darcys

hey everyone.
Hoping for a little help. I have tried to read all the posts about how to figure out what tires will fit. I will start by saying I am not the most mechanically inclined. I saw the post that spoke about certain sizes fitting and there was a link to a calculator, but the calulation might as well have been in latin. I did not understand the terminology at all. In a nutshell, I am trying to see if I can fit 19" wheels on my 1998 SL500. I believe my fenders have been rolled or whatever the term is, but not sure I am the best guy to confirm that. Anyway, that issue aside, I am hoping someone can simply answer the question of what offset range I can have with 19" wheels. Does it depend completely on other variables with the wheels or is there something I can use as a guide or? For example, the wheels I found for sale below are 19" and I think the +34 is compatible, but with the tire width, I may be wrong ( a good example of why its confusing to me). Any help is greatly appreciated
thanks

ohollenbeck

I saw your other post as well concerning 9.5x19et35, and these 11x19et34..

In general, these cars were designed in the 80's to perform best with 16" wheels and the ride the matching tires provide.

That being said, over time everyone seems to be drawn to larger and larger wheels, been there done it many times.

You should spend a little time reading about wheels sizes and proper fitment, and I'm sure YouTube can provide that as well.

First off, whatever wheel and tire combination you chose, the target overall tire diameter needs to be close to stock, as was posted in your other thread.

The overall tire diameter is factory designed to fit inside the wheel wells the best, and the speedometer is calibrated to that diameter as well.

I forget off hand, but 25.7 inches comes to mind for 129's and E500's, they share the same basic wheels.

In order to maintain 25.7" as you increase the wheel diameter, you have to reduce the amount of tire sidewall measurement.

This look is very popular today, but offers very little ride comfort, and more importantly rim protection from potholes.

The ET measurement is critical for keeping the wheel in the vertical center of the wheel wells.

Low numerical ET's push the wheels towards the outside of the fenders, high ET's push the wheels closer to the suspension.

All cars are not the same when they design for the Offset, (ET). S class cars are designed to have High offsets, 40-50 plus, SL's are designed for mid 30's and lower.

The most classic 129 wheels are the OZ 3 piece Aero I's, 8.5x17et17 & 10x17et18. Later offerings from the factory are AMG Mono I's @ 8.5x18et25 & 9.5et25.

I am running 18" wheels on both of our 129's, they look great, but I have had pothole caused flat tires and a minor bent rim.

So back to the sizes you want, the wider you go in rim width, the lower the ET number should be to keep the wheels centered in the wheel wells.
As wheel width increases, you need to push the wheel towards the outer fender, to keep the inner rim from rubbing the inner fender, hence the need to lower the ET as you go wider.

ET's in the mid 30's on these 19" wheels are potentially a rubbing issue on the inner fenders, maybe even interference with the suspension.

I would go no higher in diameter than 18", and stay within the normal width and et charts. You say you have the charts already, or I would have posted one here.

Here is a link to compare wheel & tire sizes http://www.rimsntires.com/specspro.jsp

On the left side plug in 8x16 et34 with 225/55 16 tires, this is stock from factory, then on the right side plug in your new wheel/tire sizes, (fronts = 9.5x19et35 245/35 19, rears = 11x19et34 285/30 19).

Then scroll down and read the analysis, the fronts "Might" fit, the rears I would say NO.

Also rim protection from curbing is a consideration, the tires needed to match larger diameter wheels have little of no overhang past the rim, so when you rub a curb you will get zero protection from the tires sidewall, when the tire rubs, so will the outer rim.

I would not buy these wheels to fit on a 129.

PS: Wheels & Tire trivia - Wheel and Tire measurements are a mixture of US inches and Metric units, seems odd to mix them, but that is what it is.

Wheels - Rim width & Diameter are in inches, and Offset or ET is in millimeters(mm)
Tires - Tire Width is in mm, sidewall measurement is in % of width, and diameter is of course in inches
example - 225/55 16 means the tire is 225mm wide,(8.9"), the sidewall is 55% of the tire width,(225x.55=123.75 mm = 4.9") and 16 is 16 inches
compare the 11" tire needed in your case, 285/30 19 is 285mm wide,(11.2"), sidewall is 30% of 285mm, (285x.3= 3.4") and 19" diameter

If you must have larger wheels, go to 18" at max, with 8" -8.5" fronts and 9-10" rears, et's in the 20's

Good luck

darcys

Hi , sorry for the late response, I was traveling for a bit. This was sooo helpful, thank you. I ended up not getting those wheels.
I do like the larger wheels and right or wrong, I want to try and maximize that.

I did did a comparison with another set. I tried to post below, but the formatting is a bit of a mess. There looks to be two yellow flags that are fit on the inside of the wheel as well as the outside. It suggests spacers as an option to push the wheels out if necessary, but cautious the fender may be an issue.
I have seen some posts about base models and sport models re the rolled fenders. Is there an easy way to determine which mine is? I think they are rolled based on feeling them, but not sure. I “ assume” that if they are rolled, I should be okay if I had to use spacers.

Again, your response was so helpful. I could not have figured this out without your help, thank you
Darcy