Rick:

The 29" comes from the 19 inch wheel plus 5 inches of tire, top & bottom = 10 inches. 19 x 10 = the 29 on the old tire sizes.

If you look at a model T or early Star, 30 x 3 1/2 , the wheel diameter, including rim will be 23 inches 30 minus twice the 3 1/2 inches. Similarly, our 22 Durant has 32 x 4 1/2 tires, still a 23 inch wheel. 32 minus twice 4 1/2 = 23

Hope this helps. Took me several years to get the hang of it. Still perplexed by the new radial markings.

Talk to a younger person.

Gord

Where Are You From? Guelph, Ontario, Canada

Do You own a car built by Durant? 1932 Frontenac built by Dominion Motors Ltd., Leaside, Ontario

On a hunch I measured a 4:75 / 5:00 x 19 on one of my rims and its the tire outside diameter 29 inch.

Mine should be for 1932 Durant only 5:25 x 19. 1931 and prior is the 4:75 x 19. The Queensway Tire Co in Simco has all the old books telling them just what tire size is year by year for our and other makes. Gord's is 5:25 x 18 on the 32 E 670 Frontenac. My 5:25 x 19 were such a mess from age I put the smaller ones on temporarily until I can find the large proper size. Makes the car look Gestapo with bigger ha ha

Where Are You From? Ottawa Ont

Do You own a car built by Durant? Dominion built 1932 614 Sedan

Ya made me look at a pair of old 5:25 / 5:50 x 19 diamond tread I have and they are 30 inch diameter and 5 across. So 5:50 + 5:50 + 19 = 30. Make the car go faster with larger diameter than the pre 32 and need an extra anchor to stop it lol

Gord your 18's must be 29 then on the E 670 if 5:25 / 5:50 x 18 from Queensway.

Where Are You From? Ottawa Ont

Do You own a car built by Durant? Dominion built 1932 614 Sedan