Good day all! I will want to replace my tires soon. I currently still have the factory Fuch's 14 inch 'Bundt' wheels on my 1976 450SL. I am considering replacing the wheels with some 15" in the same style as what I have now. What size tire will retain the same factory height that the current 14 inch do but will allow more tread width in a 15 inch. I want to shop tires also before buying these wheels. Is there any negative besides plunking down a fair amount of money in going to the larger 15 inch?

 

on my 129 I went from a 16 to a 18 wheel and from a 55 tire to a 45. I run 1 mph slower on my speedometer than it really is, otherwise all is good

 

There is an easy formula for that....! The OD of the tire is 26 inches. So, if you have a rim 15, you need (26-15/2=5.5" That will be the tire wall height. Converting that to mm 5.5"*25.4=139 ..
So if you use 50 series tires, your width will have to be double the wall high= 11" or 280 mm or 280/50/15....! If you use series 60 then your tire will be 9" .6xX=W W=9"