1920's Tire Size Confusion

[Samebeef]

Hello everyone,,

I'm looking to buy a spare tire for my '25 Dodge Brothers which is equipped with 20" diameter disk wheels (a popular option back in the day). The tires on it are size 6.00 - 20 and the outer diameter measures about 32". The tires are Firestone Deluxe Champions https://19216801.onl/ https://routerlogin.uno/https://192168ll.link/. I cannot seem to find this tire size listed on the Coker, Lucas or Universal web sites. This is the closest I can find but what does the 525/550 mean? Is that 5 & 1/4 to 5 & 1/2 ? I would have preferred to have a matching tire but no luck in that size. You guys with similar era cars using a 20" wheel, what tire size are you using?

Edited March 19, 2020 by Samebeef (see edit history)

[41 Su8]

The 525/550 means 5 1/4 and 5 1/2  wide at the tread.  This may be undersized for your car.  Both Coker and Universal have 600/20 tires on their website.

[Dandy Dave]

Also, originally in the 20's the tires were not measured that way.  For instance A 32 X 6 would fit a 20 Inch rim. Common on one ton model A Ford trucks. In this instance the 6 is doubled to 12 and the subtract from 32. You come up with 20 inch rim size on a 6 inch rim.

 

Here's another older link to more on Dodge Tires.   https://forums.aaca.org/topic/256053-1920s-tire-size-confusion/

[Dandy Dave]

600-20 Tires listed on Universal who recently bought out Coker by the way. https://www.universaltire.com/catalog_filter/?ftire_size=600-20

[Matt Harwood]

53 minutes ago, Dandy Dave said:

600-20 Tires listed on Universal who recently bought out Coker by the way. https://www.universaltire.com/catalog_filter/?ftire_size=600-20

 

Coker bought Universal, not vice-versa.

[Dandy Dave]

6 hours ago, Matt Harwood said:

 

Coker bought Universal, not vice-versa.

OK. I did hear that Corky sold the family business. Looks like your right. The new owners swallowed up Universal. Hard to keep up with all these corporate takeovers. Thanks for the heads up Matt. Dandy Dave!  

[Guest]

The changeover in nomenclature coincided with the advent of "Balloon" tires rather than the older high pressure tires.

[Bloo]

7 hours ago, Matt Harwood said:

Coker bought Universal, not vice-versa.

 

1 hour ago, Dandy Dave said:

OK. I did hear that Corky sold the family business. Looks like your right. The new owners swallowed up Universal. Hard to keep up with all these corporate takeovers. Thanks for the heads up Matt. Dandy Dave!  

 

Didn't that occur years ago, before Coker sold?

 

 

[lump]

Coker bought Universal many years ago. Corky retired from the business personally. But the last I knew, he still had a really strong manager running it for him, named Wade. And Wade is a great guy and good friend.