I have a '64 Valiant. I believe that my car travels slower than the speedo shows, and that this is due to the tires being smaller than original.

I found Doc's post with the Speedometer Pinion Usage Chart, and that is exactly what I need. BUT, I don't know how to read the tire sizes!

How would you denote a 650-13 in today's tire sizing convention, i.e. mm width/aspect ratio?

This is my first post. I have been perusing the forums and articles for a while. I love this resource.

Tires suitable for your application: assume you are using stock 13 rim. 155/70R13 5 inch tire or the following 6 inch tires 175/80R13, 185/70R13 slightly taller profile, have run all 3 at one time or anouther and have not had to recalobrate speedo. Can't imagine running smaller then the 155 as these are hard to find these days. Dave