Help Me Pick A New Tire Size

Here are some specifics on my Jeep:
1956 CJ5 with rancho springs (approximate 2” lift, I believe)
“Stock” 16” wheels that are pretty narrow (4.5” width, I think)
198 v6
Sm420 transmission
5.38 differential gearing
Power steering

Jeep currently sits on 6.00-16 tires, which are really old and need to be replaced. They also look too small given the lift, and their small circumference makes the top speed crazy slow. I feel like 50mph is about the max I can go and I never even use first gear. I want to keep the old school look, but definitely want a bigger tire.

is a 7.50-16 tire too wide for the 4.5 wheels? Will they look too big on my Jeep?

Any thoughts and/or pictures would be greatly appreciated.

 

6.50 x 16 is a notable improvement over the 6.00 and military settled on 7.00.
But 7.50” are certainly doable and generally considered to be the max diameter and width on a stockish type Jeep with Ross steering.
Personally I no longer will buy the 6.00 tires.
I like the STA 6.50 tires o.k. but most of my tire sets 7.50’s.
That said the narrow rims are really only ideal for the 6.50 tires and probably ok for 7.00 tires too.
Best to get a little wider rim if you go to 7.00 or 7.50.

 

Thanks for this info. I forgot to mention that I do have power steering. I added that info to the original post.

Will a 7.50 tire be dangerous on a narrow wheel?

 

The level of danger is probably relative to the speed being traveled. If it's a farm-based rig (doubtful from your pic), that only sees 10-20mph on soft soil, I'd say it was fine. On hard surfaces, though, i feel like that thin of a rim will cause the tire tread surface to curve up and out, prematurely accelerating wear on the center of the tread. Not sure how I feel about the pressure at the safety bead, either.

 

Well then steering is not much of an issue with your tire selection.
For starters jeeps are notably light weight.
As a tire gets wider the load capacity goes up.
To a lesser extent tire load rating also increases as the diameter increases.
And so to achieve correct tire contact patch with the pavement a Jeep with oversized tires will need the pressure reduced.
When you have 6.00 x 16” tires let’s say the maximum pressure is about 30 psi.
With 6.50 tires, that maximum pressure will drop to about 27psi.
7.00 at roughly 24 psi and 7.50 at perhaps 21 psi.
The pressure drop is mostly a good thing for off road use but not so desirable for road use.
If you run a tire that is normally too wide for a given rim width, then the “ crown “ effect of the tire tread is being diminished as the pressure is being dropped.
There is a simple method by which one can determine optimum “ on road” tire pressure after mounting the tires onto the Jeep.
With normal loaded Jeep setting on smooth flat concrete .
Air up all tires to 32 psi.
Wet the tread surface with water.
Roll the Jeep across concrete to see how much tread makes contact .
Lower all tire pressures equally until tread contact occurs across full with of tread.
That is the on road pressure you should be running and it compensates for non standard rim or tire sizes.

 

Chalk lines sideways across the tire tread then going for a short drive works well too. If there is still chalk on the outer edges of the tread, lower the pressure.

 

I have bias 7.50 on 16" rims.

20200402_164500 by Joe with a jeep, on Flickr

4.3 t90 and 5.38 axles
I had a 200ci Chevy but sank it and went to the 4.3 for cost savings. with the Overdrive it would go as fast as a CJ5 ever should. These things get sketchy at speed so don't try Kansas city rush hour but I didn't have any issues driving an hour to Kansas city in college. I also drove with the f134 from Rochester New York, to central Missouri three times the last trip was with a trailer. Those trips were a steady 60mph.

You will want to upgrade brakes to 11" drums or disks

 

Thanks. Those look great.

 

I have bought these tyres, they are of good size 6.5 R 16 when you look at them , and the look of the Jeep is correct, not small tyres.

 

Switch to radials and you'll think you have a new jeep. 215/85r16 would be a good size.

 

Patrick put some good-looking radial M/T style tires on his flat fender a few years ago, but I have not found the thread. Yokohama? Something. Firestone makes a 215/85R16 Destination M/T that is a very aggressive tread. Spec'd for 5.5" rims, but I expect they would be ok on 5". No worse than 7.50-16 bias ply, I'd think. Goodyear Duratrac also comes in that size, a less aggressive tread, and is well-regarded by the owners of KLs like my Cherokee.

 

I have P225/75R16 on stock 4.5" rims. Guy at the tire shop said wear pattern will be sub optimal but that it's safe. I think they don't look the best for stock appearance but they ride well. With stock springs on a closed knuckle front axle the tires are not the limiting factor in steering.


PS with 5.38 axles an overdrive is a game changer.

 

Thanks everyone. I ended up ordering byas ply 750-16 tires, as I really want to retain the old school look. I also have a set of 6” wheels that I could mount them on if the 4.5” wheels prove to be too narrow.

I’ll report back with some pictures once they arrive and I can get them mounted.

 

So I ended up getting the speedways brand “military” model tire in 7.50-16. I haven’t mounted them yet, but first impression is that they look very nice but are extremely small. 30.25” tall and they’re only 6” wide from end of the lugs and about 6.5” from outermost point on the sidewall. Glad I didn’t get the 7.00 size. They’d probably be smaller than my current 6.00’s!!! Lol.

 

installed my new tires. ended up buying the md Juan reproduction combat wheels, which are pretty sweet. I’m really happy with the wheels and tires. They drive nice and smooth and the size fits the Jeep better than the old ones.

as I mentioned earlier, these are quite small for a 7.50 tire, which is good as they fit the narrow Jeep wheels perfectly.

 

That's a great look on your jeep. Mine has a 3" Black Diamond lift and I went with just some cheap 15x8 black wheels and 33 10.5 15. But a little late to help change your mind!