Member Since: 08 Nov 2005
Location: Oldbury, WM
Posts: 10299
tyre pressures - cold to hot
We all know that tyre pressures increase when the tyre is hot, but I didnt realise just how much. For those that tow with the D3 and D4 its has been the case to raise the rear tyre pressures, I know I have, usually to 41psi, but after finding that running on 275/45/21's a better ride was gained by running at 39psi (these being cold PSi numbers). I just happened to check the pressures (via the dash) after a couple of hours towing, so hot tyres, and they were are 45psi - so 6PSi up. Didnt realise it was that much of an increase.
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15th Aug 2017 9:59 am
D&G
Member Since: 29 Jun 2017
Location: Charente 16480
Posts: 3483
That is interesting. I put mine at 41 psi when towing my digger. Total trailer weight bang on 3.5t.
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15th Aug 2017 11:01 am
RRSTDV8
Member Since: 07 Apr 2014
Location: Here
Posts: 13121
Rule of thumb is 1psi rise per 5 deg C rise in temp. So your tyres were 30deg C warmer after your trip. It would have been interesting to know what the pressure would have been if you'd run them at the higher initial pressure.
A good reminder of why checking and adjusting tyre pressures as the weather changes through the year is also important.Visiting from rrsport.co.uk
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15th Aug 2017 4:23 pm
peteyd
Member Since: 08 Mar 2016
Location: South Bucks
Posts: 551
Thread resurrection...
During the cold snap, my TPMS said one of my tyres was a bit low. Now it has warmed up, it is no longer too low.
Is there an ideal temp for setting the tyre pressure, or should they hit the required pressure at whatever the current running temp is?MY16 D4 Graphite in Loire Blue
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