Torque causes tire to slip on tracked wheels

[Hrant]

Intersting observation from yesterday's track event. I had marked a particular 1" section of my RA1 where it meets the wheel's edge before the track event. The car was pushed hard fending off some serious challenges. Today, I looked at the markings, and the tire had moved 0.25" forward from where the parallel marks were on the wheel! Tire pressure was 36 hot at the track.

After a few track days, I would think the tires will rotate/slip enough to change the balance as well no? YMMV.

 

[nsxnut]

Just .25" You need to get on the gas harder...
When I used ra1's they moved 4-5" over the cource of a day.

The Michelin Pilot Sport Cup don't slip.

 

[Hrant]

Just .25" You need to get on the gas harder...
When I used ra1's they moved 4-5" over the cource of a day.

The Michelin Pilot Sport Cup don't slip.

That is because you brake too much, hence have a hard time staying up with me :biggrin: :tongue: But seriously that much movement might due to underinflation and if I recall you were using 33 psi hot at the time, no?

As for Michelin Cup, I don't have a trailer like you ...... I still commute to/form the track and to shows :wink:

 

[nsxnut]

I was running these on stock chrome rims. I thought this may have
attributed to this? After the first occurrence I marked the them and indeed they would move a bit. I never had any trouble with them though.

Last July when my truck was down I drove to sears on the Michelins.

 

[Andrie Hartanto]

Intersting observation from yesterday's track event. I had marked a particular 1" section of my RA1 where it meets the wheel's edge before the track event. The car was pushed hard fending off some serious challenges. Today, I looked at the markings, and the tire had moved 0.25" forward from where the parallel marks were on the wheel! Tire pressure was 36 hot at the track.

After a few track days, I would think the tires will rotate/slip enough to change the balance as well no? YMMV.

Hrant, who mounted those tires? We saw this when I used to work on the tire shop. Mounted them dry help. If it still a problem, we even used sealant.

I discussed this matter few years back, but our resident expert, Harry Sommerfield, shot me down. Glad, someone else confirm this happened to them.

 

[Andrie Hartanto]

I was running these on stock chrome rims. I thought this may have
attributed to this?

Chrome is the worse. I saw an S500 tried to burn rubber, instead it has the wheels spinning on the tires!! You guessed it, chrome wheels.

 

[Hrant]

Andrie it was mounted by AIM at Sears last year - and I was not pleased with their service as they scratched my - as well as Steve's brand new - wheels, though their price was very competitive. I already had at least 5 track days on them before the above post.

But last Friday I had to take a precautionary looksie. So perhaps they moved even more when they were first installed and by now they have stabilized? I agree the chrome wheels would have caused some of that on Don's car but also low inflation will do that too. America's Tire Co said low inflation can break the steel belts by the torque/tension that they will create on the side wall and this could be visibile with a vertical crack/slit on the sidewall. A stress crack would be horizontal, often caused by hitting a pothole or a berm.

Not sure what Harry may have disagreed with your post, but we have busted many other "theoretical" truths and "myths" and "exposes" that are often espoused on the forums ..... sometimes we post our experiences given how we have not heard/read of such occurrences in hopes of being educated as well as give a heads up to others, and other times we just chuckle at some posts and let it go to avoid the notorious inflammatory debates of past years ....... but as always, there are a few on Prime whose post I read carefully and try to learn from their real experiences on the track and their solutions :wink: