Flat Tires, Yikes!

Originally Posted by Ronzi

Pete: A "boatload" compared to what?

A couple of yrs. ago I needed to replace two of the four Conti 17"ers and checked Tire Rack vs the shop I typically deal with in Boulder. After including shipping and the cost of mounting and balancing, there was virtually no savings whatever over what I paid the local shop for two tires, with no shipping cost and mtng/bal "included".

I know a lot of folks think Tire Rack is the greatest thing since canned beer, but that just hasn't been my experience. Not cost-wise anyway.

Good point, Ronzi! People should use the pricing knowledge gained from places like Tire Rack, and use that to negotiate a better price with the dealership or local area tire shop. Lots of local tire places do price matching of other advertised pricing (sometimes regardless of the other price not being local).

[SD987]

My experience has been similar to Ed and Ronzi's, in that when I replaced tires I found that Pioneer Porsche pricing was on par with Tire Rack for PS2s, when taking shipping, balancing etc. into account.

This would seem to make sense as when you're dealing with a commodity like Porsche parts you can jack up the price, but for goods that are readily available, like tires, the dealers have to be somewhat competitive.

[xavier405]

There is a brochure probably at your dealer that lists Porsche approved tire selections for the Boxster. On the back of the brochure is a statement that any plugs or repairs on the tire nullify the speed rating on the tire. But there is no comment on whether you have to go out and replace the tire altogether.

[MNBoxster]

Hi,

Before anyone gets the wrong impression, a nail/screw through the tread and into the carcass of a Tire does a lot more than simply nulify a Speed Rating. The Tire is compromised - period.

At speed, the plug/patch can work loose causing the carcass to disintergrate. And the extra mass which the plug/patch adds produces a Hot Spot in that area of the tire further raising the possibility of a Blowout and loss of control. The only way I would put a repaired Tire back on a performance car is only to buy enough time (read 1-2 weeks) 'til I could afford to replace it.

Considering the cost of repair and accelerated depreciation to the car should it sustain body/frame damage, the cost of the Tire pales in comparison, and we haven't even mentioned the possibility of injury or worse.

Be Safe , and think of the others you share your car and the road with and replace the tire. It's too bad that tires can be struck down in their prime with lots of tread left, but that's just the way it is sometimes...

Happy Motoring!... Jim'99

[Adam]

Originally Posted by MNBoxster

Hi,

Before anyone gets the wrong impression, a nail/screw through the tread and into the carcass of a Tire does a lot more than simply nulify a Speed Rating. The Tire is compromised - period.



Happy Motoring!... Jim'99

So, what your saying is it wasn't such a good idea for me to be doing 150+ mph on a plugged rear tire a few months back. I guess it's a good thing I'm replacing those things soon. A blow out at those speeds wouldn't be pretty.

[MNBoxster]

Originally Posted by Adam

So, what your saying is it wasn't such a good idea for me to be doing 150+ mph on a plugged rear tire a few months back. I guess it's a good thing I'm replacing those things soon. A blow out at those speeds wouldn't be pretty.

Hi,

Absolutely not a good idea. A repaired Tire should not exceed 65 MPH, 55 MPH for a sustained drive.

Heat is the enemy and with a plug/patch, that area of the tire has more mass and therefore greater heat retention to that localized area, it sheds this heat at a lesser rate than the rest of the tire.

This heat build-up can cause the rubber cement which holds the plug/patch to soften/loosen causing a loss of integrity to the seal of the plug/patch allowing air to leak.

Also, the dynamic forces can cause the plug/patch to work loose altogether, especially with an already softened glue. Also, there may have been severed cords from the puncture all adding up to a fair potential for disaster.

Now does this occur to each and every repaired tire? No. But, not every puncture is the same or every repair for that matter. Some hold better than others depending upon the degree to which the tire was compromised and
the skill and knowledge of the person repairing it. More repaired tires will fail in the manner described than not. Are you willing to take the chance with your car and your body (or those of others)? As I said, no one wants to throw away an otherwise perfectly good tire, but you have to realize that it is no longer perfectly good.

Happy Motoring!... Jim'99

[xavier405]

This is a good thread and I totally agree that Be Safe is the mantra here. I am about to pose a technical question but let me be clear I am not trying to argue that plugs are safe, I'm just trying to understand...!

It makes sense that 1) heat build up is bad, and 2) a plug/patch adds mass to act as a heat sink and retain that heat. But my question is how severe is the heat build up at 60, 70, 80 mph really? The rubber cement is designed to survive sustained heat and loads at 150mph. The energy at these speeds is much more than the energy at 75mph thanks to 1/2 mv2 plus dynamic vibration plus any other forces I don't think of. And while the plug adds mass, does it add that much more mass? The heat load at 75mph at the plug itself must be many times more than normal, to match the heat a tire would see at 150mph.

I'm sure there are lots of variable like have been mentioned, the quality of the fix, the size of the patch. So there is a good likelihood that you have a BAD fix and have to lower your speed! That said, DO NOT drive a plugged tire at any great speed! This is not worth experimenting with!

[Dr. Kill]

Originally Posted by SD987

My experience has been similar to Ed and Ronzi's, in that when I replaced tires I found that Pioneer Porsche pricing was on par with Tire Rack for PS2s, when taking shipping, balancing etc. into account.

This would seem to make sense as when you're dealing with a commodity like Porsche parts you can jack up the price, but for goods that are readily available, like tires, the dealers have to be somewhat competitive.

Ahhh, Pioneer - great shop! If you run into Matt Bang, please tell him that his New Jersey customer says hi.