Alpha ceramic rotors

Discuss light weight issues concerning mountain bikes & parts.

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TheRookie
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Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

Image

This is apparently one of their discs

and this one
Image
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

by Weenie


SportingGoods
Posts: 38
Joined: Wed Jun 03, 2015 10:16 am

by SportingGoods

Test completed. I don't recommend Carbon rotors (all Carbon rotors in general, including these ones).

Not a catastrophic failure but I understand now why rotors are made of metal. That's because metal can be bent. As I mentioned, the rotors are perfectly flat, on the table. But once mounted on the hub they are out of true. I used my torque wrench to tighten the bolts evenly at 6 Nm (recommendation from Alpha). Could be that the rotor contact points of my hub are not perfectly flat or that when you compress the rotor the constraint causes warp. Don't know. The only thing I know is that because it is made of Carbon you can bend it. You just can't fix it. Period.

They don't rub badly, but they do. I could certainly massage them to stop rubbing (by a perfect alignment of the caliper and some magic spells) but this is not a robust solution.

Then, they seem to stop me efficiently (tried on the front brake only). I guess there is some breaking-in that needs to happen, but they are a bit noisy (dry weather) and vibrate. Hopefully this is just because they are new.

So, again, I don't recommend Carbon rotors. Never, ever would I use these on a MTB. You hit a rock and they most likely break, leaving you w/o brake. I'll try to fit them on my road bike once I have my carbon wheels built, but if I had the option to send them back I would.

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ms6073
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Location: Houston, Texas

by ms6073

That is the exact issue I had with all iterations of the Kettle carbon rotors, well that , and a screeching noise that would wake the dead under heacvy braking.
Michael - The Anaerobic Threshold is neither...

TheRookie
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Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

From the photo's they look like plain CF sheet cut to a disc, is that they case or are they actually 'special' in come way?

I have a CF bash made out of a sheet of 2.5mm, cost me £20!
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

SportingGoods
Posts: 38
Joined: Wed Jun 03, 2015 10:16 am

by SportingGoods

Honestly it would well be Carbon in Epoxy!! I found the source of the pictures above. They are indeed Alpha rotors.

Test is over for me, and I've already requested my money back :-[
For those who don't speak Spanish they can use Google translate.
http://www.foromtb.com/threads/discos-d ... s.1366597/

Not taking any risk. Lucky I paid with my American Express card, if they don't send the money on their own I'm protected 90 days past the purchasing day.

tonytourist
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Location: 93306

by tonytourist

My friend ordered a set and his first ride on them went well, however, on his 2nd ride they ended up looking exactly like the pictures above. They are trying to blame his choice of pads (Swiss Stop Exotherm) but it doesn't seem like it is an isolated incident. I would definitely avoid these until they refine the process or perhaps make their own pads.

TheRookie
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Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

I do t think it's a case of refining the process, that would imply they had a process to begin with!
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

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marecej
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Location: Prague

by marecej

thanks for the pictures, saved me a lot of trouble with mine :)
Ellsworth Truth = 9371g

poynt
Posts: 105
Joined: Sat Mar 13, 2004 5:31 pm

by poynt

If Alpha bothered to have done more R&D before releasing these to public use, ie: they cold recommend a specific pad that they know works then maybe we'd all be a lot happier and feel more covered if there was a failure and were using recommended pads etc.

wingguy
Posts: 3514
Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

tonytourist wrote:My friend ordered a set and his first ride on them went well, however, on his 2nd ride they ended up looking exactly like the pictures above. They are trying to blame his choice of pads (Swiss Stop Exotherm) but it doesn't seem like it is an isolated incident.

How can they blame pad choice if they don't say which pads to use, or not use? :noidea:

tonytourist
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Joined: Sat Oct 10, 2009 7:13 am
Location: 93306

by tonytourist

The directions were long and made no sense. When he emailed them about the failure they told him that they only recommend organic pads and that was the reason his set had failed. Since his first order was lost in the mail, Alpha sent him another set, which conveniently showed up after the current rotors disintegrated. I'm not sure if he is willing to test them again or not, but if he does it might just be at one end of the bike.

UpFromOne
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Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

Thanks for placing the bet, SportingGoods. I hope you get your refund.


FWIW, a cursory search finds several successful carbon rotors on motorized applications:

http://braketech.com/axiscmc-rotors/

http://www.wilwood.com/Rotors/RotorList ... C%20Rotors

http://www.starfiresystems.com/docs/mat ... 4-2010.pdf

Years ago I had the BrakeTech CMCs (pic attached) on my Honda superbike, and they were the best brakes I ever used.
Why in the hell can't someone just use a smaller version of these materials for bicycles?
Attachments
Rotors.CMC.pair.jpg

bikewithnoname
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Joined: Tue Sep 22, 2009 1:29 pm
Location: UK

by bikewithnoname

Maybe if they were made of some sort of carbon/ceramic by a company like brembo I'd try them out, looks like these are just 3k weave with maybe a different resin? I sincerely hope no one was hurt experimenting with these!
"We live in an age when unnecessary things are our only necessities." Oscar Wilde

Pegoretti Responsorium, Parlee Z5i, Donhou Commuter, 1946 MacLeans Featherweight L'Eroica!, 2x MTB 'dales

wingguy
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Joined: Thu Mar 08, 2012 11:43 pm

by wingguy

UpFromOne wrote:FWIW, a cursory search finds several successful carbon rotors on motorized applications:


The only one that has a price listed is the Willwood, and it's $2400 per rotor...

Years ago I had the BrakeTech CMCs (pic attached) on my Honda superbike, and they were the best brakes I ever used.
Why in the hell can't someone just use a smaller version of these materials for bicycles?

How mch did they cost on your Honda, and who's going to pay that for the much, much smaller weight saving on an MTB?

UpFromOne
Posts: 644
Joined: Wed Apr 08, 2009 5:23 am
Location: Olympic Nat'l Park, WA

by UpFromOne

wingguy, yes they were expensive but worth it.
I'm suggesting that the proper materials have already been worked out, it's just a matter of not trying to short-cut the proven designs.

As for our required sizes and thicknesses, it appears that Alpha (a "motorcycle" company no less!) did in fact short-cut the materials and designs. Hopefully one day some company will do it right and take over the racing market. For now still a dream.

by Weenie


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