Flat spotted front tires, suggestions...

[SoCal Rebell]

Went to the track yesterday and due to an incident I had to lock em' up. Afterwards I was getting a thump, thump, thump well I checked the tires on a lift and the two fronts had a flat spot. After reducing psi back to street 29 psi it is "just" bad enough where I have to do something. What are my options? New tires? Shaving (never did this)? Anything else?

 

[Tom F&L GoR]

Try having them balanced. Won't make them round, but they will feel better. (from similar unfortunate experience.)

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by SoCal Rebell:
Went to the track yesterday and due to an incident I had to lock em' up. Afterwards I was getting a thump, thump, thump well ... What are my options? New tires? Shaving ...Anything else? <HR></BLOCKQUOTE>


1) Shaving is indeed the best fix....but finding a vendor to shave used, treaded tires may prove difficult. Some vendors won't risk damaging/nicking the shaving blades on embedded gravel, and only shave NEW tires....

2) Mount the fronts on the REAR...and do several long, smokey burnouts! They really spin faster, and you end up shaving your own tires. Of course, you need some OTHER fronts to use in the process..

 

[Paul Hawker]

Sorry about the flat spots. Seem to happen lots at the track. Often times just the right front at willow.

Best solution is to get new tires. Shaving is usually done to new tires to get them perfectly round after they are mounted, and to reduce tread depth to eliminate "squirm" on new tires.
Most shavers will not touch used tires, as dirt and stones picked up while driving will ruin their expensive knives.
Some exceptions can be found, but you will need to call around.

Driving with flat spotted tries stresses shocks, suspension and can cause rattles.

Once again sorry about flat spots. They really make the tires unusable, and un-safe

 

[Tom Welch]

Ron,

Hello, hope all is well. Go buy a new set of front tires. Make sure first that it is in fact the fronts. I spun out at a road course(my first and only time on one) and flat spotted the tires. I was so sure that it was the rears that I bought a new pair, mounted them and the bumpity-bump remained. I jacked the car up and slowly rotated the fronts and was able to actually see the flat spots on them.

Im still waiting for my audition!!!!!!!!!??????????

Tom
Http://btrviper.com

 

[ACR Joe]

SoCal Rebel:

I had the same problem. Here's what worked for me. I found a shop in PA that has a Hunter balancer that also measures the runout of the wheel, the runout of the tire, the balance of the wheel and the balance of the tire. A computer matches the low spot on the tire with the high spot on the wheel, and the heavy spot on the tire with the light spot on wheel. The tire is then rotated on the wheel to matches these positions, re-inflated and spun balanced. I purchased new tires never expecting that this procedure would produce meaningful results. I was wrong! The shimmy was completely eliminated and 4,000 miles later, my new tires are still sitting in the garage waiting.

I can't recall the model number of the balancer, but you could go to Hunter's web site for more information or EM me and I will call the shop and obtain information for you.

Hope this helps ......

 

[jcaspar1]

I saved this post just in case it ever happened to me. I have not tried this:

I shaved my own (instructions enclosed)
Posted by Tom Friend (99 GTS Mikita Maniac) on Monday, 18 September 2000, at 9:32 a.m., in response to What is the best cure for Flat Spots on the Tires??, posted by Eric Lesher on Saturday, 16 September 2000, at 9:41 a.m.
I phoned all over 3 counties and could not find a single tire shop with a shaver who would do the deed. Since I had nothing left to lose, I thought I'd try it myself... (liberal grunting noises here, ala Tim Allen)
1. Put the snake on blocks- all fours.
2. Remove rear tires, put front tires on rear. Inspect the tires very closely, and remove all screws, rocks, metal bits, etc.
3. Roll the tire and hold a piece of sidewalk chalk up to that big rain groove strip in the center of the tire. The chalk gap will show you the location of your flat spot(s). Feel the spot with your hand and get an idea of how big it is. Mark a solid patch an inch or two bigger than that with the chalk- side to side.
4. Idle car in fourth gear. road speed ~18-20 mph.
5. Get out your Mikita angle grinder. I used a 36 grit steel grind abrasive wheel. Use light pressure and be patient. Work side to side. Be patient- it took me about 20 minutes per tire. You will feel the "bump" becoming less and the chalk spot on the tire will become narrower. I got a little bit impatient and only ground until the chalk strip was 1 1/2 inches wide. Less would be better, especially above (ahem) legal highway speeds.
6. Swap back the tires and try it out.
7. Clean up all the rubber dust off the garage floor so the house keeper doesn't get pissed. ;-)
NOTE: One interesting side-effect was that the front tires got real sticky after this procedure. I tried an "anchors out" stop after this and the rears actually locked up! I have a 100% stock brake system- no prop valve mods.
Seems that roughing up the tires might help for certain conditions like autocross or 1/4 mile. The condition is not lasting, as 250 miles

 

[Paul Fischer]

Once you get your tires dialed back in check the archives for info on pulling the O ring from your brake bias adjuster. It saved me a lot of flat spotting on the street.

 

[Tom Friend]

Hot dog! Somebody save my post from the old board. Thanks Jeff!

Grinding your own tires down is best done with a follow up visit to a tire shop with a Hunter 9700 road force balancer.

 

[ruckdr]

Definately have them trued(shaved). I had my fronts done, and it drives soooo smooooth and vibration free, and of course NO THUMP !!You should fins someplace in your area, and the cost is $30.00 (what I paid) to $50.00 per tire. You will get many more tire miles. DEFINATELY WORTH IT !!!