Changing from BB5s to BB7s?

[Globalti]

New CX bike came with AVID BB5 disc brakes and 160mm rotor front and 140mm rear.

Apparently the BB7 is a much better brake so I'm thinking of buying a pair of these and selling the BB5s unused on Ebay. With CRC selling BB7s for £55 the change will hardly cost me much at all.

The BB7s come with a 160mm rotor. Presumably the BB5s that are fitted to the bike are attached with special mounting brackets, which accommodate the two disc sizes? Presumably therefore it will be a simple matter of unbolt - bolt on the new calipers?

Thanks!

 

[PK99]

New CX bike came with AVID BB5 disc brakes and 160mm rotor front and 140mm rear.

Apparently the BB7 is a much better brake so I'm thinking of buying a pair of these and selling the BB5s unused on Ebay. With CRC selling BB7s for £55 the change will hardly cost me much at all.

The BB7s come with a 160mm rotor. Presumably the BB5s that are fitted to the bike are attached with special mounting brackets, which accommodate the two disc sizes? Presumably therefore it will be a simple matter of unbolt - bolt on the new calipers?

Thanks!

I'm interested in exactly the same question re the CX bike i'm about to buy.

Which bike did you get?

 

[Globalti]

Tricross Elite disc. here: https://www.cyclechat.net/

 

[PK99]

Tricross Elite disc. here: http://www.cyclechat...oss-elite-disc/

Ahha! Same bike too! i had a test ride on one the other day - the BB5/7 issue was the only downside. i'm surprised that specialized scrimped on that

 

[henshaw11]

Re. the mount bracket - yes, I bought some a while back and there was a second bracket included, to cover both front and rear mounting.

 

[steve52]

i have bb5 and have no probs with em there better than rim breakes so can see the point of changing? what am i missing?

 

[Globalti]

Well the BB5 only operates from one side so the static pad needs adjusting inwards from time to time to compensate for wear. The adjuster is awkward apparently and needs a special tool. The BB7 pads are actuated both sides though I'm not quite sure how as I'm not familiar with this brake. Generally people say the 7 is a better brake than the 5 so as PK99 writes, it's surprising that Specialized scrimped on this. You'd have thought they would put 5s on the Sport and 7s on the Elite.

PS: Something I've just discovered: the black calipers are different from the silver ones; they have different pull ratios so black is for MTB brakes and silver for road. A pity as I'd have preferred black but then I have just found one on CRC in silver with slight cosmetic damage to the mounting bracket, for a big discount.

 

[byegad]

They simply unbolt from the nearest set of bolts to the calliper. I used the same rotors that were on the bike and the whole thing took less than 20 minutes.

 

[byegad]

Set up is similar for both, but adjustment is far easier and because the pads on the BB7s are bigger they are lighter to operate for a given braking effect.

 

[Globalti]

Thanks! Anybody want a pair of unused road BB5s?

 

[potsy]

Thanks! Anybody want a pair of unused road BB5s?

Free?
Decided to stick with the BB5's on mine, can always upgrade in future if I'm not happy with them.
Just need to find a decent place for buying replacement pads now, £12ish a pair and they apparently don't last very long

 

[andrew_s]

http://www.discobrakes.com/

Pad life will depend where you ride.

 

[Globalti]

So far I've only done 75 miles on the CX bike and the pads are nowhere near worn in; they still squeal like hell until you use them hard. The explanation seems to be that they are still only sweeping part of the disc, some of the disc is still virgin metal, untouched. I have reset them twice following demonstrations I've seen on Youtube but they are still not parallel to the discs, which I'm sure explains the squealing. As the bike is used mostly on tarmac and not in the same wet muddy abrasive conditions as a mountain bike I reckon they are going to take a long time to bed in and stop squealing.

Anybody got any suggestions? The hydraulic Hope minis I've had for years on my mountain bike were never this noisy.

 

[potsy]

I've done 76 miles on mine and the front one does squeal (don't need a bell)
I have read you should do some deliberately heavy braking a few times to speed up the bedding in process, maybe find a hill or two if you have any where you are

 

[byegad]

Mine, I have them on two trikes, don't squeal unless there's a little there is damp in the air, or water on the discs. They took about 50 miles to bed in and I don't use the brakes much at all and never, well almost never, ride off road. I'd suggest you need to look at the set up, the disc rotor size is either right or wrong, it's all about washers and set up to get all of the pad onto the discs, one of mine sweeps the dead centre of the disc leaving an unswept area of the disc above and below the polished braking surface, the other is a bit high but all of the pad does hit the disc leaving a broad unswept area toward the centre of the disc and a very narrow band outside the polished area. .