History of 10.50-16 tyres

[rob love]

We used to get the same thing on the 11.00-20 tires used on the MLVW fleet back when we used bias ply tires. The Firestone and Goodyears were close enough that we could interchange them, but then General tires started to show up which were skinnier and significantly taller. A message came out that the Generals were not to be mixed with the other tires, and that in the future the tires would be sole-sourced to one manufacturer only (not General).

We had the same thing with the old 5/4 ton.....Goodyears and then someone bought a bunch of Cooper super traction. The 5/4 ton was especially picky about tire diameters and pressures. If the stresses built on the powertrain, the transfer case would not kick out of "loc" and eventually the front diff (weakest link) would boil the oil out of it.

It is very important on an allwheel drive vehicle that tire circumferences are the same.

[gazzaw]

Thanks Bob I better start saving then

Gary

[rob love]

You could buy them from one of the American dealers ( https://www.summitracing.com/dom/sea...illocation=dom )
and take advantage of the free shipping to get them to someone with a container heading overseas. I think Issah/Jim Burril mentioned today on the forum they have a container about to go over. Toss them a little towards the shipping, and that way the tires will make it over to the Uk, so you are just looking at domestic shipping from there.

I put a set of those onto the C15TA here at the museum. They really look the part.

[Hanno Spoelstra]

Originally Posted by gazzaw

Whilst whetting me appetite on the tyre history does any of you knowledgeable people have any idea or intel on a source for 10.5 x 16s as will be needing a set soon

Gary,

Other than the tips provided by our Canadian friends, you could also refer to the earlier posting by Tim Bell. Many vehicles in Europe requiring new 10.50-16 tyres today, revert to the Mitas IM-01. They can be bought from several distributors. This thread is also available in 9.00-16, by the way.

HTH,
Hanno

[Ilian Filipov]

Hi all,
I want to replace the wheels of my CMP scale models with something more decent and it looks the only right way would be to print them in 3D. Can somebody tell me the outer diameter of 10.50-16 tyre? For 9.00-16 it was found: 905 mm.; but I can't find anything on the bigger size.
Thanks in advance!

[David Herbert]

These are 100% profile tyres so they SHOULD have an outside diameter when mounted of 10.5 + 10.5 + 16 = 37" or x 25.4 = 940mm

David

[Andrew H.]

Doesn't 10.5" refer to their width? If so, it would not indicate height.

[Andrew H.]

The modern equivalent of the original 10.5 X 16 tyres as used in WW2 is 262/75/R16 (10.5' X 25mm = 262mm). In other words, the tyre is 262mm wide and the chord is 75% of that = 196mm deep. Also the rim at 16" X 25mm = 400mm. Therefore the diameter must be 196mm + 196mm + 400mm = 792mm or 31.68 inches.

Thats the arithmetic, but we found that modern 262/75/R16 tyres looked too small on our LRDG truck (based on WW2 photos) and we had to go another size up before we got a tyre diameter that "looked right".

[Lang]

Andrew

The reason they did not fit was all the old tyres were basically 100 height ie height of the tyre is the same as the width. They had various specialist odd-ball heights but you would expect any normal tyre of the period to be equal height/width.

This construction was so standard across the auto industry that tyres used to be measured by height with no wheel size ie 30x3. Everybody knew that the tyre was the same height as width so they knew that the 3 inch wide tire would go on a 24 inch rim (height of tyre top and bottom subtracted from overall height.

When they started with radial they messed with profiles so your 265/75 is only 3/4 as high as it is wide. To match the !0.50 you would need a 265/100 which I doubt is made.

As you found out we are now forced to use over wide tyres to get the original height if we want something off the shelf or go to the few specialists around the world still building 100 profile bias construction tyres.

Lang

[Grant Bowker]

The AEDB design record gives outside diameters for 10.50-16 tires that vary by brand:
Pneumatic cross-country 37.4-38.2 inches (2% variation)
Pneumatic highway tread 37.0-37.6 inches
Run-flat cross-country 37.6 inches

[Andrew H.]

Originally Posted by Lang

Andrew

The reason they did not fit was all the old tyres were basically 100 height ie height of the tyre is the same as the width. They had various specialist odd-ball heights but you would expect any normal tyre of the period to be equal height/width.

This construction was so standard across the auto industry that tyres used to be measured by height with no wheel size ie 30x3. Everybody knew that the tyre was the same height as width so they knew that the 3 inch wide tire would go on a 24 inch rim (height of tyre top and bottom subtracted from overall height.

When they started with radial they messed with profiles so your 265/75 is only 3/4 as high as it is wide. To match the !0.50 you would need a 265/100 which I doubt is made.

As you found out we are now forced to use over wide tyres to get the original height if we want something off the shelf or go to the few specialists around the world still building 100 profile bias construction tyres.

Lang

Thanks Lang!
Thats good information I didn't know.
We are still working on a plan to get your tyres across the ditch (a friend has a large yacht)
Andrew

[Lauren Child]

Originally Posted by Lang

Andrew

The reason they did not fit was all the old tyres were basically 100 height ie height of the tyre is the same as the width. They had various specialist odd-ball heights but you would expect any normal tyre of the period to be equal height/width.

This construction was so standard across the auto industry that tyres used to be measured by height with no wheel size ie 30x3. Everybody knew that the tyre was the same height as width so they knew that the 3 inch wide tire would go on a 24 inch rim (height of tyre top and bottom subtracted from overall height.

When they started with radial they messed with profiles so your 265/75 is only 3/4 as high as it is wide. To match the !0.50 you would need a 265/100 which I doubt is made.

As you found out we are now forced to use over wide tyres to get the original height if we want something off the shelf or go to the few specialists around the world still building 100 profile bias construction tyres.

Lang

I hit this problem with 1050R20 being 75% hieght versus 1050-20. I'd assume the same is true for other sizes, with the "R" being shorthand for a lower profile.

[Ilian Filipov]

Thanks for your answers guys, you're really awesome!

[Lang]

Lauren

The "R" stands for RADIAL and is not a size indicator.

For instance, the very common 7.50x16 used on Landrovers, Landcruisers etc for 50 years was a 100 profile (height equals width) tyre.

The world moved on, so for about 20 years in the 70/80 period they designed a new radial construction tyre to match equal height and width of the old bias construction. They called it 7.50R16

As those old vehicles were superseded by modern types wanting wider profile tyres without increase in rolling diameter we started to see the width-height relationship change with percentage profile measurements.

For those old vehicles still operating, they now have to go to the 235/85x16 which is the same height as the old 7.50x16. The difference is that it is 235mm (instead of 7 1/2 now about 9 1/2 inches) wide but, only 85% of that in height, to achieve the same diameter as the old tyre.

All the various commercial tyres (and most car tyres too)of whatever size went through that progressive change.

Lang

[Tony Smith]

Originally Posted by Lang

Lauren

The "R" stands for RADIAL and is not a size indicator.

Lang

Almost universally, Radial tyres with R in the size are 78% aspect ratio.

[Lang]

Tony

Where abouts is the reference to that. I can't find it in the Tyre and Rim Association manual.

Not saying you are wrong but the manual says the difference between 7.50x16 and 7.50R16 is only 4mm overall height (within normal manufacturing leeway). Everything I can find says the old tyre is 100 aspect ratio making the "R" tyre the same.

Maybe some of the other sizes went with the 78%?

Of course that stand alone "R" measurement only applied to tyres in the transition period between bias and radial construction - you can still find a few sizes so marked being produced for older applications. I think the 8.25R16 is still in use with the little 3-5 ton Isuzus and Mitsubish/Hinos.

All tyres have "R" in the size now but it is preceded by the aspect ratio so has nothing to do with size eg 185/65R14

Lang

PS

I just measured the 8.25R16 tyres on my OKA. Exactly 8.25 wide and 8.25 high giving an aspect ratio of 100.

PPS

I went looking and found a 7.50R16 M&S pattern on a wheel. Measured exactly 7.50 X 7.50. Measured the 7.50X16 Military ND on my 1/2 ton Dodge - exactly 7.50 x 7.50

[gjamo]

There appears to be seveal alternatives here.

https://www.vrakking-tires.com/14-16...tegory=14&n=75

[Lang]

This seems to sum it up for truck tyres.

Tube type tyres, whether radial or bias have a height close to width (98%) What I found with my two measured examples above.

Tubeless radial tyres unless profile specified have an 88% height.

Aspect Ratios
Truck tires sizes starting in 8, 9, 10, 11 and 12 are standard profile tubeless with the tire body width in inches. Standard profile tires have an aspect ratio of 88 percent. The height of the tire from rim to tread will be 88 percent of the width. An 11R22.5 tire will be approximately 11 inches wide and 9.5 inches high. Low profile tires show the width in millimeters and the aspect ratio. A 275/80R22.5 tire is 275 millimeters wide 220 millimeters high. Typical low aspect truck tire ratios are 70 percent, 75 percent and 80 percent. Tube-type tires are given widths as 9.00, 10.00 or 11.00, as in 1000R20, pronounced "ten hundred R twenty." Tires requiring inner tubes have an aspect ratio of 98 percent.