Slick201

I recently purchased a 91 300CE (https://mbworld.org/forums/e-class-w...24-thread.html) and ordered H&R Springs and Koni Sports for it. While installing the new springs and shocks I removed 4 well worn KYB's and a set of AMG springs (KYB's are in the dumpster, springs will go on fleabay).

The car came with AMG Aero I Monoblocks 17x8 ET28 and 215/45 tires on all 4 corners. With the new Koni's I have to keep the fronts adjusted to firm other-wise I get minor tire rub (the fender lips were previously rolled) and she will "lightly" drag/scrape her underbody over speed bumps.

What (if any) is the optimum tire size for 17x8 ET28's on a 124 or should I start looking around for a pair 17x7.5's or install 25mm spring shims (which I'm guessing are the rubbers that fit over the top of the springs )? The 215/45's have a harsh ride over minor bumps (not enough sidewall). I don't autocross nor do any serious high performance driving.


Thanks in advance,

Chad

fredtga

215/45/17 is the correct size for the w124 for those Aero I rims. You can change tire size, but you'll be running in issues like more rubbing and inaccurate speedometer reading.

If your car rubs on the front with current 215/45 tires, then it's too low, change the rubber spring spacer to a thicker one.
I had 3x w124 cars with same exact setup like yours and never had issues with tire/wheel setup.

The Aero I monoblock wheels came only in 17x8 size and correct offset for w124 is +28mm which is yours. The other only option was +11 offset for w126. There was no other thinner or thicker rim sizes in aero I monoblock.
The aero I 3-piece setup done by OZ offered a variety of setup options in widths and offsets, but prepare to pay a hefty sum for these. I paid close to $3000 for my last set which was in close to mint shape.

Slick201

Thanks Fretga,

I was hoping to be able to run tires with a little more sidewall. The 215's that came on it are mis-matched (I don't think any two are the same brand) and they are probably contributing to the harsh ride quality. I'll order a pair of the thicker 23mm spring shims and hope to have the time to do new front steering components this week and new tires next weekend.

I was up in your neck of woods (L.A.) 2-weeks ago, Janet and I stopped by Extreme Dimensions in Fullerton to pick up a AMG style front bumper cover to replace the one that's missing.

Stay dry,

Chad

S70Houston

Mismatched tires, not sure why peeps do this???? And probably cheap and old tires as well, so I would imagine this contributing to your harsh ride.

Bet your vehicle will look pretty sweet once you got all your little issues worked out and you put on your own personal touches.

ohollenbeck

The tire size meant for these wheels was 235/45, which has a sidewall height of 4.2", which is .8" less than the side wall of original 124 tire size of 195/65 15, (5" sidewall).
The good part of 235/45's is you would get a good cushion to ride on, the bad is it would rub like hell, giving you a 25.5 overall diameter. Rubbing will happen with about any tire size you try because of the et28 and the wheel width of 8". On top of all that, you have lowered the CE, making everything even worse. If you had a 500E with the wide wheel arches they would fit fine, but for all non-500's Mercedes - AMG had a kit to push out the fenders to make room. The part numbers were still active about 10 years ago, but I doubt any exist anymore. Regardless, you could do this without the AMG kit by improvising custom fender spacers.

I'll attach a pdf file which is the installation guide for putting Aero I et28 wheels on a narrow body 124.

Also here is a neat web site, it allows you to compare stock wheel setups to custom setups.

http://www.rimsntires.com/specspro.jsp

And here is a link to the list showing Mercedes wheels per model, look in the 124 section of this list, and you will see what the factory specs are for wheels and tires.

http://www.alloywheelsdirect.net/inf.../mercedes-benz

Personally, after trying about every size wheel about possible, I went back to 16". I also have a 300CE like yours and I just didn't want to make the modifications required for the Aero I et28's, so I picked up a set of 16" OZ Aero I 3 piece wheels. They are only 7.5 wide with ET31 and they fit perfect, never a rub and they arguably look better on the coupe than the 17"aero I mono's.

I ran a 8" square set of Mono II 129 wheels for a couple of years. They looked absolutely great, but I could never get them to stop rubbing up front, even the rear rubbed a little on larger bumps. Also got 2 flats and had to have rims repaired, potholes with almost no sidewall to protect the wheels.
The 16" OZ's are running 205/55 tires, and have a 4.4" sidewall, more than enough to ride nice and protect the rims.
The lesson I learned from running those 8" wheels, is to keep the fronts down to 7.5" max, (unless your going to widen the wheel well.

Original 124 wheel/tire combo's were designed around an overall tire diameter of 25", that's what 195/65-15's gives you. In order to keep a fatter sidewall, you need smaller diameter wheels in order to maintain the 25" diameter. I think 16" wheels are optimal for non-500E 124's, I will never go back to 17's or 18's on the coupe.

Anyway, good luck with your wheels...

Attached Files

Slick201

Thank you for the very informative information ohollenbeck!

As it sits now with the H&R 29569-1 springs (1.5" drop front) from center of wheel cap to fender lip is 13.0" (up .5" from the AMG spring hieght of 12.5"). I can't see the "nubs" on the spring shims to see what's installed now so I ordered a pair of 23mm (.9") shims hoping that they will bump the springs enough to be able to fit 235/45's on all 4 corners.

The "Conversion to 235/45 R 17 tyres and 8 J x 17 H 2 ET 28 disk wheel" pdf is exactly what I need and I can't THANK YOU enough for for supplying it. I was getting ready to pull the trigger on a set of 215/45 Conti DWS 06's and now there's hope that I can use 235/45's.

Best regards,

Chad

Note: I didn't buy the H&R's to give the car a "slammed" look, I bought them purely to improve cornering (anti-roll/lower center of gravity) characteristics. Our un-modified 1995 300TE has a wonderful ride quality and my wife and I LOVE IT! The CE is our "guilty pleasure".

ohollenbeck

After researching this topic for quite a while, the best advise I had gotten was to install the "Sport" spec components in these cars. Those who have 124's with the "SPORT" option and have tried everything else, ALL say, that the Mercedes Engineers hit on target with the "SPORT" models. I'm told they handle better than any 124, having that perfect balance everyone is looking for. A very good friend of mine replaced the suspension components involved on both his 124 sedan and a coupe, with "Factory available SPORT components", and they handled excellent, a big difference over non-SPORT...I hope you get that balance the way your going.. My solution is buying a 500E that needs a lot of work, and build it back slowly. I'll have it on the road soon.. unfortunately my CE will probably get sold to make room... My et28 Aero I's will get sold as well... I have 3 piece OZ's for the 500E....Good Luck

Slick201

Okay folk's here the final on my "Tire size for 18x8 ET28 Aero I's".

Purchased and installed:

1. Front shock bump stop P/N 1293230744 (pair). $43.10 from the dealer.
2. Coil Spring Shim ("4-bump') P/N 2013211284 (pair). $22.81 from fleabay.
3. Continental ContiProContact 245-40-17 all 4 for $160.00 (used with 50% tread left) from a local used tire store.

I haven't had time to really drive the coupe much lately.. I immediately liked the "look" of the car post purchase/mod (wheel well spacing (side-wall height) and tire width viewed from behind). The few times that I've had her out on the road she now has a firm/sporty feel in both ride quality and handling (And my dentures now stay in place going over speed bumps and on rough roads!).

Aside from the parts purchased specifically to fix my problem; If you're going to do any suspension work on a Mercedes, a "Mercedes-Benz Telescopic Coil Spring Compressor Strut Tool" is worth it's weight in gold! (I bought mine on fleabay for about $75.00).




And now for the obligatory "If there's no pics; it ".






Before 1




Before 2




Before 3

and the after..





After 1




After 2

I apologize that she's a little dirty in the pic's.. I've been a bit busy!

allenjdmb

I too had several pre-merger AMG 124's, and ran these wheels on many of them....at that time (this would have been about 1987/8), the 235/45 tire was not readily available. Back then, the only company that had a bunch of 17" sizes was Pirelli, and the P700 was the tire of choice.
Just like now, that Pirelli tire did not have quite the meaty sidewall that was seen in other brands. That made it lees susceptible to interference with the inner fender. When the 225/45/17 began to become available, lots of folks tried those with pretty good success.
Also, all the cars that I had that came from Hartmut had the fenders radiused out, it was considered part of the drill. Many folks are not aware that there was some experimentation in using spacers/washers in the front fenders, so as to effectively give it more room. Seems primitive now, but hey, back then it was all new, at least to me. Keep in mind also, if your shocks are worn, or even a certain brand, the ride height may not be exactly what you think it is. I liked it when we could change the buffers, it was a little more scientific, with a little voodoo thrown in...
Those were the days...