Confusing tyre pressures

[Duggy72]

Hello,

i am confused with the recommended tyre pressures for my allroad. The label inside the fuel cap says 33 front and 30 rear for light loads and 39 front and 42 rear for heavy loads. The handbook says audi recommend running on heavy load figures for for economy.

i am worried that i may prematurely wear out the tyres on the heavy load as I don't carry a heavy load regularly. The light load figures also seem very low for such a heavy car.

my wheels are 17" with 225/55/17.

amy view would be welcomed. I have scoured the Internet to no avail.

 

[Audi Dynamik]

If you have a heavy load then put in the higher pressure, if not then put in the lower pressure.
If you don't carry a heavy load regularly then if i were you i would but the light load pressure in.
There will not be a noticeable difference in economy tbh.

 

[Duggy72]

Thanks, I will run the lower rating then. It does seem low for such a heavy car do you not think?

 

[Audi Dynamik]

Yeah it does actually it is probably down to your tyre size, i don't know mine from the top of my head but i know the rear for my 255/35/19 is 33 low pressure because i got a nail in the thing yesterday which cant be repaired, i need some new tyres soon anyway so i will have 4 new Dunlops on Saturday.

 

[Duggy72]

Thanks, had Dunlop sports on mine, bought some uniroyal Rainsport 2s for it. Hope they are good.

 

[MarkyM]

I've had Uniroyal Rainsport 2's on my Jag XK8 and have to say the best tyre I've ever had on them in 8yrs, no lit whatsoever in the wet and I think they com with 9mm of tread from new.

Sidewalls are a little flimsy though and ripped two of mine mounting kerbs...slowly

 

[Duggy72]

I've had Uniroyal Rainsport 2's on my Jag XK8 and have to say the best tyre I've ever had on them in 8yrs, no lit whatsoever in the wet and I think they com with 9mm of tread from new.

Sidewalls are a little flimsy though and ripped two of mine mounting kerbs...slowly

i have read that the sidewall are flimsy. Mine are 101 XL rated, hopefully that will mean they are slightly stiffer and less prone to tearing.

 

[MarkyM]

Mine were 101XL's too, two of them caught a curb (at the same time!) and blew on me was at low speed too (less than 15MPH) that was a complete pain. Easily overcome by the benefits of this typically soggy British weather :O)

 

[Duggy72]

Mine were 101XL's too, two of them caught a curb (at the same time!) and blew on me was at low speed too (less than 15MPH) that was a complete pain. Easily overcome by the benefits of this typically soggy British weather :O)

you are just the person I need to ask advice from. Do I need to run the XL tyres at a higher pressure than a standard tyre? My car requires 33psi front and 30 at the rear for a light load. Some people on forums say that XL tyres would need to be run at a higher psi than a standard tyre. I personally think this is wrong and that the advantage of an XL tyre is that it can take higher pressures in order to then carry heavier loads.

what do you think?

 

[MarkyM]

Duggy it's a very 'suck it and see' thing, extra load tyres for example wouldn't be used in a Aygo/smart/C1 running at full load, they're usually reserved for cars with a pretty impressive curb weight

At times when I've run Extra load at max inflation for a few thousand miles (e.g. a house move) I've found that the tyre centres wear atrociously which is a clear sign of over inflation. By the same token I have winter tyres on my A6 at the mo...temps are mainly below 7.5 and they're not XL's but I run those at standard inflation as the harder compound can take it.

The best method for me is checking the tyres for uneven wear every 500-1000 miles or so and adjusting pressures accordingly. I find this artical useful.

Tire Tech Information - Tire Specs Explained: Maximum Load

 

[Ste_Nova]

you are just the person I need to ask advice from. Do I need to run the XL tyres at a higher pressure than a standard tyre? My car requires 33psi front and 30 at the rear for a light load. Some people on forums say that XL tyres would need to be run at a higher psi than a standard tyre. I personally think this is wrong and that the advantage of an XL tyre is that it can take higher pressures in order to then carry heavier loads.

what do you think?

i think you should post a pic of your tyre sticker

 

[Duggy72]

Mark,

thanks for the advice and the link. The link confirms my theory that the XL tyre needs only to be run at higher pressure if a heavy load is going to be used.

there are some very confusing theories on other forums saying that if my car was on standard tyres a light load would be 33 front and 30 rear, but the same light load on XL tyres would require higher pressures to achieve the same load capacity. The link you sent disproves that.

thanks very much mate.