Largest tire size for stock (no lift) 83 CJ5
- Thread starter Wyohab
- Start date
codesertrat
Geoff
31x10.5R15
Lee_N
Member
I have a bone stock YJ with 30X9.50s mounted on the stock 15X6 rims. I rub lightly on the front springs when turned hard but otherwise clear. I haven't tried 31s but looking at how mine fit, I don't see that there is enough room for anything bigger. Rim selection would be critical. I'm not sure if a CJ has more room but I always thought it was about the same.
codesertrat
Geoff
I owned a '79 CJ5 for many years and have been around and worked on many other AMC-era Jeep CJ's, and that size fits fine on the stock suspension and wheels. I think it was a factory option for some years, but I could be wrong. '76-'83 are all identical in regard to suspension since there were no wide-track CJ5's. I later put a 2.5" lift on mine with 33x12.5R15 which did rub the springs when turning tight - a slight adjustment of the steering stops on the axle solved that.
Any good quality heavy duty shock will be fine. Gas-charged is always good to prevent shock fade on washboard roads.
'83 is the last year for the CJ5, have you got any pics of it? I've got a soft spot for Jeep CJ's!
Any good quality heavy duty shock will be fine. Gas-charged is always good to prevent shock fade on washboard roads.
'83 is the last year for the CJ5, have you got any pics of it? I've got a soft spot for Jeep CJ's!
codesertrat
Geoff
CJ's do have a bit more tire room that the YJ's due to the CJ's taller height, bigger wheel openings, and narrower spring width. '72 - '83 CJ5's can fit slightly larger tires than older CJ5's too due to the AMC body and chassis changes in '72.
What gear ratio do you have in your '83? Some of the 1980's Jeeps had very high axle ratio's (2.73 - 3.08) to help meet government fuel economy standards which may make it seem pretty gutless on 31" tires, especially at Wyoming altitudes. In that case, a 30x9.5 may be better.
Thanks for all the responses.
The reason I am looking at bigger tires is that I'll be doing a lot of driving on washboard roads. My thinking is that with a larger tire I'll be able to air-down more to save my kidneys while still remaining in a safe load rating.
I'm not sure on the axle ratio - I've just pulled the Jeep out of the barn after not starting it for almost 10years. It was an impulse purchase when I was in PDX many years ago. I grew up with a '66 w/ the Buick V6 and always wanted another. When I found an 83 with less than 50k city miles - I just bought it. Now I'm going to use it.
The reason I am looking at bigger tires is that I'll be doing a lot of driving on washboard roads. My thinking is that with a larger tire I'll be able to air-down more to save my kidneys while still remaining in a safe load rating.
I'm not sure on the axle ratio - I've just pulled the Jeep out of the barn after not starting it for almost 10years. It was an impulse purchase when I was in PDX many years ago. I grew up with a '66 w/ the Buick V6 and always wanted another. When I found an 83 with less than 50k city miles - I just bought it. Now I'm going to use it.
Zeiderman
Adventurer
I would think that better shocks and a softer spring rate would be much easier than airing down and up. Have you considered how you are going to air up once your off said washboard? CJ lifts are fairly inexpensive, I went full Pro Comp spring lift with shocks and stabilizer, Spydertrax spacers, Currie shackles and Bushwacker flares with cut out and stayed under 1G'ish. Well able to run 33x12.5x15.
Happy Joe
Apprentice Geezer
IMO, codesertrat hit it nearly right on the head with 31 inch tires.
...some points... Tires are rarely the size specified on the sidewall (usually they are undersize diameter wise).
The rear wheel openings of my CJs and YJs, over the years, would not take a 33inch(size on side wall) diameter tire at full stuff without rubbing/damaging the tires and/or the sheet metal.
The largest tire that I have been able to use in a stock sprung CJ was an undersized 32 x 11.50 ... it would rub occasionally on the street but not enough to damage the tires or sheet metal (your results may be different).
IMO, the shock absorber mounting points of CJs need to be moved to enable the use of longer shocks (if difficult off roading is planned).
I have been universally dissatisfied with the ride given by "Heavy duty" or "off road" shock absorbers, for the stock springs and shock mounts I found that brand name regular duty replacement shocks (from autozone or other store) give the best ride, good life and reasonable cost.... find a store with a friendly parts guy/girl that will go through the boxes to find the right length if the springs have been replace with lifted springs or if they have sagged.
I like the ride that soft springs give.
If planning a spring lift try to get low spring rate springs and avoid stiff "lumber wagon" extreme arch lift springs.
For my '81 CJ-5 and my current CJ-7, I used stock YJ hard top 6 cyl. springs (lift kit take outs) in the rear I believe they have 5 leaves, avoid the YJ 4 leaf soft top springs they seem to bend pretty easily. Initially install the stock shackles then if necessary, make shackles to adjust the ride height give or take an inch or so from stock (adding 1 inch of shackle length will give roughly one-half inch of additional height. but do not use the shackles to try to get more than an inch of lift.
NOTE; if you wheel it hard YJ springs will eventually assume a W shape and sag but it normally take several years.
For those that want to use 33 inch to 35 inch tires with a compliant suspension I would suggest investigating cutting the rear wheel openings and adding TJ rear flairs (35s will necessitate slotting and bending the metal lip at the front of the wheel well and probably bump stop modification and lift springs).
To avoid loosing too much performance, I do not recommend significantly increasing the tires size more than 1 or 2 sizes over stock without re-gearing the axles to compensate.
Airing down is the cheapest, easiest way to get traction, but the tires should be aired up to highway pressure before getting back on the road (most carry a compressor for this). airing down a 16.5 inch tire wheel combination will probably result in the tires becoming unseated but no other size that I am aware of is as problematic; though tires at low pressure can become unseated in any size... just know and be prepared to reseat tires on rims (15 psi will normally retain the tires on the rims but only gives a marginal traction improvement)
Enjoy!
...some points... Tires are rarely the size specified on the sidewall (usually they are undersize diameter wise).
The rear wheel openings of my CJs and YJs, over the years, would not take a 33inch(size on side wall) diameter tire at full stuff without rubbing/damaging the tires and/or the sheet metal.
The largest tire that I have been able to use in a stock sprung CJ was an undersized 32 x 11.50 ... it would rub occasionally on the street but not enough to damage the tires or sheet metal (your results may be different).
IMO, the shock absorber mounting points of CJs need to be moved to enable the use of longer shocks (if difficult off roading is planned).
I have been universally dissatisfied with the ride given by "Heavy duty" or "off road" shock absorbers, for the stock springs and shock mounts I found that brand name regular duty replacement shocks (from autozone or other store) give the best ride, good life and reasonable cost.... find a store with a friendly parts guy/girl that will go through the boxes to find the right length if the springs have been replace with lifted springs or if they have sagged.
I like the ride that soft springs give.
If planning a spring lift try to get low spring rate springs and avoid stiff "lumber wagon" extreme arch lift springs.
For my '81 CJ-5 and my current CJ-7, I used stock YJ hard top 6 cyl. springs (lift kit take outs) in the rear I believe they have 5 leaves, avoid the YJ 4 leaf soft top springs they seem to bend pretty easily. Initially install the stock shackles then if necessary, make shackles to adjust the ride height give or take an inch or so from stock (adding 1 inch of shackle length will give roughly one-half inch of additional height. but do not use the shackles to try to get more than an inch of lift.
NOTE; if you wheel it hard YJ springs will eventually assume a W shape and sag but it normally take several years.
For those that want to use 33 inch to 35 inch tires with a compliant suspension I would suggest investigating cutting the rear wheel openings and adding TJ rear flairs (35s will necessitate slotting and bending the metal lip at the front of the wheel well and probably bump stop modification and lift springs).
To avoid loosing too much performance, I do not recommend significantly increasing the tires size more than 1 or 2 sizes over stock without re-gearing the axles to compensate.
Airing down is the cheapest, easiest way to get traction, but the tires should be aired up to highway pressure before getting back on the road (most carry a compressor for this). airing down a 16.5 inch tire wheel combination will probably result in the tires becoming unseated but no other size that I am aware of is as problematic; though tires at low pressure can become unseated in any size... just know and be prepared to reseat tires on rims (15 psi will normally retain the tires on the rims but only gives a marginal traction improvement)
Enjoy!
Last edited:
cruiserdude80
Observer
I had a 69, and 76 CJ 5, 78 CJ 7 and ran 32x11.50s on all of them with the stock suspension. I did have some rubbing while off roading which was minimal. You can run 32s but the biggest problem will be performance with stock gearing.
31s are a good size to run on a stock CJ too.
31s are a good size to run on a stock CJ too.
Happy Joe
Apprentice Geezer
It depends on the actual size of the "32", almost all of the new tires that I have measured were under sized by some amount; some fit and some hit and there is no consistency between manufacturers. The 32s that I mentioned above actually measured less than 31.5 inches in diameter when new and they still rubbed on the street...
If you measure the stock wheel CJ/YJ rear wheel openings and do the math (since you can't get a direct measured diameter due to the shape of the wheel opening/curve at the back) you will find that 33 inch measured diameter tires will rub, and 32 inch measured diameter tires will probably rub at full stuff (the axle will move a bit front to back as the tire goes up and down); if you run narrow enough tires on narrow rims and axles you may be able to miss the sheet metal though... I like FAT tires and so have never tried this.
I would say; play it safe and do a test fit before purchase if you plan to try to run 32s; on a CJ/YJ especially off road.
Besides the tire size variability; there is some wheel opening position tolerance and some body and axle position tolerance so tire fitment can, sometimes, be a matter of luck.
I agree that for most, especially newer CJ's and YJ's the OEM axle gearing is not usually low enough.
Enjoy!
If you measure the stock wheel CJ/YJ rear wheel openings and do the math (since you can't get a direct measured diameter due to the shape of the wheel opening/curve at the back) you will find that 33 inch measured diameter tires will rub, and 32 inch measured diameter tires will probably rub at full stuff (the axle will move a bit front to back as the tire goes up and down); if you run narrow enough tires on narrow rims and axles you may be able to miss the sheet metal though... I like FAT tires and so have never tried this.
I would say; play it safe and do a test fit before purchase if you plan to try to run 32s; on a CJ/YJ especially off road.
Besides the tire size variability; there is some wheel opening position tolerance and some body and axle position tolerance so tire fitment can, sometimes, be a matter of luck.
I agree that for most, especially newer CJ's and YJ's the OEM axle gearing is not usually low enough.
Enjoy!
Last edited: