How big is the ring gear on an HO52/HO72?
 

Just wondering.. I can't find any info on them at all. :flag:

It's been a long time since I called Randy's Ring & Pinion, but they were the only r&p guys that even knew what I was talking about. I can't remember for sure, but they either told me it was a 12¼" or 11¾". Pretty sure they said 12¼".

I will try to measure in the next few days i have a 3.90 gear set setting here to go in mine:flag:

http://www.drivetrainspecialists.com/setupspec.htm

http://www.favorites.com/~jolly/Jolly2500.htm


http://www.dynatrac.com/gm_rear.html

I just eyeballed several of mine, and they're all a hair under 10.5".
Ever since that 4WD magazine incorrectly stated that an Eaton was 12.25", everyone has been using their wrong quoted number.
It feels good to get that off my chest.

Funny thing. After this thread, I was browsing my '72 Chassis Overhaul Manual. It has the ring gear dimensions in it.

Duallie is absolutely right. The H-072/H-052 do not have a 12¼" ring gear. They have a 10 1/8" ring gear. The H-110 (1-ton axle) has the 12¼" ring gear.