Cummins 4BT & Diesel Conversions Forums banner

1 - 19 of 19 Posts

·
Administrator
Joined
·
4,161 Posts
Discussion Starter #1
Ok, my driving experience dates back before radial tires were available. I have followed Jeep CJ's with the big fat tires on the highway at 55 mph and noticed they have a tendency to wander quite a bit between the lines. I see some of you are planning on running 34 & 36 inchers at 70 mph. I'm just wondering how the new jumbo tires are handling at these speeds, what you guys are currently running them on, and how they handle compared to a standard 15 or 16 inch tire on both wet and dry roads. I have had the impression that these tires were designed more for the off roader than an interstate cruiser. Your thoughts and opinions?

Bob
 

·
Registered
Joined
·
808 Posts
I run STA Super Lugs, Tube and Flap Tires. They are designed for 16 inch rims with a width of 6.5 inches and are 36 inch diameter. I rarely run 70 but I to run steady 60 and road conditions permitting run 65. These are not the big fat large tires but more of a aggressive tread mud and snow.

I have over 5000 miles on the with my Carryall and really like the STA's In snow, they bite real well and clean well, on wet roads they are no different than running a aggressive mud/snow tire, I have had no complaints. On highway at highway speeds, there is little sing, and they track well. I have no wandering issues whatsoever. I have no experience in DEEP sloppy mud as I stay out of that stuff. But on normal trail mud, they bite and clean well.

I also have them on my Power Wagon with equal results. I like them so much I just bought 10 more to shoe my M37 when Complete and my Future Swivel Frame Power Wagon to be built.

The STA's do require a Dynamic Balance for best results

For my application I would rate them a 10

Paul
 

·
Registered
Joined
·
3,391 Posts
The Jeeps with big fatties often have some peculiar problems. The have a very short wheelbase which isn't conducive to tracking properly. A longer wheelbase and/or a heavier vehicle has much more tendency to keep going straight.

Often the Jeeps are radically lifted and may have very stiff re-arched springs, very stiff shocks etc. Also it may be used more often on the trails because of the way it's set up. So, many air down their tires both to soften the harsh freeway ride and for better traction offroad. Another consideration: radical lifts often cause bump steer, where normal steering efficiency is lost. Instead of smooth steering you get a lurching & innacurate wheel motion, causing vehicle to be all over the road, nearly out of control.

I use Hercules Terra-Trac on my Ram and LOVE THEM! Quiet, smooth ride, excellent traction in mud, snow, sand, solid firm handling with no wander. Of course the Ram is a long wheelbase truck. Many swear by some BFG's and some of the big Michelins.
 

·
Registered
Joined
·
713 Posts
I run 35 BFG muds. They drive fine on the street. Highway is even smoother than backroads. Right now I actually have 2 different brands on the front since I popped one. That's a little shaky but it's something to get used to until I buy a new BFG.
 

·
Registered
Joined
·
329 Posts
I ran metric 35s and they were not a problem. I am going to 36 bias.......we'll see
 

·
Registered
Joined
·
1,203 Posts
It depends on quite a few different factors. the Tire is one, and Suspension is another. along with wear on steering parts/bearings, etc.

my experience:

grand cherokee with 4-5" lift:

34"x10.5x15 bias ply LTB's. They were extremely worn with lots of cupping. On the road they were terrible. they had flat spots after sitting for a few hours. They were somewhat hard to control at times, though it just took a bit of getting used to, then they were tollerable. they made the jeep sound like a small airplane...

35x12.5x15 BGF M/T's. compared to the LTB's were extremely well mannered on the road, good manners, not much noise, you could only tell they were M/T's when coming to a stop.

If you just want big tires, M/T's or A/T's are really good on the road, but bias swampers will hold up much better offroad.

all in all, my jeep has been very drivable on the highway. it's got it's own issues that i will get taken care of one of these days.
 

·
Registered
Joined
·
60 Posts
I run the Pro Comp X-Terrains they are sized at 35x12.50 on 15" rims, I've run them on my Scout II for awhile now. The are nice and quiet and since I added a bit of caster to the axle it tracks just fine, where before the axle mod I would wander all over with my 31's. -wingnut13
 

·
Premium Member
Joined
·
1,660 Posts
35" tires comes on H2s from the factory, for what its worth.. Generally 35" radials are just fine on the highway for the most part...
 

·
Registered
Joined
·
89 Posts
Raise suspension - increase castor

wingnut13 hit the nail. Put bigger tires often requires lift which requires more castor.

castor makes the front end track back to center.

Low castor angles, and it'll be all over the road like a shopping buggy, more castor, like a chopper bike, hard to turn, but steers with no hands.

Just right castor angles (found at the end of the experiment)

wayne
 

·
Premium Member
Joined
·
1,660 Posts
agreed.. I added caster so I was about 4-6+ degrees, with 35s, I could track straight as an arrow even at 90 mph..
 

·
Registered
Joined
·
500 Posts
I run the Pro Comp X-Terrains they are sized at 35x12.50 on 15" rims, I've run them on my Scout II for awhile now. The are nice and quiet and since I added a bit of caster to the axle it tracks just fine, where before the axle mod I would wander all over with my 31's. -wingnut13

Yeah Scouts came with 0 degrees caster if I remember.
 

·
Premium Member
Joined
·
1,660 Posts
and cruisers are about 1-2 and that's it.. Slight lift on them too and you get grabby tires that follow the ruts in the road... The solution in a lot of those has been caster shims, which helps a lot even with the short wheel base rigs...
 

·
Registered
Joined
·
89 Posts
Early Bronco Castor

I never got mine right with 3.5" lift and 35" tires . Installed the 7* bushings, and while it was better, it was squirrley at 70+ If they made 9*, that would have been about right

Removed the 3.5" coils and now have stock coils. Going to leave 7* castor because the steering was with one finger before, so I really want it to track.

Wayne
 

·
Administrator
Joined
·
4,161 Posts
Discussion Starter #15
Great information guys! The caster information will be useful to keep everything running in a straight line.
 

·
Registered
Joined
·
1,366 Posts
But only if the vehicle is moving from right to left.

When you guys are talking about caster angle, are you talking in terms of the angle in this picture or the opposite? [angle forward]
 
1 - 19 of 19 Posts
Top