Tires, Brakes and Suspension

Tire and Wheel combinations for the W109018 (300 SEL 6.3)

Abstract:
From the original combo towards today’s choices. All mentioned can also be used on the sucessor, the 450 SEL 6.9 as well. All input on the choices for the 600 is welcome.
For quick reference jump directly to the shopping list.

Designators:

You may read 225/50 VR16 on the side of a tire. What do these stand for?

Width – 225mm
Ratio - the heigth is 50 percent of the width, in this case 112,5mm (if nothing is mentioned it is 80)
Speed - The index lists from Q (100mph) to Z (above 140mph), the 6.3 would require V or higher
Diameter 16 inches in this case, and in a way this is where the problem starts, originally the 6.3 came on14 inch wheels, performance and avaiability lack nowadays, especially with the recent trend towards bigger wheels reducing the number of 14 inch tires avaiable

History:
When introduced, the 6.3 was tested in the 6/1968 issue of „Auto, Motor und Sport“ with 205 VR14 tires. In the workshop manual of later years it would appear to require 215/70 VR14 as a replacement for the former designation 195 VR14 type 70FR 70 VR 14, got it? Me neither...

Very common seems to have been the 205/70 VR14 combination giving a distance of 196,4cm for one turn. We will assume this the starting point for all further calculations.

MB part numbers and KBA numbers:
While they should help you to find the wheel you want in the rest of the world they have a legal meaning in Germany as well. Every wheel/tire combination has to be approved by the car authority (Kraftfahrzeugbundesamt aka KBA). As OEM Mercedes-Benz would then give out a part number, all test regarding rigidity, maximum load etc. are filed with the KBA. Aftermarket part suppliers would get a KBA number after their wheels passed these tests.
To sum it up, these numbers nowadays help you to identify you have found the wheel you were looking for.

Einpresstiefe (ET):
Another important factor, the offset of the wheel.

Bigger is better:
Apart from the fact that there are hardly any correct choices in the 14-inch size, bigger (wider) wheels also mean a theoretically better performance. With a bigger area for the forces to be transfered (linear and lateral) you should be able to corner quicker or accelerate faster (without wheel spin). However I would like to point out theoretically, as there are limitations. First the linkage joints and mounts should be good (don’t expect a worn out car to do better with wider tires), second the force onto the linkage is increased and the W109 steering does suffer mechanical stress from tires that are too wide and third, there is also a limitation in space avaiable. Especially with the early series 6.3 using the ventilated rear brake discs which were dropped to solid ones to save some money in the production for later cars.

Shopping list:

Material Size ET PartNumber Tires Remarks
1084000802
Steel 6,5x14 30 1164000402 205/70-14 Original combo
1264000402

205/70-15 Steel wheel as on W126
Steel 7x15 25 1264002802 215/60-15 series,
225/60-15 from MB aviable

Alloy 6,5x14 30 1084001002 205/70-14 Original 1264002102 alloy wheel

205/65-15 Original (Fuchs) alloy
Alloy 7x15 25 126 400 22 02 215/60–15 15 inch
225/60–15 a replica was produced in 2004

Aftermarket Alloys:

205/65-15 Cast alloy wheel, close
ATS 7x15 23 KBA 7055 215/60-15 to Fuchs
225/60-15 ring, a good choice

205/65-15 Forged alloy wheel
BBS 7x15 23 KBA 40399 215/60-15 crossspoke
225/60-15 a rather sporty choice

215/55-16 Cast alloy wheel
Rial 7x16 23 N7016523 225/50-16 crossspoke
225/55-16 for the looks

On the scale:
And which one weighs less in the 15 inch range?
I have found the ATS to beat the 7x15 steel wheel by 2kgs (1 lb. is about 0.453 kgs) with 7.1 kgs to 9.1kgs.

Put together from W111.net, own material and the workshop manual by
Konrad Linckh, pictures by Stephan Haupts

PS:
Please email errors you have found in this list, your experience with wheel/tire combos, and more choices especially on the 6.9 and 600




7x15 ATS versus 6x14 MB, note that the ATS has a hard edge and a polished ring, also KBA numbers are stamped outside MB Numbers inside the wheel

Argh...

please someone help me that the message appears in 1280x1024 by standard, otherwise (now) the numbers completely mix up and are of little (if no) help...

*gruesse

Konrad

ich wäre dann soweit...

You need to post in 800 x 600 format

Gerrett Conover
1970 600 LWB
1971 600 SWB
1995 Impala SS
1999 E55
[img=left]http://www.bostonisland.com/600/Images/flatprofile.jpg[/img=left]

Gerrett,

I think I've figured out what's happening.

When you post a picture that is wider than 800, the software will expand the screensize for the entire thread to fit the picture. This is what was hapenning before in the 600 forum.

Michael.

Konrad,
I was thinking that the alloy wheel for the 6.3 originally was 6x14, rather than 6.5. Am I wrong on this?

Mike Freed

Michael Edwin Freed

Mike, as far as I know, all 14 inch 6.3 wheels, either steel or the Bundt alloy, were 6 1/2 wide. 108 wheels were or better said, could be 6 inches. At least that's what I've found on 108s.
Thus to us M100 fans, 108 wheels are only for a spare at the most but I would't risk the confusion. Personaly, I consider 108 wheels worthless.
Once again, the 15 inch wheel is so superior to the 14, there is no comparison. I even have great repro Mich tires. You just better not forget that when you are driving it. In a heart beat you are hit with over steer. Saved a 6.3 with 14s recently by giving it power in a corner to staighten up the rear end drift. Wouldn't even been in trouble with 15s.

Dear Konrad,

thank you very much for this effort. Indeed, I regularly get mixed up with tires issues. First some comments :

- From my experience, I confirm that the 6.3 came with 6.5" wide rims, while other 108 are mostly found with 6".

- The MB Manual gives 215/70/14 as an equivalence for 195/14 to preserve the development of the wheel, even if the first is wider then the latter (involving increased stress on steering linkages).

- my 6.3 is currently equipped with (damn expensive) 215/70/14 XWX Michelins and the handling is quite OK: Contrarily to Dan, I was never cought in a brutal oversteer despite some rather sporty trips, including in the French Alps (anyone knows the Napoleon road?). I find the handling quite homogenous, even if bigger rims and wider tires would be more efficient, but the car would be less comfortable.

I recently looked into tires issues for my 6.9 W112 Coupé. It is currently equipped with 225/60/15 tires on ATS 7x15 alloy rims, which gives a rather sporty handling (and rather uncomfortable at low speeds). As I would like to equip the car with bigger brakes in the front, adapted from a W126 560, I have to keep 15" rims. But I would like the car to have a stock look, so I am going to use 7x15 stel rims from a W126 500 SEC. As for the tires, I was planning to use 215/65/15 ones as on stock W126 560. I may also look into 205/70/15 ones.

Any comment and recommendations are welcome.

Happy new year!

Gaël

Konrad, after reading your tech info again, after much confusion, I know what KBA, means. I assume then, if the wheel has KBA ON IT, it could be used in Germany. In otherwords, KBA means it's a good product.
I have a set of those cast wheels in the photo but mine have Mile Miglia, ot something close stamped on them along with KBA and the ET and the 7 by 15 size. Have you ever heard or read about that brand name??? It's a new name to me.
Your idea about weighing them, is super.

quote:

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I recently looked into tires issues for my 6.9 W112 Coupé. It is currently equipped with 225/60/15 tires on ATS 7x15 alloy rims, which gives a rather sporty handling (and rather uncomfortable at low speeds). As I would like to equip the car with bigger brakes in the front, adapted from a W126 560, I have to keep 15" rims. But I would like the car to have a stock look, so I am going to use 7x15 stel rims from a W126 500 SEC. As for the tires, I was planning to use 215/65/15 ones as on stock W126 560. I may also look into 205/70/15 ones.

---

I wouldn't use steel wheels for one reason...the Mass of the steel wheel and tyre is going to be heavier than that of an equivalent alloy wheel .Result?, an additon of 'unsprung weight',something you Do Not want to do.
I have often fitted Merc Alloys to cars after changing over from steel rims and the difference in steering and general driveability is amazing.
If i were to go to stock look i would explore the possibility of getting alloy rims (FORD,Toyota,and Chrysler all have the same stud pattern)and nmodify Hubcaps to fit .
15" Steel Mercedes rims are very Uncommon in Australia on the W126 although I have seen several sets of W124's on Ebay here.They don't interest me because of the already mentioned weight factor.

The other day We have handled both my ATS alloy rims and the iron 15" rims, equpped with tires in both case. We were surprised not to feel much weight difference, and we thought that the ATS may not be as light as other alloy rims. Of course this is very approximative as we did not weight them accurately. The idea of fixing iron hubcaps on alloy rims is a good idea. I was initially thinking of 600 second generation ones. What do iron W124 hub caps look like? I only have plastic ones coming to