MTFCA Forum

A friend asked me these questions but I do not know the answers. Please educate me and my friend. What are the width dimensions of a 30x3 and 30x3-1/2, 4 lug rims? What are the outside diameters of the 30x3 and 30x3-1/2, 4 lug rims? Are the 30x3 and 30x3-1/2, 4 lug rims the same but only the tires and tubes are different?

I don't know of any 30x3 wheels with removable rims. The early T's had 30x3 tires in front and 30x3 1/2 on the back. So they carried two spare tires, one of each size. You had to change the tire on the car. Later they came out with the de-mountable rims, all 4 wheels were 30x3 1/2 so only one spare tire and rim was necessary.
The 30" is the outer diameter of the tires, so that size was the same front and back. The front tire was 3"wide. It was a complete circle, so the width was 3" as well as the height from the rim. And the 30x3/1/2 has a diameter of 30" and a width of 3 1/2". So the rim was 1" smaller in diameter.
Norm

Here is a chart with the differences of the clincher rim sizes for those tires.



Today we have 'oversize' 31"x4" tires, from all the new clincher tire companies, they are really 31" in outer diameter, unlike the true 30 x 3 1/2 of early days.

Thank you so much for the education