The car I recently purchased had been sitting for some time. Its tires are flat spotted .... they are Pirelli CN36s. The tires look to be in very good condition other than their drivability issue.
My question -Will flat spots just normally come out after warming them up and with possibly extra inflation (Not to exceed limit on sidewall of course)?
Haasman
Haasman
Registry #2489
R Gruppe #722
65 911 #302580
70 914-6 #9140431874
73 911s #9113300709
Yes, try a long drive, they often will round out again.
Early S Registry member #90
R Gruppe member #138
Fort Worth Tx.
If they've been sitting in one position long enough, they will never fully round out. You will only know this by trying, unless you have the history of how long they were sitting. Anything over a year and you are probably wasting your time trying to get them to round. Either way, it does shorten the life of the tire.
Jim
__________________________________________________ ___________
Early S Registry #2359
1970 Porsche 911 Rally 2.4
2018 Porsche Macan GTS
Thanks, you both are confirming what I've suspected. I hope to run it this week for over an hour. I'll report back to this thread either way.
Haasman
Haasman
Registry #2489
R Gruppe #722
65 911 #302580
70 914-6 #9140431874
73 911s #9113300709
A more radical idea, but might be worth considering if the tires are in decent shape and have some tread left. Go to someone like Roger Kraus Tire and have them shaved. Then you can tell everyone how you're running shaved racing tires!
Jeff Jensen
Love it! We we'll see hopefully this week.
Haasman
Haasman
Registry #2489
R Gruppe #722
65 911 #302580
70 914-6 #9140431874
73 911s #9113300709
For thems that is concerned about "flat" spots . . .
I'm neurotic about this stuff because my cars sit for months in the winter on a battery tender, not moving. Some people roll them a little in the garage, but I decided to get "flatstoppers" (link here: http://www.raceramps.com/flatstoppers.aspx) which are particularly useful for vintage/vintage style tires. I was told that tires manufactured today don't show flat spots until they haven't been moved for over six months.
A nice feature of this unique ramp is that, in the summer, I still leave the "front" pair in place and my car is always parked properly in the garage!
I would check the date stamp on the tires before going out on them. Wouldn't want you or the car to get hurt.
http://www.tirerack.com/tires/tirete....jsp?techid=11
http://www.aa1car.com/library/tire_expire.htm
Early Pirellis were notorious for flat spotting from setting. Even the early P-7s required some explaination to the new owners. We noticed if you come in from a hot or even warm run and stop on a cool day they were terrible until they warmed up again. If yours are flat due to long term storage, they may not come back. The only cure that we found was heat....and if you are warming an old tire you may not have a good result.
There was even some testing on storing new tires on a two bar rack that showed some damage from storage on the tread as compared to side storage.
H
If they are original CN36's, i wouldn't use them no matter what they looked like.
We've had a rash of tire failures on ones that looked perfect, no sidewall cracks at all.
If they're over 10 years old, throw them away.
Also, check your date codes on newly purchased tires, as they may have been sitting in a warehouse.
Posting Permissions
Reply With Quote