So today, I went to have my summer wheels and tires installed on my W213 E63S. When the reputable tire store went to mount them, they noticed this (see below) on both front tires. Apparently, the 265/30/21 on the front that were recommended are not the proper load index. They searched their database and nothing populated for a 21 inch tire for the E63S with the proper load index. Then I remembered, I saw that you, @ryandeeez , have the 285/30/21 on the front. I asked about that size and it does carry the proper load index so I ordered them(no charge since I had the hazzard/replacement certificates even though for a different tire than the ones ordered... WHEW!!!). Then the sales associate tells me that the rear, 305/25/21 is not the proper load index and said the rear ones might suffer the same fate. Ughhhhhh. They won't mount any tires and have the incorrect index load, even though they did last year, however, they did not check for the proper index load. So now I am trying to find rears in a 21 with the proper load index. I might have to go else where just because they won't mount the rears. I obviously would rather have the proper tires.

Suggestions, anyone, on the rear in a 21?


Attachment 439088

What you need to do is calc OEM Tire Load Capacity, for MB Air pressures - front an rear probably different since fonrt load does not change where rear can.

GO look on door sticker and get original size tire with all the codes.
Find that tire spec online -
Find max Load capacity based on Max Air pressure (how they are rated)
Then calculate MB required load capacity based on MB recommended pressure. (Use max PSI MB shows)

Tire Max Load / Tire Max PSI * MB Max PSI = Tire Load Capacity MB Requires.
Do for Front and rear Axle.

Whatever tire you put on there needs to meet or exceed.
So if you change tires size, the new tire tires load capacity will be different and you may not need an XL rated tire or you may need more/less Air pressure.

Have to do the calculations to be sure OR buy MO tires.

Tires a bit more complicated then most think in that you could buy the same size tire from another brand yet it does not work on your car due to Max Load Capacity.
All this is due to tire internal design/construction.

Lots of info @ tire Rack and some Tire Manufacturer websites.

Good Luck.

PS have Camber checked it almost looks like that tires is 1leaning big time based on tire wear marks down sidewall.

Thank you!!!

That’s right - tire load capacity is one thing but to FIX IT RIGHT THE 1ST TIME - you also need “Camber adjustment” but regrettably there is no Front Camber (or Caster) and no rear Camber OEM !

The often stated / reassuring “Full Front & Rear ‘4’ Wheel Alignment” - is in fact only basic Toe “directional” adjustment.

Yet Camber adjustment is essential - to allow to adjust costly, premature excess edge tire wear.

Excess edge load can also lead to higher impact, ruptured side walls and rim damage.

Lack of adjustment (OEM industrys best kept secret) - is all to do with cost cutting and ever increasing speed of new car assembly lines !

We saw the need therefore and have taken on the role of manufacturing once again adjuster kits similar to those fitted OEM back in the 90’s.



W213 E43, E53, E63/S (see Website re all models 1968 - 2023).

FRONT CAMBER (Only) #503416-1i $345 (Both Sides)
Less cost then one hi-performance tire.
(Have designed so fit on car without need for arm removal).

CAMBER (& ALSO CASTER) #503416K $480 (Both Sides)
This kit replaces the 4 highest wearing front bushes at the same time. Caster bushes replacing the air voided rubber bushes with Mono ball / Self aligning which also significantly improves brake and steering response.


REAR CAMBER (& EXTRA TOE) #502326-1K $480 (Both Sides).
(also designed to fit without need for arm removal)


Both front and rear kits allow ultimate adjustment - single wrench accurately (under load) direct on alignment rack (K-MAC unique patented design breakthrough - no more what has plagued the industry for years - the need for time consuming disassembly each time a setting change).


Kevin



AUDI to VOLVO - K-MAC Experience Of Resolving OEM Suspension Shortcomings Since 1964 !

Thanks for the info!!!