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School me on early tire/wheel sizes


pkhammer
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  I am pretty well versed in modern tire sizes; rim diameter, rim width, section width, etc. Where I get confused is with the early stuff. If somebody says they need a 3.50 x 30 tire I'm guessing the width is 3 1/2" and the outer diameter of the tire is 30"? And rims are even more confusing, especially with wood spoke wheels. Think clincher, demountable, split rims, etc. This is where it gets confusing to me. I have a stack of early wood-spoke wheels I need to identify. What is the best way to measure them? Photos would be helpful.

  Thanks in advance.

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PK

The early tires are identified by height of wall and overall diameter. Thus, a 30x3 has a 30" diameter and 3" wall height. To get the wheel size of a 30x3 tire, you would double the wall height (because you have two sides of the tire) and subtract that number from the diameter. 6 from 30 equals 24". A 30x3 tire fits a 24" wheel. The wood spoke wheels either have a wood felloe (pronounced fellie) or a metal felloe. The felloe is the part of the wheel that goes around the circumference of the spokes. There is either a rim (the part that receives the tire) affixed to the felloe or a mechanism for affixing a rim to the wheel. There are many different brands of wheels and methods of affixing rims to wheels. Too many to try to explain here. But to determine a wheels size, it is necessary to measure the diameter of the wheel with rim on, measuring to the bottom of the rim, or allowing approximately 1" greater diameter, to the closest inch. Hope this helps.

 

Wood spoke wheels typically range from 23" to 28", measured with the rims on.

 

 

Edited by AHa (see edit history)
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Something else to remember is that 30x3 1/2 is the proper way to write an high pressure tire size. diameter first and height second.  When balloon tires became available the nomenclature changed.  For example a tire was listed as a 4.50 x 19.  Tire width first and diameter second.

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Yes and exactly. The description I gave is for the early style high pressure tires. In later years wheels continued to have wood spokes but the formula changed. The pile of wheels you posted recently shows mostly high pressure tire wheels, I think most with metal felloes.

Edited by AHa (see edit history)
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That is my understanding, back then tires were more  outside and tubular diameters, "profiles" were a post WW II thing e.g."low profile" was about an "80".

Some early "tires" were solid rubber, then pneumatic tires (1880s) for bicycles expanded to early cycle cars and gradually became larger. Balloon tires (lower pressure/larger diameter) came in the late teens and early 20s (?).

 

I have wondered in idle moments and reading the '08 race book what the race would have been like with high flotation tires.

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  I am going to go thru the pile of wheels tomorrow. Most are wood spoke but are missing the rim the tire mounts on so the best I can do is measure the diameter of what's there. Not sure what that tells us without the actual rim that the tire mounts to present. 

  I plan to post photos and measurements here and maybe some of you smarter than me people can identify some of the pile.

  I also have a 7' x 12' enclosed trailer FULL of hubcaps (hundreds of wheel covers) from the 30's to the 70's I plan to go thru Saturday. Need to take advantage of these warm temps! Supposed to be sunny and in the 70's for the next week or so! 😁

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1 minute ago, BobinVirginia said:

@pkhammer

I think it’ll be like old car trivia and most will enjoy figuring it out. I’m really good with engine, trans and mechanicals as to how they function. The 1930 and earlier wheel and tire knowledge is all still a bit of a mystery.

Your confusion is not irregular! 
 

   I had fooled around with Model A Fords for long enough I know my way around them pretty well and it's a good thing they're pretty simple because so am I! When I acquired this last batch (mountain!) of parts I had no idea what I was getting into. The education is half the fun however and the guys that frequent this forum and freely offer help and advice, I cannot express how appreciative of that I am! There is so much knowledge on this forum that needs to be shared, especially with younger enthusiasts lest it be lost forever.

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On wood felloe wheels there is often a stamping on the felloe band stating size and sometimes the manufacturer . Metal felloe wheels without rims can be a bit harder to determine even basic information like rim size . But by the time metal felloe wheels came along { about 1923 -24}

there were somewhat fewer makes on the market making it a bit easier to I.D. most wheels. If you have a rim in each diameter from 19 " up to 26" or 27" you can usually figure out the wheel diameters. 

 

Greg

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Greg, or 1912 Staver, as he is better known, recently posted a picture of Firestone wheel parts. When it comes to the types of rims, demountable, detachable, split, etc, explanations without pictures is difficult. A split rim is a tire rim that is split  in two horizontally across the rim. Most detachable rims are split rims. Many of the clincher rims are not demountable or detachable but are made directly affixed to the wheel. Ford model T rims are of this type. They are not split, at least up to 1926, 1927.

 

As I stated before, in order to determine a wheel size that is lacking a rim, measure the overall wheel. If the wheel measures 24" without the rim, it is most likely a 25" wheel. Demountable and detachable rims also require wheel hardware consisting of wheel bolts and keepers to keep the rim on the wheel or rings to keep the tire on the rim. A detachable rim comes off the wheel; a demountable tire will come off the wheel by removing a lock ring.

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