Tyre Pressures

thensum · Jul 9, 2021

Hi All,

Only just joined this forum today, so apologies if this question has been answered previously. I did do a quick search of this section but couldn't seem to find the answer, so here is my post I have 'cut and pasted' from the Caravan & Motorhome Talk Forum that I asked earlier:

Hi all,

I have the following tyres on my VW Tiguan R-Line 2.0TDI 150PS: 255/40 R 20 V 101 Continental - Conti seals. The tyre pressure table inside the driver's door only lists the following tyre sizes 230 and 260, not 255. The figures for these two tyres sizes when fully loaded (towing) are quoted as follows:

260 - fully loaded: front 38 PSI, rear 45 PSI

260 - part loaded, not towing: front 38 PSI, rear 38 PSI

The figures for the 230 tyre size are only listed for light loads, so not quoted these here.

I have been inflating my 255/40 R20 V101 when towing based on the 260 figures on the car's table as follows:

Front - 38 PSI

Rear - 45 PSI

I am wondering if this might be a little too high, although the car has always towing exceptionally well, but sometimes our previous Swift looked at little nose up even though the nose weight was at 90 - 93kg. The R-Line also has sport suspension doesn't it?

Finally I looked up my vehicle on Tyre pressures.com and the following pressure were quoted:

255/40R20 V101 - Front 35 PSI & Rear 35 PSI but nothing to say if this is when light load, or heavy load/towing.

We are picking up our brand new Coachman caravan tomorrow morning so I just want to get some feedback and advice please before I pump up the tyres.

Thanks,

thensum

Tammma · Jul 9, 2021

I inflate my 255/40r20 RLine tyres to 36psi all round. Some have found higher pressures make the ride a little too stiff for their poor 'tushes and go for lower pressures.

I have conti sport 5s which are notoriously soft and known to wear prematurely, which is the other reason the tyres are a little higher psi to stop premature wearing.

I believe that 36 is slightly higher than the recommended 32. The idea being that balances out when we have the car loaded and unloaded. I have never towed but presume that is the equivalent of loading up the boot full, so logically a higher rear pressure sounds logical to me...

T

Tubemonster · Jul 9, 2021

The 260 and 230 are not the profile of the tyre but the kPa (kilopascal) equivalent to the psi or bar reading depending on which measurement scale you prefer to use. The 230kPa reading has an "i" next to it and equates to 33psi which may be the so called "comfort setting". I always set it for the weight guidance shown on the sticker inside the drivers door, 38psi front and rear for normal use or 38psi front and 45psi rear for a car full of people and luggage or in our case towing. Putting more pressure in a tyre makes it harder, it does not lift it up higher so you should see no difference to the level at the hitch.

thensum · Jul 9, 2021

Tubemonster said:
The 260 and 230 are not the profile of the tyre but the kPa (kilopascal) equivalent to the psi or bar reading depending on which measurement scale you prefer to use. The 230kPa reading has an "i" next to it and equates to 33psi which may be the so called "comfort setting". I always set it for the weight guidance shown on the sticker inside the drivers door, 38psi front and rear for normal use or 38psi front and 45psi rear for a car full of people and luggage or in our case towing. Putting more pressure in a tyre makes it harder, it does not lift it up higher so you should see no difference to the level at the hitch.

Thank you so much for this, I did wonder if I was reading it all wrong. This make perfect sense so thanks for the clarity.

Tubemonster · Jul 9, 2021

In the two and a bit years of towing on 45psi in the rear I have found it a very stable unit. I carry an air pump in the car as 38 psi in the rear is firm enough solo so if you leave 45psi in it I would imagine it would hop around like a kangaroo with a thorn in it's foot

Tyre Pressures

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