safulop

OK, so this morning about 3 miles into my trip to work, I realized I have a flat on left front. And I do mean f-l-a-t. I checked tires 2-3 weeks ago and seemed fine, and they hold pressure, so I'm still getting to the bottom of why it was flat.

I pumped it up at gas station, continued to work, no hissing heard, it is still good right now.

Anyway, I am still not used to these performance tires obviously, since I cannot see whether they are flat. I'm used to my touring tires on the 944.

My question now is, is this a dangerous front tire? It is not visibly damaged, except that the printing on the side is sort of "smushed" from where the sidewall was bent. I overpressured it at the gas station before letting the air down to 36 psi where I normally run.

These are Dunlop Z-rated 235/45 on the front IIRC. 18" cup II rim is undamaged (PTL!).

-Sean

safulop

Well this tire is still holding pressure, so that means that some clown at my university let the air out of it on Thursday, and I didn't notice until Friday morning. Amazing how stable the steering is with a flat! I feel lucky I never made any sharp turns, I might have lost the tire and ruined a whole bunch of things. An incident like this is one of the hazards of driving an attention-grabber to work at a college campus.

Nicole

If you drove with this tire when it was deflated, you most likely caused damage to the side wall. I would consider it unsafe to continue driving with this tire, and would replace it before I'd drive more.

A slow drive to a tire place might be OK, but be careful in turns. Tell the guys at the tire place what happened, and let them inspect it. If they feel it's safe to use... I doubt it, though.

Bill Ball

I agree with Nicole. Also, the damage might not be easily detectable - creased, weakened belts that may take a while to fail.

safulop

Yeah, it would be smart to replace the fronts at least after this, I drove on it for probably 8 miles or so, not more than 40 mph. It was not 100% deflated or I think it would have completely dismounted, but still I don't know about long distance travel on this tire. They are fairly old tires too, coming up on 5 years, plenty of wear.

So, what are the important things about the 928 at a tire shop? I know the suspension is sensitive, the alignment more so. I don't need an alignment. But I don't want the shop to mess up the alignment. Maybe I'll ask my 928 mechanics about the tire shop they would use.

-Sean

Nicole

If those tires are 5 years old already, you haven't lost too much. High performance tires and snow tires lose their grip over time by hardening of the rubber. They say that winter tires last only 4 years; I would think high performance tires last a bit longer...

Please make sure they only lift the car at its designated lift points - NOT the floor support underneath the car. Many technicians seem to mistaken that for a "Frame Rail", but it isn't, and can be dented or bent very easily.

Also, ask for "road force balancing" to get the smoothest ride possible. I'm always doing this when I get new tires, and it helps keep wheel shake to a minimum by matching tire and rim in the best possible way and balancing with simulated road forces. If you do a google search for Hunter Road Force Balancing, you should find the website for the machine, which has a locator feature that lets you find tire dealers in your area with this kind of machine.

Mrmerlin

the damage if there is any will be most noticable on the inside of the tire there you will find lots of little pieces of crumbled rubber this is the tire delaminating . its time for a fresh tire.

Also buy an air pump keep it in the spare tire well.

Also and do a walk around of your car before you drive it,
it is easy to see if you have a deflated tire

David L. Lutz

Be careful, check that tire in question.

You don't want it to end up like this PS2 that was only 4 weeks old.

dr bob

Sean--

Take the tire shop's habits around car damage and the air wrenches out of the equation-- remove the wheels and take them to the tire store in the back of another car. My local Costco moves me right to the front of the tire-chane que if I bring the wheels in clean and ready. I alert the installer to be careful with the wheels so they aren't damaged, and give them wheel balancer settings for these wheels. The balancer expects to have clip on weights at the edge rather than stick-on weights inside the barrel section, so the width, diameter and offest numbers plugged into the balancer need to be adjusted if you want it to be right the first time. Most places never adjust the balancer for anything, unless you ask. Oh, and bring a box of donuts.

Back at home: With the wheels off and before the tire store, you can thoroughly clean them inside and out, after popping off the old wheel weights. Brake-Clean or a bit of acetone will make short work of any glue or foam tape residue. The brake dust and crud comes off with some Simple Green and a scrub brush. Be careful laying them down so you don't damage the front faces.

When you get back from the store with the new tires on them and weights in place, apply a thick coat of good poly wax-sealer-something to the insides and outer face so the brake dust will clean off more easily. The Rejex product is especially good for this duty. A search on Rennlist will hook you up with a Renn discount buy on it. Or use you toughest wax/sealer, knowing it wo't last as long.


Peek at brake pads, inspect the ball-joint boots, etc., while the wheels are off.

A little anti-sieze on the cupped faces of the lug nuts on installation means no galling on lug nut removal next time. Torque the nuts to 94 lbs/ft and you'll be good to go.

safulop

Well this is good advice for preserving the vehicle, but it is kind of tough to do road force balancing without my car. I have had balancing problems for years with my 944 precisely because of never doing it road-force, I recently found out. Currently these tires are so perfectly balanced there is no freeway shimmy at all, it is making me weep to have to remove them and start over. I'll decide what to do with it this week, since I don't have to drive too far or hit a freeway.

Nicole

Road force balancing and on-car balancing are not the same. You don't need to have your car with you to have a wheel road force balanced.

Unless there is an imbalance on the car itself, you should not need on-car balancing.

Here are a few links:

http://www.gsp9700.com
http://www.tirerack.com/tires/tirete....jsp?techid=40

Those websites explain things better than I can.

Eturbo924

Had the same thing happen to my tire recently. Unfortunately it only had 3K miles on it... no road hazard coverage.

I did not go far on it ... since I only travel .6 miles to work... but it junked the tire and warped the rim to boot. I did re-inflate the tire but noted a real bad shake afterward. So I took the rim/tire off and sent it to the shop for correction. Once the tire was off they saw the tell tale signs... side wall damaged and rim warped. Oh and nail in the tire to boot!

So $140 later (tire rack) for Eagle GT and $80 to straighten rim.