astroguy Posted November 6, 2018 Share Posted November 6, 2018 Looking for information about tires for my 1925 Seagrave. Current tires (Original tires and also with original tubes!!) are 40x8 12 ply. A visit to Les Swab tires provided me with the following: the rims are 26" and they can not provide any tire in this size. A look on-line shows 40x8 tires are equivalent to 900-24 which can not be correct. So, where to find tires and tubes for a 26" rim preferably will perfectly replace my 40x8 ? Thank you!! Link to comment Share on other sites More sharing options...
lump Posted November 6, 2018 Share Posted November 6, 2018 I bought some tires for a Seagrave firetruck from Coker Tire about 10 years ago. They are an excellent source. Link to comment Share on other sites More sharing options...
Guest Posted November 6, 2018 Share Posted November 6, 2018 40x8 is a measurement for high pressure tires. 900X24 is a balloon tire measurement and obviously for a 24" rim.. The conversion to balloon tires for a 26" rim would be 700x26 (7+7+26=40). HIGH pressure tires are always measured as the outer diameter times the height of the tire. BALLOON tire measurements are always given as tire eight times the rim diameter. RADIAL tires are measured differently again. For example, in a size P215/65 R15 tire, the 65 means that the height is equal to 65% of the tire's width. The bigger the aspect ratio, the bigger the tire's sidewall will be. Link to comment Share on other sites More sharing options...
1912Staver Posted November 6, 2018 Share Posted November 6, 2018 (edited) Have you measured the rim ? Early car rims vary a great deal, early truck rims are almost always 24" diameter. The increase or decrease in tire size depending on the weight capacity of the truck just makes the rim wider or narrower while maintaining the 24" diameter. Pneumatic tires only, early solid rubber tires vary in diameter quite a bit. Most likely 900 x 24 is correct. Greg in Canada Edited November 6, 2018 by 1912Staver (see edit history) Link to comment Share on other sites More sharing options...
R Walling Posted November 6, 2018 Share Posted November 6, 2018 (edited) Google search = BF Goodrich Blackwall 40x8 10 Ply | Coker Tire https://www.cokertire.com › Tires › Brands › BF Goodrich $859.00 - In stock BF Goodrich Silvertown bias ply tires were original equipment on many American cars and trucks that we now consider classic or collector vehicles. Coker Tire's ... 40x8 BFGoodrich Truck Tire - m. e. MILLER tire www.millertire.com › Truck Tires › Antique Truck Tires › 9.00-24__(40x8) 40x8 BFGoodrich Truck Tire. Bias ply, all position "Oval Block" tire. 40x8 is the old number size, today is 9.00-24 and fits on a 24" rim. Used on many older Fire ... Note, I doubt that they are less than 6 years old, as recommended by many, however I am running tires that are 25 years old on my fire engine that my tire store says they are OK because they are bias ply and I never go over 50mph for any amount of time. Edited November 6, 2018 by Roger Walling (see edit history) Link to comment Share on other sites More sharing options...
NickR Posted June 26, 2019 Share Posted June 26, 2019 Hello, I was wondering who your truck originally belonged to ? Link to comment Share on other sites More sharing options...
R Walling Posted June 26, 2019 Share Posted June 26, 2019 In regard to high pressure tires, I once owned a 1924 Auto car and the tire pressure recommend was over 100 lbs, so I filled them and put the truck into storage right next to my 58 restored Mercury. The next spring I noticed that the tire had exploded and the air pressure caused the door panel of the Mercury to cave in 4". Opps! Link to comment Share on other sites More sharing options...
46 woodie Posted June 26, 2019 Share Posted June 26, 2019 Lucky you weren't standing next to that tire Roger. At 100 psi, your Auto Car must have felt like it was riding on steel rims. Link to comment Share on other sites More sharing options...
Spinneyhill Posted June 27, 2019 Share Posted June 27, 2019 On 6/26/2019 at 3:08 PM, NickR said: Hello, I was wondering who your truck originally belonged to ? The OP hasn't been here since 6 Nov. Hover over his handle to see this. Send a p.m. Link to comment Share on other sites More sharing options...
Restorer32 Posted June 28, 2019 Share Posted June 28, 2019 A 40x8 would be a 24" rim. 40 minus 2 times 8 equals 24. Modern tractor trailer tires are usually 24". Link to comment Share on other sites More sharing options...
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