badwithcomputer

I'm seriously thinking of upgrading my current tires which are Goodyear Wrangler SR-A they are light (40lbs each) but suffer in the load range department at 2600lbs per tire.

There is a set of Duratrac's on sale currently and I can't quite decide which route to go 275/60/20 with a load rating of 2679lbs (not much greater than what I have) but weighing in at 46lbs each

OR 275/65/20 with a load rating of 3750lbs but weighing in at 57lbs each.

I plan to tow a 19-23ft trailer this summer and haul odd bits of building supplies. Would you guys recommend jumping to the 275/65/20 or will I be ok with the 275/60/20 Duratrac or am I even wasting my time even considering upgrading tires as what I have now will do the trick?

uzikaduzi

your axle and likely rims are not rated high enough to use tires requiring more payload... but i do find a stiffer side wall to be nice when pulling... anything load d or e will be great but your stock tires were rated for more than you can tow anyways

Norotso

https://www.f150forum.com/f82/tire-r...towing-301539/

https://www.f150forum.com/f82/towing...-index-285757/

smokeywren

You omitted part of the tire specs. The tires with 2,697 load rating is with 51 PSI in the tires. And the ones with 3,750 load rating are LT-series tires in load range E with 80 PSI in the tires.


As uzikaduzi noted, adding load capacity to your tires will still not allow you to increase the load on the truck without busting some other weight rating. So the only thing you will gain by switching to LT Load Range E tires is a harsher ride and reduced MPG.


With 2,679 load rating, your tires can handle a weight on the rear axle of up to 5,358 pounds. However, the rear GAWR of your truck is probably less than 4,000 pounds, so you won't gain any rear GAWR by beefing up the weight capacity of your tires.


Also, look at the specs of the tires. The tire revs/mile is importante a. The 275.65R20 has 610 revs/mile. The 275/65R20 has 633. That's a 3.6% difference. If your speedo is accurate now, it will be 3.6% off with the taller tires. That's over 2.5 MPH at 70 MPH.

DieselDawg

When looking at load range capacity for tires that are rated P (passenger) for any SUV or PU...you need to reduce the Load Carrying Capacity by the factor .91x The Load Rating...


Just because the Max Load Rating for an LT/E tire is at 80psi...does not mean that you have to run them that rock hard. At the same psi as you stock tires...they will be rated ~9% higher because of the LT/E rating...and adding psi will increase the Load Carrying Capacity of them.


Sidewall stiffness when towing is important when your truck is loaded/pulling.


Yes, heavier tires will hurt mpgs a bit...being just a tad taller doesn't always hurt mileage if it hits your sweet rpm spot!


EPA Ratings are why makers put "P" rated tires on TRUCKS. If you drive them like a car...then they will be fine. If you sometimes, but not often, haul some bags of dirt etc...they will do just fine. Once you start using your TRUCK like a TRUCK, beefing up the tires is a good thing.


Will towing a 30ft TT on "P" rated OEM Tires be ok? Yeah, maybe just barely ok. I tow a 29ft TT they scales at about 7400#s and I would not tow with "P'" rated tires. I raced for Mazda and towed, I own a Statewide Moving Company in Texas and towed, I worked at VTS (Vehicle Testing Services) while I raced Karts and towed and tested all sorts of tires...I would upgrade your tires if doing much more than small hauling. Better Safe than Sorry.


As for GAWR...it is true you can not "officially" raise the number, but that being said our rear axles are underrated by Ford based on the shoes they wear. Heck, find a good "C" rated tire for a bit of extra insurance if nothing else.

uzikaduzi

i would be careful with this advice... I agree that stiffer side walls do provide a more pleasant towing experience; however, like Smokey said, they are rated to be able to hold more than your rear axle rating and saying that they are the the limiting factor seems to fly in the face of logic since the HD payload package comes with a different rear axle and heavier duty springs... is the truck going to explode and kill everyone on the highway if you're slightly over on your numbers? no, but the amount you'd need to go over on payload to overload those tires is not slightly exceeding your ratings, it's completely ignoring them.

for the record, i do like to run either load d or e tires... but it's strictly a comfort thing for towing... unloaded they provide a much harsher ride that i am willing to sacrifice for my towing comfort.

DieselDawg

I never said to run over what the axles are rated...my whole point it that I think it is safer to run better tires.

acadianbob

Load Range C is a very nice compromise. But I'm not sure what you will find available in 20's . . . . .

uzikaduzi

my apologies sir for missing/misreading your point.

DieselDawg

No problem. It was more of the "weak link" of a stock f150 IMO is the tires. Next I would consider it to be the brakes (longevity and stopping power with a big load).


Its all good