I wanna get my ratio down but in Canada finding another diff is out of the question. Oversize tires is not. Wondering how others found big tires. Mostly the height aspect. How big will fit on the 81 TD, cant find the max size in search so I am askin again.

I attempted to do the same thing when I had the W123. I put 215/70/14's on the Bundts. No problems with the fit. However, there is so much sidewall with these tires that the handling is a bit soft. I currently have them on the SD and I would advise against this tire unless you are a very conservative driver.

Your alternative would be to go to a 15 inch wheel. A 215/70/15 would gain an additional one inch in diameter. I'm not sure if this tire will fit the W123, however. It would look absolutely gigantic if it did fit and it's possible that it could hit the top of the fenderwell on a real good bounce.

If this tire is marginal, a 215/65/15 would definitely fit.

I think your right, a 15 is the way to go. Never really liked the bundts anyway. How did your rev with the bigger tires, any noticable difference?

Going from 195/70/14 to 215/70/14 results in about a 5% change in rpm.

At 70 mph, the engine revs drop about 150 rpm with the larger tires.

If you could fit the 215/70/15's you could get almost 9% which would be a drop of 270 rpm at 70 mph.

This may come in handy.
Tire size calculator

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