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1 hour ago, Vladislav said:

That too might be not a missprint.

In this discussion we missed one fact so far.

If you look over the tyre sizes there are 11.00's and 11.00 R's.

This means two mentioned sizes exist(ed) in both bias and radial design. And according to the chat above they have different sizes.

Actually it's difficult to suppose exact dimentions of some tyre taking to account so wide variety of them.

But from my practice 12.00R24's (tube's) I put on my WW2 Mack are really huge. Sure larger than 12.00R24.5 I have a pair of in my yard. And talking closer to the matter of question they are noticably bigger than 10.50-24's (!!) which my truck rode when was purchased. The truck had two tyre sizes from the factory in different years - 10.50-24 and 11.00-24.

As far as i remember reading in different sources in the past older (bias) tyre sizes had the first figure in their designation as the heigth of its profile. So when you put that heigth twice and add the rim size that would mean the overall diameter.

But for radials (or just newer wheels starting from some date in years) the firs figure is the profile width. When you have a profile share (/75, /60 e t.c.) marked, the higth might be count as the percentage of the width pointed behind the slash. And when you have it NOT, you should count the profile higth as 84% or 100% referring to different sources.

Taking all that into a sum we can explain all those differences in tyre sizes we use to deal with together with difficulties to recognize an actual wheel's measurements. 

And getting further that's the reason I keep alot of scepsis to different tyre calculators and chats and trust the most to an actual size I can just measure with a bend.

 

Actually Vlad to go back to my point I misquoted- the misprint I believe is in the comparison with the 11:00R 24.  If the revs/mile go down, it has to mean the radius of the tire is greater.

  • Like 1

Not a great picture but 12R24.5 on the red one and 11R24.5 on the white one. The 12's are quite a bit heavier than the 11's. Have 12.00x24 on the autocar and they are much heavier. Unfortunately they are getting hard to find in my area.  I love the look of  a big tired truck but the cost differance is substantial. 

image.jpg

4 hours ago, Red Horse said:

Actually Vlad to go back to my point I misquoted- the misprint I believe is in the comparison with the 11:00R 24.  If the revs/mile go down, it has to mean the radius of the tire is greater.

It does not say but perhaps that is not a loaded radius. different tires flex differently especially radials vs. bias.  Anyway the bridgestone book gives a static loaded radius of 22.2 and revs per mile of 432 for 12.00r24  that not that different from what you posted

My RD822 sx came with 12.00R-24 on the front and 11.00R-24 on the tandems. I don't recall the weight rating on a 12.00R-24 but I think it's right around 9,000 lb single.

I looked at a old 100 ton Talbert trailer the other day that had 14.00-24 tires, talk about some big tires.

  • 2 months later...

I'm noticing that the trucks I've seen with 12x24 tires are always 3 axle.  I never see extra axles (pushers/tags).  You would think with high weight capacity being the reason for the large rubber that you would see multi-axle setups. Anyone know why this is?  Just curious.

By the same token, does a big-rubber truck on 3 axles have more carrying capacity than a multi-axle truck on regular rubber?  I wouldn't think so.  

Seems like around here high weight = multi-axles.  Maybe laws are different elsewhere but I don't recall ever seeing a big-rubber 3 axle truck here in the Midwest.  So how are they allowed to haul big weight on 3 big axles out east?    

At any rate, I loooove those big tires on a Mack of any persuasion!  Everyone feel free to add more photos of them to this thread!

On 11/27/2016 at 10:38 PM, m16ty said:

My RD822 sx came with 12.00R-24 on the front and 11.00R-24 on the tandems. I don't recall the weight rating on a 12.00R-24 but I think it's right around 9,000 lb single.

I looked at a old 100 ton Talbert trailer the other day that had 14.00-24 tires, talk about some big tires.

yes they are big. and heavy too. if i remember correctly around 400lbs without tubes, boots, or rims.  my old DM800 lowboy had 14X24 sneakers on all axles. i was legal for around 210,000 lbs with the "S" tags

when you are up to your armpits in alligators,

it is hard to remember you only came in to drain the swamp..

It all gets down to what the state you are running in allows per axle. Most states you are limited to 22k per axle (as long as it's rated for it) A few states Ma, Ri, Ny( NYC and Long Island) and Nj deviate from that a little. Ma and Ri allow 73k on 3 axles and Ny and Nj allow 70k on 3. This means that a lot of thes 3 axle trucks up here are spec'd with 18 or 20k fronts and 58k rears. This is when the tires become the weak link in the chain. On 58 rears you have an individual axle rating of 28k instead of the standard 22k. In order for the four tires on the axle to cover the capacity of the axle you need the 11.00r24 tires. On the front to cover the 20k with 2 tires they need to be 12.00r24. Now you wouldn't use these tires if you didn't have the heavy set up and are allowed to run the weight because the weigh a lot more and cost quite a bit more. Not to mention reduced fuel economy.

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