Tire Load Range Discussion

[Hollywud]

OK, I've been trying to figure this out for some time now. Tire dealers haven't even been able to answer my question satisfactorily... . I'm sure someone out there knows this answer.



My truck came with 245/75R16 - Load Range E tires. When it was time for new tires, I wanted to fill-out the wheel wells some more and get better off-road traction (the stock Michelin's were phenomenal on the road but, horrible off-road). I looked at all the options available in the BFG MT line (brand/model loyal) and chose to install 285/75R16 - Load Range D tires. My dealer specifically told me that I must replace my load range E tires with load range E tires. I assumed this was to maintain my max GVWR and tow rating however, no one could tell me what the difference in construction was. Soooooo.....



What is the difference, in construction, between Load Range D & E tires? Number of belts?



I chose the tires I did, because they had the maximum single tire load capability in a Load Range D tire. For discussion purposes, I'm including a list of tire specs for the tires sizes most used on our trucks (my opinion of course)... all tires specs are BFG MT's:



* 245/75R16 - Load Range E - 3042 lbs @ 80 psi max. single tire load

* 285/75R16 - Load Range D - 3305 lbs @ 65 psi max. single tire load

* 305/70R16 - Load Range D - 2910 lbs @ 50 psi max. single tire load

* 35X12. 5R16. 5 - Load Range D - 3415 lbs @ 50 psi max. single tire load



Why is it possible for a Load Range D tire to have a higher max. single tire load (for example 285/75R16 & 35X12. 5R16. 5 have higher single tire loads vs. OEM Load Range E)?



What is the advantage of the higher pressure, related to the max. single tire load, of Load Range E tires (for example 245/75R16 = 80 psi)?



What is the formula between tire height & width, related to max. single tire load psi?... ... I don't understand why, for example, 285/75R16 tires (theoretically measuring 11. 3" wide and 33. 1" high on an 8" wide wheel) have higher max. singe tire load & psi. vs. the 305/70R16 tires (theoretically measuring 12. 2" wide and 33. 1" high on a 9" wide wheel). I understand that the volume of air inside the tire would be different but don't understand the fluctuation in max. single tire loads and psi for 2 Load Range D tires with the same theoretical height and delta of 0. 9" in width.



I am an engineer so, don't be afraid to answer this question with technical specifics. I probably just have a mental block that needs to be dislodged... Maybe I'm making it more complicated than it needs to be.

 

[Hollywud]

Mistake Found in Previous Post

In installed 255/85R16 tires on my truck, after OEM's were worn..... not 285/75R16's. This doesn't change my question at all but, I wanted to clarify... . been staring at the BFG tire spec sheet too much and it has made me googly eyed



Here are the specs, for the tires I currently have installed:



* 255/85R16 - Load Range D - 3000 lbs @ 65 psi max. single tire load

 

[Okie-Go]

To make it simple, with 3000 lbs max on each side you should be ok of course if the weight of the rear axle with a load is under 6000 lbs. I also like the tread design on some of the load range D tires. I have weighed my truck loaded and unloaded on the rear axle. That would be a good place to start and help you decide. IMO

 

[Diesel Gunner]

Hollywud,



Being an engineer will be an advantage for you here. First, I would ask myself "What is the weight of the things that I am going to load into the bed and hook onto the hitch?". Next, calculate the actual weight that will be on each axle, front and rear. The better way to do this is to hook up and load the truck as you would travel with it and go to the public scales and actually weigh the rig. Ideally you would weigh the truck empty, then loaded, then loaded front axle, rear axle, and then hook up yout toy.



Next weigh the truck by axle, the truck and trailer, and then the trailer axle weight. Now, you have your data. You can calculate the total vehicle weight (GVW), tongue weight, etc. Now you can determine which load range tire you need.



If you only tow a jet ski trailer, you would not need load range E tires. However, if you plan on towing a 11,000 lb TT with a bed full of quad and extra gear I would not reccomend them. Tires can achieve load range ratings in different ways depending on their construction and materials used. That would end up being a discuaion all to its own. My very best sugestion is to weigh your rig and honestly analyze what you intend to use it for.



Also, keep in mind that having properly rated tires for your rig is far more important than the looks. Most hiway patrol offices are more interested in load range rating than they are in those hot looking tread paterns and how they fill up the fender wells.



I am sure that many more will chime in here and many more good suggestions will be coming. Good questions, and, I too, am interested in others responses.

 

[FDziurda]

Tire Loads

Hollywud,

My understanding, from previous posts on this subject is to look at the single tire load capacity of the tires you would like to use. As long as they meet your loaded requirements, then you should be okay and yes there are many Load Range "D" tires that have higher capacities than some Load Range "E" tires.



I recently replaced my OEM Michelin All-Season 245s with Michelin All-Terrain's and noticed quite a difference in the ride. I have much better traction in snow but the ride is noticeably more harsh.



You might want to run a search for previous discussions on this subject.



Good Luck,



Frank

 

[Chief USA]

Load range E = 10 ply rating



Load range D = 8 ply rating



weight = weight... ..... in a nut shell, as long as you stay within the load capacity of the tires. You will be fine.



I put the Walmart Liberator series 285-75R 16 tires on my truck. 3305 max. weight cold @ 65 psi.



For $443. 91 with road hazard warranty, that is not bad for 4 tires. Just remember that the spare will not fit underneith with tires that big.



Is the load range E tire a stronger built tire? Absolutely, but how much are your uses going to require?

 

[LSMITH]

Letter rating is only a "class" of tire within a given size. Load rating letter means NOTHING when different sizes are concerned.



The wider tires have a higher load rating given similar construction simply because the load is spread over a greater area, it reduces the load per square unit of measurement.



Weight capacity of the tire is the ONLY specification that any agency is going to go by. If load range C tires will carry the load of your vehicle at GVW (some 36" and larger tires do this easily) there is NO PROBLEM.



Letter rating of tire load capacity is a useless outdated system. Pounds at pressure rating would be much much better.



The differences in construction vary so greatly between tire models and even sizes of the same tire that it would be nearly impossible to define a "rule" for that. Construction of the tire is the sole property that deterimines load capacity.



Maximum inflation is not a factor in quality or useability of the tire, it is just the pressure at which you can expect the maximum performance of the tire when loaded heavily. It will increase sidewall stiffness, which will make the truck drive and handle differently.

 

[boatpuller]

I'm not an engineer or a tire person but here is my understanding of how this works.

Tires were originally rated by the number of layers of cords(plys)then they went to the system where they used letters:2plys per letter

A=2ply

B=4ply

C=6ply

D=8ply

E=10ply

Then in an effort to make tires cheaper they came out with better cord material and now instead of the actual number of plys they are given a ply rating to match up to the old system even if they don't actually have that many plys.



Now to answer you question about the different weight carrying capacities of different size tires it is based on the road contact area of the tire and the air pressure it can handle. If by the casing design the tire can hold 80psi X the number of square inch columns in it's contact area that comes out to how much load it can handle. That's why a smaller tire holding more air pressure than a larger tire with less air pressure can have a larger load carrying capacity.

Basically the formula would come down to surface area multiplied by the air pressure to equal the load carrying capacity.

Surface3 area would be determined by the size of the tire and air pressure capacity is determined by the design of the casing.



Hope this helps, kind of long but don't express things very well, if I can answer any other questions I'll try.

Tired of typing for now



Caleb

 

[Hollywud]

Keep 'Em Coming

WOW that was fast, guys!!!



So far you all have validated the way I've been thinking about tire load ranges/max. single tire load ratings. Your responses have been very similar to what tire dealers have told me. Matching max. single tire load rating to the max. load I carry/tow with my vehicle seems like a no-brainer... . and that's the theory I've applied to date.



Like I said earlier, maybe I'm making this more complicated than it needs to be (typical engineer right ).



The answer to my main question, that has eluded me to date, still remains unanswered: What is the difference in construction between Load Range D & E tires? Why do tire/truck manufactures even suggest a load range, if consumers/dealers seem to throw it out the window and go by the max. single tire load rating???



For the record, I don't use my rig for major towing/hauling (yet ). The largest job my truck has is towing a 21' boat (approx. weighs 4,500 lbs... it's an old wood/glass boat). I am contemplating a future lift, hence thinking about tire sizes again. I have swayed more than a tree in a hurricane, regarding lift options. I still haven't decided but, I am now thinking I may just do a 2. 5" coil spring up front with dual shocks and leave the rear alone (except for matching shocks front-2-rear)... . to level out front-2-rear and provide better handling from the front end (I hate bottoming over small stuff). If I can't get an answer buy the time I start doing heavy hauling, my suspension would still be "almost" stock and I could just swap the larger rubber with OEM wheels & 245/75 Load Range E tires..... just for peace of mind, even if the Load Range D tire I choose has a higher max. single tire load.



Also, my off-roading is limited to fire roads, lumber trails, un-improved roads (w/snow), etc. I don't do or plan to do any serious off-roading (i. e. rock crawling or mudding). My goal is and has been to fit a tire that can do double duty (i. e. meet me half way between off-road & on-road performance). I do currently have MT tires installed and all the figures I quoted were for MT tires (because I had the spec sheet right in front of me and so long as we are comparing like models... well compare apples to apples not oranges) but, I will install AT tires this time round... . which should suit my driving/hauling needs better than the MT's.

 

[boatpuller]

Man you guys are fast, it took me 15 minutes to type all that and you guys answered in the time I was typing, guess I need typing lessons

Caleb

 

[Hollywud]

WOW AGAIN!!!!!!!!!!!!!

I must agree with Boat Puller! I type fast but you guys are quicker... in the time it took me to compose/type my last post, you guys have answered my question.



Thanks a ton (literally)!!! :-laf :-laf :-laf :-laf

 

[tbowyer]

I work for Michelin but I'm no expert either. As I understand it the load range differences are for listing the heavier ratings in the same tire size/type. The C, D, E seperates the weight classes in ( from outside apperances) the same tire. You've got to compare the same size/make of tire, not different brands.



Terry

 

[AKDrifter]

I understand whats being said about the load =load part, but I'm not going to put my 255/85-16's back on come spring, this is why.



They are not only light to the feel, but they ride spongy. I'm concerned with the sidewall stability in the lateral sence. I've noticed the rear end sways out and it does not make me feel good.



I originally purchased these tires to gain a little more speed in the summer. My winter tires are 235/85-16's, I like these in the winter because they put me in a comfortable RPM/speed zone better matched for the roads I'm driving.



I'm going 19. 5's this summer, spendy but safe for cruising the country with the camper and family. Can't imagine blowin' one of those 255/85-16's in this truck; I know they are rated for the wieght, just too much sidewall to be safe.



Our trucks only touch the ground in 4 ( or so ) places, not a place to chance it!

 

[Hollywud]

I agree AKDrifter, with your assessment on 255/88R16's. At the time I purchased my BFG MT's in this size, I didn't have the time or $ to deal with new tires, wheels, and a possible lift all at once. I simply wanted to replace my worn OEM rubber. After doing much research, the 255's seemed like a good compromise. Load Range D yes but, it nearly equaled the max. single tire load of my OEM rubber. Off-road the tires handle great but, cornering on-road is for the birds. If you push the truck hard enough in corners, it feels like you are riding on elastic bands (pretty scary, even for someone with a road racing background).



Has anyone had any experience with 285/75R16 BFG AT's on Weld 16X8 wheels?... . with Skyjacker D25 coil springs up front? These tires are Load Range D but, have a max. singe tire load of 3305 lbs @ 65 psi (significantly higher compared to OEM).



Dependant on my last question, what I may do in the interim is purchase Weld 16X8 wheels and mount my 255's on them. I think this would improve on-road handling characteristics greatly, flattening the tread and giving more side wall support. I will only do this if I hear good reviews on the 285's, since both could be mounted on 16X8's... ... if I hear bad things, I'll hold off for a while as, tire choice drives wheel size (or visa versa... ..... is the glass half empty or half full? )

 

[Hollywud]

Correction For Mistake

I gotta slow down while typing!!! I the first line I meant 255/85R16's not 255/88R16.



Oh well... . getting sleepy I guess.

 

[LSMITH]

I run the 285's on 6. 5" wheels, they are dead solid at 65 PSI which is the max. If you take them down below about 45 they get soft, but over that and all is good.

 

[GAmes]

I'd tell your dealer to pack sand. My truck came with D rated tires and it has one heck of a GVWR. Is he going to tell me I can't upgrade to load range Es?

 

[Hollywud]

LSMITH,



What Brand/Model 285's are you running on our stock wheels (assuming your stock wheels are 16X6. 5)? Do you have a leveling lift or other suspension lift goodies (judging by your auto-sig, I'd say no but... . want to make sure)?



I didn't go with 285's, when I purchased the 255's because BFG's recommend wheel width is from 7. 5" - 9. 0". While their recommended wheel width for 255's is 6. 5" - 8. 0".



Thanks!

 

[LSMITH]

I am running the BFG AT KO's in 285/75/16 on stock 16X6. 5 wheels. No levelling kit, no lift or anything, they NEVER hit or rub. Lots of crap on my truck that is not in my sig, sorry. There are quite a few guys running 285's on 6. 5" wheels with no problems. The tire guy will likely throw a fit and try to sell you new wheels, tell him to put them on or pack sand.

 

[Hollywud]

LSMITH & everyone else... ... THANKS!!!



One last question... I think



Could someone post a picture or two of the 285's (stock wheels or otherwise)? LSMITH, do you have a photo?... . so far your set-up matches closest to my future plans (specifically interested in getting a birds-eye view of the BFG AT's in your size so, I could see how they compare to my BFG MT 255's).



Thanks!!!! You guys have been a great help!!!!!!!!!!!!!