Posted By: HEMIBERT588
high speed wobble anyone?? - 01/03/12 05:59 PM
I recently put on some hoosier 32 x 14.5 radial tires after running bias tires for years. from half track on the car would shake from the rear side to side and increase with wheel speed. this has never happened before. its a 4 link chassis car, qa1 coil overs and there is nothing broke or bent. the car was running mid 8's around 160mph and everything looks fine but sure doesnt feel that way. i was running between 7 and 14 psi in the tires with no change. has anyone had this type of problem?
Posted By: MR_P_BODY
Re: high speed wobble anyone?? - 01/03/12 06:01 PM
Did you balance the tires
Posted By: MR_P_BODY
Re: high speed wobble anyone?? - 01/03/12 06:17 PM
Also while its on the balancer, check the runout on
them and out of round.... most big slicks that I have
used took a FAIR/to alot amount of weight
Posted By: FastmOp
Re: high speed wobble anyone?? - 01/03/12 06:25 PM
U need radials on the front too.
Posted By: HEMIBERT588
Re: high speed wobble anyone?? - 01/03/12 06:30 PM
Yes they were balanced, now running radials on the front i think can also be an issue. its seems like the car was trying to get up on the tire and thats what caused the wobble. if i got out of the gas even at 100mph it quit right away, get back on the gas and its back.
Posted By: Dabee
Re: high speed wobble anyone?? - 01/03/12 07:27 PM
Check your rack and pinion. I had the same problem you are having. About halfway down the track the car would start to wobble, let up and it would go away. I found the rack and pinion was loose. I tightened up the rack mounts, problem solved.
Posted By: HEMIBERT588
Re: high speed wobble anyone?? - 01/03/12 07:53 PM
Thank you all for your input, i just think its weird that the ONLY thing i changed was the tires and it caused that much of a problem. i will for sure go over everything again.
Posted By: moderncylinder
Re: high speed wobble anyone?? - 01/03/12 08:21 PM
run 16lbs,,, at 14 lbs it might get down the track,, anything less than that id be shocked if it even left the line without balling the tires up
your problem "radial wobble" has been known about for years,,,, the guys i know who run hoosiers run 16lbs to cure it
Posted By: Dyno1
Re: high speed wobble anyone?? - 01/03/12 10:59 PM
Like Jeff said, this has been a problem for years with the big drag radials. It seems to be a problem with some cars more than others. A sway bar in the back helps alot, plus keep the tires up in air. Good luck. Dyno
Posted By: HEMIBERT588
Re: high speed wobble anyone?? - 01/03/12 11:21 PM
These are an actual radial slick, no tread grooves at all. hoosier 32 x 14.5R 15's
i think they are also a fairly new tire.
Posted By: HEMIBERT588
Re: high speed wobble anyone?? - 01/03/12 11:28 PM
thanks again for all your input, i will now have to wait and try it again!!
Posted By: Ben Holt
Re: high speed wobble anyone?? - 01/04/12 12:14 AM
I agree on the radial wobble scenario. Tire pressure and shock settings are the two most important things to play with to help fix it.
Posted By: vc360
Re: high speed wobble anyone?? - 01/06/12 01:54 PM
More air like Jeff said even 18-20 and dont use a radial on the front its gets worse IMO.
What he said...
Don't forget that every tire gauge does not read exactly the same, most of the smaller drag radials I have race on like 18lbs + up to 22 lbs. I have several tire gauges, including a very high dollar C gauge, it reads different than the other less expensive gauges form Moroso and Mr Gasket do 
I will take my gauges, both high and low pressure gauges, and check thier tire pressures for them 