Does this brake disc need to be replaced?

[RCinNC]

I had my head up my ass and didn't catch this in time. Today I heard that noise coming from the rear wheel, and I knew even before I stopped that I'd put off checking the rear pads for too long. Checked the pads and they were toast. My question is, is the brake disc in need of replacement too? There are no gouges on the disc that will snag a fingernail or the edge of a razor blade, but I've never run down a pad this far, so I don't know if this is what a damaged disc would look like.

 

[Pterodactyl]

Service Manual should provide tolerances to guide you in making a decision.

 

[RCinNC]

I have a service manual. The issue isn't the thickness or runout of the disc; I was more concerned with whether there appeared to be enough surface damage to the disc to warrant a replacement. The service manual doesn't go into specifics about that.

 

[bigbob]

I would put on a new set and ride 100 miles. If shiny like normal you are good.


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[Pterodactyl]

Okay then, arcane knowledge and Indian lore is that if the difference between a ridge and valley is greater than 0.4 mm then the rotor should be replaced. This is for cars and one can only assume it is the same for a motorcycle.

If in doubt, then replace.

Hope this is of some use.

 

[RCinNC]

Thanks, Pterodactyl. I'm probably okay then. I did go back out and dragged the tip of a No.11 X-acto blade lightly across the surface of the rotor at various points just to re-check it, and the tip doesn't get hung up on anything. I figure if there were any deep grooves or gouges worn into the disc, the X-acto blade would have caught them.

BigBob, I'm taking your advice. I ordered a set of EBC HH pads on line tonight (the nearest Yamaha dealer is an hour from me, so getting OEM stuff is a pain in the butt). I'll put them on and just see how it goes. I'd rather not drop $170.00 on a new rotor if I don't have to.

 

[OldRider]

Thanks, Pterodactyl. I'm probably okay then. I did go back out and dragged the tip of a No.11 X-acto blade lightly across the surface of the rotor at various points just to re-check it, and the tip doesn't get hung up on anything. I figure if there were any deep grooves or gouges worn into the disc, the X-acto blade would have caught them.

BigBob, I'm taking your advice. I ordered a set of EBC HH pads on line tonight (the nearest Yamaha dealer is an hour from me, so getting OEM stuff is a pain in the butt). I'll put them on and just see how it goes. I'd rather not drop $170.00 on a new rotor if I don't have to.

If you end up having to buy a new disc, Babbitts.com has them for $115 + S/H.

 

[RCinNC]

Thanks, OldRider. I checked around at the various online Yamaha OEM parts suppliers (Cyclepartswarehouse, Cyclepartsnation, Bike Bandit, etc) and they all have better prices than retail (I've seen a rear rotor as low as $106.00). The problem is that there seem to be a LOT of dissatisfied customers with lots of customer service complaints for those suppliers. Babbitt's seems to have a better reputation, so I appreciate the info. I hadn't heard of Babbitt's before.

 

[limey]

They look fine. ::026::

 

[EricV]

If you're really worried, there is some build up on the rotor, just use some crocus cloth and rough up the disk to clean some of that off. Not super aggressive, just a sanding block method and you should quickly feel it smooth out w/o taking any significant amount off the actual disk.

 

[RCinNC]

Thanks Eric...I'm not familiar with crocus cloth, is it something along the lines of a scotch brite pad, or more aggressive like emery paper?

 

[EricV]

Its a type of sand paper, but with no aluminum oxides and cloth backed. Honestly, you could probably just use some 220 grit sandpaper with similar results. You just want to smooth the surface a bit to take off any high points of build up. The new pads will do the rest.

 

[RCinNC]

Thanks, Eric. I'll go over them with 220 grit on a block before I put the new pads on.

 

[steve68steve]

If the thickness is well above spec, you could turn them or have them turned. If I were desperate and had no lathe but DID have a solid drill press...


I've always wondered why grooved disks are such a terrible thing. The pads will wear into the grooves and thereby be provided even more surface area to bear against, right?

 

[AVGeek]

If the thickness is well above spec, you could turn them or have them turned. If I were desperate and had no lathe but DID have a solid drill press...


I've always wondered why grooved disks are such a terrible thing. The pads will wear into the grooves and thereby be provided even more surface area to bear against, right?

I looked into having motorcycle disks turned, but never found anyone who would be willing to do it.

Rocky Mountain ATV is another good source for OEM parts, and I have personally had good service from Bike Bandit as well.

 

[RCinNC]

Thanks, AV Geek. I checked Rocky Mountain (I do a lot of shopping there and they're great), but the only rotor I found for the S10 was a Galfer. They only had aftermarket brake pads, too.

Bike Bandit seems to be about 50-50 on bad reviews for customer service. Naturally there is probably a bias there, but the complaints seem to revolve around orders that take far longer to ship than promised, showing parts as available on line when in fact they aren't, and hidden shipping/handling costs. Fortunately, I apparently won't need a rotor immediately, so a delay in getting one won't cause a whole lot of problems.

 

[Xt1200zsupertenere]

Put bike on centerstand , start it , take find sandpaper and to the serfice ,, clean then rotor , new pads .... that's the way i woud have Done it

 

[Xt1200zsupertenere]

Put bike on centerstand , start it , take find sandpaper and to the serfice ,, clean then rotor , new pads .... that's the way i woud have Done it

You Will get A foult code .... Will disipere next time you drive

 

[magic]

You can get a new brake rotor (disk) at Partzilla for $103 and a set of pads for $24 (Yamaha OEM). I have turned brake rotors on a lathe, but a surface grinder can be used also. Either way, the thickness cannot be below the minimum specs. A thinner rotor will heat up faster and distort. Lay a straight edge across the face of the rotor and see how bad the grooves are. If it is at all questionable replace it. Unless you know someone with access to a lathe it will cost you some machine shop time $$$ to get it turned.

 

[magic]

Also, I have used Rocky Mountain ATV in the past with good results, but Partzilla usually is cheaper. Look in their OEM section for your parts at both vendors.