[tlm]

Hi Everyone,

First post, long time reader.

Putting on some shiny Avid Ultimates on the IF Planet Cross.

When trying to set the tension on the springs, I cannot get it to hold tension and allow the caliper to move. When I apply torque to the fixing bolt at the right tension, the bolt tightens and also causes the caliper to lose all ability to freely move.

It appears to be binding on the boss, not sure why???

If you have experienced this on installing the Ultimates or any other caliper, please help!

Previous set of brakes were the IRD Cafam that presented no issues.

thanks in advance!

 

[skepticman]

Some people with Moots frames were having issues. They had to machine the brakes to remove some material.

http://www.moots.com/index.php/forum/viewthread/1467/

 

[MarvinK]

I have a Trek X0 and had to do the same thing. Lame.

 

[tlm]

Thanks for that link to the Moots thread. It explains exactly what I'm seeing.

I helped a buddy of mine install some Ultimates on his rig and ran into a problem with the inside diameter of the inner shoulder that goes over the end of the bosses. Had file away to get the calipers to clear. Fortunately, we didn't run into a problem of the length bosses.

 

[vwvoodoo]

...Same problem on a Gunnar Crosshairs and Edge forks and many other canti studs. Apparently there isn't a standard length on canti studs - when we went through our stock of random studs at the shop, we found about 3mm of variation - the Ultimates require a very precise stud length and shaving material off the brake isn't always a solution as the spring will bind if you take too much off. When we called SRAM they didn't recognize any issue with it, but something will have to be done if it they don't work with the most common high-end fork of the season (Edge). SRAM, are you listening? Any thoughts? We haven't had this issue with any other canti brake - the fact that the body of the brake is also the pivoting bushing (as opposed to having a separate bushing that's longer than the stud) is the issue here. They need to be made shorter and then small shim washers included to accommodate stud length variation.

 

[tlm]

Update: Rears on! Fronts tomorrow

After doing a little more digging around, I found a posting on Weight Weenies about an older Shimano Canti Stud spec change that occurred in 2008.

http://weightweenies.starbike.com/forum/viewtopic.php?f=4&t=76052&start=0

I had the original canti studs from my '97 IF and slapped them on the rears and voila, the Avids now installed in a snap, just as they should have in the first place.

Now gotta find some friendly canti-studs for the Alpha Q CX fork...

So close!

 

[Big Baby Jesus]

...Same problem on a Gunnar Crosshairs and Edge forks and many other canti studs. Apparently there isn't a standard length on canti studs - when we went through our stock of random studs at the shop, we found about 3mm of variation - the Ultimates require a very precise stud length and shaving material off the brake isn't always a solution as the spring will bind if you take too much off. When we called SRAM they didn't recognize any issue with it, but something will have to be done if it they don't work with the most common high-end fork of the season (Edge). SRAM, are you listening? Any thoughts? We haven't had this issue with any other canti brake - the fact that the body of the brake is also the pivoting bushing (as opposed to having a separate bushing that's longer than the stud) is the issue here. They need to be made shorter and then small shim washers included to accommodate stud length variation.

Exactly! I went through the same process and was surprised to see such variations in stud lengths. When I mounted the ultimates to my bike I started with the fronts and they went on smoothly, but the backs gave me a hard time because the stud length was too short. New studs and now it is all sorted. Definitely not the brakes though, maybe Avid should include studs.

 

[vwvoodoo]

Problem is there is a huge variety of stud thread size and pitch for different frame materials and brands. We counted 5 varieties in our parts bin. I would prefer that Avid provide the materials to work with the selection of studs out in the market. The fact that modern bikes aren't following the new '08 Shimano standard (as described above) means that it hasn't been adopted industry-wide, and/or they're still working through old stock.
BTW, they worked fine on my Ridley.

 

[avalnch33]

mine did the same thing, and i called sram warranty. they are aware of the problem and are going to release a second version of the ultimates that won't bind up on the rear. what is happening is that there are 2 standards of canti stud, and sram made their mounting plates a little too thick. file it down by about 1-2mm and it works fine and doesn't bottom out.

 

[tlm]

Ultimates on now, finally

Well after mucking with the front for about an hour, the brakes are on.

Had to remove the bosses and take off the spring mount that is slid on behind the end of the boss. This is a Alpha Q CX fork. The newer Alpha Q CX20 has an integrated spring mount so if you have the newer CX20 or a fork that either has no spring mount or an integrated one, you should have clearance. I know the CX20 has no issues with the Ultimates. Of course, there was a reference above that the super cool Edge (now ENVE) forks have issues.

Should have taken pics, but was anxious to get it all put together.

Braking is strong and the lever feel is very good. Took a bit of time, more time than necessary, but glad it went together without resorting to milling, lathes, sanding, filing or hacking the brakes to get them to work.

I can take pics of any of the components since now everything works and is easily removed and installed...

 

[reptilezs]

yup filed a set of brakes that were binding up on a custom seven frame