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Old 02-21-2013, 01:23 PM   #21
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In this article of an American J.C.Daws , he explaines a new way of calculating, and compares it to the old power-formula and its diferent used powers in America and Europe. A stiffer tire in his formula ( G-load stiffer then E-load ), has a smaller construction load ( my word for the load that is bare at zero pressure) then a less stiffer tire .
So in his calculation a stiffer tire needs a higher pressure for the same load then a less stiff tire.
So there are 2 things that are wrong, first is the power used in America of 0,7 , while in Europe it is 0,8 , and he even advices 0,9 to 0,95 for for tires with high maxloadpressure ( referencepressure). Second is that every maxload/referencepressure combination needs a seperate calculation.
Hover over this article and search for the conclusions and the endconclusion.
The first formulas I dont understand too.

I even concluded my own formula , wich is a combination of the "Daws"formula and the old Power-formula, and use that now in my spreadsheets.
You can also read my article about it, in wich I compare the different calculations , but I admit that I am not an authority in this field, Yust got interested in it and searched it out. But if you read it , and use your own technical intuition , you will come to the same conclusion.
My article "proveofwrongcalculation"can be found in the "all about tire pressure"map on my skydrive. wich I made to support my mail-discussion with Mr. Daws. E0EEE092E6DC%21601
you see that my tire-pressure interest has gotten a bit out of hand, but I discovered much more about tiresload and pressure, there is more wrong in the tire-business. But one thing at the time.
First this use of lists that lead to tire damage out of the world.

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Old 02-21-2013, 01:39 PM   #22
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Originally Posted by Ditchooker View Post
Staying with the factory size would be ideal, however, Finding a 14" tire in load range D, is much more difficult, and looks to be non existant in Canada, whereas the 15" tires are much easier to find.
Here's a LR D 14" tire.

RADIAL 857 - Kumho Tire USA, Inc.

Here is where I bought mine.

Kumho*Radial 857

If you order, be careful to check the circumference of the tire. I had 205/75/14 Marathons that were replaced by 195/82/14 Kumho's to get the same circumference. The tires have a different aspect ratio. Overall, I got quite a bit more capacity. Another advantage is 99 mph speed rating; not that you are going to tow that fast.

Also remember to consider the maximum pressure for your rims. You will also have to go to steel valve stems.

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Old 02-21-2013, 08:25 PM   #23
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Location: Langley, BC
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205/75/14 (1760lbs -800lbs TW) is what I currently have, I really like Kumho, the tread pattern looks very robust, and the ideal replacement, but shipping them to Canada makes it rather cost prohibitive ($170 shipping plus taxes (,levies and possibly brokerage fees) and then mounting on top of that.

the steel stems are a given regardless, Good advise all around! Thanks for the tip on the aspect ratio!

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