rmmagow,

I've done it of thousands of miles with no problems. I don't use the same size tires either. Look at all the sport and race cars that use larger tires on the rear.

I think the original size tires 185R80X14 that come on a 300SD are too small for that weight car. Much smaller and lighter American cars use that size. 205R70X14 is a good replacement because the speedo and odometer are both correct. I use 205R70X14 on the rear but anything else I have on the front.

P E H