Tyre pressures are important?

[dozypillock]

After towing a caravan this weekend with my CLK320 and putting 40PSI in the rears (ignoring the guidance from the filler cap for 4 passengers plus luggage) I can confirm that it does not feel "right" when the van was not attached. It has massive AMG wheels/tyres on, on 18" rims and another caravanner commented that it was not an ideal towing vehicle. I found it could easily accelerate past a "plonker" in a Vauxhall Zaffira? that was stuck at 50 with no problem, much to the surprise of the car that let me out, (and left behind) before panicking when I realized I had hit 75 and there was a caravan on the back.
When I popped out in the morning, as hunter/gatherer, to find bacon, fresh eggs etc, it was very twitchy on wet roads. Scared me a bit (ok, I nearly had an underpant accident on one bend with a bad rut in it).
The point I am trying to make/ask, is that tyre pressures can have a massive impact on car handling, but finding the right ones, based on what the car is doing, is not easy.....ie...a bit trial and error?

Neil

 

[Giantvanman]

tyre pressures can have a massive impact on car handling, but finding the right ones, based on what the car is doing, is not easy.....ie...a bit trial and error?Neil

Not really. There are a few caravaners on here who will have greater expertise than I but when I towed a caravan, I set the tyres no more than the maximum pressure for people and luggage.
If you think about it, the nose weight of the caravan is limited by what the car (towing equipment) is rated as….check the handbook. Most are about 60-70kg nose weight. That is equivalent one person. So unless all your luggage is in the boot as well as having a full compliment of passengers, why exceed the pressure table and probably the tyre manufacturers range?

 

[BTB 500]

It's generally recommended to use the maximum plated tyre pressures (front and rear) when towing a caravan. Higher than normal tyre pressures when the car is unloaded can reduce grip as the contact area with the road is smaller.

AFAIK the reason for increasing the pressure is mostly to do with stability rather than the actual weight on the axles. At higher pressures the tyres are stiffer and will resist sideways forces better e.g. if the caravan starts to snake.

 

[V12]

AFAIK the reason for increasing the pressure is mostly to do with stability rather than the actual weight on the axles. At higher pressures the tyres are stiffer and will resist sideways forces better e.g. if the caravan starts to snake.

Bingo.