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Discussion Starter · #1 ·
Hey all

Had my 8" hayes on for about 3 months and the front and back disc both scrape on the pad in certain places...I didn't hit any trees or anything so why did they buckle/bend/warp so easily? Maybe this is a common occurance with hayes and I'm just the newest sucker...are there any burley kick-ass discs that won't warp and are compatible with the HFX mag?

Thanks!
 

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I'm in the same boat...

gigamanx said:
Hey all

Had my 8" hayes on for about 3 months and the front and back disc both scrape on the pad in certain places...I didn't hit any trees or anything so why did they buckle/bend/warp so easily? Maybe this is a common occurance with hayes and I'm just the newest sucker...are there any burley kick-ass discs that won't warp and are compatible with the HFX mag?

Thanks!
After a day of DH at Sunrise Ski resort, my rear rotor was warped too, and I didn't hit anything. Beats me, I just replaced it with another I had lying around, but it was not any stronger.
 

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I don't think it's Hayes discs necessarily...

I think warping rotors is something that you have to deal with, no matter what rotor you actually use. I have a set of Avid mechanicals on my hardtail, and Hayes hydraulics on my fully, and I warp both sets of rotors pretty regularly. In my case, I think it's heat build up that is the problem. I notice more "warpage" when I've had a long or steep downhill. I'm a pretty big guy, and a lot of energy gets transferred into those rotors. Fortunately, I've found that those kinds of bends are the easiest to straighten...maybe it's just 'cause I'm getting lots of practice! :p

gigamanx said:
Had my 8" hayes on for about 3 months and the front and back disc both scrape on the pad in certain places...I didn't hit any trees or anything so why did they buckle/bend/warp so easily? Maybe this is a common occurance with hayes and I'm just the newest sucker...are there any burley kick-ass discs that won't warp and are compatible with the HFX mag?

Thanks!
 

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I have the same issue with mine on my D9 Pro.

8" rotors are rather large.. so therefore getting the perfectly true from the factory would cost a lot of money. How do they solve this issue? Cutting costs by making them imperfect. To get rotors perfectly flat, and perfectly true would cost probably $80 a piece, as precision parts are not cheap (look at custom-ground cams for a car :eek: ).

Anyway, you could certainly try taking them to a machine shop, and having them put in a hydraulic press. One of my friends has one, and I've used it before for that very reason. Friends price, zero. Your price? Prolly only like $5.00. It's a good solution, and an easy fix.

If you want new rotors.. I'd highly recommend Galfer's wavy rotors.. or a set of Hope Gothic M4 rotors (in the 203mm size).

Good luck bro, and I feel your pain. Both mine and my bro's bikes have the 8" Hayes on there, and they both continually make "pinging" noises.... no matter how well the caliper is setup.

-Matt
 

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Get used to the noise

Disc brakes make noise. Almost all the time. There is only one solution: get used to it. Sometimes they make that "shiiiiiiing" sound, sometimes it's more of a "scraaaaaape". It's nearly impossible to keep that from happening. And it's really not a problem, just annoying, until you get used to it.
 

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Chea...my hydro discs make that "shiiiiiing" noise all the fricken time... lol... especially when railing corners... :D

(and there's equal distance on each side of the rotor to the pads too).

oh well. I really dont care... as long as they stop good!


:D :D :D
 

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watermoccasin said:
Disc brakes make noise. Almost all the time. There is only one solution: get used to it. Sometimes they make that "shiiiiiiing" sound, sometimes it's more of a "scraaaaaape". It's nearly impossible to keep that from happening. And it's really not a problem, just annoying, until you get used to it.
this should be the only answer to this tread.. it is 100% true.....
 

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BigHit-Maniac said:
I have the same issue with mine on my D9 Pro.

8" rotors are rather large.. so therefore getting the perfectly true from the factory would cost a lot of money. How do they solve this issue? Cutting costs by making them imperfect. To get rotors perfectly flat, and perfectly true would cost probably $80 a piece, as precision parts are not cheap (look at custom-ground cams for a car :eek: ).
FYI, rotors are perfectly true when they come from the factory, if you've ever seen a stack of them from the factory you'll see that they *are* perfectly flat. whether they survive shipping in a bike box or a build is another matter.

Easiest thing to fix, though, just use a rag (so you don't scratch them) and bend them back into place with a pair of pliers. You should be able to "true" them relatively easily.

dante
 

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I would think that any 8 inch rotor would warp easily. There's much less side to side stiffness than in a 6 inch rotor.

The number one cause of car disk brakes warping is by heat. It's not the heat itself that warps rotors.

It's the cooling down from a long hot descent that warps rotors. You can prevent this by not locking up your brakes after they've become hot. Most people will warp their brakes while waiting to get back on the ski lift.

Imagine that the whole rotor is red hot from a 4000 vert ft run down the mountain and you sit there waiting in line for the lift. The whole rotor is going to cool down very quick except for the area where the caliper is still in contact. The caliper itself should also be very hot and will retain heat longer than the rest of the rotor.

By sitting on one spot after riding really hard you are forcing the rotor to cool off unevenly. 90% of the rotor will have lost 50% of it's heat while the portion still covered by the caliper has only lost 10% of it's heat. The portion left inside the caliper (only takes several seconds) will remain more thermally expanded than the remainding 90% that has cooled off and contracted it's thermal expansion. it's in that exact spot where your warp will show up.

Basically sitting in one spot after a hard run is what causes rotors to warp even if they haven't been touched by anything that can bend them. You want to keep the rotors spinning for a minute or two after a hard ride to prevent them from warping due to thermal inconsistancies..
 

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Discussion Starter · #10 ·
.WestCoastHucker. said:
this should be the only answer to this tread.. it is 100% true.....
That's probably the only answer I needed :) I'm used to noise from chain guides, chain slap, crunching gears, etc...so knowing that the disc is just a part of the mess is ok by me. As long as I know I should expect it.

Although, the explanation of the particle heat transfer exchanged through the relative gerbal cycles of air impacting with extreme terrain requiring my need to increase silicone pressure in the artificial boobyplants thus slowing the bike like a weak driver's side airbag...or whatever buddha said, was very inventive.
 

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Advice from a novice ->

On long DH trails I learned not to ride my brakes. Grab traction suddenly in good braking sections and let go. Just really crank em when you need em, otherwise lay off. So basically I just learned to ride faster and brake more suddenly. It works for me. Even on super long shuttle DH trails (like 3hours). You probably already knew this.
 

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gigamanx said:
That's probably the only answer I needed :) I'm used to noise from chain guides, chain slap, crunching gears, etc...so knowing that the disc is just a part of the mess is ok by me. As long as I know I should expect it.

Although, the explanation of the particle heat transfer exchanged through the relative gerbal cycles of air impacting with extreme terrain requiring my need to increase silicone pressure in the artificial boobyplants thus slowing the bike like a weak driver's side airbag...or whatever buddha said, was very inventive.
hahaha

That's the problem! People are using too low of an octane gas in their boobyplants.
 

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Stan of "no-tubes" fame has Aluminum rotors on the market...would this cure the heat warping problem caused by long down hill runs?
 

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Discussion Starter · #14 ·
vermont said:
Stan of "no-tubes" fame has Aluminum rotors on the market...would this cure the heat warping problem caused by long down hill runs?
possibly, although they do add +10 to the XC-weight-weeniness of my DH bike and they look like shite. I'll stick with the wobble so my bike can look cool when I stop.

What they really need to invent is rotors with the cool LED's like on cars so when you're riding urban they would look schweeet (patent pending)
 

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dante said:
Easiest thing to fix, though, just use a rag (so you don't scratch them) and bend them back into place with a pair of pliers. You should be able to "true" them relatively easily.

dante
Adjustable wrench is good too (rivetless). Throw that puppy on there, find out where it scrapes, and minutely bend the rotor the opposite way of scrapage. It only takes a few minutes.
 

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I do the same thing and it seems to work for me. I haven't had a rubbing or scraping sound out of them for months.

And, to tell you the truth, Budda was right. When you heat up metal, it can change the microstucture of the material, along with having it all expand some little bit. If one part cools faster than the other, then when the last part cools that is stuck in the caliper the edges of that area are already bound by metal that is thouroughly cooled, causing the last bit to "bind up" when cooling. Also, the part that cools slower will have a softer microstucture than the part of the disc that was cooled fast, but only if they were heated to a high enough temperature. Anyways, enough of the engineering knowledge for ya. If you want to know more, I'll tell you what book to read.
 

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gigamanx said:
Hey all

Had my 8" hayes on for about 3 months and the front and back disc both scrape on the pad in certain places...I didn't hit any trees or anything so why did they buckle/bend/warp so easily? Maybe this is a common occurance with hayes and I'm just the newest sucker...are there any burley kick-ass discs that won't warp and are compatible with the HFX mag?

Thanks!
anytime you repeatedly expose a sheet of metal as thin as a rotor to a heat in excess of like 350 degrees and then have it cool, the metal will warp. No real way avoiding it
 

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Discussion Starter · #18 ·
Micheal said:
I do the same thing and it seems to work for me. I haven't had a rubbing or scraping sound out of them for months.

And, to tell you the truth, Budda was right. When you heat up metal, it can change the microstucture of the material, along with having it all expand some little bit. If one part cools faster than the other, then when the last part cools that is stuck in the caliper the edges of that area are already bound by metal that is thouroughly cooled, causing the last bit to "bind up" when cooling. Also, the part that cools slower will have a softer microstucture than the part of the disc that was cooled fast, but only if they were heated to a high enough temperature. Anyways, enough of the engineering knowledge for ya. If you want to know more, I'll tell you what book to read.
Does the book title start with "Engineering to help you pick up chicks"
 

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gigamanx said:
possibly, although they do add +10 to the XC-weight-weeniness of my DH bike and they look like shite.................
i've got the wavy rotors from Braking (available at Go-Ride) and they are way lighter than regular rotors and look wicked....

they work awesome when combined with some EBC reds.........
 
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