kobenguy

Hi,

I ordered some wheels for my 2014 E550 4matic. The wheels required 255/30/20 all around with a 97 load rating. Is it ok if I can mount some 92 XL rating because there are no tires out there with a 97 rating? Will I have any problem later on? Is this a safety issue or not? Thank you!

thefisch

I am no expert, but I looking at the tire rack load index explanation, I would be concerned if I were you about going lower than OEM.

92 rating - 1,389 lbs
97 rating - 1,609 lbs

You are giving up 220 lbs of load capacity per tire, or 880 pounds in total. My 2011 E550 came with 99 rated tires (1,709 per tire)

EDIT: I read some posts online that say you can get away with using a lower load index than OEM. Look at the max load weight rating on your car (like the GVMR on your driver door placard) and divide that by 4. That should be the minimum load rating you need. However, that doesn't mean it is safe to go lower than OEM as road conditions, proper inflation, etc. all play a factor on how your tires perform.

DerekACS

Yes, I agree with thefisch, you would be ill-advised to equip your car with tires having a 92V load rating in place of the OEM 97V rating.

threeMBs

Do not get carried away by the numbers. 2014 E550 W4 is around 4,400lbs (or about 1,200 each corner - well within 92load range). 255/30-20 with tire pressure of at least 41lbfttq (I would use 43) will do the job safely. Also, 265/30-20 tires (a "better" 94 load) could be used on E550 W4 with a 9" wide wheels with a "perfect" offset.

Do not forget that 97 load factory tires are set at around 36lbfttq. A "rule" of thumb is to add 1-1.5 tire pressure for each 1 load reduction.

thenew3

Don't forget the weight of people and cargo and the fact that weight is not evenly distributed on all 4 wheels and weight can shift during acceleration/deceleration/cornering etc and you can see how dangerously close that 92 load rating of 1200 lbs is to being overloaded.

It's always better to with with the minimum weight loading the mfg recommends or higher.

threeMBs

True, but not possible if going to 20s on W212, unless its an airmatic E550 which can accept 245/35-20 - 95 load - tires. On a side note, several W212 E63s W4 that our dealer (which is a certified Kleemann installer as well authorized MB dealer) "upgrades" use 265/30-20 - 94 load - tires at all corners on 9.5" wheels (not really applicable to non-AMG W212s).

threeMBs

Interesting. OEM tires for that year 245/40-18 (front or all 4 for W4) and 265/35-18 (rear) are all 97 load. If your car has/had a 99 load tires, it means it has/had non-OEM for non-AMG W212 255/40-18 front and 285/35-18 rear, which if done for "load" purpose is an overkill.

thefisch

That's a good point about distribution/shifting during driving. I think the GVWR takes all that into account. My door placard says that is 5,346 for my car.

Sorry I wasn't specific enough about my car. It is the luxury 4mactic version with comes with 245/45-17 tires at all four corners. Since sports are prevalent, I should have mentioned it. Perhaps the higher load rating has to do with lower recommended pressure for the tires of 33/35 for a normal load. Or maybe it is overkill. Fortunately, that load rating is common for that size tire.

threeMBs

That's exactly what I sad above - higher load goes hand in hand with lower OEM tire pressure - to maintain "softer" ride lower tire pressure is used hence higher load tires, and vise versa - to maintain the same (or close) safety for lower load tires, higher tire pressure is used (the lower the load - the higher the pressure), As stated above, for 92 load (255/30-20 tire) - pressure of at least 41 (or higher) is mandatory. The real problem is that most here on 20s use 245/30-20 tires - with load of only 90 - and how many of those use at least 43 pound pressure? Probably none - most probably use 36-38.

thefisch

It sounds like you are someone who keeps up with their tire pressure so you should be fine. But as you said most probably don't so it would appear more foolproof to go with higher load rated tires if they are available. If they are not, then swim at your own risk.

mikeyle

92 is cutting it a little close, because driving 3-4 passengers who are either close to or over 200lbs happens often enough that it might worry me, especially if youre including luggage for a trip also.

Swoosht04

So if you have an original rating of 97 and go to a 93 you will have to compensate with higher PSI in the tires but won't that throw off the TPMS or is that only calibrated to go off with a "drop" in pressure not an increase.
(Sorry just noticed this thread is 2 years old )