Brake rotors

[Gearhead]

Any of you guys ever put a caliper (the measuring sort) on your rotors? I installed HH sintered pads on the RF brake (the one that works with the lever) about 19k miles ago. I had heard mixed reports that sintered pads can be hard on rotors, so I miced the rotor at installation, after a couple thousand miles, and again this morning. Then I looked in the manual. I included the boring details below for those of you inclined toward boring details, but in short, both my front rotors are under the min thickness spec. It seems that there is only about .020" from new rotor thickness to minimum thickness, which is a little chincy I think.

 

So I wonder how many others have rotors worn below spec? How many ever measure to find out?

 

EBC sells rotors for about $150 each for these bikes. Has anybody used them?

 

Thanks, Jeremy

 

BORING DETAILS!

I checked out my brakes. The sintered pads have been on the RH front brake for 19k miles and are maybe 2/3 worn out. Interesting, because the LH front and the rear organic pads - which I have never replaced so they have at least 26K, and I don't think the PO replaced them so they have more than that - are still very thick. I thought sintered were supposed to last longer, although that's not why I put them on (I wanted the extra bite with the hand brake). Either that info is incorrect OR I use that one front brake (hand lever) a WHOLE lot more than the linked foot brake, which is entirely possible given old habits.

 

Both front rotors have a ridge on them that measures .281, so that must have been the starting thickness. At 54k when I installed the HH pads, I measured .253, .243, and .240 working from just under the ridge toward the axle. Now at 73k I measured .248, .239, .234. So there's been 5-6 thou of wear. If you look at the original thickness, and figure that 5-6 thou" represents 19k out of 73k total miles, and that 19k had heavy usage on that brake, it's pretty reasonable wear really. I wonder if organic pads would have done the same? For comparison, the LH rotor today measures .255, .248, .246 (I didn't measure it before), which are closer to the RH "sintered" numbers than to the original .281.

 

I just checked the manual and the listed minmum thickness for the front rotors is .260, so mine were under that before I got the bike. Hmmm...

[Rocket]

 

EBC sells rotors for about $150 each for these bikes. Has anybody used them?

 

Thanks, Jeremy

 

 

I installed all 3 of them on my 83, about a year & half ago. They are solid cross drilled rotors, much heavier than the OEM rotors.

[capn eddie]

JC whitney has the EBC pro lite rotors for the front for $125.99 each and they have the rear rotor also, i think the rear is around 250.00 give or take. about the cheapest price i could find , hope this helps .

[jasonm.]

Yes, my front rotors went below spec. many years ago. I have the EBC solid rotors(like OEM) from years ago...not the pro-lite floaters of today. I have nothing good to say about the ones I have. I will simply say the EBC HH pads don't like the EBC rotors I have at low speeds strange harmonic at 15mph causing sudden lock up under moderate braking. Rotors checked to be dead nuts true. Funny thing- SBS HH pads works fine...better. No low speed lock up.The rotors I have- holes for cooling, the hole spacing is very limited. More for looks than performance. Maybe the Prolites are better?

[skydoc_17]

The stock Yamaha rotors on the first gens. are made from a relative "soft" alloy steel by todays standards. The use of the aftermarket "HH" cintered pads really take their toll on them in the way of excessive wear and warpage. The optimal union was the organic pads and the stock rotors. This and the linked braking system were cutting edge technology..... in the eighties! The reason you are seeing "chatter" on the aftermarket Rotors and HH sintered pads is two fold, you are using a more modern rotor made from a "Harder" more wear resistant alloy composition and you have a "harder" HH sintered pad in a two piece caliper which is 25 year old technology. There isn't a performance motorcycle currently produced that uses two piece calipers any more. As far as running rotors that are under spec thickness wise goes, the problem is that the pistons are extended so far out of the caliper bore that they actually "cock" which causes premature seal failure and compounds the "caliper flex" which causes chatter and lock-up. One trick I have had good luck with is to replace the pads at 50% wear to keep the caliper pistons from overextending, This gets expensive if you do a LOT of riding. The other thing you can do is change your braking habits and use more brake pedal instead of always grabbing the the hand brake, after all you are using ONE caliper and ONE rotor to stop an 800+ pound motorcycle when you have THREE calipers and THREE rotors available. Option "C" is transform your 22 year old braking system to more modern technology as shown here:

 

http://www.venturerider.org/forum/showthread.php?t=27170

 

Have questions, need parts, want someone to install this mod on your bike, PM me.

Earl