Tyre pressures

Herman

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Finally after 3 years of ownership I decided to drop the tyre pressures on the back axle from 70PSI to 65PSI and wow! what a difference to the internal travel noises, the bathroom door being the main one not rattling any more. I'll try dropping the fronts by 5PSI next.

What pressure do others run their tyres at.
 
Ours are supposed to be 79 psi all round. I have run them at around 68psi too and not noticed any difference in the ride quality. What I did notice though ( having a Tyrepal kit fitted) that the tyres run much cooler at the recommended pressures.
 
After nearly 4 years of wondering what pressures should I be running, after reading all sorts of suggestions from various posters, I finally got round to going to a weighbridge and had the axles weighed. Then dropped an email off to Continental for the correct pressures.
what an eye opener! Have had the 5-5 bar in, as recommended by both the dealers and also on the sticker inside the door on the van. After speaking to Continental, am now running 3-25bar in the front, and 3-5 bar in the rears, and what a difference it has made to the ride quality.
Well worth the trip to the weighbridge, not only to get the pressures sorted once and for all, but also the peace of mind that I am also within the 3500kg overall weight restriction.
 
Only a point to consider, this summer temperature will increase tyre pressure in the sunshine :)
 
I agree with Harrow outside temperature needs to be considered high tyre pressures are ok in the winter but in the summer pressures increase quite a bit especially if you do a bit of mileage on hot tarmac/roads
 
With our tyres at the recommended pressure, I noticed on a hot day travelling ( 300 miles on motorways last week) the pressures increased by around 8 psi.
When we ran them at the lower pressures, temperatures went up by around 12 psi.
 
You may find some of the recommended tyre pressures are max pressure for the tyres so worth looking at the tyre and seeing what the max pressure is for the tyre and then making your own decision on what pressure you want to use in them
 
In Australia we used work on 6psi rise . So you check tyres cool before start of travel , after say 20 miles or so check again , there should be a 6psi rise , if more then they were underinflated to start , so say 8psi , you raise start pressure by 2 psi next time . If rise is only 4 psi , then over inflated at start so drop start pressure by 2 psi . This works for a given load and for bitumen running .
 
harrow said:
Only a point to consider, this summer temperature will increase tyre pressure in the sunshine :)
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the same is true in the Winter as well :) and the variation is actually a fair bit greater (A tyre temp once the vehicle has been running for 20 minutes or so is very unlikely to be any lower than any ambient air temp in the UK at any time of year)
in my RAV4 back in 2006 I used to inflate the tyres to the pressure needed, and would often get low PSI warnings in the morning when the ambient temp was very low - I don't think people appreciate just how much temperature affects pressure until they have a TPMS system.

I've never tried it myself but apparently doing a Nitrogen fill (rather than standard air) is meant to virtually eliminate that variation.
 
The higher temperatures produced by the lower p.s.i. is simply down to the tyre deforming and reforming ( flexing ) more when in contact with the road.
 
Nigel L said:
After nearly 4 years of wondering what pressures should I be running, after reading all sorts of suggestions from various posters, I finally got round to going to a weighbridge and had the axles weighed. Then dropped an email off to Continental for the correct pressures.
what an eye opener! Have had the 5-5 bar in, as recommended by both the dealers and also on the sticker inside the door on the van. After speaking to Continental, am now running 3-25bar in the front, and 3-5 bar in the rears, and what a difference it has made to the ride quality.
Well worth the trip to the weighbridge, not only to get the pressures sorted once and for all, but also the peace of mind that I am also within the 3500kg overall weight restriction.
Click to expand...
Did you get written proof from Conti?. Just in case you get pulled in for a VOSA check. They will go with what is stated on the plate. Saves the hassle of having the vehicle impounded. I know this from a Professional point of view, and 'They' do not have any sense of humour:)
Plus it stops the attendant Police officer giving you a ticket for underinflated Tyres. Iff that happened you would probably have to attend Court with your evidence. All a load of faff to be avoided at all costs.
 
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Do VOSA actually check Tyre Pressures on a private vehicle? I can imagine they might be able to see an obviously underinflated tyre, but there is not a "one pressure fits all" tyre pressure to suit all circumstances - it depends very much on the loading of the vehicle and the type of driving.
 
When we where stopped, about 15 years ago, they checked weight, but didn't notice them checking pressures. In my 'paperwork pack' I have the chart with axle loads and pressures as these are significantly different to the label.
 
wildebus said:
Do VOSA actually check Tyre Pressures on a private vehicle? I can imagine they might be able to see an obviously underinflated tyre, but there is not a "one pressure fits all" tyre pressure to suit all circumstances - it depends very much on the loading of the vehicle and the type of driving.
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Good point. They may not on a private vehical. I'd still like to carry written proof though, Police might check on a vehical inspection. They certainly would in a bad accident. As said Tyres pressures have to be adjusted for load as well, each and every trip. I actually try and get mine somewhere near, like Sundays blast, unloaded. Reduced pressures by 5 psi.
You would have to be pretty unfortunate for VOSA to check I think. Unless you got one of our lot, then it's fine tooth comb and magnifier glass time. They are Twats. :)
 
Nigel L said:
After nearly 4 years of wondering what pressures should I be running, after reading all sorts of suggestions from various posters, I finally got round to going to a weighbridge and had the axles weighed. Then dropped an email off to Continental for the correct pressures.
what an eye opener! Have had the 5-5 bar in, as recommended by both the dealers and also on the sticker inside the door on the van. After speaking to Continental, am now running 3-25bar in the front, and 3-5 bar in the rears, and what a difference it has made to the ride quality.
Well worth the trip to the weighbridge, not only to get the pressures sorted once and for all, but also the peace of mind that I am also within the 3500kg overall weight restriction.
Click to expand...

If you do run your tyres with significantly lower pressures than those given in the owners handbook then make certain that you carry a copy of the email/letter you received from the tyre manufacturer with you, just in case you ever get stopped for a DVSA road side check where they will almost certainly test the tyre pressures and if they vary from those given by the vehicle manufacturer, then they might well prosecute unless you have proof that you have been acting responsibly.
 
Millie Master said:
If you do run your tyres with significantly lower pressures than those given in the owners handbook then make certain that you carry a copy of the email/letter you received from the tyre manufacturer with you, just in case you ever get stopped for a DVSA road side check where they will almost certainly test the tyre pressures and if they vary from those given by the vehicle manufacturer, then they might well prosecute unless you have proof that you have been acting responsibly.
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Good point, I have a copy email from Conti dropping our front axle spec from 80psi to 55psi, I'm surprised they gave a rear spec as per #3 as they usually will not risk giving a rear axle calculation because of comeback if the vehicle was then run at a higher load which potentially contributed to an RTA.
 
If your tyre pressure is correct the wear acrossthe tyre will be even. If the middle of the tread only shows signs of wear the pressure is too high.
If the edges show signs of wear then the pressure is too low. However if the wear at the edges is not equal then the tracking is out regardless of the pressure.
 
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