Jump to content

Why would my rear rotor wear like this

Recommended Posts

20170508_172458.jpg

Why would my rear disc just dish from wear like in the pic ? Mud, dirt,,, but shouldn't the brake pads take the hit before the metal ? My buddies KX is doing same thing.

Share this post


Link to post
Share on other sites

Why would my rear disc just dish from wear like in the pic ? Mud, dirt,,, but shouldn't the brake pads take the hit before the metal ? My buddies KX is doing same thing.20170508_172458.jpg

Share this post


Link to post
Share on other sites

From that blurry picture I don't see a problem.  A disc will leave ridges on the edges because the pads don't extend all the way to the edge. 

Share this post


Link to post
Share on other sites
2 minutes ago, ttreewalkerr said:

It's dished. Middle is 2mm thk. Sides are much thicker.

Are you saying that it is a different thickness where the pads contact the rotor, thinner in the middle?

Edited by cjjeepercreeper

Share this post


Link to post
Share on other sites
1 minute ago, ttreewalkerr said:

Yes

The rotor is toast. Why would a rotor do that

Variety of reasons.  Bad metal.  Pads rubbing too hard on the rotor causing too much heat when the brake isn't applied.  Riding the rear brake.  There are probably other reasons as well.

Share this post


Link to post
Share on other sites

Hmm,, been riding for 40 years, many bikes, never had a rotor wear out.
Wonder if it was the better after market pads I got,, metal fiber, etc.

Share this post


Link to post
Share on other sites

Mine's similar, but not as pronounced.  Definitely worn more in the middle than the edges, when I mic it it's measurable. 

But that's also with close to 30k miles.

Need to replace them before this season.

Share this post


Link to post
Share on other sites

Pads don't cover entire surface and or if it was wore to rivets a few times will do it

Share this post


Link to post
Share on other sites

The rear rotor on my 2012 wr250r looks the same, so does my brothers klx 300, my neighbors kx 100 and 250.

I blame riding in mud, it gets in the holes/grooves in the rotor and grinds em down, there's no holes in the top edge and very bottom of the rotor to hold the mud so that part doesn't wear as much.

When I need to replace a rear rotor I'm getting a solid one to avoid this.

Share this post


Link to post
Share on other sites

Rotors are wear parts, thats why they sell replacements ,kind of like tires. I get about 6 sets of pads per rotor. I ride in wet and muddy conditions and can go thru a set of pads in 5-10 hours when conditions are bad. Typically  I burn thru rear rotors in about 150hrs. 

Share this post


Link to post
Share on other sites
2 hours ago, ttreewalkerr said:

Hmm,, been riding for 40 years, many bikes, never had a rotor wear out.
Wonder if it was the better after market pads I got,, metal fiber, etc.

:facepalm:

Share this post


Link to post
Share on other sites

Honda, Kawi, and Sukuki use CARBON steel rotors. They are soft, and less grabby (and cheaper).  The pads wear 1/2 as fast as the rotor.

200 hours and they show signs of wear. They are worn out by then if you are an aggressive rider.

KTM uses Stainless Steel hardened rotors, which last longer, are grabby as hell, and also do not dissipate heat very well. But you stop faster. The sintered pads and discs last a long time.

In my opinion they suck for off road, and that is why aftermarket companies sell so many carbon steel rotor replacements for the KTM's. 

Share this post


Link to post
Share on other sites
2 hours ago, ttreewalkerr said:

 

Why would my rear disc just dish from wear like in the pic ? Mud, dirt,,, but shouldn't the brake pads take the hit before the metal ? My buddies KX is doing same thing.20170508_172458.jpg

 

If you look at your pads, they are severely damaged and pitted. That is why you have a strange wear pattern.....plus the discs have tons of hours on them. 

Share this post


Link to post
Share on other sites
2 hours ago, ttreewalkerr said:

20170508_194410.jpg

Maybe the brake pad flexes from the tremendous pressure of the caliper's piston.... It looks like the profile of the caliper's piston wears through to the rotor's surface. 

Share this post


Link to post
Share on other sites

You also have to make sure the pads and the caliper assembly are not binding up and applying drag to the rotor even when you are not stepping on the brake.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×