Re: Watch your summer tires in cooler/wetter weather... Had a close call today...

Not paying as much attention as I should have been this cool AM in the fog and took a sharp turn that I have taken many times in the past at about the same speed in the same car (Boxster) with no problems, until today.

The Boxster's front tires instead of holding the car to my intended line around the turn broke loose and and before I knew it my car was over the center line. Oncoming driver in a pickup truck had to take evasive action to avoid a collosion. Good driving on the part of the other driver. Bad driving on my part.

I had thought I might push the front tires another 20K miles just fitting a new set of rear tires -- thus after the new set of rear tires wears out getting 60+K miles from the front tires -- but I think when I go to replace the rear tires the fronts will get replaced too. While there is plenty of tread left on the front tires the tires are simply too hard and less grippy after so many heat cycles to risk pushing them another 20K miles.

Anyhow, other than scaring myself and undoubtly the other driver no other harm done. Still, it could have ended badly.

Sincerely,

MarcW.

Although not tire related I did have a close call the other day as well. I was driving home from work and needed to make a left turn on to a side street. There were two lanes in each direction, so I put on my left turn signal and begin to brake as there was traffic approaching me. I look in my mirror and see a woman in a Tahoe or Denali pulling up behind me and NOT slowing down. There was an open lane to my right and as I braced for impact, she slammed on the brakes and swerved into the lane to my right, missing my rear end by less than a foot!

I'm sure she had to change her pants!

One thing that it reminded me was; when turning left, keep your wheels straight until you have a clear shot to cross. With my wheels turned to the left, had she hit me, she would have sent me right into the on-coming traffic for a rear-ender and head-on crash.

Stay safe!

Minus 40 degrees... Is that Fahrenheit or Celsius?

I've learned and forgot many things... a little refresher never hurts.

Minus 40 degrees... Is that Fahrenheit or Celsius?

As tires age, they harden with the recurring heat cycles, even from street use. Had a situation a few years back when my track tires felt like they had heat cycled out but still had plenty of tread. Decided to replace them with my street tires to finish out a season; bad move.
Despite having at more than half tread left, they had less grip than the dedicated track set, even though they were used just for street driving. At 3 years old (PS2's) and only 18 k on them, they weren't worth much at the track.

IIRC, there are durometers you can buy (longacre) to get a handle as to what the hardness of a particular tire might be, but have never used one myself.

I don't know if it is due heat cycling, or something else, but I have always thought (through reading here and elsewhere) that the quality of tire rubber deteriorates over time. I think a rule of thumb is that after four, maybe five years, regardless of mileage, tire rubber is reduced in quality to the point that replacement should be considered. That is why you want to check the date on tires you purchase.

1999 Arctic Sivler/black/black (sold)
2008s Silver/black/black - so predictable
2011 Outback
8/24/2011 first Grandson

Both true, but also a bit of fear mongering on the part of TV news "death just lurking in your garage!" and tire companies "replace those perfectly fine old tires - gimme money"

There is truth to dry rot. The rubber will break down, accelerated by exposure to sunlight and ozone. But, on the other hand, tires can last 10+ years and be perfectly safe. Heck, I've DE'd on 10 year old (NOS) tires. Dry rot can be found by visual inspection (inside and out) for signs of whitish residue in and among micro-cracks. Also use a black light.

Now, the heat-cycling is another issue that can make tires harder 9 and therefore have less friction) and i guess more susceptible to failure. It clearly does the former, i've never seen the latter. bear in mind that a cycled PS2 is still >>> than a brand new all-season, hgih-mileage, low-rolling resistance tire.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

I was complaining about the cheesy Toyo TPTs on my Honda. They've become lousy on wet pavement, including front wheel tramping under moderately hard acceleration. I'm not going to deal with it until spring, as there are four snows that'll likely be going on soon... and they're on their last legs, too, as the youngest two of them are about five years old.

Minus 40 degrees... Is that Fahrenheit or Celsius?



Edited 1 time(s). Last edit at 12/03/2011 09:45AM by Laz. (view changes)

Laz, You have old tires which are losing grip on dry pavement. Must be worse on wet roads, and even worse in snow. You plan to run them through snow. Why wait until spring?

[www.worldcarfans.com]

a Cayman on a lift. I spotted some odd front tire wear and looked closer and then spotted some cracks in the rubber where teh tread adn sidewall meet.

While this may not be dry rot the front tires (both front tires had these cracks) were in need of replacement. I didn't have a chance to note the tires' manufacturing dates nor take pics.

Sincerely,

MarcW.

Wife's car is a 2006 Acura MDX with under 30K miles, most of which are just highway miles on long trips. Always garaged, always treated the tires with Armorall or similar protectant. Still has the OEM tires with about 2/3 of their tread and still look like new. I feel like I ought to be replacing them due to age, but darn it, I have a hard time justifying it. I keep thinking, "Next year, when I don't have so many expenses" and then next year comes and I have a whole new set of expenses. Sigh.

performance tires. I'm not sure the tires on your wife's Acura qualify as high performance tires. As for if they need replacing due to age check with your dealer or check the tire maker's web site to see what if anything either has to say on this subject.

I must point out your dear wife is out and about in her vehicle and it is running on aging tires. Even though they have some tread life left, if the tires are past their use by date well, your dear wife I think deserves to have safe tires on her vehicle. Understand I'm not saying the tires are unsafe but if your research finds the tires are questionable due to age I think you know what needs to be done.

Sincerely,

MarcW.

1) Deterioration of that type of tire's compound material; and/or
2) Expected greater wear and tear due to being driven hard, thus at its service limit; and/or
3) Given that the above two conditions are equal for either type of tire, the greater possibility of loss of control or outright tire failure due to the way the performance tire is likely driven?

Quote
Laz
1) Deterioration of that type of tire's compound material; and/or
2) Expected greater wear and tear due to being driven hard, thus at its service limit; and/or
3) Given that the above two conditions are equal for either type of tire, the greater possibility of loss of control or outright tire failure due to the way the performance tire is likely driven?

has an age limit on tires. Porsche can't know the usage a particular vehicle will be subjected to so it issues guidelines that I guess cover the worst case.

I had thought that other car makers, at least car makers offering vehicles of less performance than Porsches and, other tires makers (suppliers of tires for these other brands of vehicles), might allow for tires older than 6 years to be still ok, but Grant says there is no distinction between high-performance and regular tires/other tires so that's that.

As an aside, unless a utility trailer, or camper trailer, or any kind of trailer intended to be towed behind a passenger vehicle, is newer than 6 years old, I would be (almost) willing to bet that some if not all tires are older than 6 years. Whenever I see a privately owned trailer it is the rare case the condition of the tires gives me the creeps.

Sincerely,

MarcW.

I've heard it referenced on "consumer advisory" news (which i think is fear mongering), and been told the same by two local tire shops, never with any caveat for the type of vehicle. I can only imagine the confusion over what is high performance. Plus, i expect that the tires most likely to suffer failure might include those on trucks and SUVs that are loaded heavily and not designed for high heat int he first place.

Whether Porsche also has its own recommendation, i don't know. Once an industry association acknowledges that something "might" happen most legal departments will adopt a conservative view. Frankly, they have to since that data is now admissible in court. Common sense doesn't always playa big role.

Again, i go back to - observe, test and consider your own storage and use profile.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

A garaged car won't be getting as much UV, for one thing. Et cetera.

Quote
grant
I've heard it referenced on "consumer advisory" news (which i think is fear mongering), and been told the same by two local tire shops, never with any caveat for the type of vehicle. I can only imagine the confusion over what is high performance. Plus, i expect that the tires most likely to suffer failure might include those on trucks and SUVs that are loaded heavily and not designed for high heat int he first place.

Whether Porsche also has its own recommendation, i don't know. Once an industry association acknowledges that something "might" happen most legal departments will adopt a conservative view. Frankly, they have to since that data is now admissible in court. Common sense doesn't always playa big role.

Again, i go back to - observe, test and consider your own storage and use profile.

Grant

Tyre age

Note Tyres should not be older than 6 years! Not even the spare wheel!

There is a table with directions on how to interpret the manufacture's code:

DOT DM CP05 Y 2200

where "22" is the production week and "00" is the production year in this case 2000.

As for high performance tires...since we're talking specifically about Porsches I would think that is any tire suitable/approved/recognized at being appropriate for use on these cars.

As for testing tires... I seriously doubt any signficant number of vehicle owners are going to the expense of acquiring whatever tire testing equipment is necessary to use to determine if their vehicles' tires are in need of replacement. Many owners don't replace tires that are obviously worn past their safe point and all this requires is one simply look at the tire or pay heed to a mechanic's recommendation the tires are worn and should be replaced.

And to expect every owner to have the savvy to make the right call regarding this usage of his vehicle, the conditions he subjects his vehicle to, and make the call as to when the tires need replacing... Yeah, right.

I think the 6 year rule is a good one and I don't think it is fear mongering. Most owners will wear out the tires long before 6 years roll around. For those that don't the 6 year rule is there. But of course chances are high the owner will ignore it, even if he knows it exists in the first place.

Sincerely,

MarcW.

i noted what to do above. Its not complex.
Any good tire shop can do so as well, although they probably prefer to sell you new tires.
Is 6 years a nice conservative rule of thumb, capable of capturing most of the faster deteriorations? Yep.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

inspect the tires and do so correctly and then be willing to put into writing the tires are ok to continue to use even though they are past the age (in this case 6 years) that Porsche advises they be replaced.

The tire store owner is then placed into the position of having to have more knowledge than Porsche does regarding tires for Porsches.

But assuming one can find such a tire store, then at what frequency should these now over aged tires be inspected? Is the deterioration constant or does the tire deteriorate at a faster rate as it ages?

Sure, what you say is possible, but it just seems like too much work. Either an owner is going to drive his car enough tires are replaced before they are too old, whatever that is, or he's faced looking at old tires and wondering. Were it my car, and someone I cared about riding on the tires, I'd leave the blacklight in the box and just get new tires installed following either the tire maker's guidelines,or the automakers, whichever were more conservative. I mean to ensure the safety of a loved one replacing a set of tires every 6 years due to age seems a small price to pay.

(I have to admit I'm not consistent.... While osche says 'no' to fixing these tires, and the tire maker says its ok given the tire qualifies for fixin', I go with the tire maker and have the tire fixed.)

Sincerely,

MarcW.

"The tire store owner is then placed into the position of having to have more knowledge than Porsche does regarding tires for Porsches."

nonsense. Porsche cannot inspect tires, and therefore, given deep pockets conservatism, picks a period sufficiently short to meet 99% of situations. The tire dealer need know very little - they have the advantage of an actual inspection of the tire.

Incidentally, did you not see the additional data i posted? The tire shop , mechanic or owner would be in good company, in the company of the Rubber manufacturers association, British Rubber Association and the US DOT all of whom either use a 10 year rule, or acknowledge that data is not sufficient to support any assertion, yet.

Of course, tire stores are likely the worst place to go for this - a good mechanic is likely to be more willing and have fewer conflicting goals.

Grant

Grant

gee-lenahan-at-gee-mail-dot-com



Edited 1 time(s). Last edit at 12/10/2011 03:10PM by grant. (view changes)

above, via inspection and best with black light. No micro-cracks, no spider-webbing or white deterioration under black light (in and out), no problem.

Why speculate when we can test?

Grant

Grant

gee-lenahan-at-gee-mail-dot-com

VW Type 3 back in the '60s slid on a reverse camber curve where it was just beginning to rain. Car had less than 1k miles on it since bought but I have this feeling the seller swapped tires between the time I bought the car and the night time when I picked it up. They were bald when the accident occurred...at less than 25MPH. The front tires just didn't bite. Took out from the firewall forward but was repairable.

And of course my '99 Boxster which had summer tires on the day after Thanksgiving when the temps had been below freezing overnight. When I asked it to stop, it just slid. Tires were in good cosmetic shape with good treads. Had just been inspected.

When the '01S got to 15k or so miles on the tires and they were at least 8 years old, I just replaced them even though they were wearing evenly and surely had 5k more they could have gone.

I no longer take any tire chances.

Figuring out what preventative maintenance to do and when is not an exact science. I've over and under maintained many cars over the years and now I just do what makes me feel comfortable.