XL or "standard" tyres?

[rob 2.2dti]

When replacing tyres it is important to ensure the new tyres, even if a different size, have the same or a higher load rating. It is normal for the combined load of the 4 tyres to exceed the maximum weight of the vehicle by about 20 to 25% to allow for uneven load distribution or excessive loads when cornering or braking.

Remember a load rating is about the "Service" load rating, ie the load the tyre could normally be expected to support. As others have said the axle that supports the motor is going to have the have the lions share of the load, add to that the effect of kinetic energy when braking and turning and surely the load will be far higher. Im sure kinetic energy increases with the square of the speed, so at twice the speed you have four times as much kinetic energy to loose, also im fairly sure kinetic energy can be in the form of rotation - thats what flywheels use, so even the spinning of your wheels themselves has energy your tyres are going to have to deal with. I have 97 load rated tyres on my 1.9 diesel saab, I have had rim damage from a pothole with 93 rated tyres and am hoping the stronger and stiffer sidewall on the 97's will offer more protection. I didnt know they required more pressure but had found out myself they felt much better around 38-40 psi anyway so thats what i use. I know some of this applies to the traction rating as much as it does to the load but I do try and buy the best tyres I can - currently summer tyres are conti sport 3's on a 97W rating. Not crashed much recently so must be ok.

[FLOB]

I was always told to buy the best brakes and tyres you can as they are the bits that keep you alive.

I changed from 215/50/17 91w to 225/45/17 94w xl when my tyres needed changing as a tyre with a higher than needed weight bearing capability and a higher than needed speed rating is much less likely to fail- hence being safer.

I don't agree with the need for increasing the tyre pressure on the xls though as my tyres are still at vx recommended pressures and are wearing evenly. its tyre wear that shows if they are under or over inflated after all and over pressurizing the tyres just makes rim and suspension damage more likely as the tyres transfer rather than absorbing forces.....

Further more- over inflation leads to less tyre on the road and therefore less grip.

Thats science- not opinion by the way lol

[Cyruskint]

When my 3.0 Siggy recently required two new shoes, the fitter at my favoured tyre garage did say: "You're close to the limit for normal load tyres (In this case, Goodyear Excellence 225/24 17, to match the other pair) do you want XL?" I told him that it didn't say anything about that in the book, and I was replacing like-for-like. At least he thought to ask