Tire sizing need help
 

I have a 70 Nova that has MT 33 X15 X 15 ET slicks on Convo Pro rims. I was told that 33 X 18.5 X 15 ET Streets would be able to fit on the back. I have a little over an inch clearance from the slicks to the lip of the wheel well. The math doesn't work for me for them to fit but my buddy is positive they will fit. I would appreciate any help with this.
Thanks, Peter

According to the M/T specs the 33x15x15 ET slick has a section width of 18.1" and a tread width of 14.8". The only street tire I could find on the M/T website that's listed as a 18.5 is a 31x18.5x15. They do list a 33x19.5x15 which has a 18" section width and 14" tread width. These are both measured on a 14" wide wheel. The section width is the widest part of the sidewall bulge. So according to M/T's specs, your buddy is correct and they will fit.