Bias-ply slicks and Steel radials.

Timbeaux

Timbeaux

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So I was conversing with a friend about some of the recent on-track incidents we have seen with fluid on the tires and he asked about the front tires on the trucks. It is his belief that steel radials and Bias ply slicks out back can get "upset" faster or more violently than Bias ply tires or even cheater slicks up front. Here is what he told me in his message:


Running bias-ply slicks, which have very little sidewall strength on the rear in combination with stiff steel radial tires up front, magnify steering input and can induce yaw oscillations, "wagging tail". Everything is fine as long as you do not have to steer the car/truck going down the strip, or nothing "upsets" the car into a direction change.

I have run cars/trucks both ways, but it is just asking for trouble to have steel radials up front with slicks. We have seen dozens of crashes over the years caused by this, and I can tell you from first hand experience that you have far more control if you put tires with more sidewall give up front.

Worse ones are wide steel radials. Best are bias-ply racing tires but size issues make it difficult. Drag radials would be better than steel radials, like the M&H 275-55-16? which fit stock wheels.

If you must run steel radials up front, reduce pressure. 80psi is going to make things worse than 32psi. Running higher pressures in the rear can help, as can inner-tubes. 8 psi slicks with 305/40-20 steel radials up front is the worse possible scenario.

Get going on the street at 35mph and give the car/truck some steering input. If it "wags" you know that you might have an issue.
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I can see where having a front end that is handling like a shifter cart and a rear end that is on ice can make the back end wash easier... what do you guys think, and is this an issue that some of the sanctioning bodies need to look at? Obviously, if it can make a 3000 pound Camaro act funky, a 5-6k truck would magnify the problem.
 
I can tell ya my Black truck was night and day diff. to drive after I went to bias 26/4.5/15 Hoosier's up front, from 245/75/16's wich I ran at 80# for less rolling resistance. The truck felt lots safer and under more control after the hoosier's up front. I ran them at 40# per Hoosier rather than what ever the sidewall said [32# i think], and they still squat quite a bit with the Cummins over them.
Ryan
 
Sounds very logical...and I've been told numerous times by car drag racers that if they find radials on the front of my 1/2 ton I'm in big trouble with them.

I plan on bias all the way around just to make sure!
Chris
 
Its totally true with the cars I've raced. And Id imagine it carries over to these trucks for sure.
 
My Junker drag truck came with bias ply trailer tires on the rear. They are really skinny but have the weight capacity to work fine on the front end. Wonder if they could be used as a cheap front tire. Then again, I don't know if i'd trust trailer rubber for my steering tires!
 
i have been running goodyear slick out back and steel belted radials all year sofar. mine feels great under power and on the slow down.
 
Big Blue24 said:
My Junker drag truck came with bias ply trailer tires on the rear. They are really skinny but have the weight capacity to work fine on the front end. Wonder if they could be used as a cheap front tire. Then again, I don't know if i'd trust trailer rubber for my steering tires!
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I at first bought 2 new trailer tires for it but after mounting them I hated the way they looked on the truck and went to the Hossiers instead. The trailer tires are a good idea in theory becuase thier made to handle lots of weight but that blocky look with the goofy all terrain tread on the sidewall was'nt for me. I also mounted up a set of new VW tires but they were not up to carrying the weight, the squated really bad and felt dangerous......I'd recommend the heavy duty MT front runners for others wanting to go this route, thier a little wider but still look good on a 4-6" wheel, the tread pattern looks good, and thier a much heavier construction or more ply; 8 vers 6 I think. Ryan
 
Well the problem is when a Slick suddenly breaks traction, it pretty much deflates. So when it has traction it feels fine, giving us all a false sense of control. Just my 2cents.
 
didn't we go over this after Gary's (Wrongway) crash at breakaway track last year? slicks in the rear, street radials on the front...we see what happened there.
 
but in that crash he roll off the line and never set the tires. as boost came up up it started to break loose. it i leave at a roll then floor it it will do half track burn out. but if i leave leave at 30psi it will set the rear tires and go.
 
BigDodge said:
but in that crash he roll off the line and never set the tires. as boost came up up it started to break loose. it i leave at a roll then floor it it will do half track burn out. but if i leave leave at 30psi it will set the rear tires and go.
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So how do they feel when they break loose a 120? No rolling into it then!!!WTF
 
but had he not had radials on the front he very may well could have pulled out of it.
 
You guys are talking about using trailer tires up front, but what kind of speed rating are we looking at with those, 90mph?
 
Timbeaux38 said:
So I was conversing with a friend about some of the recent on-track incidents we have seen with fluid on the tires and he asked about the front tires on the trucks. It is his belief that steel radials and Bias ply slicks out back can get "upset" faster or more violently than Bias ply tires or even cheater slicks up front. Here is what he told me in his message:
Click to expand...

Tim thank you for bringing this up, we all have a lot too learn as our trucks get faster. Everyone Keep safe.
 
I don't know much about racing, but how is the weight distribution on these trucks? How much is on the rear axle, and how much is on the front? Also, are these all short wheelbase trucks as far as moment equations go using the rear axle as a fulcrum? 2wd?
 
This makes sense but hasn't 2 of the 3 or all 3 crashes been freeze plug failure induced? Why aren't freeze plugs being pinner or epoxied in?
 
A radial in the front is going to react differently than have a bias ply up there. A radial is meant to be more street driver-friendly and long term driving. Its not going to have a "wrinkle" wall or have as much sidewall movement. A slick or bias ply in the rear is going to "give" under the weight of these truck or anything in general since the tire is designed to "give" in the sidewall for maximum traction during acceleration. If you have a Radial on the front and a bias ply in the rear the front of your truck will react faster to changes than the rear making it very easy to OVER CORRECT the vehicle. just my .02
 
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