Flat Spotted Tyres

[bonjo]

I have been storing my RAV 4 (2003) for the past 2.5 years. During this period, I have used it twice (3 weeks each time).

When I drive the car, I noticed "out of balance" type of vibration which I feel it through the steering wheel. Balancing the front wheels has not really helped. The garage thought, long term storage of the car my have flat spotted the tires which means new ones!

The steering wheel shake happens between 75~85 mph.

Has anyone had a similar experience?

[FROSTYBALLS]

Not had a similar experience. However have extracted some info on flat spotting below from an American website:

Flat spotting happens when a tire is compressed against a hard surface while the car is parked. A section of the rubber becomes softer or stiffer than the rest of the tire. The tire flat spots cause a noticeable disturbance when the car is in motion. Flat spotted tires can cause vibrations as soon as you pull out of the garage, but sometimes are only noticeable at higher speeds when you get out on the highway.

Flat spots on tires can develop overnight, but typically occur when a car is parked for 30 days or more. Extreme temperatures, vehicle weight, tire size and tire composition all play a role in the physics of tire flat spotting.

Though flat spots on tires are a normal occurrence for many brands and types of tires, high-performance, high speed rated (H or higher) tires are especially prone to have this problem. High performance tires are engineered to maximize contact with the road surface in order to improve handling at high speeds. Such tires are typically softer and stiffer, with a low profile and larger tread elements.

The very qualities that make tires capable of high performance leave them vulnerable to tire flat spotting. The larger, softer surface of the tire is more likely to absorb heat, cold, moisture, and chemicals from the ground itʼs parked on, especially concrete floors.

Factors that increase the likelihood of a tire flat spot include:

• Low profile tires with short side-walls and a wide footprint

• Nylon-reinforced internal constructions

• Heavy loads

• Under-inflated tires

• Fluctuations in temperature

• Long periods of storage/lack of use

Almost all short term flat spots can be driven out in a short distance if you grit your teeth until the tires warm up and regain their original shape. However, driving on flat spotted tires after long term storage can be far from pleasant. And though a tire flat spot often disappears after a 25+ mile drive, many times it doesnʼt. Tires on vehicles stored on the ground for several months, especially in extreme temperatures, can become permanently flat spotted.

In some severe cases tire flat spotting becomes permanent, effectively ruining the ride quality of a vehicle. Also, if tires are not stored properly, their appearance, performance, and compound integrity will deteriorate when not in use. Parking a car flat on the ground – especially on bare asphalt, concrete, or other heat-absorbent surfaces – can cause the tires to age and crack over time in addition to developing a flat spot on the tires.

Tires on a car in storage should be protected from sunlight, ozone, extreme temperatures, moisture, oil and grease. The longer the storage period for your vehicle, the greater exposure there is to damage and the more precautions you should take.

Parking your car on carpet squares, sand bags, plywood, and other do-it-yourself contraptions is simply not effective to prevent tire flat spots. In order for tires to maintain their shape in long-term storage the weight of the vehicle must be lifted entirely off the tires or evenly distributed over the tiresʼ surface.

[bonjo]

thanks very much for finding this info.

It certainly describes the situation very well. I have taken some precautions though: over inflating by 10psi, puttinh the car on

chipboard so that the tyres do not touch the concrete floor and using a de-humidifier on a timer. But I guess this was not enough. Oh well c'est la vie

Now that I know, I think I have to look into changing the tyres once the standard suspension checks have been done, next time I put the car back on the road.

Much appreciated

[Cyker]

How bad is it? Maybe they'll fix themselves if you take it on a long country road run with lots of braking and twisty turny bits to heat up the tyres and stuff! :)

I was going to say go for a long drive on a hot day but if you're in the UK you might be waiting a while for one of those!

[spoofpig]

http://www.hamiltonclassic.co.uk/acatalog/Tyre_Trainers.html

found these for you

[bonjo]

I did over 500 miles; had to keep the speed below the vibration speed but unfortunately it has not disappeared.

So whatever the answer, it will cost money!

Spoofpig, the trainers are certainly something to consider if I go through the same situation again.

Thanks guys

[ANNAWONG]

Puit it up on wooden blocks next time you leave it for a period, just so the tyres are of the ground. No weight on tyres, no problem!

[bonjo]

I think this is my only option in the future. I have axle stands which I can use. I didn't use this because of the tight space inside the

garage. Now I know better!

Thanks for all your thoughts

[ANNAWONG]

Perfect Bonjo, good thinking!

[Davrav]

I think this is my only option in the future. I have axle stands which I can use. I didn't use this because of the tight space inside the

garage. Now I know better!

Thanks for all your thoughts

And you will be able to leave the hand brake off and rotate the wheels every now and again to keep everything freed up

[ANNAWONG]

But!

If it's an auto and you wish to spin the wheels, (not very quickly I assure you!) you will have to leave it in neutral, which means leaving the ignition key in ............?

Unless anyone can tell us differently?

[Hoovie]

If it is on axle stands, won't get very far though ;)

I can stop the engine and turn off the ignition with my car still in drive - I do have keyless start, but I don't think being able to so that is unique to keyless start though?

[bonjo]

I keep the hand bake off anyway and a wooden block to keep the clutch pedal depressed (just in case the dehumidifier stops working in my absence).

Yes being able to rotate the wheels on the axle stand is a bonus; only if I were there...