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Old 11-18-2016, 09:30 PM   #1
jmak
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No LT Tires

2014 F150 FX2 is my tow vehicle for our Cougar 26RBI with max loaded weight of 7800lbs. Need new tires 275/55R20. The most I can find is passenger XL tires which give a load rating of 117 or 2833.

Lots of people seem to suggest LT tires however I cannot seem to find LT tires in my tire size that are not off road tires?

Why do I even need LT tires if even if I manage to max out my payload and gross vehicle weight of 7100lbs. 7100/4 is 1775 per tire well within spec of a standard load tire and very much within the XL tire of 2833.

Am I missing something?
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Old 11-18-2016, 10:12 PM   #2
Desert185
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Re: No LT Tires

These 275/55-20's are listed under LT, but they are XL. Strange.

http://www.nittotire.com/light-truck...ht-truck-tire/
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Old 11-19-2016, 10:21 AM   #3
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Re: No LT Tires

Quote:
Originally Posted by jmak View Post
2014 F150 FX2 is my tow vehicle for our Cougar 26RBI with max loaded weight of 7800lbs. Need new tires 275/55R20. The most I can find is passenger XL tires which give a load rating of 117 or 2833.

Lots of people seem to suggest LT tires however I cannot seem to find LT tires in my tire size that are not off road tires?

Why do I even need LT tires if even if I manage to max out my payload and gross vehicle weight of 7100lbs. 7100/4 is 1775 per tire well within spec of a standard load tire and very much within the XL tire of 2833.

Am I missing something?
When Ford fitted those tires to your truck they were required to adjust the load capacity. They did that by dividing 2833# by 1.1 which equals a maximum load capacity of 2575# for them while fitted to a pick-up truck. However, they still provide more than adequate load capacity for your maximum loaded truck. I would insure they are inflated to 50 PSI when hauling something.
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Old 11-19-2016, 10:42 AM   #4
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Re: No LT Tires

Quote:
Originally Posted by jmak View Post
2014 F150 FX2 is my tow vehicle for our Cougar 26RBI with max loaded weight of 7800lbs. Need new tires 275/55R20. The most I can find is passenger XL tires which give a load rating of 117 or 2833.

Lots of people seem to suggest LT tires however I cannot seem to find LT tires in my tire size that are not off road tires?

Why do I even need LT tires if even if I manage to max out my payload and gross vehicle weight of 7100lbs. 7100/4 is 1775 per tire well within spec of a standard load tire and very much within the XL tire of 2833.

Am I missing something?
This is my opinion, so you'll get what you paid for LOL

Tire height is measured by a percentage of the tread width. So 275 mm wide tread tires rated as 275 55R tires, the height of the sidewall is 55% of 275mm. while 275 85R tires have a "sidewall height of 85% of 275mm.

To answer your bottom line question, no you're not missing anything. Here's the situation as I see it: Years ago, tires had a much higher profile than today's current "sport truck" tires. "Back in the day" almost all tires were the 85% profile. That was done so the sidewall flex could be used to help compensate for the heavy duty suspension by reducing the tire pressure when the truck cargo load was not "heavy". The sidewall "flexing" helped dampen the suspension "jolting". Back then, almost all wheels were 16". Then, along came the 16.5" "wide oval tires" around the early '70's, and although the tire diameter/circumference was the same, the sidewalls were in the 75% range. Next came the 17" wheels and 70 series tires, then 18" wheels with 65 series tires and 20" wheels with 50/55 series tire profiles. As the suspension systems improved, the sidewall flexing could be eliminated causing tire sidewall height to be more "asthetics" rather than "functional". You'll notice better "drivability" with your "low profile" tires. There's less roll, less potential for loss of control with a blowout and better stability in emergency maneuvers. It's essentially because the tire doesn't "roll out from under the wheel" (improved sidewall stability).....

So, with your truck, if you had "XL" rated P series tires in the 275 75R or 85R profile series, you'd likely have some pretty significant sidewall flexing based on the height of the sidewalls. It would be extremely difficult to reduce that flexing, even with the maximum tire pressure, so to compensate for the tire "instability" with P series tires, your best option would probably be to go to LT tires which have a stiffer sidewall.

I believe that with your 55 series sidewall height, you're not going to "introduce" nearly as much sidewall flexing (call it sidewall sway if you want) because of the much smaller "height" of the sidewall. Keep in mind that as the wheel diameter increases and the tire "profile height" decreases, the actual diameter of the tire and the circumference remain very much the same.

You'll probably notice that on your truck with 20" wheels, the tire size is 275 55R20. On similar model trucks with smaller wheels, you'll probably find 275 65R18 tires or 275 70R17 tires. All three have similar tire diameters and circumferences, but your tires will have significantly less "sidewall roll/flex/sway" because they are "shorter in the sidewall" so there's less to "flex"...

I hope my "theory" comes across with some logic and not just "all banter".....
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Old 11-20-2016, 12:56 PM   #5
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Re: No LT Tires

I put a set of these on the wife's 2013 F150 Platinum.

My cousin has run them on all his F150s and said he gets 100K miles + out of them.

We just made a 1700 mile trip with the camper and I like them a lot better than the Bridgestone Duelers they replaced.

-Brian
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Old 11-20-2016, 03:21 PM   #6
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Re: No LT Tires

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Originally Posted by B-O-B'03 View Post
I put a set of these on the wife's 2013 F150 Platinum.

My cousin has run them on all his F150s and said he gets 100K miles + out of them.

We just made a 1700 mile trip with the camper and I like them a lot better than the Bridgestone Duelers they replaced.

-Brian
Good tire, but the crossover version of the Defender is surprisingly noisy. Taking them off after Thanksgiving. The wifey can't wait for them to be gone. The pickup version Defender LTX is quiet, I understand.

FWIW...
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Old 11-21-2016, 05:46 AM   #7
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Re: No LT Tires

What about these?
http://www.nittotire.com/light-truck...ht-truck-tire/
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Old 12-21-2016, 12:12 AM   #8
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Quote:
Originally Posted by 24v View Post
Read carefully because this does include trailers.

https://www.nittotire.com/media/1529...TSD-12-011.pdf
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Old 12-21-2016, 04:40 AM   #9
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John's explanation is long, but IMO he hits the point very well. The tall sidewall on P tires creates a lot of flex under load so people recommend LT tires with a stiffer sidewall for better control and stability. With a 55 series tires, much of the flex is eliminated. As CW pointed out, there is more than enough load capacity with the tires you are looking at especially considering that with a properly adjusted WDH, the majority, probably around 55% of your loaded weight will be on the front axle which will leave around 3,500 lbs on your rear tires.
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Old 12-21-2016, 10:18 AM   #10
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You can get LTs in 275/60R20. I have them on my truck. BF Goodrich A/T KO2
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Old 12-22-2016, 05:34 AM   #11
24v
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Quote:
Originally Posted by CWtheMan View Post
Read carefully because this does include trailers.

https://www.nittotire.com/media/1529...TSD-12-011.pdf
I'm not sure why you linked me to info about tire load ratings and pressures?

The OP asked for a LT tire in a specific size and I provided a link to one.
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