Suspensin,Gears,Tires

[86jpcj7]

I have installed a 4 inch suspension lift on my CJ7 and a 1 inch body lift. What size tires do you think I should have with that lift total? Also when telling me what you think can you please tell me the ups and downs of the tire size.

I have stock gears.

Please help and thankyou.:ty:

 

[poppatello]

Well I can tell you that I know you can run up to a 35" tire. But it really depends on what you plan to do with your jeep. EVERYTHING you do depends on what you intend to do with your jeep will determine what we answer to your questions.

I would think if it's just for show you should be able to run 38's or even 40's but you will have little to no flex room to wheel it (mall jeeper).

What is your current gear ratio? That will effect your overall performance on the road...

 

[86jpcj7]

I cant find my gear ratio so im leaning towards 33s that way i dont have to worry about breaking anything. I want my jeep to look good but I will be doing a lot of mudding,crawling,etc.

 

[Old Dog]

If you are going to run it off road and flex it at all 35's will rub the wheelwells front and back.
33's might be ok, if they rub you can move your bumpstops down some.
Your 86 probably has 2:73 gears. I'd be thinking about regearing if I were you.

 

[Petescj]

The crappy gear ratios in the 80s Cjs are one of there biggest downfalls in my opinion. If you have the 2.73 not only do you need to regear you have to get new carriers for the lower gears. 2.73 use a smaller weaker carrier. I would jack it up and check your ratio first though since you really dont know.The largest tire Id run with that ratio is a 31in. and even that is pushing it in my opinion.

If your looking at wheeling your Cj and want it to perform well Id look at 35 in being the tallest tire you can run with your gear ratio being in the 4.10 to 4.88 range.

 

[Fastatv]

I have installed a 4 inch suspension lift on my CJ7 and a 1 inch body lift. What size tires do you think I should have with that lift total? Also when telling me what you think can you please tell me the ups and downs of the tire size.

I have stock gears.

Please help and thankyou.:ty:

You can get fairly close on calculating your current gear ratio. Mark your rear drive shaft, mark one of your tires ( place rear axle up on jack stand ). Slowly rotate the tire, counting the revolutions while also observing the mark on the drive shaft. Count how many revolutions your tire has turned relative to the d shaft turning one complete rev. Lets say your tire turn about 2 3/4 turns relative the the d shaft, then say 2 3/4 equals 2.75....which would be your approx diff ratio. Its not a perfect means of checking as there is another variable there, however, but should get you close.

 

[poppatello]

The crappy gear ratios in the 80s Cjs are one of there biggest downfalls in my opinion. If you have the 2.73 not only do you need to regear you have to get new carriers for the lower gears. 2.73 use a smaller weaker carrier. I would jack it up and check your ratio first though since you really dont know.The largest tire Id run with that ratio is a 31in. and even that is pushing it in my opinion.

If your looking at wheeling your Cj and want it to perform well Id look at 35 in being the tallest tire you can run with your gear ratio being in the 4.10 to 4.88 range.

I've been playing round the gear ratio calculator myself last night just for fun. I had already decided on 4:56 gears. However, something seems wrong. When I plug in my info going from 4:10's up to 4:88's then numbers all come out the same! I couldn't understand that. But when I change the ratio to 5:32's it changed...

 

[Petescj]

What are you using? I use the one below.


Gear Ratio Calculator

 

[86jpcj7]

thanks guys but is there any way of checking the gear ratio with it not running?

 

[poppatello]

thanks guys but is there any way of checking the gear ratio with it not running?

Yes, as a few have posted up you need to spin your tires to count the revolutions on your drive shaft. If you want to just look @ a tag I don't think it will be that easy. I did the drive shaft method myself. Not hard just be safe...

 

[1986cj7]

Or you can pull the diff plate off and count the teeth on the ring gear and the pinion gear and divide the ring gear number of teeth by the pinion number of teeth. This will give you the ratio.

 

[CJim7]

I would stay with 33's.....anything bigger opens up a whole new can of worms, an expensive can of worms. With stock gearing, I can guarantee 33's will be too tall also vs. powerband, but it will be do-able if you are in the 3.xx's, it will be a struggle if you are at 2.72.

For actual fitment, you can go up to 36's with fender trimming and bumpstops. I run 36's this way with no issues, and it's primarily a rock crawler.