Tyre size and rim type?

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Model T Ford Forum: Forum 2012: Tyre size and rim type?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Russell Prideaux on Wednesday, October 10, 2012 - 09:07 pm:

Working on a '23 Roadster Pickup. I have 30 x 3 1/2 on beaded rims up front and 23 x 4.40 on split rims at the back.
It appears the rims are all the same size.
What was normal/ acceptable for this period?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hap Tucker on Wednesday, October 10, 2012 - 09:41 pm:

Russell,

A USA produced 1919-1924 could have had non-demountable 30 x 3 up front and 30 x 3 1/2 in the rear clinchers.

They also could have had 30 x 3 1/2 demountable clinchers all around (closed cars 1919 and later in 1919 for open cars as an accessory.)

I suspect that someone put the later 21 inch balloon demountable tires and wheels on the rear of your truck. They became optional equipment in 1925. They fit and function fine. If the tire size says 23 x 4.40 -- then we need to look further into what you have. See: http://www.mtfca.com/discus/messages/50893/70290.html for some photos of the 21 inch wheels and tires.

Respectfully submitted,

Hap l9l5 cut off


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Wednesday, October 10, 2012 - 11:15 pm:

If you reported the size correctly, 23X4.40, you may have after-market accessory rims or 23 inch rims from some other car such as a Chevrolet or Overland that used the straight side type rims. The key question is, are they straight side, or clincher?
Tire sizes can be a bit confusing. Usually, most early (high pressure) tires were measured from the outside (tread). That became standard before the industry figured out that it was confusing given the rim size varies with the size of the tire itself (30X3.5 is actually 30 inches minus 3.5 inches twice, being the top and the bottom of the tire/wheel equals 30-(3.5X2)=23 inch rim).
In the early twenties, a newer development in tire design was the lower pressure "balloon" tire. At that time, the industry made a real effort to switch to rim size as the key size indicator. So a 4.40X21 common '25/'27 model T balloon wheel/tire will be a 21 inch rim PLUS 4.40X2=8.8 (top and bottom again) equals 29.8 inch outside tire measure (before road wear). So a 21 inch balloon size is only slightly smaller in circumference than a 30X3.5 clincher/high pressure tire.
To confuse things further, during the '20s and '30s, the industry sort of mixed up the sizing between high pressure and low pressure straight side tires. They can be either type tire with either or both type measurement. Rarely, but once in a great while, you may find a clincher listed as a rim plus 2X tire size. Model T size is almost always given as tire outside minus 2X tire (you get to figure out the 23 inch for yourself).

Did I make any sense at all? Or am I too wrung out from a difficult month?
And, we haven't even gotten into the "oversize" thing yet.
Drive carefully, and enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Layden Butler on Wednesday, October 10, 2012 - 11:53 pm:

Truck chassis?
Russell.. Is the wheelbase 100" or 124"? Center of front wheel to center of rear wheel.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Russell Prideaux on Thursday, October 11, 2012 - 12:14 am:

100 inch. Fronts are marked 30 x 3 1/2
Rears are marked 4.40 - 23. They appear to be the same height but slightly wider at the rear


Top of pagePrevious messageNext messageBottom of page Link to this message  By Russell Prideaux on Thursday, October 11, 2012 - 12:16 am:

Should have added this is a Canadian built Australian delivered car


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Richard Bennett on Thursday, October 11, 2012 - 04:52 am:

Russel,Wayne has the right idea. If the tyres are straight sided, they are most likely from another make of car. Yours should be the same 30 x 3.5 BE tyres front and rear.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Danuser on Thursday, October 11, 2012 - 09:47 am:

In the new Coker's catalog they list EXCELSIOR tire 30 x 3 1/2 SS straight sided tires, 189.00 ea, I have some 23 in SS rims, demontable for them, I already have a New pr I've had from Coker for 20 years, never mounted them, except mine say COKER


Top of pagePrevious messageNext messageBottom of page Link to this message  By Russell Prideaux on Thursday, October 11, 2012 - 11:38 am:

The 4.40-23 rear tyres on the split rims are balloon tyres


Top of pagePrevious messageNext messageBottom of page Link to this message  By Layden Butler on Thursday, October 11, 2012 - 01:18 pm:

Both Hayes and Kelsey made 23" straight side rims that would fit on Model T wheels that came with clincher rims for those that wanted greater load capacity. The Hayes No.120 commonly supplied on Chevrolet closed cars will fit on T wheels by redrilling the valve stem hole in either the rim or the wheel felloe.

h1
h2

k1


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