Poprad Disc - Weak Brakes - Fixes?

[twangston73]

I bought a used Poprad Disc a while ago and really enjoy it, but the featured attraction (the disc brakes) don't seem to have the stopping power I'd expect. (They generally won't lock up on pavement) It has the original 105 brifters and BB7 setup and my LBS shop guy has tried adjusting everything to little avail. He suggests that a more modern Ultegra or 105 brifter might pull more cable and provide better results. Any thoughts on the brifter upgrade or other solutions would be much appreciated.

[Admiral Ackbar]

compression less housing is a worthwhile investment for mech discs

could try some new pads too

[gavingould]

New pads, and try Yokozuna housing. a buddy just put some of that on his mech disc bike and it helped a lot.

[Don49]

I had BB7's on a Titus mtn bike and could lock up either wheel on pavement very easily. I would try replacing the pads or breaking the glaze on your pads with crocus cloth or fine sandpaper. If the pads aren't broken in correctly they will glaze and never develop full stopping power.

[oldpotatoe]

I bought a used Poprad Disc a while ago and really enjoy it, but the featured attraction (the disc brakes) don't seem to have the stopping power I'd expect. (They generally won't lock up on pavement) It has the original 105 brifters and BB7 setup and my LBS shop guy has tried adjusting everything to little avail. He suggests that a more modern Ultegra or 105 brifter might pull more cable and provide better results. Any thoughts on the brifter upgrade or other solutions would be much appreciated.

Sure they aren't 'MTB" version of BB7? Not sure that makes any difference..maybe try EBC pads?

http://ebcbrakes.com/product/ebc-brakes-green/

[christian]

New pads, compression-less housing, but I always found BB7s to be pretty dreadful, tbh.

[David Tollefson]

Sure they aren't 'MTB" version of BB7?

That was my thought as well. Even with compressionless housing, if you're pairing MTB discs with road levers, stopping power will be less-than-inspiring.

[4Rings6Stars]

Assuming BB7 road calipers...then I would guess the housing / cable routing is to blame.

I am using BB7 road calipers on my commuter (mated to Chorus 10 ergos) and am using full length housing but just standard jagwire. They lock up on command...but only if I want them to. They modulate very well. My only complaint is the occasional howl.

[Mark McM]

That was my thought as well. Even with compressionless housing, if you're pairing MTB discs with road levers, stopping power will be less-than-inspiring.

This is very unlikely to be the problem. The MTB versions of cable disc brakes have higher leverage, so if anything, you'd get excessive braking force if you mixed road levers with MTB calipers.

I'd go with the recommendation of replacing the pads. Pad performance can degrade due to a number of factors including glazing and contamination with grease or oil.

[twangston73]

Wow! Many thanks for the insights! I have some things to buy and try!!

[David Tollefson]

This is very unlikely to be the problem. The MTB versions of cable disc brakes have higher leverage, so if anything, you'd get excessive braking force if you mixed road levers with MTB calipers.


The issue is that you'll never get the pads to the rotor (with any appreciable force) because the cable pull is much less on road levers.

[Neil]

^Exactly this.

I had BB7 with Force levers, I could set it up in the stand so that the pads didn't drag on the rotor yet you had full clamping force before the lever hit the bars.

However, that state of perfection typically wouldn't last a commute.

This was with compressionless housing cut with a dremel so that the cuts were dead straight.

I ended up using a Problem Solvers travel agent, it reduced overall clamping force but meant that the pads could stand far enough off the rotor not to drag yet still provide decent clamping before the lever hit the bars.

I switched from that setup to MTB BB7 and Tektro linear pull levers (Retroshift units) and that works perfectly- better than the Hope V-Twin that I had through one winter.

In summary: Road BB7 don't work with road levers, in my experience- not for long, anyway.

[christian]

BB7s don't work at all unless they go scrtch-scrtch-scrtch the whole time. Apparently this is part of their charm. Like the hydro-SRAM turkey warble.

I have Shimano brakes now. (On my mtb, road is obviously Campagnolo)

[d_douglas]

I dunno about all this BB7 bashing - if set up correctly, they are very effective. I use them on three bikes and ironically my fancy ti bike has the worst setup. My everyday commuter is mated to TRP levers and the setup is great - I can lock the brakes up and skid on a dime if required.

I look forward to hydro brakes for my road bikes, but until Campy makes them, I will keep using BB7s. The recommendations above are correct - compression less housing all the way!!

[Neil]

This worked, but the kludge aspect of it annoyed me:

https://lh5.googleusercontent.com/-ZwLLISNDZZw/To4KKJfZ2fI/AAAAAAAABkw/fDqge9ZUAjw/w440-h587-no/IMG_20111006_210455.jpg

[dhalbrook]

^Exactly this.
In summary: Road BB7 don't work with road levers, in my experience- not for long, anyway.

Yeah, my BBy Roads with SCR-5s drove me nuts as they were always rubbing. I think my next road disc caliper will be TRP Spyres simply for this reason.... or something else where both pads move.

[4Rings6Stars]

I set my BB7 road calipers up with factory pads and have commuted on them for ~1800-2,000 miles with out a single issue, zero rub, and they stop on a dime...

I think we have some hack mechanics on this forum!

[twangston73]

Thanks all! The variety of experience is interesting. I have BB7s on another bike and they have worked without incident or complaint for several years. On an unrelated note the most trouble I have ever had with a drivetrain was with a campy record 10 setup, while SRAM setups have been problem free. As they say, your experience may vary!

[Neil]

This is where I ended up:

http://farm4.staticflickr.com/3723/9211364600_5740b0b7a8_b.jpg

But this did work (just not as well):

http://farm9.staticflickr.com/8349/8184591474_904a4cc54f_b.jpg

(Same bike)

To answer the hack mechanic charge - ner ner ni ner ner.