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Old 08-06-2013, 02:34 PM   #11
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Originally Posted by KewlKamperz View Post
We currently have 205/75/D15 6-ply. They are Trail Express. They are being replaced under warranty because they are horrible tires and have excessive, uneven wear. We want to pay extra out of pocket (Forest River is giving us $260) to get a better tire. I found Maxxis at Discount Tire online, but I can't tell what ply they are. I'm assuming the D1 B will tell me.
The letter “D” in the tire size you have identified above means it’s a bias ply tire. Personally I think you will get better service from radial tires (R).

There is not much gained by going to the next load range (D) unless you have rims capable of the increase in tire pressure to 65 psi.

Discounter Tire is a retailer for Maxxis tires. They can order them. They may have other name brands in stock they are pushing because of age or $$$.

Here is a Maxxis load inflation chart.


Update Note on edit: Maxxis does have a full line of bias tires. Here is the link.

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Old 08-07-2013, 03:44 AM   #12
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I have checked the list from Maxis that Airdale gave in post above here.
It prooved to be made with the formula for Diagonal tires and calculated from the B-load ( 35 psi) tire , though its a radial tire there.
Calculated back the first tire, and asume the others are done about the same.

So advice is to not use this list , it leads to to low pressures for the load , or the other way around to high loadcapacity for the same pressure.

Even a list made with the power in the formula that is used in America for LT tires of 0.7 is to low . Europe calculates for all tires with power 0.8.
The higher the power the lower the loadcapacity for the pressure.
X to the power 1 ( X^1 notated mostly) is X, X^2=X times X so square.
X^0,5 means rootX.

I constructed my own universal formula from wich the others can be made by filling in the right power and construction load ( Lc'. If power is 1 and Lc=5% you have the formula presented by an American IR J.C.Daws for LT tires.
I made pressure/loadcapacity lists with power 0,95 ( so almost 1) and Lc depending on Pr ( referencepressure is not the maximum pressure,D-load 65 psi) and to my opinion this comes closest to the ever to be constructed ideal formula for all kind of tires.
To be found in next map on my skydrive. E0EEE092E6DC%21904
But think I already made a topic about it on this forum so will search it back and give the link to that.
EDIT: here the link to the topic

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Old 08-07-2013, 03:55 PM   #13
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I contacted Discount Tire and confirmed that "D1" is the code for 8-ply. The "B" stands for blackwall.

The tire company we are stuck using (because it is the dealership's tire company [this is a warranty item]) can't get Maxxis. They only have two radial tires in my size: Carlisle 8-ply or a Marathon 6-ply (or a third option which is Turnpike [I can't find any reviews on this brand]. I think I'll go with the Marathon.

Thanks for all of the input!
2012 26TBUD
2004 Suburban
3 Kids
2 Dogs

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Old 08-20-2013, 09:30 AM   #14
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Originally Posted by KewlKamperz View Post
Can anyone please tell me what the "D1 B" stands for? :205/75/R15 D1 B
Where are you reading the "D1 B" ?

Some are providing DOT serial information, which is the 11 or 12 characters right after the DOT symbol.

A picture would really help as you omitted some of the most important information that would help us give accurate answer.
The letter(s) before the "205" "P", "ST", "LT" or none

You should find the words "Load Range" followed by a "C" or "D" unless the tire is a passenger tire.

What are the tire Max Load and inflation numbers?

If you haven't "read" a tire sidewall you might want to review this post.

Write a blog on RV tire application 40 years experience as tire design engineer. Freelander 23QB on Chevy chassis is my RV. Giving seminars on RV Tire applications (not selling) in Elkhart May 17-19, Allegan MI June 6-9, & Gillette WY July 18-21 RV Tire Safety Blog
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