Avoid This Costly Mistake With Load Range F Tires

[@zekester1]

People also need to watch the load capacity of their rims also...I've seen as much as 1k pounds difference in the same size rims...many aftermarket rims are designed with looks over function!!

[@truetexan7755]

Good point,, also valve seems should be looked at sue to the increased air pressure.

[@powerstrokemaintenance]

That is a great point! It’s easy to start making upgrades without paying attention to what they’re actually rated for and whether it’s up to OEM spec

[@dbkonkle]

In my opinion the biggest reason you were having tire wear issues was because you mounted a 12.5” wide tire on a wheel that was too narrow. You can compensate by running lower tire pressure to some degree, but running the pressure lower causes higher tire temperatures. Try a narrower tire or get some wider wheels and I believe your tires will wear much better and allow you to run correct pressure for the loads your tires are actually carrying. I run into this same wear issue on my dually because Ford used the narrowest wheel they could get away with for the tire size they chose to install. Load range F will absolutely carry more weight than the same size tire with a load range E designation, but only if it’s properly inflated. The F rated tire is built stronger to handle the higher pressure which is why it weighs more. They also generally have a stiffer carcass and harder tread compound which can increase resistance to damage and increase tread life when compared to load range E. This comes at a cost though. You mentioned the weight increase, but the stiffer carcass tends to cause the ride to be harsher and wear shocks more quickly. The harder compound gets you more tire life at the expense of grip, but you probably wouldn’t notice it much except in cold wet conditions. Everything is a trade off when it comes to tires.

[@madweazl]

"Load Index" is what will determine the max supported weight for the tire; it is represented as a number on the sidewall (typically 126 on a 1 ton truck which is good for roughly 3750lbs).

[@hangryalpaca4390]

Thank you so much for informing us! This saved me a lot of time and money.

[@powerstrokemaintenance]

Glad it was helpful!

[@sweb4614]

Thank you for the good information based on real world experience. I will be needing tires soon for my PS250 and I;m looking at the Defenders - load range E. Thanks again. PS on a separate subject, maybe it's just me, but my engine seems to but runnig smoother since I have started using ArchOil fuel treatment.

[@powerstrokemaintenance]

Thanks for the comment! Glad the archoil is working well!

[@71usmc]

You also need to adjust your PSI. You don't need max psi if you're not max loaded.

[@powerstrokemaintenance]

Good point!

[@birdden4x4ambulanceoverland]

My F rated 35x12.50x18 nitros. Have way more load capacity than my E rated. I have over 40,000 km. On my 4x4 ambulance that weighs 12,000 lbs.

[@powerstrokemaintenance]

Nice! What E rated tires do you have?

[@birdden4x4ambulanceoverland]

@@powerstrokemaintenance I have F rated nitto grabblets 35x12.5x18. Heavy but they got me from Vancouver island to the Arctic ocean out to Saskatchewan back to the island then baja for 4 months and the trip back to Alberta. They are getting low and tread now after 40,000 km.

[@powerstrokemaintenance]

@birdden4x4ambulanceoverland that’s solid miles those for 35s with hard use!

[@jasonkubitz9410]

If you look at the specs for random brands, they will have varying load ratings within the E, F etc standard. I believe that has to do with what type of tire it is for a certain terrain and other factors like size etc. I'm going with load range G tires for my toy hauler. Not for more weight capacity but for a stiffer side wall for less flex. More flex on a trailer = more sway. Many of friends have done it and it's night and day. As for the truck tire, just make sure it is rated for the load you are carrying and you're good. Not sure about the extra mass because these trucks don't care about a 100 or so lbs extra. Size is the biggest issue since it throws off your overall ratio. New set of gears is the the only answer to that.

[@powerstrokemaintenance]

I didn’t realize how much tire sidewall influenced trailer sway. That’s really interesting. And you’re right, these trucks don’t typically feel an extra few pounds, but as I’ve continue to load my truck up, especially since it’s a 250 I definitely have to be careful of weight

[@jasonkubitz9410]

@@powerstrokemaintenance I've seen some of these 3/4 ton trucks hauling super heavy loads. Way over their "limit". Air bags definitely help regardless of the load capacity. I just towed my trailer only about 5 miles to a camp site last weekend with my truck tires at 50 psi. That's what I run when empty. Granted my trailer was empty since we were going to a KOA but the sway was definitely there on the freeway with my truck tires at low psi. Too much flex. The trailer tires act the same way. Good shocks help tremendously with sway as well. I crank mine up when fully loaded and they took away a lot of sway I would get with set it and forget it shocks. I was actually surprised how much. Not everyone is running Fox racing 2.5 inch shocks with high and low speed compression adjustments but I think a good heavy duty shock would be good. If towing all the time, I would change out every 25K miles.

[@vica153]

So excessively large and excessively heavy tires on the highway will have lots of negative effects without any real benefits and you're surprised?

[@powerstrokemaintenance]

Thanks for watching!

[@paul91103]

Great breakdown of all this information. Are you just keeping the Coopers until they wear out and stay with Load Range E going forward?

[@powerstrokemaintenance]

Thank you! I actually sold the Cooper tires and will be running the highways going forward. Just didn’t make sense to have 35 inch tires sitting around.

[@gchsbus]

On counter-point, i had a coworker who had a very heavy GMC van he would tow his boat with all the time. He got new very large wheels with 35 series tires. I said to him those tires aren't for heavy loads. He told me to get lost. Well he is on his 6th set on the rear now and he is lucky he has not lost a trailer yet while towing. Just cuz it looks nice does not mean its safe.

[@powerstrokemaintenance]

That is true!