Disc skim?

[Zadkiel]

Can motorcycle disc brakes be skimmed like automotive ones? Obviously they are a fair bit thinner but I'm hoping it can still be done. Mine seem to be warped.

[FJRider]

They can be ... but to take enough off to take out the warp, will usually take it below the mimimum thickness ...

[AllanB]

F1 Engineering in Hamilton advertise that they can correct warped disks - to a extent and it will be dependant on each individual case.

[riffer]

The price it costs to fix them you're better off buying a set of replacement Chinese ones mate. Nought wrong with them for a road bike.

[Zadkiel]

That's the choice really. Fix these ones or buy Ebay specials!

[imdying]

You could of course buy some that are known to be of good quality. Brakes seems like a funny place to be cheaping out.

[riffer]

You could of course buy some that are known to be of good quality. Brakes seems like a funny place to be cheaping out.

Okay then, let's hear from YOUR personal experience the problem you've had with the Chinese brakes.

Not what someone said once, or what you've read on the net.

[tigertim20]

Can motorcycle disc brakes be skimmed like automotive ones? Obviously they are a fair bit thinner but I'm hoping it can still be done. Mine seem to be warped.

for all the effort takng the bugger off and getting it skimmed etc, just go buy a new disc, they can be had from about $150 onwards for a good one.

[imdying]

Okay then, let's hear from YOUR personal experience the problem you've had with the Chinese brakes.

Not what someone said once, or what you've read on the net.Sure.

Buttons that have rusted preventing the disc from moving on the carrier, hairline fractures from cracking at the holes due to (my assumption admittedly, I am not an engineer) insufficient stress relief, black anodizing that goes purple after a short duration of time.

Personally I didn't think the hairlines fractures were fatal (they were less pronounced than I've seen on Porsche/OSCA race cars, but admittedly they have a lot more meat, albeit with a lot more mass to stop), but I wasn't prepared to hang my hat on that so advised the customer accordingly. Problem is, road bike or not, you can't assume the customer will treat it like one... most bikers think they're Rossi at one time or another. If it had been on a 4WD and it had a tow bar fitted, I would've advised replacement then too.

The buttons and anodizing failure is just typical of the Chinese stuff (levers, rearsets etc), and purely cosmetic, but indicative of the quality.

/edit: I've tried the MetalGear replacements, they seem ok for the money. They look a little cheaper than the Japanese parts, but then they are cheaper to buy also.

/edit2: On this note, I did see a set recently that had a manufacturers name stamped into them. I consider that to be a 'good thing' (TM). Manufacturers that aren't even prepared to put their name to a product are best to be avoided. Finally a note on Chinese parts... just because it comes from China doesn't mean it's an instant failure... I'd wager that 95% or more of the discs in service (on cars) in NZ are made in China.

I only see these occasionally, it would be wise to go to a large dealer and ask the mechanics about them, they will have seen a far greater sample size than I. Generally if something gets to me, it's because it's fucked.

[riffer]

... 95% or more of the discs in service (on cars) in NZ are made in China.

Yeah, that was kind of the point I was making. For most road bikes I reckon they're up to the job.


Generally if something gets to me, it's because it's fucked.

Yes, I can imagine. It's a bit like asking the Special Crash Unit what they think of motorists' driving isn't it?

Having said that, I've not had trouble with my brake disks, which are of the wave unlabelled Chinese variety. I will be interesting to see how they last, especially as they replaced some EBCs which pretty much fell to pieces on me.

[DEATH_INC.]

You could of course buy some that are known to be of good quality. Brakes seems like a funny place to be cheaping out.

I've seen some genuine H*nda cbr disks that were full of hairline cracks, even tho the were above minimum thickness too. They don't need to be cheap to be shite. :blink:

[DrunkenMistake]

If you buy off ebay its the same as TM, alot of people assume because its on TM, its all good. infact most stuff on TM has been brought off Ebay and sold to you lot for x3 more.
Just make sure you buy off someone with alot of good feedback and a top seller.
:yes:
I wouldnt bother getting them skimmed, you have to take alot out of it to get them smooth and they arnt all that thick anyway.

[Harvd]

Okay then, let's hear from YOUR personal experience the problem you've had with the Chinese brakes.

Not what someone said once, or what you've read on the net.

Heres a personal experience for you.

I bought a set of "Arashi" discs. Yes i cheaped out. I had done a lot of research and hadnt found anyone that had had a negative experience. Yes plenty of people saying a guy they knew or whatever but no one coming forward and saying that they themselves had had an issue.

Anyway i got them. I had a good look over them and was initially impressed. Went out and bedded them in. But as soon as i started to do higher speed stops i noticed a vibration at anything over 80km/hr. When i went home i put the bike up on the front wheel stand and spun the wheel. The discs were eccentric. I was not impressed. Eccentric as in they had a vertical runout. Not a normal warped disc scenario of horizontal runout.

I talked to the supplier who was a guy on an english 400 forum and he said that it would be faster if i went direct through the chinese. I talked to them and they were happy to send me new ones once they had recieved mine and determined if they had a manufacturing fault. They got them and agreed with me and sent me a new set. They said they would reimburse me for the shipping if they found that they were at fault. (i still havnt seen the $94) I got the discs and guess what... one of the discs was eccentric again! This time im pissed off but think maybe its just that they are new and it will go away (i mean how could they fuck up like that twice???). The vibration was also much less than the first set so i took them to the track along with a couple of good discs just in case. The vibe was horrible at high speeds and after one session i took them off and spent the rest of the day on old thin stock ones. I subsequently got my money back from the english guy who even paid for the return shipping. He is now in serious talks about the quality and customer service and doubts he will continue dealing with them.

I now have a lovely set of Galfers.

Heres some pics of the first set. You can see the differing wear patterns on opposing edges of the disc.

[bsasuper]

Dont go thinking they are not worth repairing.It only takes a few thousands of an inch to make the lever pulse.If your handy and can get the disc off the carrier(assuming they are floating), they can be surface ground.

[RobGassit]

I now have a lovely set of Galfers.

Where did you get the Galfers from and at what price? Can you recommend the seller?

[tigertim20]

$200 delivered to your door, go new
http://www.bits4bikes.co.nz/parts/honda/2208.aspx

[RobGassit]

$200 delivered to your door, go new
http://www.bits4bikes.co.nz/parts/honda/2208.aspx

Thanks but I'm after Galfers.

[gatch]

Dont go thinking they are not worth repairing.It only takes a few thousands of an inch to make the lever pulse.If your handy and can get the disc off the carrier(assuming they are floating), they can be surface ground.

I have ground the front disc on my own honda spada at work, using a lathe and the tool post grinder. Worked ok too.

[Zadkiel]

I would definitely buy the ones off bits for bikes if they were correct. Unfortunately I did some further research on their site and those are the same code as the rear disk for other bikes that share the same brakes (CB600 Hornet for example) so I think they have just screwed up. The cheapest I found any new non-Chinese disks for my bike is $600 so that is what makes me think other options might be worth it.

[DrunkenMistake]

I would definitely buy the ones off bits for bikes if they were correct. Unfortunately I did some further research on their site and those are the same code as the rear disk for other bikes that share the same brakes (CB600 Hornet for example) so I think they have just screwed up. The cheapest I found any new non-Chinese disks for my bike is $600 so that is what makes me think other options might be worth it.
Send them an email,
they will sort you out pretty quick, when you sign up to their site they also email you a $25 off voucher.

[Zadkiel]

I emailed them, $400 each, ouch!

[imdying]

I have ground the front disc on my own honda spada at work, using a lathe and the tool post grinder. Worked ok too.I've seen (someone actually doing it) a disc de-lipped with an angle grinder :facepalm:

[imdying]

Heres some pics of the first set. You can see the differing wear patterns on opposing edges of the disc.Cheers for that, hadn't considered that they would get something as simple as that wrong, I'll check for it in the future.

[Zadkiel]

I think I'm going to try F1 engineering in Hamilton. COuld be just the carrier, I can't actually see where is bent, just feel the pulsing in low speed front braking.

[erik]

I think I'm going to try F1 engineering in Hamilton. COuld be just the carrier, I can't actually see where is bent, just feel the pulsing in low speed front braking.

It could be that it's not warped but unevenly worn around the disk ie. the thickness of the disc might vary. On my bandit it was by 0.025mm on one disc only and I could feel the bike pulsing slightly when coming to a stop under light braking. I got new discs, then noticed the (within spec) side to side run out was making them brush the brake pads at the high point and that they were starting to wear more at this point on the disc. So I switched back to the old discs and tried replacing the piston seals in the callipers to see if it'd make the pads retract further. It didn't, but I found the pulsing wasn't so bad anymore (disappeared even) and I just ended up using them till they got below the minimum thickness, then put the new discs back on.
I'm not sure if cleaning and rebuilding the callipers (with rubber grease) reduced the pulsing or if I put the old discs on at a different angle (although if the pulsing was due to the variation in disc thickness this shouldn't have affected it), or if it was the new brake pads or what.
I've just bought a gsr600 and the brakes are doing the same thing, will have to measure them and test them and decide what (if anything) to do. I'm hoping it might just need the callipers cleaned and reassembled.

[reggie1198]

sorry mate, I don't want to jack your thread, but I'm looking for anyone else that has had worn rivets on Brembo disks - which allows the outer part of the floating front disk to move (a lot)