tyre weight rating

[Plumber1]

Does it make any difference if the tyres fitted to rear are 93Y or 97Y ???

[Gadgeroonie]

i guess the sidewalls may be stronger - so a harder ride

[joust]

93 is 650kg load, 97 720kg at 42psi. To that end to maintain the correct load carrying capacity you would need to inflate the 93s by around 2-3 more PSI. At around 1100kg weight though, 93s should be fine as the actual load will be much lower.

There is a good TOYO guide to replacing tyres, you can easily google it (IIRC it's in the Wikipedia tyre markings page reference. On my mobile so can't easily find it for you)

[R0162]

I ordered a set of PS3 and later noticed they say "extra load" on the side walls, not good, they give a harder ride and weigh more, for our lightweight cars it is not necessary.

[joust]

XL doesn't necessarily mean stiffer Walls at inflation pressure. XL from a specification means load can continue to increase if you increase pressure above 42psi.

To that end XL can use air pressure to take load as well as implicit strength, not that they can actually intrinsically take more weight at, say, 30psi, and hence XLs may or nay not have stiffer sidewalls.

The Toyo guide shows this in a graph - it's spooky how close the non XL and XL track each other for weight up to 42psi.

J

[joust]

Now I'm back, the Toyo document is here

http://marktg.toyotires.com/file/loadinflationtabl...

On the XL/non-XL point page 64 with the graph on 65 is the pages you want.

J

[Scooby P1]

R0162 said:

I ordered a set of PS3 and later noticed they say "extra load" on the side walls, not good, they give a harder ride and weigh more, for our lightweight cars it is not necessary.

I seem to have Bridgestone SO2 run flats on the front of mine. I assume this is not a good choice?
Annoying as they are very new but imagine it does no favours for the ride! Any thoughts?
Cheers