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What kind of performance should I expect from Avid BB7s?
So, I've never ridden disc brakes before, and just bought a bike and had Avid BB7s installed by the shop. I broke them in (rode about 40 miles in 4 days or so, with some intentional stopping thrown in for good measure, way more than the 40 stops that Avid calls for), but they still feel like average-to-bad caliper brakes. I can't lock up the rear wheel on the hoods, for example. I was expecting awesome performance (do a stoppie with two fingers :D), but this is very underwhelming. The shop doesn't seem to really think the performance I'm getting is abnormal. Is this really all I can expect from disc brakes on a road bike? Because, if so, I'll probably just throw some linear pull brakes on there.
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Avid BB7's are rated very highly. You should be stopping on a dime.
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You've got road BB7s designed to work with road levers, I assume? Have you played with the adjusters on each brake? Outer pad should be as close as possible to the rotor with a bigger gap to the inner pad.
I've never locked up a wheel with BB7s nor tried to do that. My experience with BB7s on a hybrid and a couple of recumbents has been positive. The braking is consistent. Doesn't make me any faster........ |
Originally Posted by pkulak
(Post 14128791)
So, I've never ridden disc brakes before, and just bought a bike and had Avid BB7s installed by the shop. I broke them in (rode about 40 miles in 4 days or so, with some intentional stopping thrown in for good measure, way more than the 40 stops that Avid calls for), but they still feel like average-to-bad caliper brakes. I can't lock up the rear wheel on the hoods, for example. I was expecting awesome performance (do a stoppie with two fingers :D), but this is very underwhelming. The shop doesn't seem to really think the performance I'm getting is abnormal. Is this really all I can expect from disc brakes on a road bike? Because, if so, I'll probably just throw some linear pull brakes on there.
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I've heard that the right brake cables make all the difference in the world.
Cheap cables/housings have too much flex and rob the brakes of power. Quality compressionless cable sets transfer all the force to the brakes, resulting in greater stopping power. |
They do take some time to break in and their performance will improve a lot after several days of NORMAL riding. Don't try to break them in by doing aggressive stops in the beginning, you may actually end up glazing the pads. Just ride normally. Also, you may need to re-adjust the cables after they stretch some.
Mine will lock my fat 26x2.0 wheels on dry asphalt. But on my 700c Kona Sutra they didn't seem as powerful indeed. I suspect then that 160mm rotors may underperform on 700c wheel due to larger leverage of the wheel? Too bad most frames are no designed for larger rotors. I'm building up a Surly Disc Trucker with BB7s so I will know soon how they work on 700c wheels. And I assume you had the road version installed on your bike? Or, if not, have linear pull levers? |
40 miles isnt breaking in anything. Discs need at least 200 miles of strong riding in order to be somewhat broken in. I can lock up rear on my road bike with MX4‘s, so if BB7 wont do it, then it is not set up properly or not broken in.
Disc brakes have lower initial bite then v‘s, but braking is more consistent up to the limit when the tire starts to loose traction. V‘s tend to grab quickly and proceed even quicker to lock-up, they are mostly an on/off brake. Discs on the other hand dont have such an initial bite, but they scrub speed down much more quickly then v‘s, because you can balance the braking with them right up to the point where tire almost starts to skid, but not yet - and that is the point of max deceleration, efficient braking that scrubs the most speed in the least time. |
They get better and better. Mine have 2000 miles on them now and they work great.
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Originally Posted by 40SpokeOD
(Post 14129373)
They get better and better.
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Hmm... looks like I am expecting behavior I shouldn't be. Thanks for all the help, guys. I'll just take them as they are now and see what happens after breaking them in for a lot longer.
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Originally Posted by whitecat
(Post 14129308)
40 miles isnt breaking in anything. Discs need at least 200 miles of strong riding in order to be somewhat broken in. I can lock up rear on my road bike with MX4‘s, so if BB7 wont do it, then it is not set up properly or not broken in.
Disc brakes have lower initial bite then v‘s, but braking is more consistent up to the limit when the tire starts to loose traction. V‘s tend to grab quickly and proceed even quicker to lock-up, they are mostly an on/off brake. Discs on the other hand dont have such an initial bite, but they scrub speed down much more quickly then v‘s, because you can balance the braking with them right up to the point where tire almost starts to skid, but not yet - and that is the point of max deceleration, efficient braking that scrubs the most speed in the least time. The rest of your post rates a giant "Huh?" I've never heard anyone refer to v-brakes as 'on/off brakes' nor have I ever experienced any v-brake to be such. I have experienced the on/off effect with discs but not with the BB7s.
Originally Posted by pkulak
(Post 14129731)
Hmm... looks like I am expecting behavior I shouldn't be. Thanks for all the help, guys. I'll just take them as they are now and see what happens after breaking them in for a lot longer.
The BB7s I have, and the ones I had in the past, were well 'broken in' but they really haven't improved any. The sponginess at the lever isn't a function of the pads and the discs bedding together...which is what 'breaking in' does. It's a function of the mechanism from the lever to the caliper. Perhaps compressionless housing would help but that seems a bandaid fix. I don't need to use compressionless cable housing on rim brakes...front or rear...and those brakes seems to work just fine without it. My rear brake follows the same route...with the same housingless sections and only slightly more cable housing from the seattube to the caliper... as my rim brakes did but the rear brake is even more spongy then the front brake is. |
Originally Posted by cyccommute
(Post 14129762)
Pkulak, I think all this 'breaking in' stuff is hokum. What you get out of the long break in period is used to how the brakes work and how to deal with their shortcomings.
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i upgraded my shimano M416 brakes to BB7s (also swapped the rotors!). there wasn't anything wrong with the M416s, as such, but adjusting them and keeping them tuned just right was a PITA (reaching through the wheels with an allen key). when the pads wore down i got the BB7s. the BB7s work just as well (after a few days to break them in) and keeping them adjusted in the sweet-spot is simple and easy.
for me the advantage of the BB7s isn't performance (although they're great), it's the ease of keeping them adjusted just right. |
Originally Posted by pkulak
(Post 14128791)
So, I've never ridden disc brakes before, and just bought a bike and had Avid BB7s installed by the shop. [...] they still feel like average-to-bad caliper brakes. I can't lock up the rear wheel on the hoods, for example.
Are you sure that you have the proper levers set up with your brakes? i.e. if you have the road bb7s, do you have short pull levers? |
BB7s work magnificently. I think they are still, all these years later, the price/performance sweetspot for MTB. Set em and forget em. I have never used em on a 700c wheel though, but your experience (and Cyco's for that matter) sounds strange.
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Originally Posted by SnowJob
(Post 14129925)
Something is wrong. I have a bike that is less than 2 weeks old with BB7 road disc brakes and the stopping power is extreme, even in the rain. The lever pull feels slightly mushy, but is easy for me to get max stopping power just by using one or two fingers. If I'm not careful, I can easily lock the rear tire up during stopping. Right now I've got a set of 32mm t-servs.
Are you sure that you have the proper levers set up with your brakes? i.e. if you have the road bb7s, do you have short pull levers? |
I have mountain BB7s on my Bike Friday, 160 disc 406 wheel, I have to be careful.
too much, front, slow speed, braking, and I get thrown off the saddle, when the bike stops but I don't. ratio of disc and rim diameter makes these a pretty big disc, bigger wheel bigger disc .. a 210? |
Something isn't right. I have BB7s on my mountain bike and they work great. Great since day 1, and still great after a lot of rough off-road miles through mud, streams, sand, you name it. I can lock the wheels on any kind of terrain, whenever I want. And sometimes when I don't...
Since installing the BB7s, I have changed my grip and usually keep only one finger on the levers. If it's a particulary steep or scary descent I'll go with two but that's only for peace of mind. Granted my brakes are the mountain version, but I would think you can get the same performance with the road version. Only complaint I have is that the inner adjustment knob is hard to turn unless I take the wheel off for better access. - John |
BB7s are not difficult to set up...but they are exceptionally sensitive to proper setup. A lot of rim brakes will work great when hastily rigged up "just close enough", which is about what you get from a lot of bike shop employees.
As far as performance; I have BB7s on one of my bikes. In dry weather, they perform exactly the same as the Force calipers on my road bike, or as the Shimano cantis on my crosser. I'm sure there are differences, but without applying quantitative rigor I can't subjectively tell the difference. In wet weather, those BB7s shine. The other brakes noticeably lose effectiveness, while the BB7s work exactly the same, albeit with some squealing on the wet rotors. |
Originally Posted by pkulak
(Post 14129975)
Do you have the road BB7s? My brakes are set up with the stock Sora ST-3400 that were on my bike. I'm not sure what "short pull" means.
I do have road BB7s and they work wonderfully. I haven't got through the "break-in" period, either, but I get excellent response and power. I'm not so mechanically inclined, but the difference between road and mtb BB7s are the amount of cable pull required to get the caliper to close on the rotor. Mtb brakes use a longer cable pull while road brakes use a shorter cable pull. This means that mtb disc brakes can be modulated a bit more while road disc brakes are less subtle. I would recommend taking the bike back to the shop and have them make sure they installed the "road disc" version of the BB7s. Perhaps they put the mtb on by mistake. This would mean that you are using short pull levers (your Sora brifters) with a brake that requires a long cable pull. Alternatively, perhaps they didn't set the brakes up correctly. Here's a video that helped me adjust my brakes: http://youtu.be/NasGJFtgq0A |
Originally Posted by gearheadgeek
(Post 14130066)
Only complaint I have is that the inner adjustment knob is hard to turn unless I take the wheel off for better access.
- John |
Originally Posted by SnowJob
(Post 14130090)
I would recommend taking the bike back to the shop and have them make sure they installed the "road disc" version of the BB7s. Perhaps they put the mtb on by mistake. This would mean that you are using short pull levers (your Sora brifters) with a brake that requires a long cable pull. |
Originally Posted by stdlrf11
(Post 14129196)
I've heard that the right brake cables make all the difference in the world.
Cheap cables/housings have too much flex and rob the brakes of power. Quality compressionless cable sets transfer all the force to the brakes, resulting in greater stopping power. |
Originally Posted by cyccommute
(Post 14129762)
Sorry but any brake should be able to lock up the rear wheel of any bicycle. A coaster brake can lock up the rear wheel of a bike. It's not exactly the gold standard for brake effectiveness.
The rest of your post rates a giant "Huh?" I've never heard anyone refer to v-brakes as 'on/off brakes' nor have I ever experienced any v-brake to be such. I have experienced the on/off effect with discs but not with the BB7s. Pkulak, I think all this 'breaking in' stuff is hokum. What you get out of the long break in period is used to how the brakes work and how to deal with their short comings. The BB7s I have, and the ones I had in the past, were well 'broken in' but they really haven't improved any. The sponginess at the lever isn't a function of the pads and the discs bedding together...which is what 'breaking in' does. It's a function of the mechanism from the lever to the caliper. Perhaps compressionless housing would help but that seems a bandaid fix. I don't need to use compressionless cable housing on rim brakes...front or rear...and those brakes seems to work just fine without it. My rear brake follows the same route...with the same housingless sections and only slightly more cable housing from the seattube to the caliper... as my rim brakes did but the rear brake is even more spongy then the front brake is. I get that you are a die hard for obsolete technology -I can gather as much from your track record -but please dont try to convince me of that by using some twisted logic. It simply wont work. Only real pity here is that you can, and probably will, confuse someone who is searching for good advice. And, judging by the respones of others, wr can see just how ineffective discs really are. Go figure. |
Mine work great. I have the road BB7's with Sram Apex levers. My only complaint is they have howled and squeeled since day 1. No matter what I have tried. My LBS is going to look into it soon for me.
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