakes which provide much more noticeable benefits.
As for sanding pads, lots of mechanics and some manufacturers will recommend doing this. Just use fine sandpaper, make sure to sand flat, and wipe clean with isopropyl alcohol.

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XXX

May 13, 2014, 02:19 PM

Sounds good I will probably do that then. The reason I was thinking the BB7's is because the set I have are not very good at all and they rub no matter how you adjust them. I figured it would be better to get nice mechanical brakes like the bb7's than a cheap set of hydraulics, which would probably be about all I could afford.

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XXX

May 13, 2014, 03:29 PM

If your mechanical set is rubbing it might not be the quality of the caliper. The issue is probably a warped rotor, dirty pads, or bad alignment of the caliper. I would first back out the pads and give the rotor some more space (if your caliper has this adjustment) then loosen the caliper mounting bolts slightly, grip the brake lever and re-tighten the mounting bolts at the same time. You could also check how true your rotors are by spinning the wheel and watching for wobble inside the caliper.

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XXX
Bmoha7311
Specialized Jeremy

May 13, 2014, 06:18 PM

I agree. Upgrade to hydraulic. Improve brake performance. Check for warped rotors.

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XXX

May 14, 2014, 10:50 AM

Caliper alignment is what gets me most of the time and I find it to always be a little tricky to get right. It's easy enough to get the pads to not touch the rotor but if the pads are not exactly parallel to the rotor then the brakes will feel weak unless you set the pads so close that rubbing is an issue.  The best way I've found to get the alignment right is to:

- Make sure the wheel is aligned properly in the dropouts and the skewer is as tight as you normally ride it.
- Get into a position where you can look through the caliper and see the gaps between the pads and the rotor.
- Put something nice and bright, a well lit white sheet of paper works well, on the opposite side of the caliper to make the gaps really easy to see. That is key to getting this right.

- Loosen the caliper bolts just enough that the caliper can be moved easily by hand, not so loose that it's jiggling around, just enough to be shifted in all dimensions.
- Now shift the caliper around until you can see that the pads are parallel to the rotor and then tighten the bolts.
- Spin the wheel slowly and see if the rotor is warped, if it is then use a monkey wrench to true it up with some gentle bending, it's easy enough to do by hand as well.
- Once you have the caliper aligned pretty well you may find the gaps between the pad and the rotor is pretty wide now so adjust them closer and repeat the alignment process if necessary.

I used to use the loosen bolts, squeeze brakes, tighten bolts method but found that being a bit more careful using the process above makes a huge difference in getting rid of rub and improving braking force.

Also, BB7's are great when they are setup right, you can't really beat them for the balance between cost/performance/durability.


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TheMayor1
Trail Steward - CamRock
Trail Steward
608-772-7833

May 14, 2014, 11:23 AM

Rich, great information on the set up.
Also, I run XT's on the 29 full Susser, and BB7's on the fatty. Gotta say the difference I have found in performance is pretty negligible. The price difference is definitely steep.


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~ Chuck Hutchens


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Bmoha7311
Specialized Jeremy

May 14, 2014, 04:22 PM

Great description of the process adjusting disc brake calipers Rich! I too have moved away from trying to adjust with the brake lever.
I'm 275#. Cable mechanical disc brakes do not stop me. Hydraulic do.

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XXX
Bmoha7311
Specialized Jeremy

May 14, 2014, 04:25 PM

I have seen sales on Shimano disc brakes thru JensenUSA and other places for surprising prices. I think I paid $149 per front or back for XTR.

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Bmoha7311
Specialized Jeremy

May 14, 2014, 04:29 PM

And even Shimano SLX hydraulic have very good performance. You don't have to go for XT or XTR.

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