The Disc Brake Naughty Corner Thread

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Manc33
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Re: The Disc Brake Naughty Corner Thread

Postby Manc33 » 21 Apr 2016, 3:18pm

reohn2 wrote:I can't speak for hydraulic discs,but the Avid BB7's provide far better braking in all conditions than any other type of brake I've used,and are an absolute doddle set up and maintain which is minimal, and by far easier and less trouble than rim brakes.


Have you used Dura Ace 7800/7900/9000 calipers?

I had 7800's with Kool-Stop "salmon" pads and they were more powerful than my BB7's are now.

On the 7800's I could risk entering corners faster (not even racing, it is an instinct you acquire when using those brakes!) but on the BB7's I wouldn't dare ride like I used to on those Dura Ace calipers.

Maybe its the stock pads I got with the BB7's and there's softer pads out there but I would rather get more life out of them, they are powerful enough, but not like the 7800's were.

There's too many variables but I would stick to discs now, I am sure a good hydraulic disc brake beats the best rim brakes, but then you're stuck with hydraulic and the chance of it leaking.

You can't have it all.

You can have powerful brakes and a risk it might leak (hydraulic disc).

You can have powerful brakes and brake pads wearing out your rims (high end road calipers).

You can have reasonably powerful brakes that don't wear rims out and won't leak (mechanical disc where it has to be the BB7 because nothing else compares).

All I care about is wearing out expensive parts (like decent rims that are going to be £50 a pop to replace when that eventually happens) and it working properly all the time. With both rim brakes and hydraulic disc brakes you have those problems of rim wear and it leaking... so to me only mechanical disc makes sense for long term usage and ease of use.
Only weird bikes are interesting anymore.

reohn2
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Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 21 Apr 2016, 9:30pm

Manc33 wrote:Have you used Dura Ace 7800/7900/9000 calipers?

No.
The last DP's I had were RX100,which were pretty good,but suffered slightly with modulation at slow speeds,and notice needed to be given in the wet,they were greatly improved with BBB Techstop pads.
I've used Koolstops and most other recommended pads over the years,non better the BBB Techstops for DP's and Tristops for V's and canti's.

I had 7800's with Kool-Stop "salmon" pads and they were more powerful than my BB7's are now.

Braking is this simple,more squeeze more brake if that's infinitely variable with one or two fingers on the lever(from hoods or drops),that's good modulation.When the wheel locks up then the brake is too powerful.I can lock up either wheel with BB7's with two finger on the lever(drops or flats),you can't better than that and modulation is great.If that same effect is available in wet and filthy weather it's the ultimate stopper.
BB7's are good enough to tick all those boxes and leave me without a need to look for any better brake :D

On the 7800's I could risk entering corners faster (not even racing, it is an instinct you acquire when using those brakes!) but on the BB7's I wouldn't dare ride like I used to on those Dura Ace calipers.

This I don't understand :?
Brakes never come into the equation on entering corners fast,brakes are used before the bend or not at all.

Maybe its the stock pads I got with the BB7's and there's softer pads out there but I would rather get more life out of them, they are powerful enough, but not like the 7800's were.

The stock pads with BB7's are sintered which are harder than organics,I've not found sintered pads to have any problems stopping and they last longer too :)

......to me only mechanical disc makes sense for long term usage and ease of use.

That's my conclusion too.
BB7's do everything I require of them ie;stop PDQ with superb modulation,in all weathers.Totally dependable,easy to maintain(I can strip a calliper down service it and rebuild in half an hour),pads last and last,and don't cost the earth to replace,and only need minimal attention.
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Stevek76
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Re: The Disc Brake Naughty Corner Thread

Postby Stevek76 » 21 Apr 2016, 10:45pm

reohn2 wrote:The stock pads with BB7's are sintered which are harder than organics,I've not found sintered pads to have any problems stopping and they last longer too :)


Stock pad does vary based on the variant of bb7. The road sl ones come with the alu backed organic pads. Ime these aren't very good. Initial feel/power is reasonable but they fade pretty badly under any serious effort. They do last fairly well and run quietly, even in the wet but longer steep descents were not fun.

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 22 Apr 2016, 12:16pm

Stevek76 wrote:
reohn2 wrote:The stock pads with BB7's are sintered which are harder than organics,I've not found sintered pads to have any problems stopping and they last longer too :)


Stock pad does vary based on the variant of bb7. The road sl ones come with the alu backed organic pads. Ime these aren't very good. Initial feel/power is reasonable but they fade pretty badly under any serious effort. They do last fairly well and run quietly, even in the wet but longer steep descents were not fun.


In the past four years I've bought four pair of BB7's two road and two MTN,all came with sintered.
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jb
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Location: Clitheroe

Re: The Disc Brake Naughty Corner Thread

Postby jb » 22 Apr 2016, 6:15pm

Brucey wrote:in the case of brakes with DOT fluid, even if the system is 'sealed' water from the atmosphere will diffuse into the system and contaminate it, whether you use the bike or not.

There is always water hanging around the seals in bikes that are used, and the system sees negative pressure every time the pistons retract. Brake piston seals only seal properly when they are under positive pressure; that is how they are designed to work. The rest of the time they seal rather badly and can let all kinds of rubbish past.

Seals wear, too, and if you don't change the fluid the debris compromises the system integrity.

Trust me, brake fluids of all types do get contaminated in service, and should be renewed at regular intervals.

Ignore this fact at your peril.

cheers

edited for typo

I don't dispute what you say, but having spent a good few hours on what should have been the ubiquitous 10 minute job changing fluid in some avid juicy or some such with all the proper kit I would say it is not a job for the faint hearted. Removing all the tiniest air bubbles without introducing more was quite the Challenge. It's not one of those jobs that if your not mechanically minded your better off leaving well alone, and if the bike isn't used a huge amount probably will be ok for quite a number of years.
Cheers
J Bro

mattsccm
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Joined: 28 Nov 2009, 9:44pm

Re: The Disc Brake Naughty Corner Thread

Postby mattsccm » 22 Apr 2016, 8:48pm

I fail to see the practical objections to hydros. Millions of MTBs prove they work. Of course they go wrong but so does the SA hubs. I have 5 set of hydro discs working. Haven't done anything except the pads and a clean ever on 4 sets and the 5th has just had a bleed after 9 years. The oldest set is 12 years old. Sure I have broken all the rules of maintenance but so what? They work. My Vauxhaul Chevette van did 140 thousand miles with nothing but an oil top up. The chassis rotted first. My point is that the objections are mostly based on theory not practicality and where real examples are given they are few and far between but vociferously voiced. No one ever say how well something works, just how bad it can be.

The cable discs on my gravel bike are in a different league to the rims brakes that were fitted from a stopping point of view. They work. In 5 years of discs on that bike I have spent less than the cost of blocks for 1 year on the rim braked version. Yes nice rim brakes work but discs of the same quality work as well if not better.
Sorry chaps but I feel that the same type of objection was given to handlebar mounted gear levers, 6 and more rear sprockets and quite probably inflatable tyres. I am most definitely not a fan of change, indeed Luddite might be my middle name, but in this case methinks that its time to accept that change might for once have its good points.

Choose. Discs or CUK :D

Brucey
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Re: The Disc Brake Naughty Corner Thread

Postby Brucey » 22 Apr 2016, 10:29pm

having personally experienced the effects of neglected hydraulic brakes, I can't say I can recommend it as a policy.

Not unless you like adding superfluous excitement and danger into your life.... :roll:

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Manc33
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Re: The Disc Brake Naughty Corner Thread

Postby Manc33 » 22 Apr 2016, 11:14pm

Some of my reckoning about the BB7's not being as powerful might be the fact that even now they are still being worn in, I think they must be at around 80%-100% by now but yes they get more powerful each ride it seems.

Isn't it also true they are more responsive if you've already been braking and they are warmed up a bit?

I am not bragging but honestly, braking is evil and there's plenty of rides where the only time I touch the brake is stopping at the kerb back at my house. That night I first got the 7800 brakes I got back to my house and hadn't even realized I didn't really test them out lol... went back out again.

You don't even need to go out on it though you can tell in the house when you switch brakes if the newer one is more bitey. Thats what I liked about those DA brakes, they had a lot of bite to them.

Its one thing to say "its enough to lock the front wheel" but if you slow from 30 MPH to 10 MPH with the front brake you can brake pretty hard... IMO then having brakes that go "beyond being able to lock the front wheel" are still advantageous. Thats what it was like with those DA calipers, thats what I meant by entering corners faster, you can literally brake at the last second, on BB7's I dunno, that might be risky or, I just haven't got used to them yet.

Its not a comparison really because the bike I am on now weighs 38lb (with the "MTN" BB7). The other bike with the DA calipers had to be 10lb lighter easy.

In fact the road frame and fork (with DA 7800's) came in at 2,150g and my MTB frame and fork (with BB7's) comes to 6,500g, so thats the difference roughly, 4,350g or about 10lbs. If I lightened my current bike by 9lbs then it would be a lot nearer to the weight my road bike was at... which is exactly the plan, a carbon hardtail and Seba fork. Then the frame and fork will come in at 2,800g. Getting that down to what the road bike weighted would be tough, expensive and would have to compromise wheel strength.

Since the above is with a full water bottle I can take that off to test with the BB7's and it will then be about the same weight. Thats easier than lightening a load of components at great cost all for a (proper) comparison test. :mrgreen:
Only weird bikes are interesting anymore.

reohn2
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Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 22 Apr 2016, 11:56pm

Manc33 wrote:Its one thing to say "its enough to lock the front wheel" but if you slow from 30 MPH to 10 MPH with the front brake you can brake pretty hard... IMO then having brakes that go "beyond being able to lock the front wheel" are still advantageous.....

Once a wheel is locked up it doesn't matter what brake's been used to achieve it.
With powerful brakes what matters is the the feel/modulation and predictability when lock up occurs.
Good feel/modulation is very desirable IMHO,if that feel/modulation is with minimum effort ie;two fingers on the lever,and the same feel/modulation is achievable in wet mucky conditions such a brake is very desirable.
BB7 cable discs give me that kind of very predictable braking in the way rim brakes never did.


Some of my reckoning about the BB7's not being as powerful might be the fact that even now they are still being worn in, I think they must be at around 80%-100% by now but yes they get more powerful each ride it seems.

BB7's need a short running in period to reach optimum,it's usually about 30 to 50 miles with some heavy squeezes on the lever during ,a good descent on the brakes usually does the trick,or if you go for a ride in mucky wet conditions the running in period is reduced,I think this is due to the muck and grit scoring the rotor quicker.

Isn't it also true they are more responsive if you've already been braking and they are warmed up a bit?

No,my experience is after the running in period they work just as good from the off,don't get any better than bladdy good,and don't fade or alter in performance until new pads are needed,which is a loooooonnnnnggggg time unless used continually in very abrasive/mucky/muddy conditions.New pads after the first run in period don't take anywhere near as long to run in,usually about 10 to 15 miles(?)

I've had six bikes with BB7's,in short they're great and all I need or desire from a braking system :)

I've also had one set of TRP Spykes on my MTB,which worked just as good as BB7's but I couldn't cure them squealing like a pig with sintered pads when hot,and they went through organics like a dose of salts.
I also didn't like the very minimum clearance between calliper and spokes,2 mm on the font hub,even with spacers between rotor and hub,so I sold them and bought a pair of BB7's.
Bliss like status was resumed :) .
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Manc33
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Re: The Disc Brake Naughty Corner Thread

Postby Manc33 » 23 Apr 2016, 5:07am

Those BB7's are so easy to adjust yes and with the matching levers, are a nice setup. I went down a 10% decline the other night on my 38lb bike and the control was good, I had faith in them. On a lightweight bike they would be better.

Most of those carbon FS frames are around 2500g but is there anything getting around 2,000g or under?
Only weird bikes are interesting anymore.

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 23 Apr 2016, 8:12am

Manc33 wrote:Those BB7's are so easy to adjust yes and with the matching levers, are a nice setup. I went down a 10% decline the other night on my 38lb bike and the control was good, I had faith in them. On a lightweight bike they would be better.

Most of those carbon FS frames are around 2500g but is there anything getting around 2,000g or under?


We now have two tandems on BB7's,the latest addition just this last week,is on 160mm rotors but won't be doing any serious hills,so I've nothing to report on that one really,though I've no doubt they'll work OK even better at present which is predictably good,once bedded in they'll only get better.
The other we've had for over 7 years and is fitted 203mm rotors front and rear,it stops better than any other tandem we've owned,not quite as good as a solo but with an extra 70 odd kgs of bike and stoker on board it stops PDQ for a tandem :)
If you're a heavy rider and a heavy bike,assuming you've got 160mm rotors fitted, perhaps a step up to a 185mm on the front will sharpen up the stopping.You won't need to fit one on the rear,it'll just lock up easier with a 185 up front,a few MTBer's ride 185fr 160r .
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Brucey
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Re: The Disc Brake Naughty Corner Thread

Postby Brucey » 23 Apr 2016, 9:59am

I think it is worth mentioning that (in terms of braking effort) 160mm discs on 20" wheels are better than 203mm discs on 700C sized wheels. The new tandem's brakes ought to be pretty stupendous.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

reohn2
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Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 23 Apr 2016, 10:07am

Brucey wrote:I think it is worth mentioning that (in terms of braking effort) 160mm discs on 20" wheels are better than 203mm discs on 700C sized wheels. The new tandem's brakes ought to be pretty stupendous.

cheers


I'd not thought of that :oops:
Perhaps I should've gone for 140's :?
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colin54
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Re: The Disc Brake Naughty Corner Thread

Postby colin54 » 23 Apr 2016, 10:25am

Should these be in the naughty corner ? I noticed them whilst buying something else from the seller.

They call them BB7, but no mention of Avid and are marked Redland (!), I wonder if they're a nightshift job from the same factory,

I believe quite a bit of that goes on.They're cheap but would you buy/trust them ?

http://www.ebay.co.uk/itm/BB7-MTB-Bike- ... 2040816226

reohn2
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Re: The Disc Brake Naughty Corner Thread

Postby reohn2 » 23 Apr 2016, 10:56am

colin54 wrote:Should these be in the naughty corner ? I noticed them whilst buying something else from the seller.

They call them BB7, but no mention of Avid and are marked Redland (!), I wonder if they're a nightshift job from the same factory,

I believe quite a bit of that goes on.They're cheap but would you buy/trust them ?

http://www.ebay.co.uk/itm/BB7-MTB-Bike- ... 2040816226


Those are definitely knock off's and from Hong Kong :? .
But at under £9 inc post world wide,some will buy them I've no doubt.
I was tempted if only for spares but it feeds the knock industry which isn't healthy IMO.

By comparison,I've just paid £57 for a pair of MTN Avid BB7's free postage from a UK seller,and thought they were a good price,the cheapest I've had Road BB7's were £107 from Taiwan,but that was 18months ago.
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I cycle therefore I am.