So are there two different rear rotors for the 2500HD's?

I bought aftermarket EBC dimpled/slotted rotors for a "2005 2500HD" (obviously), and I go to put them on and the rotor hat on the EBC rotors measures ~2 1/4" tall and the stock rotors' hats are ~2 1/2" tall. So the EBC rotors dont go "in" far enough and obviousy the calipers and caliper brackets dont fit.

Only thing I can think of is the hats are different sizes on the 10.5" and 11.5" rear axles? I ordered from ............ and just used their "vehicle locator" to search parts. The rear rotors I got are EBC part number GD7210

But if I look up a GMC Sierra 2500HD, It shows GD7216 as being the rear rotor part number. So maybe its just an error in their website, and I need the GD7216 rotors which might have a taller hat?

anyone have any ideas?

arrghh!!!! :mad:

ben

alright I did a little research and it appears there are two different size rear rotor hats and hub holes. Typical GM.

one is an 86mm hat, the other is a 92mm. I received the 86mm rotors, and my stockers are 92mm. I looked around and found the equivilent EBC rotors in the 92mm hat size are GD7216...

I have the new front rotors and pads on already, but Im still breaking them in so I havent had a chance to really test them. They feel amazing so far though...

Always has to be something....Murphys law ya know :)

Ive been lookin into some brake upgrades....keep us updated when you get everything installed and the pads are broke in with some feedback on how they increased performance.


EDIT: How bout some pics of what ya got right now :D

Sorry to hear about that Ben... good luck with getting the new ones.


And technically uh..... shouldnt you remove that vendor link from your post? :D

Sorry to hear about that Ben... good luck with getting the new ones.


And technically uh..... shouldnt you remove that vendor link from your post? :D


:banghead: :o:

Ben, did the dealer accidentally get you the 'regular' 2500 rotors?

alright I did a little research and it appears there are two different size rear rotor hats and hub holes. Typical GM.

one is an 86mm hat, the other is a 92mm. I received the 86mm rotors, and my stockers are 92mm. I looked around and found the equivilent EBC rotors in the 92mm hat size are GD7216...

I have the new front rotors and pads on already, but Im still breaking them in so I havent had a chance to really test them. They feel amazing so far though...

Why does GM do this? I freaked out last night after reading your post, thinking I put the big ones on the small one. :o: Turns out I also have the 4.84" rather than the 4.63". My friend's NAPA shop never asked me what size I had. :eek:

Glad you were able to find out what was wrong.

I replaced mine at all 4 sides with slotted rotors and non ceramic pads . I will never go back . I may replace pads every 35k and it may be a bit dirtier but it stops !

Did you use EBC pads and rotors too Chris?

Ben, did the dealer accidentally get you the 'regular' 2500 rotors?


Juice thats the first thing I thought of...maybe they got me 1500HD/2500 Suburban rotors...

Or the 10.5" rear axles have the shorter hats?

Either way, Im going to have to send them back... :mad:

That sucks!!!! Nothing worse that trying to do a job and then finding out it is not the right parts. Especially after have to brake those damn bolts!!!!

How did your brake install go Ben? Everything turn out swell with the new rear rotors? How do you like them? Im thinking this EBC route is for me.

There is a difference between the brakes on the 6.0 2500HD and the brakes on the Duramax/8.1. I had a picture of them side by side not too long ago but can't find it.

Good Luck

There is a difference between the brakes on the 6.0 2500HD and the brakes on the Duramax/8.1. I had a picture of them side by side not too long ago but can't find it.

Good Luck

10.5" rear axle vs. 11". The rotors for each axle have different hat heights. 86mm vs. 92mm.

If this is the case, then why do the part numbers match for both 2500 and 2500HD? Am I missing something here?

I do know about the 4.84 - 4.63 diff though. Makes buying parts tough, as you have to tear the axle down first, then buy the parts...but then the truck is down, so what do you drive? Just stupid on AAM's part.

This reminds me of when I had to buy rear brake and wheel parts for my 1994 K2500HD 6.5. On those the gasser models got the 9.5 axle and the diesel got the 10.5. They would ALWAYS try to sell me the wrong parts and argue with me.

There appears to be no rhyme or reason as to which rotor to use. I've always had to measure the center hole when ordering rotors on my 2500s.

Heck, I've gotten three three sequentially serial numbered trucks and even the AM/FM antenna was different on one.

I think its just GM being confusing, coupled with the "parts selector" feature on websites being inadequately informed.

This may sound like a simple question but how do you find out what size hub/rotor you have with out taking the rear tire off? I am going to do my rear brakes and the part store said to take off the old one and bring it in to size it up,da. But I only have the truck to get to the part store so I need to figure out the size before I go.
Thanks for the help,
Rice FARM

10.5" rear axle vs. 11". The rotors for each axle have different hat heights. 86mm vs. 92mm.

Exactly. I came across this when doing my 2500 last year. Since I have the 2500(LD) it has the 10.5" and takes the 86mm. The Duramax (and 8.1) have the 11.5" and takes the 92mm. They sent me the 92mm, and I was trying to put it on, and was looking at it, nope that ain't going to work. Its a bit of a headache, no matter where you get them. Parts guys aren't usually mechanics for a reason. Of course there are exceptions...

I have had the same problem trying to figure out which rotors I have on the rear. I finally called the dealer and gave them my VIN#. They came back with the 4.84in or 330.4 mm x 90mm size. It's been a pain in the butt sorting this out.

If the rotor dimensions are the same why not just order the larger one and call it a day? A small peg will fit in a big hole just fine. :D


I'm ordering new rotors and as much as I hate to pay more I like the idea of zinc coating them. The stockers rust out so damn bad. Well unless I buy some spray galvanizing and go to town.