Tyre Pressures, Who Is Right?

Hi All
I've just found this website on tyre pressures.
On a 2.5td estate they recommend 36psi ...my door pillar says 33psi, irrespective of what load you are carrying.
Could this be a deliberate ploy to buy tyres more often - softer tyres wear down faster, more drag etc etc...
It has all makes and models recommended psi settings.

So, should I put 36psi in, or leave them at 33?

Check it out here:
http://www.thetyrepressuremonitor.com/loca...n&car_model=433

shoestring

Hi Shoestring

I will stick with the Citroen recommended pressures. The tables given in the link are NOT the manufactures pressures. They are an advertisers listing with ammended pressures rounded up to the pressure values available with the check devices he has for sale. My guess is that for XM's he can only supply 28psi/32psi/36psi devices so Citroens 27 becomes His 28 and 33 becomes 36.

Regards

XMexc

Hi Shoestring

I would go with XMexc, I run mine all at 33 psi unless I am carrying something very heavy. Its suprising what a diferrence 3 psi can make to the ride, and after all thats what most of us buy them for!

Peter.N.

The spare tyre on an XM Estate should be set at 41 psi. It is always more likely to be checked less often than the other 4; and that figure is the one recommended by Citroen. as is the 33 psi all round.

Hi Techmanagain and All

According to my handbook only the spare on the 24valve XM should be filled to 41psi (2.8bar) and other XM spares to either 36psi (2.5bar) or 38psi (2.6bar) depending on model. For the spare none of this is particularly critical, as the tyre should be reduced to correct pressure when put into use, except that the harder the spare the more likely that the thin rods of a tight spare wheel carrier will damage the tyre sidewall.

Regards

XMexc

but as internal tyre pressure equates to a pounds per square inch of tread contact, if you have a different size tyre, should pressure be adjusted accordingly ?

Wow old thread!

Ive been searching around to find what pressure people use.

I know i should use Citroens pressures. My door says 32 front and 27 rear. The rear especially does strike me as being very low.

So, ive had 35PSi front and 32PSi rear for a while now. It seems fine, the tyres look better than they do with the recommended pressures. However the back of the car likes to break away early when pressing on, but the front still grips and grips. This is probably down to the tyres though.

Ive always found with other cars its better to have a lower pressure in the rears than the fronts but i thiink i should probably reduce mine!

I have pretty new Vredestein Sporttrac3s on the front - excellent tyres! And Lassa Impetus or something on the back - Not so good!

I had thought about swapping them front to back, but ive had the lasas on the front and they are pretty awful, far too much flex and they just flop onto the sidewalls under cornering.

So my question, what pressures do you use?

Do you up them for more load or long distances?

Sorry if its a silly question

This post has been edited by Citroenmad on November 07, 2008 02:38 pm

The estate is supposed to be 33 psi all round but I find that's a bit hard so I run mine at 30 unless I am carrying a lot of weight. I prefer comfort to speed although it still seems to handle perfectly well at that pressure and I'm still getting 50mpg + on the motorway.

Peter.N.

I have just noticed that I have contradicted my previous post - it was a long time ago - 30 psi is the figure I use.

This post has been edited by Peter.N. on November 07, 2008 03:06 pm

Hi All

On the bigger engined cars 33 on the front makes the tyre look a bit flat. At the rear an empty estate is nearly as light as a car so if it is used as a car with the odd load then perhaps you could get away with car pressures at 27. Putting higher pressures in that recommended reduces the tyre footprint and increases the unit area loading. This will also make the lateral breakaway speed a bit lower. The back end of an XM actually the worst case which is one of the reasons why new tyres should go on the back and in pairs. The old rears should then have a good tread depth to use as a pair on the front because the rear brakes do so little work so tread wear on the back is very low.
The correct size tyres and pressure also gives the designed suspension effect as the tyre/air combination is the primary suspension of the car.

John

This post has been edited by xmexclusive on November 07, 2008 03:34 pm

Hi all

I have to admit my alloys have given me real trouble, after fitting them i ran at cits specs but suffered with wear on the shoulders, i now have them at 35psi at the front and 30psi at the back, all seems well with normal tyre wear now though.

D

Thanks for the reply, i might try letting a little air out of mine then, 35 and 32 is probably too much for the standard 195/65/15s, they just look better than stated, when the look soft. Ill try them at 33 and 30 again to see how i get on.

The sportracs seem to have a stiffer wall, so i should be ok with a lower pressure.

I did used to have them at 32 front and 29 rear, the wear on the front shoulders was bad, the n/s/f shoulder was bald well before the tyre wanted changing.

Oh, i should have said, my rear tyres have only done 4K miles at most, and my fronts about 2K or there abouts. So both have similar tread, just different makes back and front but the same across the axels.

So with my new tyres i tried more pressure to avoid the shoulder wear, but it seems to make the back end more lively, having a little too much pressure.

So ill drop a few PSi out.

Cheers