Thread: P38 DIY wheel alignment.

I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

Originally Posted by PeterH

I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

A lot of car manufactures have a recommended pressure which is lower than what tyre manufactures would like.

This lower pressure is ok, just not optimum. It is a compromise to try and get the softest most comfortable ride.

In the longer term the tyre wear pattern will show you if your inflation pressures are correct.

Steve

Steve I've never touched the radius arm bushes, they are probably the original ones, I'd guess they would be in need of replacement for sure.
I tightened the steering box slightly, while it is definitely tighter steering feel, it is still doing the same thing.
I might have to check the calibration of the air springs, maybe do the radius arm bushes as well.

Checking the spring calibration sounds like an excellent idea!

Steve

They are the best tires for a P38 as far as im concerned.
I have had 4 maybe 5 sets of them over the years try 38 PSI all round, If you are doing motorways a lot 40 is a good number.
I have over 350,000km on my P38 all the bushes in the front end that I replaced (original) where not too bad as far as I could tell.

Originally Posted by PeterH

I have the same tyres all round, Michelin standard 255/65/R16, they are all fairly new and in good shape.
I always thought 28 seemed low in the front too, but as Steve already pointed out, that is the factory recommended pressures, so that's why I have them (close to) that pressure.

The factory pressures would have been arrived at after many 1000's of Kms of testing by LR, I doubt the tyre manufacturers did much testing on the actual vehicle.

They are a compromise between comfort, handling, wear and safety.

Over inflated tyres are less safe and do not handle as well because less of the tyre is in contact with the road so personally I stick close to what LR specifies

Steve

Hi Steve.
Regarding the pressures, there has been extensive testing done on tyres, and lots of good information readily available regarding tyres & pressures. I also work in the driver training industry. A tyre with a slightly higher pressure would be safer compared to one which is either at, or below the manufactures recommendation, of course there is lots of different situations, and this may be adjusted depending on that. You are correct in the fact that land rover would have done lots of testing, and the pressure they have come up with is a minimum safe cold pressure, for slow, and short trips without any additional weight. As mentioned, there is lots of info around, I am happy to give a few reasons more, but thought I would just mention it. Not saying that land rover is wrong, I'm just saying it is a minimum cold pressure.