rotors

[Sixpaksteve]

Just saw your post that the original O.D. was 10.75. That's close enough to Centric's 10.98 not to cause any problems. Thanks again!

 

[340challconvert]

Steve, I physically measured the width my original 2 piece rotors to get a comparison.
Came out to 10 7/8 in which = 10.875 vs. the Centric rotor at 10.98: (difference of .105) not enough to be of any real difference.
I also went with the centric left and right brake calipers and will also put away the originals which can always be rebuilt and reinstalled if desired)
Good luck with your brake rebuild.

 

[340challconvert]

My original rotors also miked out at .9375 or 15/16 in.
Does anyone know what the minimum safety thickness is for the 70 rotors?
Is this usually listed on the back of the rotor?

 

[Sixpaksteve]

My original rotors also miked out at .9375 or 15/16 in.
Does anyone know what the minimum safety thickness is for the 70 rotors?
Is this usually listed on the back of the rotor?
View attachment 35113

Thanks for the additional info. Paharamia, I appreciate it.

I'm not sure but I think that the 1970 Shop Manual lists the minimal safe rotor thickness. I'll take a look in my manual and let you know....

 

[brian6pac]

I just measured my rotors from a 71 440-6 cuda
2 piece and they are 11 1/8 - 11 3/16 and min thickness is .940, mine are .958 and .937 roughly

 

[340challconvert]

Just the sort of detailed info. I was hoping to receive, Paharamia, thank you very much and I use Rock Auto quite a bit for all of my auto parts needs.

Several follow-up questions....
- Have you installed the Centric rotors yet?
- Are you still running the factory Kelsey Hayes disc brakes?
- Brian6pak brings up a good question re the O.D. difference of the two rotor styles. I haven't pulled a front wheel in awhile to re-measure but if he's correct did you have any problems there?

Thanks!

Steve,
Centric Rotors fit well
Just installed with standard size bearings for 1970.
Fits perfectly within the backing plate

 

[340challconvert]

My original rotors also miked out at .9375 or 15/16 in.
Does anyone know what the minimum safety thickness is for the 70 rotors?
Is this usually listed on the back of the rotor?
View attachment 35113

Picked up a digital caliper from Harbor Freight
Original rotors miked out at .971 and 1.023
In better shape then I thought.

BTW When I pulled out my original Service Manual (70 Dart-Challenger) the original KH disc brake diameter was listed at 11.75 outside diameter. When I measured my "original" two piece rotors, they both measured just slightly below the 11" mark (as noted above). The backing plates behind the rotor only measures out at 11.50. The original rotors I removed fit just inside the plate and looked appropriate. The 11.75 disc size must have been a "nominal" measurement? Anything larger would have been outside the backing plate. Just my thoughts!

 

[quapman]

Bear in mind that when parts like this are cast, the final product out of the foundry can vary a lot. I'm talking a good +/- 1/16" (.063) or more.