New Avid BB7s

[kleinhead]

Just installed a new set of 2008 Avid BB7s and took it out yesterday for the first ride. I rode about 10 miles. I adjusted lever throw, inboard and outboard distances and spring rate and things worked great in the workshop. But when under real loads, the braking was not impressive. I know that the brakes need time to bed, but how long?

Also, anyone compared the 2007s versus the 2008s? My understanding is that they went to a 2-piece design for 2008 - any chance the performace has really suffered?

Thanks,
Tom

[rciracing]

Takes some time. I'd say about 30 hard brakes/stops.

[CRAIG2]

Other than the obvious advantages over rim brakes, I was not overly impressed with mechanical discs, either. I think that if you're really looking for a huge improvement over cable actuated / rim brakes, you really should consider hydros. I'm sure others will disagree, but that's my opinion.

[jabberwocky]

They take a while. If you want to bed them quickly, go to a parking lot and do some real hard stops (get some speed, put your weight all the way back and grab the brakes hard. Repeat several times.)

If they still lack power, its possible the pads are contaminated. You didn't accidentally drip chain lube on the rotor or anything, did you?

[allencb]

I switched from BB5s to BB7s recently and noticed less than ideal braking as well. The BB5s stopped great, but lacked the adjustments of the BB7, so I "upgraded". I think the reason for the difference is that the BB5 uses organic pads and the BB7 comes with semi-metallic. I've been tempted to get organic pads for the BB7 and see what happens. I've read that semi-metallic pads last longer, but I was getting a solid year out of my BB5 organic pads, which were smaller than the BB7's pads.

That said, I get good performance with the BB7 when cold, but by the end of the ride, they're not stopping as well. The BB5 would maintain performance.

Chris

[eloach]

IMO, you need a break in period of about 20 hours to marry the pads to the rotors. This is also true for hydros, but they take a little less time. During the break in period you may need to adjust the breaks again due to cable stretch and other issues.

Mechs will not stop like hydros and will get hot on long DH sections faster than hydros. Avids are the best mechs I know of.

Make sure your levers are the same distance from the bar that they were before the switch. I find that if the lever is too close to the bar I have less power because my large hands do not squeeze as strongly with a smaller travel distance as they do when the levers are an adequate distance from the bar..

[eloach]

I switched from BB5s to BB7s recently and noticed less than ideal braking as well. The BB5s stopped great, but lacked the adjustments of the BB7, so I "upgraded". I think the reason for the difference is that the BB5 uses organic pads and the BB7 comes with semi-metallic. I've been tempted to get organic pads for the BB7 and see what happens. I've read that semi-metallic pads last longer, but I was getting a solid year out of my BB5 organic pads, which were smaller than the BB7's pads.

That said, I get good performance with the BB7 when cold, but by the end of the ride, they're not stopping as well. The BB5 would maintain performance.

Chris

See if this continues in the summer. I have condensation issues sometimes in the winter with the semi-metallic pads but then they are fine in the summer.

[philman]

The break in period is pretty key. What I've done is go for a short ride on the C&O and brake hard 20 times or so from a good speed. Makes you look like an idiot but gets the job done. If you take a look at your pads now and they are glazed you can refresh them by sanding them them on emery paper laid on a hard flat surface.

Pat

[philvw]

Also look at your cable pull adjustments, assuming you have them on your lever. If you came from V's, they probably are set for max cable pull length so pads dont rub when the wheel tweaks, etc. Get pull point closer to the bar, you pull less cable (but you dont need it with BB7's, but it gives you better power and better modulation. Leverage BABY!

[kleinhead]

Thanks for the comments. I installed Avid speed dial Ti levers and new cables along with the new brakes, so I'll try various adjustments to see if it improves. As I said, I really played with them in the shop and thought that I had things dialed in well. But sounds like I may just need to ride them a few more times.

[BikerMiker]

If you've ridden them already as much as you say, I would suggest that the install went poorly along the way.

Mech discs have less power and are harder to set up than hydraulics in my experience. Have somebody with experience take a look at them. I think one of the pads is too far away from the rotor.

mike

[rmac]

jamisdude - where do you ride? I ask because I could take a look but I'm in n.balto county. I"ve got bb7s (06) on my fool susp & found that I was adjusting them every few rides because I like my pads in tight & centered. You should be close to or as good as V brake feel after first ride, so if your not getting that maybe something is off. You do need to look at adjustment after that first ride. Re-center & dial in the pads. With new pads & new rotors you can keep pads pretty tight to rotor so fine tune, ride parking lot braking hard 10 times & long 10 times, and fine tune again. I've got hydros on the rigid & those have been set once & go, but the mechs brake well once set, just more maintenance - has been my experience.

[jabberwocky]

I'm in Reston and I'd be willing to take a look at it for you if you want. I used to run BB7s, so I have a passing familiarity with setting them up.

[kevin29r]

Jamisdude,

Here is a detailed video by Avid addressing BB7 setup and adjustment.

http://youtube.com/watch?v=x1kezXQVnLY

I would recommend verifying that you have set them up per Avid's procedure. There are a number of key points in the video such as caliper orientation, screw torques, and proper centering of the pads. If you have verified the setup and are still having problems, clean the rotors with a safe solvent such as isopropyl rubbing alcohol, and test again.

Hopefully, this will improve the braking performance. Best of luck.

[CRAIG2]

jamisdude - where do you ride? I ask because I could take a look but I'm in n.balto county. I"ve got bb7s (06) on my fool susp & found that I was adjusting them every few rides because I like my pads in tight & centered. You should be close to or as good as V brake feel after first ride, so if your not getting that maybe something is off. You do need to look at adjustment after that first ride. Re-center & dial in the pads. With new pads & new rotors you can keep pads pretty tight to rotor so fine tune, ride parking lot braking hard 10 times & long 10 times, and fine tune again. I've got hydros on the rigid & those have been set once & go, but the mechs brake well once set, just more maintenance - has been my experience.


Excellent point, and another advantage of hydros. Mechanicals are definitely affected by cable tension, of course, or the lack thereof, and like any other cables, they stretch with use. So, the braking 'feel' from ride to ride may not always feel consistent. I like consistent, at least with mountain biking - I like to know precisely how my bike is going to handle.

[rockhead]

Another thing to consider is how much cable housing you have in line. Most housing compresses under braking pressure so minimizing the amount you use is a good idea. On one of my bikes there are only cable holders, not stops, under the top tube, so I went with Full Metal Jackets and used as much of the rigid tubing as a I could. Made a big difference with the BB7s over another bike that I have set up using standard housing over the same distance.

That said, I'm working on switching to hydros to improve even more.

[mtbmore]

Mech discs have less power and are harder to set up than hydraulics in my experience.
mike


that is because you are a bike wrench God. For us mere mortals BB7s are a dream to setup and run without fail. When they get a little soft I turn the red knob a bit and am good to go.

Scud

[DaveG]

that is because you are a bike wrench God. For us mere mortals BB7s are a dream to setup and run without fail. When they get a little soft I turn the red knob a bit and am good to go.

Scud


I concur. The BB7's are dead simple to set up. No fluids, no bleed kits necessary. Tweak the red dial every once in a while.

The strongest set of brakes I've ever used were BB7's as well; 8 inch rotors I think. Way to little modulation for me though.

[chowderbutt]

I find the bb7s rock and are easy to set up for us mortals. I have older versions newer versions and hydro versions of avid disks. I also tried other brands My favorites are the older bb7's

I have noticed the newer bb7's seem to work as well when broken in but the finish on the whole thing is just a grade or two below what it used to be. knobs are cheaper and harder to adjust. finish is sloppier, but the cost is less so go avid, I mean Sram!!!

[CountZero]

The inboard pad is in a fixed position.

In operation, the outboard, non-fixed pad deforms the disc such that it contacts the inboard, fixed pad.

For the brakes to develop full stopping force, the inboard pad must be positioned as close to the disc as possible.

[jabberwocky]

BB7s have some drawbacks, but in my experience lack of power is not one of them. I would say that either jamisdudes brakes aren't properly bedded in yet or there is a problem with the setup.

[toonces]

I just upgraded from V brakes to the 2008 BB7 brakes and Speed Dial 7 levers on my Fisher hard tail and the only issue was the initial squealing until they had broken in on the first ride. They are a huge improvement over the V brakes, but like others have said, not a strong as hydraulics. I went with the Jagwire Ripcord Cable Kit (http://www.jagwireusa.com/en/diykits.html) which uses a compressionless housing that covers the entire rear cable run. I also used the Youtube video Kevin29r mentioned to help with the install and finally got to use the in-lb torque wrench I had picked up from Sears a few years ago.

One thing I had a hard time visualizing how to set was the recommended 2/3 outer to 1/3 inner gap between the pads and the rotor. I ended up dialing in the inner pad until there was only 1/3 of the available room visible for the outer pad. Then I tightened up the outer pad firm to the rotor, torqued the caliper attachment screws and attached the cable. After that tightened up the little bit of cable slack there was at the brake lever and backed off each pad about 4 clicks and that was it. The inner pad adjustment was pretty hard turn initially.

Since you're using Speed Dial levers, you should also be sure that the adjuster barrel is set half way through the available range of travel when installing the cable. This way you will be able to adjust for softer or firmer lever action. I actually backed mine off a little for softer action or more modulation.

[macdaid]

Jamisdude,

I'll second Jab's offer, I'm also in Reston (just in case you come away from your visit with him with half of your soul missing...:D). Seriously, Jab is, despite his appetite, is the MORE Reston go-to for bike tech tips....

Regarding the BB7; I came to them from V-Brakes which I never liked because they're such a pain to set up and keep adjusted. Mushy performance too. From V's to disk, there is no comparison. I'm sure hydros are buttery and powerful and all that, but you can't beat the BB7 for ease of set-up, adjustment, and maintenance for the price.

Good luck, and let me know if I can be of assistance.

Dave



I'm in Reston and I'd be willing to take a look at it for you if you want. I used to run BB7s, so I have a passing familiarity with setting them up.

[kevin29r]

The inboard pad is in a fixed position.

In operation, the outboard, non-fixed pad deforms the disc such that it contacts the inboard, fixed pad.

For the brakes to develop full stopping force, the inboard pad must be positioned as close to the disc as possible.

Ditto. That's how mine are adjusted. I get an occasional squeak, but they stop very well.

[blacknell]

fwiw, I've found it a real b)(*@# to keep these things well adjusted. But when I've gotten it dialed, I've been thrilled with it. V-brakes just can't compare.

[kleinhead]

Thanks to all for the replies. I'll check out the video. They were very easy to install. I read a ton about discs before settling on the BB7s because of their ease of use and power over Vs. I think it's a matter of use and tweaking and I should have it.

If things aren't better after the next ride, I'll come knocking on doors for help.:p