C5 REAR Rotor Dimensions

[Mean 69]

I have searched, but didn't come up with the answer I am looking for. Can anyone specifically share the rotor dimensions for a C5 rear rotor? The main thing I need at this time is the "ID" where the rotor hat would mate with the axle, or rather I need to know the required OD of the axle. Also, the dimension of the mounting "hole" on the rotor where it becomes "centric" with the hubs. Further, if there is info on the caliper mounting details, that would be huge too.

I do understand that it is easier to adapt the LS1 brakes, but that is not what we are intent on doing, so info on this way to do things is not needed for us, at least at this time.



Muchos gracias!
Mark

[MrQuick]

heres the bracket, i have a rotor at the shop.

[shep]

Here is a guy with mounting brackets that will send you the dimensions.

http://www.chevelles.com/forums/showthread.php?t=101433

[BMullin]

The deminsions on a c5 Vette 97-04 are 305mm (12.01") X 25.80mm(1.018") wheel register is 2.784" and the stud pattern is 5 on 4.75. Hopefully this is all you need. If not let me know i will do what i can to get an answer for you.

[Q ship]

heres the bracket, i have a rotor at the shop.

Vince, is that a C5 specific bracket? It looks like pics I have seen of the LS1 bracket. Does the axle offset of a 10/12 bolt work with the C5 stuff?

[MrQuick]

Hi Brian, no that is an f-body bracket, i was trying to sneek that one in. the c5 is way different and it looks like to might have to fab a flange mount. i wil try to get a close up view tomorrow.

[Q ship]

Ah darn. I was hoping!

[MrQuick]

you know Brian, not to fan the fire burning in your wallet but this should be availible soon.... [url] sorry i had too...I saw you over there.

[Mean 69]

Okay, Vince, you brat!!! That is THE reason I am so intent on running the C5 stuff front AND back, on the new kits. Sidenote, PBR has no current intentions of releasing the calipers to the aftermarket, the answer I got was capacity reasons (hopefully that means that they are making bunches of C6-Z06 cars!!!!), but it will only be a question of time.

Umm, gee, got an extra set or two?
M

[MrQuick]

I knew that would get you attention....the C5 and LS1 calipers are the same so that means same mounting. LS1 bracket should work with C6 Zo6 too.

[zbugger]

Damnit Vince!!! I gotta get one of those mini spy cameras and mount it to your forehead...

[Mean 69]

the C5 and LS1 calipers are the same so that means same mounting. LS1 bracket should work with C6 Zo6 too.

Can you clarify that, please? I have a set of LS1 abutments and rotors that I bought, thinking that I could trust part number information from a website that no longer seems to be posting this information, that was listed under a "Rear C5 Brake Upgrade." Never cross-referenced the part numbers, and now that we have parts in hand, it is obvious that the true C5 stuff is not the same as the LS1 in several regards.

The Ls1 rotors have about .5" more negative offset (i.e. inboard) than a trusted but older measurement of a C5 rotor. Additionally, the LS1 abutment "must" be different in terms of offset dimensions, from the C5 abutment. Ls1= GM# 12456459, C5= GM# 12455800.

What we are specifically looking for at this point is the mount-to-centerline of the C5 abutment bracket, GM# 12455800. In other words, if you looked at the caliper bracket (abutment) viewed from above, what distance from the inboard mounting surface to the centerline of the bracket (which is also the centerline of the rotor when installed)?

Lastly, I have read that the C5 and LS1 calipers are the same, can someone substantiate this as fact, i.e. are the part numbers the same for the calipers, if not, what specifically is different about them? Mounting pins, etc the same?

Thanks guys, we could really use the facts right now.
Mark

[MrQuick]

Sorry Mark, that should of been question mark after that statement. I'll find out tonight. I have both set ups at the shop.
I think I found that the calipers in mounting sence where the same. Im sure there are differences in piston size. Jeff and I went over this a few years ago. i will take measurments and pictures to make sure...my CRS is working over time.

[jjump59]

I used C5 calipers on the LS1 abutments, no problems at all. I also used the Z06 rotors which required a spacer between the abutments and the axle housing to make it all line up.

[Mean 69]

I also used the Z06 rotors which required a spacer between the abutments and the axle housing to make it all line up.

Do you have an exact measurement of how big the spacers were? That is the dimension we need. Well, that and of course if the pistons are different, which one is what, etc.

Gracias!
M

[Q ship]

I used C5 calipers on the LS1 abutments, no problems at all. I also used the Z06 rotors which required a spacer between the abutments and the axle housing to make it all line up.

Jeff, the last week's been bad-I was sick and my brother in California had a heart attack. I still want to try and see the setup you have, I will call tomorrow(kinda late now). Thanks!

[Q ship]

true C5 stuff is not the same as the LS1 in several regards..
Mark

Mark, jjump59's post got erased in the server meltdown, but he mentioned that the C5 backing plate and abutment were different than the LS1 pieces. It sounds like he is running the LS1 backing plates and abutments, with the C5 calipers (which look like they interchange ). To run the C5 rotors vs the LS1 rotors, there has to be spacers to offset the rotor height differences.

The pics of the calipers come from 72ssabody's site -Joe mentions the caliper interchange also.

There are good reasons to run the C5 rotors over the LS1's even if you are not looking to go C6 stuff.

[MrQuick]

Hey Mark, I have the pictures coming your way.
The Ls1 calipers do fit on C5 Z06 and visa versa. There is a difference with pad mounts. So that means you should be able to mount the C6 Z06 caliper on an LS1 set up but you would have to use the LS1 rotor unless you like the holes?

[Damn True]

The thickness of the two is the same?

Just a guess, but is the reason that the Vette is lighter thus less heat created in stopping thus it can get away with a thinner rotor?

[MrQuick]

The Z06 rotor is .200 thinner...the calipers are the same in that aspect. They make up the difference in pad thickness.