Jeep Riding Today

Three of us with CJ-7s went on a little central Texas Jeep tour today. We drove 122 miles of paved farm-to-market roads in the hill country. We only occasionally got over 50 mph but pulled several pretty steep inclines and my buggy managed almost 21mpg. I'm pretty happy with that but I still think I could regear to 3:54s and probably not hurt things. It has the stock 2:72s currently and 30" tires. 258 and 4spd.

 

I once owned a 73 cj5 with the 232 cu. in straight six with the factory 3.73 axles. under the same conditions you described I routinely got 21-22 MPG. But it was the 232 instead of the 258.

 

I didn't know there were ever such a high ratio as 2.72. Learn something everyday here on this great forum.

 

I couldn't remember exactly earlier; 2.73s I think is the correct ratio. If I'm not mistaken again, 41 teeth on the ring and 15 on the pinion.

 

2.72/2.73 were later model CJ-7. It was the only ratio that required a case change on an AMC Corporate model 20 rear differential. Not common at all. I think a swap to 3.73:1 or maybe even 4.10:1 would be beneficial. But, free advice is worth what is paid for it.

 

My son had an ‘81 CJ7 with 2.72/2.73 gearing. Even with a 304 and 31” tires, it would barely pull itself in fourth gear. 4-anything would be much better!

Jon B.

 

My other jeep is a CJ2A with 6.00-16 NTDs and it looks right to me. Maybe because of that I'm just not into big tires, my 30s seem big compared to the NTDs on the flat fender. I used the speed/rpm calculator on Randy's site and 3.54s seemed about right for my CJ7. I'll put a posi in the back and leave the front open.

I don't do rock crawling or hard core offroad wheeling. The worst my jeep might see is a little mud on a ranch road headed to a deer blind.

 

A Hill Country ride is awesome, especially in the Spring or Fall.