Tyre Pressures

My work colleague got pulled into a VOSA check last week with a small van and as one of his tyre pressures was low to what it said on his door pillar he got a ticket and three points for an under inflated tyre although it looked ok. My worry here is that i am running my dt rears 10 lb under the vehicle manufacturers pressure spec or the centres wear out.

Gary East-Yorks said:

My work colleague got pulled into a VOSA check last week with a small van and as one of his tyre pressures was low to what it said on his door pillar he got a ticket and three points for an under inflated tyre although it looked ok. My worry here is that i am running my dt rears 10 lb under the vehicle manufacturers pressure spec or the centres wear out.

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Are we talking just the one tyre or both on the same axle though?

I think you'll agree your tyres probably dont, at 10 lb under vehicle manufacturers pressure spec, look underinflated and not only that I suspect that the left and right pressures are the same?

If they're not then you too would get a ticket.

Tyre pressure will vary between brand and type of tyre. The only way to set the pressures correctly is by means of measuring the "static load radius". This is the distance from the centre of the rim to the ground. Some tyre manufacturers provide this information on their website, others don't.

But if you are finding that one end of your car is giving the correct wear and the other is not, simply measure the static load radius on the tyre giving the correct wear and adjust the tyre pressure on the other end to the same radius.

Due to all the extra weight I have up front (bullar, winch, dual batteries, etc) I actually need to run the same pressure front and rear to give the same radius.

Such a method also supports the concept of having higher pressures when carrying more weight.

Another basic measure to see if your tyre is under inflated is to check your pressures when cold and then when you are on a longish trip, check them again when warm. If the pressure increases by more than 4psi, you have the pressure too low.