[300se126]

Hi all,

I have a question about wheel fitment, and have searched for specifics on this to no avail. I think that my searches have resulted in a good working theory, but I wanted to ask directly in case I am totally off.

I got a nice set of Euro-issue W211 steel wheels with snow tires which I would like to mount to my 300SE, and realize that spacers will be needed. I've been wanting to change out the stock summer rims for a while now, so I figured the deal I got on the steels would be a good starting point and would require me to get the spacers anyway.

So, the wheels are 7.5J x 16 with an offset of ET42. Based on what I have read, I am under the impression that I will need 15mm spacers in front and 20mm spacers in the rear, and that despite the availability of hub-centric units from some makers, I will likely have to machine the fronts to fit properly (that's fine with me, I'm no stranger to machining things).

Please correct me if I am wrong, and if so, let me know what the best option would be. I appreciate the help.

-300SE126

 

[jimandsuzy]

I have ET 37 7.5x16s on my 85 300SD W126 with room to spare so you may not need any spacers on the rear. Don't know about the fronts.

 

[300se126]

Room to spare on the outside or the inside?

I'd ideally like to push the wheels out a bit in the back, but overall I'm much more concerned with proper fit and maintaining the factory offset than just getting the wheels in there. From what I have read, using spacers is necessary to maintain factory offset, not so much for fitting the wheels in general. I don't want to mess up my suspension in the process. Have you had your wheels on there for long?

 

[48hp]

The whole et thing is dizzying at times...but if you break down into "backspacing" as they often do here in the US it's much easier to figure out.

Take the wheel width/2, convert to mm and +-offset value.

You'll quickly see that an OEM 15X6.5's 25mm outside lip edge and a 16X7.5 42mm outside lip edge only differ by 5.75mm.

Cheers!

 

[300se126]

Okay, now I am getting dizzy indeed

So if that math is correct (I don't question it) then the outer lip of the larger wheels will only be app. 0.23 inches farther out from the hub than stock - which means that the inside lip is going to be 1.25 inches closer to the center of the car. That's my real worry here, and why I was under the impression that larger spacers than 5.75mm would be needed. Am I reading that right?

 

[48hp]

for the simplicity let's stick with metric once it converted...and the figure is 4.25 not 5.75mm, my bad.

OEM 6.5"/2=3.25"=8.25cm+et2.5cm=10.75cm backspacing
OEM 6.5"/2=3.25"=8.25cm -et2.5cm=5.75cm frontspacing

Steelie 7.5"/2=3.75"=9.525cm+et4.2cm=13.725cm backspacing
teelie 7.5"/2=3.75"=9.525cm -et4.2cm=5.325cm frontspacing

So, the steelie inner lip edge will sit 2.925cm futher inwards.
Compare that to a AMG/OZ 10"et17 backing which pushes the inner limits of the W126 wheel well at 14.4cm, so there is room at least out back.

and the steelie outer lip edge will sit 4.25mm further inwards.

now I'm dizzy, thanks. lol

 

[300se126]

Haha, I appreciate it!

Looks like I will probably go with 5mm front, 10mm rear in that case, and new lugs of course (my main motivation in getting rid of the stock rims... read my post titled Shear Horror from a few years back).

Seems odd to me based on those specs that the rims the Tire Rack suggests for my car have 5" backspacing when the stock is only 10.75mm...

Wish I could paste the URL here, but if you search www.tirerack.com for wheels for any 1990 W126 they all have backspacing in the 5" neighborhood.

 

[48hp]

Looks like I will probably go with 5mm front, 10mm rear in that case, and new lugs of course (my main motivation in getting rid of the stock rims... read my post titled Shear Horror from a few years back).

Seems odd to me based on those specs that the rims the Tire Rack suggests for my car have 5" backspacing when the stock is only 10.75mm...

Wish I could paste the URL here, but if you search Tire Rack - Your performance experts for tires and wheels for wheels for any 1990 W126 they all have backspacing in the 5" neighborhood.

10.75cm not mm=4.23"

Unless you're experiencing clearance issues on the front, I wouldn't bother with spacers.

 

[300se126]

10.75cm not mm=4.23"

Unless you're experiencing clearance issues on the front, I wouldn't bother with spacers.

It does help to read, huh. Oops! Cm vs. mm is a big difference. At that point I won't bother unless I get clearance problems. Thanks for the help, 48hp!

 

[BADwayz]

I agree to fit the wheels first, then decide on measurements IF needed. And our cars front hub won't allow for spacers less than 20mm either. Not sure why 20mm works when less won't, but its been tried and tried again by multiple memebers with failed results.

 

[300se126]

Update: definitely not gonna fit

The rears need at least 10mm to clear the inner wells and the fronts need about 5mm to clear the suspension. I am going to get spacers in those sizes as I initially planned unless anyone here has any reason why that should pose a problem...