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Discussion Starter #1
I have a set of new Michelin PSS tires that have been balanced at a local race shop and are giving me a vibration in the steering wheel. I took the wheels back to the shop to check the balance and it was spot on, but we noticed at that time a dip or flat spot in the tread of both front tires. It is not large, maybe about 1/32, but is visible to the naked eye as the tire rotates on the balance machine. The rims are true. The question is, how much variation is considered acceptable in a factory fresh tire? Do tires "wear in"? They are really fresh, as in made only weeks ago. The Michelin break in guide says that it can take up to 500 miles for a new tire to "deliver their normal ride quality and maximum performance" The Tire Rack is still considering what to do, but not immediately deciding to replace the tires. They are stock sizes (235/40/18) on 8.5 inch rims.

Thoughts?
 

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AJK,
What type of balancing machine did your shop use on your tires? It needs to be a road force balancer, typically made by Hunter. It applies a force to the tire and does a superior job to the regular balancer. The Hunter website can show you where a machine is located.
Good Luck,

Rob
 

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That certainly doesn't seem normal. If the car had been sitting for several weeks, I could see flat spots. But that doesn't sound like it is the case.
 

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If it were me I would be demanding a vibration-free balance or if this is not possible, new tyres. You may expect this with budget tyres but not something like MPSS which is regarded by many as about the best road tyre out there.
 

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AJK,
What type of balancing machine did your shop use on your tires? It needs to be a road force balancer, typically made by Hunter. It applies a force to the tire and does a superior job to the regular balancer. The Hunter website can show you where a machine is located.
Good Luck,

Rob
OP and Rob:

I bought a set of used Pirelli 240 (?) winter tires that had balancing problems. I got them road force balanced and they were useable.

Thanks to my great local tech with Hunter machine.

No thanks to the jerk on P-9 classifieds who knowingly sold a set of very iffy tires without informing the buyer. This is the only unsatisfactory P-9 classified experience I've had...and I've had a bunch.

:cheers:
 

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One more....

If you just bought these tires, the tire place can send them back for new ones. I don't think this will be a big deal for Michelin to cover. Even if you can get a Road Force balance (at extra cost probably) the tire is still wrong and you should send it back. I hate new tires that are made sloppily. I've had good luck with Michelin, especially the ones made in France. I've had really bad luck with Pirelli. Had P-6 All Seasons that were really bad and now these winters.

:cheers:
 

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Discussion Starter #7
Today while getting the car its annual New York inspection I also had the shop check balance with a road force machine, the first balance was not a RF. Problem solved! So, it looks like a flat area of as much as 1/32 can be OK if the balance is right. That 1/32 is eyeball only.

Thanks for all the replies.
 
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