Tyre pressue in simple terms!

[CovKid]

It gets possibly more complex with the huge variety of wheels we all use too. For instance, I have 15" merc steel rims with 195s fitted. They're not commercial ply ones as I don't carry anywhere near the weight of most campers and prefer the grip and cornering capabilities I'm getting with a slightly wider track. I can take roundabouts like a hatchback. I've never worked out what pressures i should be running but seems to work best at about 45 front and 50 rear - give a few variations when I don't check my pressures for months in between.

Incidentally, I fitted all my own tyres (first time), never lost much air and the whole set cost just £99.

[murdoch]

this thread reminded me to check my tyres at the weekend, in the twentys allround
put them up to 50 front and 55 rear and its a different vehicle to drive for it
think i need a way to remind myself to check them more often

[jamesc76]

I run mine at 50 front 60 rear but i have high rating comercial 8 ply tyres and drive it a bit quick! Plus i cart alot of gear about,Used to have it at 50/50 but once pumped up a bit more i get better mpg and no uneaven wear!

[alexm77]

are these pressures similar for other size wheels, or just standard size? I've just had new van tyres fitted (215/70/16), and the guy that did them was saying 35 front, 38 rear, which is a lot lower than what everyone is saying here.

[phade]

It basically depends on what is says on the tyre pressures sticker on your left hand front door post. That sticker will tell you the correct tyre pressures to use.

[lloyd]

alexm77, it should say on the tyre the maximum load and pressure. Use this as guide to max pressure, not the sticker on door for your 215/70/16 tyres. It all depends on how heavy your van vs rating on tyre for what your tyre pressure needs to be.

[vdubstar]

My tyres mx 65 psi hence i think he said 45 front 55 back still not max either way any sparked a good discussion didn't t! never new it was so varied! has however made me question my other vechiles as i feel there too high so will be checking my manuals!

[CovKid]

So, in summary then, it depends.

[Bowton Lad]

So, in summary then, it depends.

Yes, firstly on whether your van is air or water cooled! All the peeps who own late model water cooled vans should not be advising an air cooled van owner to use W/C van tyre pressures.

VW T25 AIR-COOLED - TYRE PRESSURES (1980-82)

TYRES FRONT REAR SPARE

185R14 C 3.0 3.7 3.7

205/70 R 14 2.1 2.8 2.8
-----
2.5

ALL TYRE PRESSURES IN BARS


N.B. These pressures are for tyres/wheels as fitted by VW. Transporters had 'C' rated commercial tyre but Buses (Caravelles) had wider reinforced tyres. Maybe peeps who convert a Caravelle into a camper with a high top/poptop & loads of cupboards etc should uprate their tyres to 'C' rated ones?

[alexm77]

I have no idea how heavy my van is, and not sure how i'd find out. i've not got a factory conversion (converted from a 82 panel van), got a 1y engine, and merc alloys.

The tyres have a max psi of 65 (c rated), so plenty of room to try raising it and see how it feels. Previous owner was running 45/55psi on 225/70/16 tyres, so sounds like i should try them a bit closer to that.

[vdubstar]

intresting that there is diff between Aircooled and watercooled! mine is Aircooled hightop you see!

[cubensis]

Ok so mine is a hightop watercooled 1.9, checked the other day and as i thought ~35 front ~38 back. This was done by a garage when we got new van tyres.

Went to fill up, played it safe 40 front 45 back, feels like a different van! Steering lighter, much firmer round bends, minimum buffeting on the motorway, when i had the tyres filled at 35/38 the van would be all over the place if a lorry passed me. So happy i read this thread, will be going 50 back 45 front tomorrow.

The way i see it, check your tyres maximum psi rating, don't exceed that, and go up in increments untill the ride gets to hard, then let a bit out.

[Grun]

Had a bit of a google as I remember putting one of my earlier vehicles on a weighbridge to determine the correct tyre pressures, but wanted to check up to date procedures.
Following is from a Michelin reply to a Motorhome forum poster:-

Plated axle weights:
Have you verified that each axle weight for your vehicle is actually being run at or below these quoted 'plated' weights, by visiting a local weighbridge?

We suggest that individual axle weights from weighscale readings are used, in order to calculate pressure recommendations for each quoted load condition. These would be preferred, due to readings being taken in the actual vehicle 'running' condition - that is to say, with all water/fuel/baggage & passengers etc. onboard - and may result in better comfort if the vehicle is running way below maximum capacity.

The results of roadside surveys indicate that some motorhomes have been found to be overladen, especially the rear axle, with potential for subsequent tyre related problems.

The overall tyre industry, therefore, tries to build-in a safety factor by fitting specific, strong 'motorhome' tyres, inflated to high pressure, in order to remove the potential for consequences of overloading &/or under-inflating the tyres.

One 'overall' weight is of no use in calculating tyre inflation pressure levels, since the vehicle may appear to be within the maximum permitted, but in reality may have the rear axle severely overladen & the front axle very lightly laden.

And this from my local authority website:-

Public weighbridges are available for use by businesses or the general public for the weighing of vehicles where determination of a specific load is important, for example - heavy goods vehicles, light commercial vehicles and caravans. A fee is charged for each weighing carried out which normally ranges from £5 to £10 and a document is required to be made out recording the details of each weighing.

Once you have the axle loads that you have decided to use (Empty, lightly loaded, crammed full, or whatever) combined with the details from the sidewalls of your tyres, googling or contacting the tyre manufacturer, should provide you with the correct pressure information.

I was surprised to find that there is a public weighbridge in a quarry not 2 miles from my house here, well off the beaten track.
Mike

[BMEC]

A cheaper method of getting the exact weight on each axle is to ask the guy who is doing the MOT. There is a weighbridge built into the latest rolling roads used for the brake testing bit of the test. Last time I had mine done it showed (with just me on board) a front axle weight of 892 kg
and a rear axle weight of 776 kg. My original handbook shows a max front axle weight of 1200kg and a rear max of 1300kg.
My 1985 1.9 DG camper is a tintop with fairly minimum gear so I would guess it is probably lighter than most. I use the recommended 185.14 reinforced commercial tyres. If the mnufacturers load/pressure tables for these tyres are reviewed they suggest a much lower pressure would be satisfactory for my particular camper setup.
As has been said...it all depends upon your vehicle set up, what you carry, and the tyres you are using.