Quote:
Originally Posted by radensb
It's that time. Michelin Pilot Super Sport seems to be well received, so Im going with them in the stock size.
I am a bit confused about the Load Range parameter on tires. America's Tire shows that an OEM matched set for the Z is XL (Extra Load) in the front and SL (Standard Load) in the back. The others show SL in the front and XL in the back, so i dont know if that is a mistake or not. If anything, I would think that you want XL in the back and SL in the front. I consistently read that XL are for higher performance, but the SL ones are more expensive (~$30/tire). Seems counter intuitive. I dont really mind the feel of the XL's that I have been using, but I wanted to get some feedback regarding what I should get, and the pros and cons for our car and see what load ratings others are using.
On the site, if I select the front and rears separate, I can select SL or XL for the rears. Should I go with America's Tire recommendation, or get all XL's?
I do not track. I do not do burnouts. I may hit the backroads every once and a while to play, but nothing too punishing or for very long. Still, I would like to make sure I really enjoy the driving experience, and paying a bit more for a tire that can provide that is worth it to me.
Thanks!
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Do not worry about the XL rating ......... what you need to work off is the load index which is the 2 or 3 digit code followed by an alpha after the size.
The Z34 requires 95W front and 96W rear "load rating".
My 2009 with 18" wheels has 225/50R18 95W and 245/45R18 96W as standard.
An "XL" tyre simply says that the load is influenced by tyre pressure.
For an explanation of "load index" - see here:
Tyre Markings - Bridgestone Australia
The "XL" designation is explained here:
Web theft yields the following...
Extra Load tyres are designed to be used at higher pressures than normal tyres. They have the same maximum load capacity as a normal tyre with the same Load Index but achieve this at a higher pressure. Normal tyres are inflated to pressures between 2 bar and 2.5 bar. They reach the maximum load capacity as specified by the Load Index when inflated to 2.5 bar (35psi) Eg for a Load Index of 94 this is 670kg. Extra Load tyres can be inflated to pressures up to 2.9 bar (41psi) and actually have a lower load capacity at the same pressure as a normal tyre with the same Load Index. To get the 670kg load capacity for a Load Index of 94, an Extra Load tyre must be inflated to 2.9 bar. At 2.5bar it will only have a load capacity of 595kg
So, and XL tyre is actually less capable that a non-XL tyre as they achieve compliance with their actual load index at maximum permitted pressure.