What size tires on 83 cj7

[fcb212003]

I am rebuilding my 83 CJ7 and am trying to research the max size tires I can put on my jeep. I am running a rear AMC20 with a 2.73 gear ratio and a front Dana 30 . I plan to install and OME 2.5in TJ suspension. I was assuming that I could run 31s, but I'm afraid my axle will not be able to even handle that. Thoughts? Please don't tell me to replace the axles or drob in different gears because I am trying to keep most of the Jeep stock with this build.

 

[BusaDave9]

You want to keep the gearing as close to stock as possible but you want to see how far away from stock you can go with the tires size. Okaaaay . . .

Lets see. If you go up to 31 inch tires the gearing would be a little taller than stock. In the early '80 the jeeps had tall gearing for the sake of mileage. You can go up a little in tire size but not much. I would say 31 inch would be about it. That would still be tall but not too bad.

 

[Old Dog]

I am running a rear AMC20 with a 2.73 gear ratio and a front Dana 30 . I plan to install and OME 2.5in TJ suspension. I was assuming that I could run 31s, but I'm afraid my axle will not be able to even handle that. Thoughts?.

The 20 and 30 can handle 31's with no problem, it's when you get to 35's and bigger you have problems.
Do you really mean YJ suspension?

 

[PaRenegade]

I would agree with these guys. The axles aren't limiting you, the ratio is. And as someone who ran 2.73's for a lot of years, 31's are about it for them. I ran 32's (11x15) for a lot of years and it was a real dog on long hills on pavement. Off road it wasn't so bad.
Your next issue once you've increased your tire size will be your rear axle shaft. The weak point in those are the 2 pc. axles (hub & splined shaft). You can upgrade these to 1 pc. for a couple hundred bucks. And use Timken bearing and National seals when you do.

I am also doing the swap to YJ Old Man Emu springs on my build. I got the CS036 springs, which are the rear heavy's, to put on all 4 corners due to a hardtop and a winch. The say the ride and flex is great. I'll be running 33's but I also have longer shackles to give me another 1 1/2". That's the set up I have/had now but they were R.C. springs, which combined with 29 year old body mounts made it ride like a tank!

 

[fcb212003]

Do you really mean YJ suspension?

Sorry, I did mean YJ. Thanks.

Thanks everyone for the help. I plan to switch to the one piece axle down the road, but for right now I am going to leave the 20 like it is and spend the money on other items for this build. Saving for the OME springs are tough, but from what I hear it is worth it.

31s it is!!

 

[PaRenegade]

Yes, it's not a cheap move and if I wasn't doing a complete rebuild I might have went another way, in fact that's not the direction I was initially heading but as I started piecing things out price wise, it wasn't much more since I was already buying some pieces anyways. You can buy the springs alone for $98 each. The bushing you have to buy separate though.

 

[hole]

I just did the OME YJ conv, you're going to like it! My 8 is an 83 with 2:73's as well, so I went with 30's for that reason. I havent noticed any great power loss.

 

[CJs 7]

I am running a 4.5" RE Lift and 33" tires and 2:73 gears. It is doable, but I live in Florida and it's flat. I never use 5th gear, won't hardly even pull it, pretty much have to keep it matted in 5th to maintain 60 mph. I don't off road it much and not hard when I do, so I can't really comment on that. I do intend to change the gearing one of these days.

I upgraded the axles to one piece, only because the seals were leaking and I had it apart anyway.