_AMG_

Is the tire load rating on the C63 really that important? I really want to get the Bidgestone RE-11's or Dunlop Direzza Star Specs. But they don't meet the specific XL load rating of the C63. (BTW i have the stock 18's) So my main question is...Is it safe to put Either one of these tires on my car without having to worry about the load index??

GBlansten

For a car with 443 ft-lbs of torque stock I'd want to err on the side of caution.

sprins

The tires are the only connection you have with the world while clowning around with 450 horses. I'd make sure that connection is proper if I were you.

mrobinso

When replacing my tires in June I asked the NTSB employee this very question and he said while they recommend tire with XL load rating for any vehicle that this is the manufacturer recommendation, it is not mandatory. The XL load rating means exactly what you'd think it means, they are low-profile tires made for heavier vehicles. Does this mean you can't drive with 'non-XL' rated tires? Not according to the NTSB employee I spoke to. He said you will notice harsher ride if you don't use XL rated tires but you won't actually run the risk of damaging your rims or blowing a flat.

bhamg

Well that makes absolutely no sense to me at all. Why have a load rating at all then? If Standard Load is OK, then how about Light Load? Are all Standard Load tires exactly the same, or do some tend towards Light Load ratings and others towards XL? And XL tires can be inflated to higher pressures, so how does a Standard Load tire ride harsher, if one doesn't inflate it to a higher pressure to increase its load-carrying capacity? If you have a choice...and you have many...why would you not get an XL-rated tire?

_AMG_

So is it cool to put either one of those tires on a C63?

bhamg

I wouldn't, but that's just me and I'm definitely no expert in these matters. For example, I do a regular distance commute on a highway where if I'm off the road then I'm probably rolling...and at my usual highway speeds that means probably dead. I'll be carrying valuable cargo on some of these trips this winter, meaning people who are important to me, and whose welfare I care about. I just can't see the logic in not using a tire of the specified load rating under these, or ANY circumstances. JMHO.

eagle_lex

i dont think i would take the "NTSB employee" word for it!!! i stuck with XL load tires. Mercedes engineers probably know a little more about what they are talking about then you typical sales guy at some tire chain....

just pick an XL load tire and to with it! then you dont have to worry.

Vegas_AMG

This is the exact reason why I chose the Conti DW's, it is an XL but only in 265. I'll sacrifice a little width for the safety of the proper load rating. Should be putting them on this weekend.

hhughes1

Tire rack provides the exact maximum load number for each tire in addition to the SL and XL designation.
PZero 255/35 XL rated for 1477 lbs
Star Spec 265/35 SL rated for 1433 lbs

A car load of wide bodies would be pushing it with either tire.

mrobinso

Did I say the NTSB employee's word was the final ruling on this? No. Simply, I was trying to offer up some information I had received from someone who works in the tire business. Someone who installs tires for a living might just know the difference between an SL and XL tire rating.

Regardless, it appears, based on the previous post, that the load-bearing weight differential is marginal between SL and XL.

_AMG_

I noticed you did have a set of star specs on your car. So you didnt run into any problems? i figure 44lbs isnt going to make a difference.

Savoy6

i use 245/265 star specs no problems. you'd have to grab a set of scales to see how close it is but my guess would be another 100 or so per wheel to play with.

hhughes1

I am on my second set thanks to 6-8 track days and I will not use another tire for daily driving. They should last a little longer now that the Proxes are available for track duty.

Questions

Really, they're that good?

_AMG_

Wow, Sounds like you really love those star specs. Hows the tread wear compared to the pirellis?

_AMG_

Do the 265's look meaner then the pirellis. When i mean a meaner, I mean does it have an aggressive stance when looking from behind? I want that mean wide stance as well.

Savoy6

i think they do. they stick out pretty far on the bottom back of the wheel well. the big thing is not really the dry performance which is a lil better than everything else its the wet where these really stand out. i think i got close to 7k outta the last set of rears. they seem to be wearing about the same as everything else full set, rears only, full set.

_AMG_

Any rubbing issues?

jvanbrecht

So, we use a XL load rating, I was perusing tireracks tech section (I am no tire expert, so I went looking for more info outside the standard tire sizing charts). They have a table that lists XL load rating at max of 41 psi.. but the rears of our cars run 46...

So.. now I am more confused...

Mort

I think that the XL load rating is taken at Max Load Pressure of 41 psi and that is not the max inflation pressure of the tire. The contis on my car have a max tire inflation pressure of 51 psi and the XL load rating.