Yet Another Tire Question

[Joe K. 99 Zeee!!]

I'm currently running PZero Nero M&S all season tires on my Grand Prix GTP. When it's parked overnight on cold days they seem to be flat spotting. I get a vibration for the first 3/4 mile of driving then they're fine. I don't really notice it so much when it's warmer outside. I've had the tires for about a year now.

While reading through tire rack I did notice one other review mentioning this problem. Any idea if this is normal or if I should be concerned?

[Joe 1320]

Not sure if this is relevant or not, but the two times that I had Pirelli tires I noticed the same problem. I thought the first time was a fluke, when another set did the same thing I never went back to them.

[Dave-S]

I have had this problem with several different sets of tires over the years. I always attributed it to the material used in the tire. Some tend to take a "set" more then others and thus you notice the flat spotting until the tires heat up. The Cooper Zeons I now have on my SS do that as well. To me this is all perfectly "normal" and not something to worry about.

[3800_Firebird]

I currently have BFGoodrich KDWS tires and they mildly flat-spot when it gets cold. The BFG Geforce Sports on my Grand Am's 17's flat-spot really bad when it gets cold. Usually during the summer they're fine. The 'bird just got the BFG's so wait and see.

[wolfdogs]

bias ply tires "flat spot"....radials dont.

what you feel is the different components that have contracted overnight due to the ambient. once you are on the road..they all come together in sinc again. its not a problem. in high speed tires you have crown edge wedges and all kinds of goodies made from nylon to to kevlar to polyester, the steel belts have stabilizers in them too..... its ok.

[Jeff_in_Atl]

Here is a good explanation of tire flatspotting.
http://www.tirerack.com/tires/tirete....jsp?techid=42

[Joe K. 99 Zeee!!]

Thanks all!!

It's nice to know that it isn't just these tires that do that. I'd been thinking that maybe it was just this design or a certain batch of these tires. I don't remember having this problem on any other tires unless I had let the car sit for a couple weeks.

[wolfdogs]

Here is a good explanation of tire flatspotting.
http://www.tirerack.com/tires/tirete....jsp?techid=42

hahahaha..good ol tire rack..that explanation is way overkill.

[Jeff_in_Atl]

hahahaha..good ol tire rack..that explanation is way overkill.

You and I have had this discussion before. I know you are THE expert on tires but I have experienced flat spotting on Z and W rated tires before so I know it happens.

One thing that could make a difference is an car kept outside rather than in an enclosed garage is going to get colder and be more susceptible to flat spotting.

I have never experienced the flat spotting with H rated tires which are on our van and sits for weeks at a time. I agree with the tire rack that it's the nylon belts that are the major contributor to flat spotting because the tires on the van don't have the 2 nylon belts. I had Bridgestone W tires that were 6 ply tires on the Mustang that sat for weeks and they flat spotted enough that you could see it.

[Steel2686]

Even in my garage, the Dunlop Direzza Z rated tires I have on my TL tend to flat spot a little if it sits more than two days. It goes away within a mile or so.

[wolfdogs]

its a harmless condition. if the tire is flawed from the factory, then its not. just like any flaw in a tire. it can also be caused by running under inflated.... how many of you check your tire pressure on a weekly basis.....? bi weekly? monthly?

[Jeff_in_Atl]

its a harmless condition. if the tire is flawed from the factory, then its not. just like any flaw in a tire. it can also be caused by running under inflated.... how many of you check your tire pressure on a weekly basis.....? bi weekly? monthly?

Daily. I love the real time tire pressure monitors in the Vette. Last week I noticed the right rear tire pressure going down. It had lost 4 pounds. I looked and I found a screw in the tire. You could not visually see that the tire was loosing pressure. What a great invention.

[Joe K. 99 Zeee!!]

I love the real time tire pressure monitors in the Vette. Last week I noticed the right rear tire pressure going down. What a great invention.

Second that!! I got a warning from my Grand Prix last week! Found a nail and got the tire repaired. No worrying about getting the jack out on the side of the road or the wait for a AAA tow.

[wolfdogs]

i have the direct type TPMS on the Sol. it reads the pressure in each wheel which i can view on the DIC. This is also a way to tell if a tire is having probs.. for example...say, all tires are equally inflated... after 30 min of driving, you notice one is 5psi or higher in pressure than the other 3... you got a problem child there.

the indirect TPMS uses the Traction Control and ABS system for their sensor... it wont tell you which wheel, just that "a" tire is low. it reads rolling diameter and resistance instead of using a sensor at each wheel position.

[Jeff_in_Atl]

i have the direct type TPMS on the Sol. it reads the pressure in each wheel which i can view on the DIC. This is also a way to tell if a tire is having probs.. for example...say, all tires are equally inflated... after 30 min of driving, you notice one is 5psi or higher in pressure than the other 3... you got a problem child there.

the indirect TPMS uses the Traction Control and ABS system for their sensor... it wont tell you which wheel, just that "a" tire is low. it reads rolling diameter and resistance instead of using a sensor at each wheel position.

If I recall correctly the feds mandated all cars to be equiped with tire monitoring. Does the requirement mandate one of those types? When does that requirement start?