Okay! So for my autocross W123 build, I've decided on 15x7 front wheels and 16x8 rear. Reason for the stagger is to run a shorter tire in the front (lower CoG).

Anyway, I got my front wheels today from a local dismantler. From what I've gleaned, these are from (the rear of?) a 2nd generation W126. They are 7Jx15 ET25. A photo follows.



I test fit a wheel to my car this afternoon. It sticks out noticeably compared to stock. Quick math tells me they are 24mm further outboard and 14mm further inboard.



Which brings me to problem #1:



As illustrated above, I have somewhere in the neighborhood of 2-3mm between the balancing weight and the tie rod/knuckle. The two never touch from lock to lock, but I imagine the wheel will flex during cornering, especially with the R-compound tires I will be running.

So, can anyone tell me if a) this is safe to run as is, or b) if not, how small of a spacer can I run to make it safe?

Thanks, and I will also be back to this thread with questions about my rear wheels once I have them.

__________________
1984 300TD Turbodiesel - 272k
- Daily Duty
1985 300D Turbodiesel - 315k
- "Recommended for competition events only"

I would definitely they to add in a couple of mm's to get more clearance to that ball joint. You can do that with a wheel spacer, but I rather would do it by putting a couple of thick washers on the tie rod arm connection to the steering knuckle/spindle.


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__________________
1983 123.133 California
- GreaseCar Veg System

Ok, I would prefer to get clearance without spacers. Would you mind explaining how spacing the tie rod would make that clearance? Having trouble visualizing it.

__________________
1984 300TD Turbodiesel - 272k
- Daily Duty
1985 300D Turbodiesel - 315k
- "Recommended for competition events only"

Sec:

Perhaps you may want to recheck the calcs of the change in wheel width. The 14" Bundt lying in the picture is either 6 or 6-1/2 inches wide. Is that wheel your baseline? If so, the change in width is either 25.4mm or 12.7mm rather than 38mm (24+14).

Re: spacers. One would not use a wheel weight of that type to balance that design of wheel. Sticky weights would be used on the inside, so located as to not conflict with the caliper. Should you feel that additional clearance is desired, a wheel spacer of 5mm will have negligible effect on steering geometry; resist any urge to relocate the steering arm, which will have a significant effect on steering geometry.

Following this pic, you would add the spacer between the arm and knuckle at the two bolts.



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Attached Thumbnails

 

__________________
1983 123.133 California
- GreaseCar Veg System

You are probably right about the wheel width. I know they came in different widths and that these are probably 6" wide. That would make the change 18mm further outboard and 8mm further inboard.

I also agree with you re: altering the steering angle. However I still would rather use the smallest spacer possible - 3mm, bringing my total ET to 22. So would 5mm clearance be comfortably safe?

I'm tempted to try running this wheel as is - no spacers, stock steering knuckle - after getting them rebalanced with stick on weights. Bad idea?

__________________
1984 300TD Turbodiesel - 272k
- Daily Duty
1985 300D Turbodiesel - 315k
- "Recommended for competition events only"

I wouldn't have any problem in altering the steering geometry by a couple of mm's, more than that would cause drastic changes to the characteristics. An alignment would be needed even if you change out your springs anyways so why not try it since you are changing out a few things.

As far as running it as is with stick on weights, go with it, you have nothing to lose. This is all a process of learning.



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__________________
1983 123.133 California
- GreaseCar Veg System