Tire Safety

[azopelnut]

With six Opels some of them see little to no mileage in a year. They are all sitting on tires most of which have under 5,000 miles.
Question
If the tire is out of direct sunlight and kept inflated (but on the car and on pavement) is it safe to drive at highways speed?

A local tire shop says if the car has been sitting on its tires for 8 months or more it is not a question of if but when it will blow!! YIKES 24 new tires! The recommendation is to buy jack stands for all the cars to get the tires in the air.

[BQS4]

Paul;
Look at it this way, you can go to Walmart, Kmart, or Harbor Freight, or Northern Tool and get a set of jackstands for about $15-25, FAR cheaper than 24 tires.

[Paul]

Paul

Keep in mind that tire shops will blow smoke up your skirt faster than a used car salesman. With the technology put into modern tires, it would take more than 8 months for a tire to go bad.

I read recently in a article about long term storage of race tires, that besides Ozone, Oxygen was a major player to breaking down the rubber bonds. They suggested filling tires with Nitrogen to help prevent the rotting of tires from the inside out.

They also suggested sealing the tires in plastic garbage bags with as much of the air removed as possible. This was to prevent exposure to sun light, ozone and oxygen.

You might consider covering the tires with an easily removable cover, such as cloth, card board, plastic etc to keep the stray sun beams off. Also, devices with an electric motor will generate ozone, keep the tires shielded from them.

GL

[namba209]

Originally Posted by Paul Keep in mind that tire shops will blow smoke up your skirt faster than a used car salesman.

Yessir!!! Margaret was out getting new tires on the Montana and called me asking if I thought nitrogen was good to pump up the tires with. I told her it's a great idea. Then she told me they had nitrogen at 78% with a 21% mix of oxygen to put in the tires. I thought about that for a millisecond, then high school education kicked in. Normal atmosphere is 78% Nitrogen and 21% oxygen, approximately. Great PR work at that tire store.

To keep this on topic, you gotta remember the road trip from hell earlier this year, 3 tires blew out and I replaced 7, all Michelins with plenty of tread, but made 10 years ago. General rule of thumb now, is to replace the motorhome tires at 6-7 years, just for a margin of safety.

[73Manta72gt]

The six year replacement is a good idea. I've had two vehicles that had the tread peel off of the tire without losing air. The departing rubber bent the fenders. Lucky it was just a junker Ford Ranger and not a valuable Opel...tires are cheaper than fenders!!

[Steve Daniels]

My Gt has been garage kept for 15 years the tires are in great shape like new. I do put the car on jackstands from Oct.- April.

[saxybiker]

We are bad. We don't put ours on jackstands. Six months they sit in the garage and six months we run them hard. So far so good.

Vickie & Allen

[GTJIM]

Radial ply tyres in particular will take a set on the bit flattened out by the weight of the car and this can cause strange drumming or slapping sounds with balance problems that can never be solved.

If you park up your car for more than a month or so the jack stands are a real good idea! Otherwise just move the car by hand part of a tyre revolution every month so a different bit of tyre takes the load for the next month.

HTH

[opelbits]

I've seen relatively new tires come apart after less than a year. Unless the tire shows visible signs of deterioration (cracks from dry rot, lumpy tread from tread/belt separation) or you drive hard and stress the tires, even ten year old tires are fine for normal driving if they have a decent tread thickness. Worn out tires are just, worn out. An old tire in good shape with decent tread is okay for light duty. An old, bald tire is far more prone to failure.

Having said that, GTJim mentioned the biggest problem. When tires get a flat-spot they are hell on you and your suspension. Remember those kids toys? The beagle/hound on wheels that kids pull around? The wheels were egg shaped and it loped like crazy? That is what a set of flat-spotted tires are like. I had a set, brand new, great shape, but the previous owner of the car let it sit without moving for far too long. At low speed I could feel which corners of the car were rising or falling. Terrible vibration that tossed off the wheel weights.
Sometimes, in really cold weather good tires will do the same thing, but go away when they get hot.

[opelbits]

Oh, I almost forgot. If you run low tire pressures (low 30's) or have under-inflated tires, expect them to fail earlier than if you run a consistent higher pressure (but not over-inflated). At lower pressures, the tires flex more. This flexing creates heat in the tire from the friction of the tire rubber or steel/poly/fiberglass belt molecules rubbing agianst each other. The less pressure, the more flexing, the higher the heat. The heat cycling really affects the life of the tire.



By the way, since we are on the subject of tires....Pirelli P600's really suck in the rain.

[Paul]

Bias Ply tires were the most prone to taking a set, radials are less problematic. I've left the Manta at the airport on many many many occations the past two years for 1, 2 even 3 weeks at a time with no problems...

Since when is the low's 30 psi range considered under low/underinflated? Most tires have max psi listing on the sidewall of 36 psi. I've found for most tire model/drive train layout combination 32 - 34 is a great comprise between reduced rolling resistance and compliance. Running 32 vs 36 won't shorten the life of the tire.... under normal conditions.... highway vs autocross....

[PROPEL]

This site has info on reading your sidewalls to determine their "freshness" date.

[baz]

good find on the site ,i think that covers almost all the questions we get on wheels and tyres

[namba209]

Originally Posted by baz good find on the site ,i think that covers almost all the questions we get on wheels and tyres

Yeah, that link should be put in the technical center, for sure.

A note on tire pressures, check the door jamb or owner's manual and you'll see the car manufacturere recommends around 28 psi for the tires under normal conditions. That means they prefer a soft ride for their cars as opposed to a harsher ride for their customers, which makes the tire folks happy, because you'll wear them out faster. Personally I run the highest pressure on the sidewalls in the motorhome (80 psi) and on the vans (40 psi) because I don't know how much load I'll have at any given time. Also the higher pressures actually slow down the advent of hydroplaning, or actually the vehicle speed increases before it occurs. On the monza and Willit? I will run 32 psi, been running that pressure in all my cars since day one.

[Paul]

On the Manta the recommended pressures listed on the inside of the glove box are 22 front and 26 rear. Besides high rolling resistance, these recommendations are heavily biased toward understeer.

[opelbits]

Paul-

I didn't mean that low 30's is low or under-inflated. Just that in the range of pressures used by tires and people, the lower the pressure the more flex. I have some Kumhos on my wifes' car that have a max pressure of low 40's. I normally run about 36.

The low pressures specs on the Manta are for bias-ply tires. Run radials at those pressures and you will really hate it.

[Paul]

No, those pressures were FOR radials. Mine is a 75 and it came from the factory with Firestone Cavillino S1 radials, French made vs the US made models. Car and Driver LOVED those tires in a tire test back in the day. The test was performed using an Ascona BTW.

On my personal car, I usually run higher pressures just like you. Actually, I usually set the front and rear pressures in such a way as to bias the car toward the type of understeer/oversteer characteristics I like. I would never do this on a car where it might get the driver in trouble especially in an emergency. For example the first year I autocrossed my Neon, I did it on street tires. To get the car to rotate, I ran 38.5 in the front and 52 in the rear.

The optimal pressure for a tire is partly dependant upon the load and partly rim width. The same exact tire in say on the front of a Manta vs on the front of a Neon would be different. Since I put 14's on the Manta, I bought the same tires for both the Neon and Manta, Bridgstone RE-950. At the 32 psi on the Manta the contact patch stays flat, the slip angles are small and the tire still has compliance over rough surfaces. On the Neon I had to run 35-36 to get the same results. Oh yea, these are cold temps, measured with a $60 gauge, in the shade.

A person can up the pressures to get improved milage, but after a point corning capabilty will suffer when the tire tends to bulge in the center.

Good discussion, btw

[Tru-Craft]

My Go-Kart racing tires are wrapped with clear plastic food wrap after each race, helps keep the durometer readings lower. Exposer to oxygen and sun will speed up the hardening of the tires!
If you are storing the cars for long periods, use jacks stands, pull the wheels and store them in the garage. In the Florida sun, car tires are only good for about 4 years!