Bb5 Vs Bb7

[RossMcd]

Heyy!

Im going to be buying a new front brake tomorrow and I want to know what the advantages and disadvantages of each are?

ideally im looking for bite and power. Modulation is nothing desired. I want to be able to pull it and know it will lock.

And the last thing is... how would i set either to make it light at the lever? I know it would be to do with spring tension. the cable will probably have to be clean to am i right?

Some guidance please

[Miles Mallinson]

Obviously the bb7 has better performance but I prefere the bb5 as its alot simpler, the bb7 uses the same pads as some of avids hydraulic brakes and I find the pad holders are abit fidderly, the bb5 is proberly more robust aswell because it has less adjustments to go wrong. But thats just me.

[rupintart]

Don't even consider a bb5.

As far as light at the lever, you set the lever so there is the most leverage at the lever and to where the pads are dialed to where they're pushed out. The action on a BB7 isn't heavy to begin with, so the lever action will be light even if you don't have the pads pressed in.

[Miles Mallinson]

I never had any problem with my bb5.

[J.KYDD]

I never had any problem with my bb5.

I have never had a problem with either of my BB7's.

BB7 is noticeably better than a BB5. More power and tonnes more bite. And, more adjustment is never a bad thing

[Ali C]

I had a bb5 once and it was possibly the most powerful brake I have had. I have just put one on the front of my natural bike too.

To make them pull easier, there is a grub screw on the activating arm on the caliper that adjusts the spring tension.

[Matt Burrows]

I had a bb5 once and it was possibly the most powerful brake I have had.

I have felt a couple of BB5s that were awesome. I guess people just assume because they are cheaper and the pads are small they won't be as good. All the guys saying they are rubbish obviously haven't used both.

[davey1991]

Obviously the bb7 has better performance but I prefere the bb5 as its alot simpler, the bb7 uses the same pads as some of avids hydraulic brakes and I find the pad holders are abit fidderly, the bb5 is proberly more robust aswell because it has less adjustments to go wrong. But thats just me.

Don't even consider a bb5.

As far as light at the lever, you set the lever so there is the most leverage at the lever and to where the pads are dialed to where they're pushed out. The action on a BB7 isn't heavy to begin with, so the lever action will be light even if you don't have the pads pressed in.

I agree with Milo, apart from the performance part.

Rupintart saying don't concider a BB5 is completely stupid, i acctually prefer BB5's, the smaller pads have a smaller area so they apply more pressure to the area of the disk they are on, this is better for trials than big pads that apply less pressure, especially if you want disks that will bite and hold like a HS33

[bikeperson45]

I find the BB7 has more bite and locks the wheel more easily and the BB5 has more modulation

Edit: Although I have an SD7 lever for the BB7 and the BB5 has the other Avid one (the standard one) so that'll make a difference

Edited December 27, 2010 by bikeperson45

[rupintart]

I agree with Milo, apart from the performance part.

Rupintart saying don't concider a BB5 is completely stupid, i acctually prefer BB5's, the smaller pads have a smaller area so they apply more pressure to the area of the disk they are on, this is better for trials than big pads that apply less pressure, especially if you want disks that will bite and hold like a HS33

COMPLETELY off base with the smaller pad more pressure. The pressure is completely reliant on the force the caliper exudes, it has NOTHING to do with the brake pad or stopping ability in that regard.

If you apply a 100lb force on the brake lever with the mechanical advantage/leverage of the lever say at x4, the force at the master cylinder will be 400lb. So let's say the master piston has an area of 1sqin so you have a pressure of 400lb/sqin. That pressure is then transferred down the hoses in (an enclosed system).

So now at the slave cylinder you have a pressure of 400lb/sqin, if the piston has an area of say 4sqin then you have a total force of 1600lb.

That force is then transferred to the back of the pad and as the back of the pad is not part of the hydraulic system, the force is applied simply as a force. If the pad has an area on the disc of say 8sqin then divide the force by the area to get pressure, so the pressure is 200lb/sqin.

8 x 200 = 1600

But even if you reduce the area of the pad on the disc to 4sqin the total force of the system will still be at 1600lb, so the pressure will be 400lb/sqin. (use simple algebra, again, dividing the force by the area to get pressure)

4 x 400 = 1600

So no loss involved as total force of the system is still at 1600 regardless. Pad size is only relevant for heat dissipation, i.e. a brake pad the size of a pencil eraser would stop a just as well as a brake pad the size currently in the caliper given nothing fails or melts from heat with the same force being exerted behind the pad. Being a mechanical engineering student helps.

As for the BB5 vs BB7, I have ran both and the only way I would run a BB5 is if the caliper were sold to me SEPARATELY at an amazing deal or given to me. Why? Because why would I buy a BB5, then buy an adapter, and then have to buy a new rotor because roundagons suck ass? If I have to go and do all this extra nonsense buying, why wouldn't I just buy a brake that has more adjust-ability and can already come with a good rotor and the adapter? Setting up a BB5 because of the lack of adjust-ability is a PITA on frame/fork were the brake tabs are far from perfect. I've never really noticed a difference in braking ability with the same pads (compound/brand) and rotor size, so that part is negligible I guess. I also haven't had a ton of riding exposure behind a BB5 because I never had the desire or need to. THAT is my reasoning behind not buying a BB5.

Edited December 27, 2010 by rupintart

[Ryan Trott]

.

Edited May 7, 2011 by Ryan Trott

[Rob Leech]

I thought the main difference was being able to adjust both pads on the BB7?

Have had my BB7 for about 4 years now, never changed the pads or rotor and it's awesome.

Would personally pay a bit more for the BB7, much easier to set up properly, no messing around with spacers trying to get the distance of the inside pad right .

Cheers,

Josh.

[Ali C]

just been out in the snow and bedded in my bb5, I have it combined with a 200mm saint rotor I had (alloy arms) and its pretty dam good! it's a LOT better than my 180 mono trials on my other bike. I must admit I only got the bb5 because Tarty didn't have the bb7 in, power wise I think they are about the same, but the bb7 is obviously more adjustable (though I think the bb5 is stiffer and stronger).

[Greetings]

The BB5 is a superb brake. Nothing comes close in terms of power, it's a simple design, easy to adjust... what more could you ask for? I had a BB7 a long time ago and it was also very good. Not worth a penny more than the BB5 though which is why I'd choose the 5 over a 7 any day.

[bikeperson45]

Is there any truth in the rumour about the newer models being a lot worse than the previous model?

[Kieran Morrison]

Is there any truth in the rumour about the newer models being a lot worse than the previous model?

Yeah the caliper on the new bb7 flex's way more than the old one.

[LukasMcNeal]

Kieran have you used both? It's not way more. It flexes but it's still an outstanding brake! I have a 160mm BB7 and having the dual pad adjustability really helps. Don't let the flex put you off!

[Kieran Morrison]

Kieran have you used both? It's not way more. It flexes but it's still an outstanding brake! I have a 160mm BB7 and having the dual pad adjustability really helps. Don't let the flex put you off!

I didn't say the bb5 flex'sworse, i meant the bb7's newer model flexs more.

And yes, I have used the bb5 + the bb7

[LukasMcNeal]

I said ment have you used an old BB7 and a new one?

[davey1991]

just been out in the snow and bedded in my bb5, I have it combined with a 200mm saint rotor I had (alloy arms) and its pretty dam good! it's a LOT better than my 180 mono trials on my other bike. I must admit I only got the bb5 because Tarty didn't have the bb7 in, power wise I think they are about the same, but the bb7 is obviously more adjustable (though I think the bb5 is stiffer and stronger).

This this this and not just because he's Ali f**king C, why does everyone assume price relates to performance!

The BB5's i've had will always be my first choice of brake.

Rupintart, i'm going from what i was told by my mechanics trainer, the smaller pads in a mechanical system apply more pressure to that area, the larger pads spread the pressure allowing for more modulation.

I may be wrong and it seems like you know what your talking about but that seemed to make sense to me at the time.

[rupintart]

This this this and not just because he's Ali f**king C, why does everyone assume price relates to performance!

The BB5's i've had will always be my first choice of brake.

Rupintart, i'm going from what i was told by my mechanics trainer, the smaller pads in a mechanical system apply more pressure to that area, the larger pads spread the pressure allowing for more modulation.

I may be wrong and it seems like you know what your talking about but that seemed to make sense to me at the time.

Logic would tell you otherwise, but mathematics and physics don't lie. The surface area dissipates the heat, but the the caliper can only exert what it can and the maximum amount of force is being pressed into the rotor. The performance can only be increased by increasing the friction coefficient, i.e. brake pad compound. A bigger pad will do nothing but make for lower braking temps and more even wear of the braking area (a large wear path vs a small wear path).

Easiest way to wrap your head around this is think of an object like an empty beer bottle sliding across a table. Take a beer bottle that's full, and it will not slide as far because there is more force being applied between the coaster and the table. The surface area is the same, but the there's more force being applied (full beer bottle) so it will not travel as far.

Edited December 28, 2010 by rupintart

[eskimo]

Someone answer this for me?

Question:

Getting +20mm mount fork. The Trialtech ones in 26". I have a BB7 from the rear with a 185mm rotor. So what adapter do i need?

This one?

[edit]

It says BB5 which i'm not familiar with. Okay for a BB7 ?

Ta very much.

Edited December 28, 2010 by eskimo

[TrialsMan Dan]

My front brake: BB7 caliper, 180mm rotor, slic cable well lubed, SD7 lever. Perfect. I was origianly just using this brake while i save up for a hydraulic but no need to BB7 is the best cable pull disc brake ive ever used, when set up square and true with a good quality cable and lever its just a really light pull and bang instant lock and bite with good hold too! Reccommended!

[rupintart]

Someone answer this for me?

Ta very much.

Nice thread jack. Yes.

[bella]

bb7 every day

Logic would tell you otherwise, but mathematics and physics don't lie. The surface area dissipates the heat, but the the caliper can only exert what it can and the maximum amount of force is being pressed into the rotor. The performance can only be increased by increasing the friction coefficient, i.e. brake pad compound. A bigger pad will do nothing but make for lower braking temps and more even wear of the braking area (a large wear path vs a small wear path).

bigger pad does mean better brakeing if the same force is applied to it