onedae

I was washing my 2011 C4S today and found a noticeable bulge in the sidewall of my right front tire. Tire is an OEM Michelin with only a bit over 10,000 miles. No pressue loss, tire or wheel scuffing, cuts, etc so no apparent cause.
I was planning on taking a trip from LA to San Diego tomorrow but now I'm concerned about taking this car.
Any thoughts as to cause? Is it safe to drive?
Comments appreciated.

LexVan

Don't take it on your trip. Too much risk of failure. Propably happened from curbing a tire or hitting a pot-hole. I suggest you purchase at least one new matching tire. You might need to buy both for the front end since you have 10K miles.

How's the alignment?

Sorry.

onedae

alignment is perfect. Definitely not from a curb or pothole - I'm such an **** nut I would have known. Could it be a tire defect after 10K miles?

jhbrennan

Possibly...but you're about at the end of the useful life of the tires anyway.

GSIRM3

Maybe not for the fronts.

sjfehr

When you say "bulge", do you mean a slight bulge like this, or a giant bubble like this:


If you could post a picture, it would help.

Sufficed to say, a bulge is a blowout waiting to happen. Sometimes it's a factory defect, sometimes it's road damage. Regardless of the cause, the pressure bladder that's supposed to contain pressure in your tire has failed and it's leaking into the outer layer. If it's very small (like in the michelin I linked to), you might be able to drive it safely a short distance at low speeds (IE, to your local tire shop to get it replaced), but I would not drive on it any more than you absolutely have to. I certainly wouldn't do a track day on it. You'll want to replace both fronts when you do.

Shoot, I'm lucky to get 5000 miles on my fronts

onedae

The bulge is small - not even as big as the small one you linked above. In any event, its pretty clear that I need to replace the tire before doing any significant mieage.
Thanks for all the help.

IslandS52

Michelin warranties are pretty good. Have it checked by a Michelin dealer and you might get lucky with at least some credit toward a new one.

rotesAuto

Quadcammer

while I cannot recommend it, I've driven cars for thousands of miles with a small bubble on the sidewall. Now mind you these were not super high performance cars and I wasn't driving them in such a way. Not the smartest thing, but if it really is as small as you are describing, you would likely be ok for a while.

either way, safety says change it.

raspritz

What you have is called a "wall-nut". It represents a failure of the tire sidewall, and you risk a blowout at any time. Because your car is a C4S, and thus 4WD, you need to buy at least two new front tires which must be the same tire as the rears. Alternatively, you can buy 4 new tires, which is probably the best solution since your tires are high-mileage.

SecretAsianMan

Why do the fronts have to match the rears? The setup is already staggered so there is already uneven rolling resistance.

cyberay

When the tire is removed, the Michelin dealer will inspect the inside of the casing behind the bubble. If there is a cut it will be deemed impact damage. It happens, and a lot of the time the impact is not noticed by the driver. Less often the tire is just defective, but most often there will be a small cut inside and no evidence of impact on the outside. Warranty coverage will be declined.

Quadcammer

diameter of the tires is important on awd systems because if the difference is too great, the car will assume the smallest diameter tires (which are rotating faster) are spinning and move the power around to avoid said issue.

Rob996

This is completely ridiculous people...

Please do not hesitate and buy new tires.. Furthermore getting 10k miles out of tires on a porsche is amazing to begin with.. Taking the risk of a blowout, with possibly destroying a wheel and worse..

Be safe..