What does "D" mean?

EddieWalker · May 31, 2022

I need to buy new front tires for my little tractor. The current tires have 7.16 R1 on them, so I'm guessing that's the same as 7-16. I've been searching online and found a great price for a Carlisle 7-16 D tire for $135. This is an 8 ply tire, where most of the others that I've seen are 6 ply. I don't know what the D means.

Has anybody ever bought from Gallagher Tire before? or ever heard of them?

CARLISLE FARM SPECIALIST TB TL (24)

7-16 D TIRE ONLY

www.gallaghertire.com

woody · May 31, 2022

I think it is Bias ply

sea2summit · May 31, 2022

D is a load range. D or E should be what you're looking for with E being greater total load/PSI rating. This is separate from ply, radial, standard loading etc. markings.

RoyJackson · May 31, 2022

sea2summit said:
D is a load range. D or E should be what you're looking for with E being greater total load/PSI rating. This is separate from ply, radial, standard loading etc. markings.

Learned something new today!!

EddieWalker · May 31, 2022

Thanks. I know auto tires have a letter rating, but didnt make the connection that tractor tires have it too. This was the only site that had a letter after the size.

sea2summit said:
D is a load range. D or E should be what you're looking for with E being greater total load/PSI rating. This is separate from ply, radial, standard loading etc. markings.

Diggin It · May 31, 2022

Reference this page:

https://www.etrailer.com/question-140866.html

The 'D' in that position, beside the size appears to signify 'Bias' rather than radial. That appears to be different than Load Range D.

Now, as to which is more correct, or reliable, or why they would use the same letter for two different things ..... well .....

oosik · May 31, 2022

OK - contacted Carlisle support team. "What does the letter "D" mean?" Response - "letter 'D' means its an 8 ply tire".

EddieWalker · May 31, 2022

oosik said:
OK - contacted Carlisle support team. "What does the letter "D" mean?" Response - "letter 'D' means its an 8 ply tire".

Thanks. I should have done that, but I thought of TBN first. Its odd that this is an 8 ply tire for $135 when all the 6 ply tires are $150 or more.

California · May 31, 2022

EddieWalker said:
... current tires have 7.16 R1 on them, so I'm guessing that's the same as 7-16.

They are likely different diameter. If your application isn't 4x4 then it probably doesn't make any difference, so long as the weight rating is what you need.

Here's an example of front-axle tires for a little 18hp Yanmar 4x4:

6.00 x 12 (the taller tire) and a 6-12 (the size Yanmar specifies for YM186D).

Width is different too. Here's the old thread with a discussion of this.

oosik · May 31, 2022

I don't have a clue either. The M6040 came with Titans on the front - Goodyear on the back. So.... I priced the back tire from Titan and Goodyear. 16.9x28. Goodyear was $125 more than Titan. I thought Titan bought out Goodyear.

npalen · May 31, 2022

And here I thought that a "D" meant I need to study a bit more.

Xfaxman · May 31, 2022

Yep, I got a lot of Ds in school.

California · May 31, 2022

HS German teacher promised me a 'C'. On condition I promised to not enroll for second semester.

jaxs · May 31, 2022

A v-e-r-y important fact many folks overlook is that unlike those sold for use on public roads,trailer,atv,tractor and such tires don't have ratings assigned nor required to meet specific standards. That little fact is why informed consumers don't buy trailer tires and opt for LT tires instead. Because age is the cause of most trailer tire failures,I replace truck tires sooner than needed and put old truck tires on trailers. If the truth were known,the mfgr's marketing people stamped that D on tires to mislead consumers. Otherwise why not put 8 ply rating instaed,eveertone know's what that means.

California · May 31, 2022

jaxs said:
unlike those sold for use on public roads,trailer, atv, tractor and such tires don't have ratings assigned nor required to meet specific standards. That little fact is why informed consumers don't buy trailer tires and opt for LT tires instead.

Good point. My neighbor who maneuvers and lifts tons of harvest bins every year, says LT tires on the front hold up far better than tractor tires for the loaded, sharp turns that his FEL-equipped tractors experience.

EddieWalker · Jun 1, 2022

California said:
They are likely different diameter. If your application isn't 4x4 then it probably doesn't make any difference, so long as the weight rating is what you need.

Here's an example of front-axle tires for a little 18hp Yanmar 4x4:

6.00 x 12 (the taller tire) and a 6-12 (the size Yanmar specifies for YM186D).

Width is different too. Here's the old thread with a discussion of this.

Thanks for this. I'm going to try and get some measurements off of the tire on the tractor and see if they match what the tire I'm considering buying. They are not original tires, but I don't remember what was on the tractor when I bought it. I tried doing a search for the front tires that came on a Century 2535, but haven't found it yet. Since it's 4 wheel drive, I want to get the correct size.

Root Cause · Jun 1, 2022

jaxs said:
A v-e-r-y important fact many folks overlook is that unlike those sold for use on public roads,trailer,atv,tractor and such tires don't have ratings assigned nor required to meet specific standards. That little fact is why informed consumers don't buy trailer tires and opt for LT tires instead. Because age is the cause of most trailer tire failures,I replace truck tires sooner than needed and put old truck tires on trailers. If the truth were known,the mfgr's marketing people stamped that D on tires to mislead consumers. Otherwise why not put 8 ply rating instaed,eveertone know's what that means.

Not trying to change your mind but it should be noted that some states, mine included (NC), does not allow LT tires on trailers and the below is an explanation as to why. You can google many other sites that will verify the same results. To each their own, I doubt any deputy stops to check out trailer tires but ST tires are different for a reason.