225 tyres on 8.5j rims

[x332race]

a) Can I fit 225/40 tyres on my 8.5J x 18 rims (standard tyre 255/35)....
Reason...I want to fit winter tyres on the rear of my CLK without having to purchase new rims...225/40/18 would then match the tyres on the front.

b) Is this advisable?

 

[khimani_mohiki]

try this tyre stretch calculator, should give you some idea of what the tyres shape will look like

http://www.vag-tuner.com/groundhaus/Str ... ulator.xls

 

[talbir]

245/40 would be the more ideal to fit on an 8.5J wheel.

225 would barely cover the width of the wheel which is usually more than the stated width. Consider that 8.5J is 216mm, 225mm tyre only leaves 9mm of play. You might find the actual rim protruding more than the tyre with such a stretch.

MB usually fit 225 to an 8J rim, so 235 would be a minimum for an 8.5J, but most spec i've seen states 245 for 8.5J. that said, many folk have run tight fit tyres.


cheers
talbir