MT Sportsman Pro tires feel....

I just installed some 26x10.5x26 Mickey Thompson Sportsman Pro's and they sure do drift alot even with max pressure of 30 psi. I don't expect them to ride like steel belted radials, but it feels like I am loosing control even at 70 mph and starts getting squarally. With the radials I had the car felt great even well over 100. The only thing I can figure is that they should have tubes in them? The place I got them from said they don't need them. Would that help? Is this normal and is it something I will just get used to? Thanks!

parthos said:

I'm running hoosier quick time pro tires, I had no tubes, but due to hard launches, the rim was slipping inside the tire. 30psi in them seems like alot, I'm only running 15psi in mine with tubes, and rim screws. I don't know if running these tires on the freeway is a good idea, for the reasons you stated, they're good for acceleration traction, but not taking turns, with big soft sidewalls they can't be expected to handle even close to a radial tire. You could have two sets of tires, one set of radials for 70mph freeway speed, and the other tires for the track. I drive with my "cheater slicks" all the time in town and short freeway trips, with a good alignment and getting use to how they feel, I don't notice them anymore.

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My alignment is right on, maybe I need to work on getting the back of my car down a little lower to lower the center of gravity? My recently installed Stumpy traction bars are preventing my leaf springs from fully relaxing as they not only make contact, but are a little tight holding the rear up some. Maybe I need to cut off some of the rubber nub and put some space in there and this will allow my suspension to work better making it less squarally?

I really don't plan to take them on the freeway much, but where I live (Houston suburbs) there is no where else to test them at higher speed within a reasonable driving distance. I figured that this would give me a little practice driving with them. The first time I layed into it with them on pulling out of the tire shop I got to about 60 mph and backed out because it started getting very squarally and I was trying to go straight. Right now I could not imagine staying in it through a quarter mile and my car is not very fast.

This is the first time I have ever been chicken of a car and I have driven cars alot faster than mine, but I guess I never really drove on a wrinkle wall tire like thise either. I just can't believe there is not something wrong causing my car to handle worse than is should with these tires. I don't think I have enough power to worry about screwing them in, but I guess I should put a mark on the tire and rim to make sure they don't slide to be sure? I do know that the traction problem sure seems to be solved, these suckers hook!

Problem solved. I took the nubs off of the traction bars for a test and it does straight lines great now with no control issues. The rear end dropped nearly an inch and it was binding the suspension. Just need to trim the nubs way down and re-install them.

CobraIILover said:

Slapper type bars should only make contact under hard launch. At rest, you should have about 3/4" of space between the leaf and the snubber. As you found out, loading the bars under normal use will make the car borderline uncontrollable, and it will also break stuff in a hurry .

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There is only about 1/4" between the bar and the leaf with the snubbers removed so I think it's time for new leaf springs. One step forward, two steps back. I'm just glad I didn't break anything. Any tips on what I might do while rebuilding my rear suspension would be greatly appreciated. Heavier springs vs. stock, measurements and reference points for re-installing the axle to get it square with the car and the right pinion angle, does anyone make a higher grade U-joint (for drive shaft since it's coming off any how) and hardware?