Trust you all do this regularly, but...
Checked bonnet fluids in wife's car today, all ok, walked around and looked at the tyres, all appeared ok, but despite cold weather, checked them with gauge anyway... o/s/r had just 12 psi - jack out, found nail through tread...
Point is, tyre looked didn't look even slightly flat despite just 40% of pressure, so regular checking is vital...
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Couldn't agree more John, appearances can be very deceptive. Likewise tyres can look flat when the pressure is OK - often depends on the lie of the ground where the car is parked.
Oz (as was)
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I'm unable to read this 'cos of the Volvo D5 advert. Can I do anything about this?
Then again, how am I going to read the reply?
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I completely agree with both points raised. Very low tyres can look OK, but equally I find when checking a low-looking tyre that actually it is fine, it is just the slope, soft ground, etc.
A point on checking that has always puzzled me is what significance air temperature has. If I check the pressures on a mild day, and then re-check next day in a hard frost, they are several pounds down. 2 to 3 pounds is the sort of range I am supposed to vary the pressures by if the car is either loaded or not.
Yet clearly the cold-setting is only a rough base-line anyway. I would have thought it is the hot-running pressure that really matters. Is this a constant irrespective of the air temperature?
And surely a lower pressure tyre flexes more so gets hotter so increases the pressure, so . . . .isn't low pressure any more ?
Can someone explain. Just how critical are tyre pressures, and how does one compensate for weather?
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>Can someone explain. Just how critical are tyre pressures, and how does one compensate for weather?<
I was taught to get the tyre pressures right when the tyres are cold. The pressure does differ by one or two pounds in the range of temperatures we have in Britain. Whatever the ambient temperature I set them to the book pressure.
>And surely a lower pressure tyre flexes more so gets hotter so increases the pressure, so . . . .isn't low pressure any more ?<
A soft tyre flexes much more, and the rubber runs hotter due hysteresis. This does not reinflate the tyre - you need a pump for that. If the soft tyre is run too long the rubber fails, and off the tyre comes. How many bits of rubber have you seen at the motorway verges due to lorry tyres breaking up?.
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I'm unable to read this 'cos of the Volvo D5 advert. Can I do anything about this? Then again, how am I going to read the reply?
Press F5 to refresh and clear the ad.
No Dosh
mailto:Alan_moderator@honestjohn.co.uk
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Had a similar experience a couple of weeks ago John. Noticed for a couple of days that the steering whell was very slightly of centre for a couple of days. Assumed that my wife had clipped a kerb and was going to take it to have the tracking checked.
Checked the tyre pressures first and the rear!! nearside was way down.
Also found nail in tread. Repaired and the steering wheel was dead true again.
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I'm probably a bit anally-retentive but I always give the tyres a press with my thumb before anything more than a local trip. Not very scientific but it only takes seconds and will alert you to a low pressure problem long before the tyre has any visual signs.
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For anyone interested... I once calculated the difference in pressure between a cold winter and cold summer tyre is 9% lower pressure with the colder temperatue of winter..
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heres a fail proof way to check your tyres..its called a kick...just kick the tyre ,if your foot hurts,that means its good,if your foot bounces back with a mild spring ,there a couple of pounds down,if your wheel comes off then get a new jam jar.another good check is the wife test get her to kick the tyre if she moans bout her foot hurting then there good,if she says "why am i doing this"then it probably needs pumping,give her the foot pump and say "you do want to go shopping darling,my toenail is ingrowing and i cant press down"
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