Tyre Pressure?

[uber cool]

Probably been asked before, :roll: But what tyre pressures do you run at? I'm on low profile tyres. Currently running at whatever the sticker on the petrol flap says. But just wondering what others are running at?

I know others have said its still the same whatever the tyre size because the weight is the same, but im not sure?

Thought the rule of thumb is the smaller the tyre i.e. volume, the higher the pressure.

For example bicycle at 60PSI tractor 12PSI

 

[Guest]

different tyres and applications equal different pressures, max pressure is always on the sidewall. Always use the correctly rated tyre for your van at full load.

 

[uber cool]

different tyres and applications equal different pressures, max pressure is always on the sidewall. Always use the correctly rated tyre for your van at full load.

Very true, that why Im not on smartcar tyres as some do :shock:

However still need to answer the question on what tyre pressures folks are running

 

[Westair]

In our 72 with 1600 we run 30lbs fron and 40 lbs rear.

Our 73 poptop with 1800 is same except when touring and loaded where rears go to 44lbs.

Link to varied tyre pressures and info here

http://thekombikonnection.myfreeforum.org/about55.html" onclick="window.open(this.href);return false;

 

[bobley]

If you reduce the load carrying ability of the tyre then you have to up the pressure to compensate. Normal tyres peg out and 2.5Bar and XL/rf tyres at 2.8 Bar. If you tell me what tyres you've got fitted I can read some figures off the chart I've got here.

Personally I run a split on 215/40/17 XL front and 215/45/17 XL rear but the load rating is just as high as the stock equivalent tyre so I run stock pressure give or take. They may need an extra psi or two at full load but nowt serious.

 

[uber cool]

whats the XL refer to? Are those commerical tyres?

 

[bobley]

XL means extra load. Its like a half way to being commercial. Usually found on people carriers and big estate cars. It means the load rating is increased by 4 points compared to the normal version. i.e. 185/65R15 on my split crewie have a load rating of 88 (560kg) but if I'd bought the XL versions they'd be 92 rated (630kg each). Not all tyres are available in XL versions. You also see Rf on the sidewalls meaning "Reinforced" but I think it amounts to the same thing.

The std tyre on a 72 Bay is a 185/80SR14 94 Rf which is good for 670kg at 2.9Bar. The load carry ability of the tyre is proportional to the pressure.

For normal running VW recommend 2.4Bar up front which according to the charts is 575kg/tyre, and on the rear they want 2.6 Bar which gives them a limit of 615kg.

For fully laden running VW say 2.8 Bar (40psi) all round which is 650kg load carrying ability. As you can see for full load they are just on their limit. The 650kg per tyre is required because the back axle of a 72 bay is rated at 1300kg so your tyres need to be able to carry 1300kg safely.

If you tyres dont meet that carrying ability then you need to think about your legal position, insurance implications etc. Basically, for the back of a bay you need a 94 or greater rated tyre.

Later bays had the option of a 185R14 C tyre which is even stronger so they could handle even more weight.

 

[uber cool]

great write up thanks, can you get commerical or XL in the lower profile size , so run low profile and still be legal?

 

[bobley]

A lot of a tyres strength is influenced by the depth of the sidewall. Big tall flexible tyres can take a lot of load. Low profile elastic bands dont have any give and can be much weaker.

I doubt you'll get anything in XL car tyres which is strong enough without going to big rims like 17" (I used to have a BMW 5 series with 235/45R17s and they were 94 rated.).

I'd have a look at this list of commercial tyres and see what takes your fancy with a 94 rating or above

http://www.camskill.co.uk/products.php?plid=m27b0s0p0" onclick="window.open(this.href);return false;

Many reputable tyre dealers wil be able to give you more specific help based on the size of rim you want to use. They can also call the tyre manufacturers helpline and get a specific recommendation based on your exact requirements.