Tire separation from wheel

[EdBarry1]

Of all the corvettes I have restored or fixed, this latest beauty which I was forced to keep due to my two boys, has had a mystery of tire separation.

On three separate occassions, after new tires were installed, usually one drivers side rear or front passenger side went flat after driving only a few blocks on the first incident. Then the second happened twelve miles from home and the third when I pulled out of the garage and found it only a few feet outside on the driveway!
Now, at no time, after review of the tire, was there any nail or screw or foreign sharp item in the tire. The first and third were salvaged but replaced anyway. The second, twelve miles from home happened during coasting to a stop light and I felt a bump/bump noise doing about 1 mile per hour. Stopping and leaning out my door to look at the rear, I found the tire flat enough that it made a mark on the sidewall and had AAA put my spare on and drove home to later replace with a new tire. This tire replaced was one of four bought and used only less than 200 miles! The tires were BF Goodrich "z" rated and specified size for this model.
checking around, I found that many wheels may have porosity thrugh the casting and may be so slow that you would not see it and advised me to check during new istallation, for leaks and this was done on all tires. I was also told that I should check the pressure of 45 pounds on each one every time I get in the car!
I was also told to make the tire installer place a glue on the inside lips of the rim!
Well, I am leary to use the vette because of not finding any leak in the rim or tire up to now, and something is definately wrong. These are stock rims too.
Any suggestions, any similar problems with good results?:confused

 

[c4cruiser]

It sounds like a wheel (or 2) has a crack of some sort in it. what condition are the outside edges of the wheel lip. If somebody had rubbed the wheels along a curb, there may have been just enough damage to cause a crack.

Another possibility is a build-up of crud along the sealing lip of the rim from previous tire mountings and use of soap to ease mounting on a machine. That could cause the tire to not seal properly against the rim.

Bad valve stems are another possibility but a good tire shop will replace the valve stem when mounting new tires. Was this done when you got the tires?

As far as porosity of aluminum alloy wheels, I have never run into this problem after close to 30 years of buying alloy wheels for my cars or have not heard of problems from any of my friends who bought alloy wheels. Most alloy wheels are aluminum but a wheel that is magnesium may have problem with air seepage. The factory Enkei wheels on my 87 hold air just fine!

I would have the tire shop inspect the sealing lip on all of the wheels and clean the inside portion of the rim where the tire bead seats. If they didn't replace the valve stems, get that done at the same time. Most tires will seat on a wheel with about 40psi and the tire sidewall specifies the maximum air pressure to seat the bead. I run 32psi in both my 87 and 92 for general street driving except for higher pressures for autocross.

You might also want to consider having the wheels inspected at a machine shop using magnaflux or some other type of process for checking for cracks. One other possibility to consider is that the tire shop may have damaged the wheels when installing tires. I've seen some real idiots run tire mounting machines!

Good Luck!!

 

[EdBarry1]

Thanks for the tips:

I will state that porosity in aluminum is a problem. I was a purchasing manager for a rocket and jet aircraft components manufacturer for 20 years, called Cercast, than called Howmet/Cercast, USA, Inc. I even made tooling and created the 69 side exhaust covers that were listed in Vette about 6 years ago.

Depending on the region location of a casting company, especially in aluminum, this problem can be major. Florida is known for this problem due to humidity and requires major equipment to reduce or remove this problem. The use of pressure vessels that act like the old day village smithy. Remember how they used to hammer on the shoe of a horse? Well that is our modern day notation of grain refinement. By this pounding, it tightens the granular structure to make the material stronger.

Yes, I agree that some idiots in the tire industry are still alive and well. But most vette owners were passing around a problem of the wheel spinning but the tire was not. This caused many to tell me to apply a glue on the edges of the rim prior to mounting a tiire! I was also told that Goodrich, although a fine tire, is a bad one for vettes! I have had Dunlops and Goodyears and now Goodrich's and I have a reservation about the metric size, but the dealer says that it is no problem.

I have had this new tire mounted now for about a month and have not driven it because I am leary of this problem coming back again. I will test the air pressure in each tire to see if I lost any of the 45 lbs. that were filled at time of that mounting and if there is a one pound loss or more, I will do as you recommend and have the tires at the bead area checked for a slow leak, as well as the stem (all were new when tires were installed). I also want to check if the idiot applied the conventional weights to the rim and if so, that was the problem (psa style weights are the only way to go on these cars).

My 87 is a L-98, white with factory smoke glass top. It will need new rubber aroundthe doors and posts and probably a new paint job within a year to keep it original and it will be done by a chevy shop that I know very well.
If in need of parts, we have an area of about 45 miles from Allentown that is a hotbed for original mechanics since the early days that are impeccible in detail and repairs that may be of help to you. I can also first hand, give you some hair raising tales experienced of some widely advertised supply houses to stay away from and those to definately consult on a honest basis.

Good luch with your 87, I enjoy it and still am looking for a 68 to 69 to redo. Also still on the hunt for those 65 to 67's still in a barn for 20 years to redo as well-LOL.
Take care and appreciate the comments. Ed