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WTF, new brake pads...
 

[Closed] WTF, new brake pads destroyed my discs!

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I'm using Alligator Windcutters which have even more cut outs on the braking surface - they've been super durable ..


 
Posted : 30/07/2015 2:05 pm
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They just reminded me of the new Avid Discs.
You can draw any conclusion you like from it 🙂


 
Posted : 30/07/2015 2:06 pm
 tomd
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I wrecked a pair of Shimano 160mm rotors in a few hundred miles. It was the fully loaded bike packing for a couple of weeks in a hilly place that did it - I reckon when you get the rotors hot enough with certain pads they just get destroyed. It's certainly not linear anyway.

Neither Superstar or Ashima will give 2 hoots about your predicament, it's not like either have a reputation to defend. After years of using superstar pads and cheap-ass rotors I've decided just to use the proper stuff. the cost difference now between SS pads and OEM pads isn't great if you shop around, same with rotors.


 
Posted : 30/07/2015 2:21 pm
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Superstar definitely won't care, it's not their pads or rotors. Discobrakes?


 
Posted : 30/07/2015 2:30 pm
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When you take your car to a dealership they always recommend a change of disks with the pads

Main stealer by any chance? Pads should be changed for new discs, but discs don't need changed just for new pads.


 
Posted : 30/07/2015 2:44 pm
 DezB
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I say [url= http://singletrackworld.com/forum/topic/how-accurate-are-digital-tyre-gauges#post-7076030 ]this[/url] ❗


 
Posted : 30/07/2015 2:50 pm
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I have windcutters on my 29er. They're nowhere near as cut away/flimsy as the OP's rotors.


 
Posted : 30/07/2015 2:56 pm
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As Milky said, brakes are an area you don't want failing suddenly.

I use XT rotors which seem to have a nice amount of material and combine them with soft pads from any old generic supplier (Superstar, Uberbike etc)....probably means I go through pads at a faster rate than some but even on my basic Deore-615 brakes the power is awesome....same combo but with my Saints and it's like being pushed into reverse!

The OP's rotors do have a 'style over substance' look to them....like those hideous rotors you get with edges cut out/designed to look like flames, teeth etc....yuck.


 
Posted : 30/07/2015 3:42 pm
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Can you still get rotors with your name cut out? (Hope?)


 
Posted : 30/07/2015 3:58 pm
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For my tuppence worth...

The wear on those pads is very uneven, to the point the top looks nearly fresh out of the box. Are you using the right size rotors? Given they're Avid brakes they're not 185mm adaptors with 180mm discs are they? (of course the very-alarming-and-immediately-obvious-with-even-a-casual-glance-to-check-your-pads-since-performance-will-have-been-noticeably-rubbish pad wear could be the result of the exploding disc shredding them.)

But yes, whateveryone else said, silly way to save weight on a normal bike, nothing to do with your new pads being rubbish. They've worn quite well IMHO of you've got 3000 miles from them before that happened.


 
Posted : 30/07/2015 4:05 pm
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[quote=thestabiliser ]Still find it hard to believe you get through that much material in 600 miles riding on the road

I think what some people are missing is that road riding can actually result in more stress on the brakes as you have no natural retardation and so on a steep hill with bends you put a lot of energy into the brakes. On the tarmac descent from Cadair Idris towards Barmouth my disc brakes started fading, whilst the chap I was riding with who had rim brakes had his tyre blow out at the bottom.

Oh and I'm a fairly extreme weight weenie with a 21lb full sus (got it under 21 at one point, but then got a bit more sensible), but wouldn't use discs like that - I have Hope floaters.


 
Posted : 30/07/2015 4:25 pm
 jedi
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looks like the rotor wasnt right size. pads only contacted half by looks of it


 
Posted : 30/07/2015 4:31 pm
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The grape is fine. The grain is fine.

But because you've mixed the two . . . .


 
Posted : 30/07/2015 4:31 pm
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Those disks look frightening, maybe one use only for racing.

Discs with grooves and drilled holes are standard on high performance cars but they are much larger diameter and thicker.

The science behind drilled and grooved disks is very simple, they displace the gas produced when the brakes are cooking, averting brake fade.

Brake fade is basically when gas forms between the disk and calipers due to friction, and the force of the gas buble forces the pad away from the disk.


 
Posted : 30/07/2015 9:13 pm
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I had some Magura discs, which came on my Jekyll and although I bedded them in and used organic pads, I managed to completely loose braking in Spain, as a metallurgist inspected them ( customer of a mate) and said that the heat had softened the material and causes them to dissolve under breaking. Looking at those discs, seems it has dissolved the area where there is minimal material. More than likely the wrong pads for the wrong discs.


 
Posted : 30/07/2015 9:41 pm
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Brake fade is basically when gas forms between the disk and calipers due to friction, and the force of the gas buble forces the pad away from the disk.

Is that really what causes brake fade , I always thought it was caused by something happening to the brake fluid in the system when it over heats .


 
Posted : 30/07/2015 10:12 pm
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Nope, brake fade is down to a gas cushion forming between the pad and disk, resulting in a loss of braking.

Brake fluid can also cause issues but that's generally due to water ingres, which will cause a more spongey feel, the effects are similar but the causes are different.


 
Posted : 30/07/2015 10:19 pm
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You're both right.....theres the gas cushion failure (levers stay stiff), and the boiling brake fluid failure (levers go spongy). I'd imagine the main one we'd suffer from is boiling brake fluid.


 
Posted : 30/07/2015 10:24 pm
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I had some Magura discs, which came on my Jekyll and although I bedded them in and used organic pads, I managed to completely loose braking in Spain, as a metallurgist inspected them ( customer of a mate) and said that the heat had softened the material and causes them to dissolve under breaking. Looking at those discs, seems it has dissolved the area where there is minimal material. More than likely the wrong pads for the wrong discs.

Ah-ha! So when I told someone a few weeks back not to roast their discs to clean them I was probably right 🙂

EDIT: pretty sure the off-gassing problem is worse for cars due to the really rather extreme forces involved.


 
Posted : 31/07/2015 5:18 pm
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why would you want a rotor with so little braking surface area? there's having lightweight things then there's just negatively affecting performance for a few grams.


 
Posted : 31/07/2015 5:54 pm
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why would you want a rotor with so little braking surface area? there's having lightweight things then there's just negatively affecting performance for a few grams.

I have those rotors on my mtb & cx bikes and they work perfectly well and were cheap.


 
Posted : 31/07/2015 7:15 pm
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Contact area does not affect brake power. Friction is independent of surface area. But heat dissipation is.

If you look closley at those avid discs the slots alternate in radius so only every other one lines up.

You get this problem a lot when there is a lot if successive holes/cut outs in a disc and this is why I stick with shimano.


 
Posted : 31/07/2015 7:36 pm
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I thought I'd update this thread because the second set of Ceramic pads lasted a few months & 900 miles while using brand new AVID HS1 Rotors, again, 95% road riding.

[url= http://www.discobrakes.com/?s=1&t=0&f=viewtopic.php?t=2133__a__amp;sid=9f605bf3819e6217159fff6bff1ac7fb& ]While having a look on their forum, I noticed I wasn't the only one having issues with their ceramic pads.[/url]
There are no pictures, but he said the pads last a few hundred kms and nearly broke his XT-discs, so no lightweight disc there.

I wasn't going to bother contacting DB, but after the second set of pads wore very quickly, I sent them an email with pictures.
They are now going to send me new pads and discs, and they want to check out my discs and pads, so I will be sending them off.

So, not a great experience with these expensive ceramic pads, but it does seem to be a bad batch because even the cheap ebay Sintered ones I got for a few pounds a pair lasted twice as long and that was through winter riding.


 
Posted : 02/11/2015 2:44 pm
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There are no pictures, but he said the pads last a few hundred kms and nearly broke his XT-discs, so no lightweight disc there.

Depends on the disk, mine (ice tech) have an aluminium core, so the actual friction surface is incredibly thin. Taken them off and keeping them for summer use with organic pads.


 
Posted : 02/11/2015 3:01 pm
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Those ashima rotors are the reason for this...

http://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/

... and the subsequent scaremongering in numerous threads about road disc brakes overheating.

"Braking was handled by Ashima’s new and ridiculously light Ai2 rotors." ...
"Being my first time on this road, I kept light pressure on the levers, dragging my brakes to keep my speed around 30mph on a very curvy, steep road. "...

You can probably guess what happens next.


 
Posted : 02/11/2015 3:21 pm
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