arjunkrsna

Hi All!

I am having trouble understanding the way the tires are rated and how the tire specs actually makes a difference in the ride quality of the car.
My GS specs are:
Front: 235/40 R19 96Y XL
Rear: 265/35 R19 94Y

Searching on tirerack i came across 2 tires:
Michelin PSS and Bridgestone Potenza S-04 Pole Position. The price difference is around $400 for set of 4!

Only thing is that the front tire for the Bridgestone is 92Y instead of the recommended 96Y XL.
What may go wrong if i take these tires?

Thanks!

er34

Each load rating increment represents a rated load increase of 20kg. So a 92 tire is rated to handle 80kg LESS than a 96 tire, this is very significant when you consider all 4 tires. The result would be a more stressed tire, generating more heat, accelerating wear, and worse, result in a blowout.

I would go with manufacturer recommendations and skip the Bridgestones. Look for something that exceeds or matches the load rating specified. Higher load rating tires generally give a stiffer ride due to the tougher sidewalls.

jdigga99

wow this is good information, sadly I never even looked that deep into tire stats.

arjunkrsna

This GS has only 4 tire options!
Michelin PSS
Bridgestone Potenza S-04 Pole Position (This is rated below manufacturer requirements)
Bridgestone Potenza RE050 (I have these but not that great!)
Dunlop SP Sport MAXX 050 (OEN on Mercedes C63S AMG but my friend says they are not the best)

That said i have to go with the Michelin PSS!

Thanks er34!

er34

​​​​There's also the option to go one size wider, there may be more options that way and you won't have any fitment problems.

Can't go wrong with PSS though.

Byprodrive

iTrader: (1)

The spec's you are refering to are a load/speed rating, load meaning weight bearing capacity, which begins to lessen @ high speeds. The tire merely contains the air which supports the weight of the vehicle, the higher the air pressure within the tire the more load it can properly support. Higher air pressure also makes the ride firmer. When I have to replace my front tires I plan to go to 245/40/18's to increase tread width & reduce required air psi. Better cornering & ride quality.

itsmike177

iTrader: (3)

Was in the same dilemma, and in the end, it's whether to get SL or XL rated tires. Given how the GS is marketed as a more "sports oriented" driving experience, it really makes no sense to go with the oem SL rated tires (any brand.) Go with the XL rating. Ended upsizing to 245/40/18 Michelin PSS as the stock size (235/45/18's) PSS comes only in SL rating.

Byprodrive

iTrader: (1)

The XL is nothing more than a extra ply in the sidewall to support more weight thru additional air pressure, it is not a higher performance modification. In many fitments it will degrade ride comfort.