Tire Fitment And Lift Questions

Greetings All: I recently bought a 69 CJ5 with a V6, I found this forum and it seems dedicated to earlier Jeeps, where some other forums cover all Jeeps, which is a huge variety. The CJ now has some 29-30" tall repro tires on it now and some pretty flat springs. The Jeep came with a new set of leaf springs and they are not going to get me where I need to be. I plan on doing some trails and mud with it, so I need much better tires.

I would like to keep the tires inside of the wheel wells, so I am looking at narrowish tires. I have narrowed it down to two options from Interco. The first is their narrow SS TSL. It comes in at 33.8" tall and they spec 7" wheels for these with a sectional width o f 9".





The second is Bias SS TSLs, they are 35.5 and they spec a 7-8" wheel for these and the sectional width is 10"


The second set weighs 68 pounds each, which is going to be very hard on the old Dana 27 up front. It will be replaced at some point, but there are a couple of trail rides coming up locally that I want to make it to, so I may have to baby it some with the larger tires, if I can make them fit.

I have been looking at a lot of pictures of various tire and lift combos and I think I would be able to fit t he 34s with a 4" lift. The 35s may require a 6" lift which makes it more top heavy.

I am looking for input on what will fit and work. I'd love to go with the 35s, but can I keep them in the wheel wells and how much lift do I need? I am open to ideas and suggestions.

Thanks, Andy

 

Those tires are good for mud and only mud.
34 is pretty big for a cj, you won't be turning left and right much.

 

I can already hear those protruding lugs hitting the leaf springs.

And a six inch lift is Bigfoot stuff.

 

The first step with tires is gear ratio. IMHO 33's are going to push the envelope with stock 3.73's, especially with the 3 speed. 35's are going to throw first gear right out the window.
Next is the transmission. The T14 is marginal at best and bigger tires are going to tax it to it's limit.
If you have the stock Ross steering, you can toss those 34-35's out the window.
Stock 10 brakes are mediocre at best. Again, big tires will tax them as well.
I've fit 33's under a 2.5" lift. Wheel spacers were necessary to get any sort of turning radius. You'll need a 4" for anything bigger.

If you are pretty new to CJ's and perhaps wheeling, I would suggest:
2.5" lift
31" tires in your flavor of tread.
Drive it a while and see what your next step may be.
I would be much more inclined to install an LS in one of the axles and keep the tire diameter a tad smaller.

 

We have been playing with our Cj (v6) on our property for a year or two. The only way to get this thing stuck is to high center- usually trying to jump a too large downed tree. It’s not rock crawling but a lot more than trail riding. This jeep mountain goats over things with ease that I wouldn’t dare with our 35” tired k5

Our jeep has the dauntless, some form of limited slip in the rear, assuming stock springs, and 235/75/15s that came off a parts truck. Front tires are highway tread. Back are mud tires.

I humbly suggest trail riding as is. You will get a feel for what’s actually needed. Like a full belly pan.

 

With 31's you don't even need a lift, and it will still climb like a goat.

 

True, but you go from virtually zero articulation with old flat springs to about five inches with the new lift and have a better ride to boot.

 

Greetings All: Thanks for the replies. I guess some background on myself is in order. I'm old, I've been off-roading and drag racing since the late 70's, back then I had two Chevy 1/2 ton short bed trucks. Between the two trucks, I broke at least one of every drive train components, except the 203 transfer cases, the 1/2 ton drivelines were not heavy duty enough. I had 38" Denman Gumbo Monster Mudders on one and 38" Ground Hawgs on the other. Even though those are mud tires, I never had any problem on any trail or surface. I've done some rock crawling, but it's not my thing, I prefer difficult trails and mud. I know where I'll be going here in TN and KY I will run into plenty of rock, but I don't shy away from purpose built mud tires like Intercos.

I also had a '67 CJ5 with the same tires that are on my Jeep now, I believe it was originally the old Firestone mud & snow tread pattern, these are STA repro tires, they are like new and they are very good off-road. My old '67 was at a decided disadvantage when it came to muddy, rutted trails.

Then in the 90's I built a '68 Dodge Power Wagon, that was the last year for the old school flat fender, flathead engine Power Wagon. That had 38" Gumbos on it. I traded it for the M-37.

The '54 Dodge M-37, I put on 38" Boggers, rear locker, 416" Dodge small block stroker, power steering and on and on. Like an *******, I sold it, that was a huge mistake, but she's gone. It was nice and short and narrow, for what it was, that was an awesome truck and would go damn near anywhere. I have a buttload of old school pictures of that truck off-road, but having recently moved, it may take me a while to find them. If I come across an M-37 with a solid body, I'll likely buy it and duplicate what I had.

So the Jeep I just bought has the Dauntless V6 and it runs pretty well, I'll pull it in the winter and do a complete rebuild, I hope there is enough meat left in the block so I can have the cylinders bored and start with a new set of pistons. Then cam, balance it, get the compression as high as possible. I have to learn about this block to see if I can go with a zero deck height and still have valve clearance with the pistons, I can always order custom pistons. I love the 225, I wish it were even fire, but whatever. I need to do something with the trans and I'm open to suggestions. I need to look at TB injection vs. the old Rochester 2 barrel which isn't a bad carb.

It came with a DUI HEI distributor, but the previous owner said it wouldn't completely seat. I don't think it's anything terminal, I'll check that out when I get back from the extended business trip I'm on. It also has a factory rear limited slip, 4.88 gears and a Saturn overdrive.

I would like to pull the body off, fix the minor rust issues it has, have it dipped and painted to keep the rust from coming back but that probably won't happen this winter.

So When I get home, I'll do some checking to see what tire I'll be able to fit, for now, I have time on my hands to keep doing research. It's very tempting to take the easy way out and throw a 2.5" lift and some 33" tires regular mud tires on it, but then I need to find that M-37 I'm looking for. At least with 33s, I can stick with the manual steering.

So that's enough about me and what's in the past, this CJ5 is what is next, I feel like I have a good starting point.

Thanks, Andy

 

This may be useful.

 

That's an interesting chart, thanks! I'm not a fan of body lifts, whatever lift I do will be springs. It's so frustrating to be sitting and a hotel room when I could be at home. When I do get home I can do some mocking up and checking to see what if the 34s are even possible with a 4" lift and the correct wheel offset.

I love your CJ3B, I found a great one near home recently, but the thing was darn near impossible to get out of, and I'm not a fatass, I don't know if it was the seats that he had, or they are all like that. I don't remember my friends CJ3B being that hard to get in and out of, but that was back when I was in my 20s.

I think the stock CJ5 wheel backspacing is 3.75", correct? Whichever tire I end up with, I'll probably go with 16" wheels, so I don't ever have to worry about clearance when I go to disc brakes.

Thanks, Andy

 

It's also worth noting that most gear makers don't warrant 34's on even a dana 30.

here is the last page of the standard gear install manual.

 

Oddly enough, the last reply only shows up on my phone. That's an interesting chart, I'd agree with most of it.

 

I ran my CJ on 31 x 10.5 on a 3" lift with the old "4 wheel RVT" tires, they were similar to "ground hawgs" in tread pattern on 3.73 gears.. I then went to 4" lift with 34 x 10.5 super swamper LTB with 4.27 gears. This was in NE TN and always did good.

They are selling Buckshot mudders again as well i N78..

 

And I just came across these in a random search.. never heard of them before..

https://tirestreets.com/products/ac...dkeldSvnkGNF5qzb_PK4023zXo384dsMaAmGrEALw_wcB

 

The V6 is a great motor and baring damage, should bore out nicely. The biggest issue for your application is the engine itself. They were inherently unbalanced due to the odd fire design. Buick's answer was to install a massive flywheel (up to 75LBS). This makes it an incredible torque monster but really limits the speed the engine spools up. This is one of the reasons they were never very popular with the speed crowd.

Kenne Bell was THE authority on the V6 back in the 60's and 70's. He, and HP books published performance manuals that give a lot of information on the V6 and modifying them. I had the HP manual and it was excellent.

The T18 and the SM series of truck transmissions are the most popular and will fit nicely behind the existing power plant. Car transmissions have been transplanted as well but they usually lack a decent first gear. Novack and AA both carry various transmission and transfercase adapters for CJ's.
https://www.novak-adapt.com/knowledge/transmissions/
https://www.advanceadapters.com/adapters-2

My CJ came with a set of fat Commando tires in the same pattern. They were OMHO one of the best patterns offered. As I stated earlier, I think you are going to have steering radius issues with taller tires that will require wider axles, huge backspacing, or spacers.

 

So I am thinking of taking a slightly different path with this CJ5, I can go with some small (33") "mud terrain" tires, sticking with a narrower tire 285/75 R16 type tire and use it just for trails and driving on the street. Then I can find an M37 and duplicate the truck I built and sold and use that for serious mud. Hopefully I can fit 33s with a 2.5" lift kit.

The problem now, the so-called mud terrain tires from the big boys, Goodyear, BFG, Firestone and so on look like all-terrain tires. I would like to find a tire like the original BFG mud terrain, that was a good tread pattern. The search continues.

 

33's will fit. You will still have turning issues with 33 (tire hitting the springs) unless you get a lot of backspacing or run spacers. I've got 33's on an old Rancho 2.5" lift and had to install 1" spacers on the front axle to regain a portion of my steering radius back.

 

I'll have to figure out the backpacking, I don't want to run any spacers.

 

Be aware, I've only had the 33's on for about a month. They fit and I've been moving rocks and the like on the property. I haven't done any real wheeling with them so there may be issues with fender clearance during suspension compression.

I would solicit more input prior to springing for a tire/rim combo that rubs during heavy wheeling.

 

Jeep Daddy, What size are your 33s?

I found some tires that might be good and a tool to help me get wheels with the correct offset. For the tires the Goodrich Mud Terrain KM3 33X10.5R15LT tires are 32.5" tall, with a section width of 10.6".