My Observations On Higher Tyre Pressure

[bosnjo]

This is just my experience:
When I got the car at September this year (new) I've got it with big discount (4000 euros) because the car was parked at the dealer's parking for 6 months and they wanted to get rid of it. It was great deal for me but as I have experience as mechanic I knew that I would have tyres problem.
The car was there for 6 months without moving, with it's all weight on the same spot on each tyre.
As soon as I picked it up, understood that I was right. 17' wheels were out of balance and steering wheel was shaking badly. Also understood that tyres were with pressure too high as driving felt like I had no tyres but just rims. Stopped on the first gas station and checked the pressure. It was 3,6 while 2,2 recomended. Down to 2,2 and driving was smooth. But shaking was the same. Next day went to tyre shop to do a balance. Paid 26 euros and yes, all 4 were totaly out of balance. Shaking was almost gone but still there. I would say 90% better.
Today I've remembered that once I've had the same problem with 1 month old tyres on one of my cars and was adviced by friend of mine to try to rise a pressure higher then recomended few times to try to find best pressure to avoid shaking.
So, went to the gas station. Checked pressure, it was still 2,2. Rised to 2,5 and drove away. Imagine, it was different car:
No shaking at all.
But beside that it started to feel smoother. Speed bumps are not that bad anymore (sport suspention, Dunlop Sport 17' tyres). I know it doesn't make sense but it feels like I brought pressure down and not up. Road noise reduced as well. Handling is different as steering is a bit lighter (but that's the way it should be with higher pressure).
So, I was thinking of changing tyres (only 2500 km) and now they might stay as there's no more shaking and I tested it on various speeds.


This was just my observation.

I was member of Toyota Forum when I owned Avensis and there were few threads about rising tyre pressure higher then recomended. It was because new Avensis has a problem with handling and rising tyre pressure solved the problem - also rising just 0,4, not more.

[Basil]

Had the same problem on SWMBO's car - only way to fix it is 4 new tires unfortunately. Anything else is a waste of time and money.

Good Luck!

Bas

[Toneboy]

If as you say the car had not been moved for six months, then it would have developed "flat spots" on all four tires or just one tire.

Lowering the tire pressure would make those flat spots more pronounced, but increasing the tire pressure forces the tire to become more rounded, hence no thump or vibration.

You could try raising all the tires up to say 50 PSI to see if this will force the tire tread back into shape especially if you can leave them inflated for the day or over night, but do not drive on them at that pressure for more than a few miles.

If you drive for a few miles then slowly bring one tire at a time back down to normal pressure this way you can often pin point which tires are faulty, after all it may only be one tire that is a duffer.

[vRSLen]

If a tyre has deformed/degraded I doubt if raising the pressure will rectify it.

I would replace all 4.

[ednmra]

I would insist the dealer replace all 4. Tyres are your only contact with the road!!