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Discussion Starter #1
Why is it that 17" tires carry the lowest load ratings? There are 2 tires, toyo mt and nitto dura grappler, that have load ratings that i can use. Why is this? Why do I need to step up to an 18" wheel to get decent load ratings? I emailed tire companies with this question and got no logical response other than, you need to get a larger wheel size. I haul a heavy truck camper and need that extra assurance.
 

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Tire and Rim Association sets all the load ratings for tires. They mandated that 17" tires be limited to 3195lb so that a 17" Light Truck Tire wouldn't be used in place of a 16.5 or 17.5" truck application.

There are grandfathered designs that have more than have more than a 3195 rating but if the design is updated they have to conform to the 3195 limit.

It is a bogus limit when a tire has the exact same load rating in a D (65psi) and E (80psi).
 

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Discussion Starter #3
Tire and Rim Association sets all the load ratings for tires. They mandated that 17" tires be limited to 3195lb so that a 17" Light Truck Tire wouldn't be used in place of a 16.5 or 17.5" truck application.

There are grandfathered designs that have more than have more than a 3195 rating but if the design is updated they have to conform to the 3195 limit.

It is a bogus limit when a tire has the exact same load rating in a D (65psi) and E (80psi).
Thanks. That's what I have suspected. I'm gonna go with my gut and assume I'll be good with keeping my 17" wheels.
 

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A lot of the D's are 50 psi max. The 37-12.50-17 Ridge Grapplers are just such an animal.
 

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No need for much pressure if the volume is large.
 

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Try throwing a cabover on there. Atypical application but it would be all over the road. They're fine for an unladen or low cog load.
 

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Try throwing a cabover on there. Atypical application but it would be all over the road. They're fine for an unladen or low cog load.
Not sure of your context. D vs E. Flotation vs non-flotation, Tall and Fat vs Tall and skinny?
 

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A D flotation tire with a heavy high cog load like a cabover with it's flexible sidewalls is not going to have the stability of an E or F. Going to the dump with a load or junk or picking up a yard of gravel is not an issue. With the leverage of the cabover over the frame and D rated are tires not a good choice regardless of the load rating.
A friend used to get 315 BFG's at a crazy low price. At the time they were D rated with a 3200#+ rating @ 50 psi. After repeated sidewall failures with his '05 quadcab longbed 3500 with a Callen camper on it he kicked it up a notch to E's same size different brand and no issues since. He uses the truck in the Baja pacific northwest and it's a test of sidewall strength being aired down. No more wander either.
 

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I basically agree with what you are saying. My original comment was it was ridiculous that the same size tire in a D and E should have the same 3195 load rating just because some bureaucrat didn't want it used in place of a x.5 tire. The load table at any given size will give the same load rating at the D pressure for a D or E, except in bigger 17" the E will have a higher load rating.

BFG have crap sidewalls so your friends failure could just be BFGs. I had BFG LT275R18E125 and had more wander, wobble and sway than a Toyo LT295/R18E129 running a at a lower pressure. The Toyo was a taller tire also.

BTW: I had an Eagle cap 950 and now run a Northren Lite 10-2 so I'm totally familiar with high COG.
 

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You will exceed the AAM 9.25 axle load rating (5511) and the GVWR before you exceed the tire load rating.
 

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Discussion Starter #12
Ha. This got pretty off topic. I was only inquiring about e rated 17" tires. I have a heavy truck camper and hang 2 dirt bikes off the back on a hitch rack. This puts my truck at about 6750 on the rear tires which exceeds the 3195 number. I would be forced to go to 18" wheels to get a higher load rating tire thanks to this stupid tra rating. I farking hate bs standards that these people pull out of the ass which basically screws people over.

This was not intended to be a debate over e and d load ratings. Just the 17" rim issue.
 

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Discussion Starter #13
905910
 

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Toyo RT 37x12.50R17LT D range is rated at 3525....your payload capacity is 3204! Your way over 10k GVWR.
 

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905912
 

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Discussion Starter #16
That's for the m/t which is what I have in the truck now. Product 360360. They are to loud and not great on ice. Otherwise a great tire. I'm going with a less aggressive at this time. Unfortunately, 37" is too big. I need to stay in the 33 to 34 inch range or the truck smokes at the high altitudes and it's hard on the tranny with a load and 373 gears. I also don't want to lift it as it's already got a high cog.
 

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Discussion Starter #17
Also, i know I'm over my gvwr. I'm at about 11800 total gvwr. Not worried as I know the axles and frame can handle it. Wheels are rated at 3650 each. Suspension is beefed up all around.
 

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Also, i know I'm over my gvwr. I'm at about 11800 total gvwr. Not worried as I know the axles and frame can handle it. Wheels are rated at 3650 each. Suspension is beefed up all around.
What is the gawr for your truck on the rear? I go over gvwr but I wouldn’t go over gawr.
 

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Discussion Starter #19
What is the gawr for your truck on the rear? I go over gvwr but I wouldn’t go over gawr.
My last scale weight loaded up with only one moto was 5240 front axle, 6560 rear axle.
 

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My last scale weight loaded up with only one moto was 5240 front axle, 6560 rear axle.
Ahhh your a fair amount over. And your adding another 150lbs? On the rear? My 16’ rear axle gawr is 6500lbs. Or sure what the difference is in the axles.
 
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