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JHylton

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I own an '06 Big Horn Edition, SWB, quad cab that is just about ready for new tires. Since I don't ever haul anything of weight in this truck (only used to tow my boat) is there any harm in downgrading from load range 'E" tires to 'D' ? There is a significant price difference and if 'D' rating will fill the bill, I am thinking of doing just that. Also, considering going up to 315-70x17 size tires. Comments ?
 
Yes, the D rated tires are all too weak in the sidewalls, DW becomes a brutal reality. Going that large with the tire in a D rating is just asking for trouble on the front. Stay with the E rated tires and just get the lighter weight ratings to be safe. Are you trying to get some longer legs on it due to a manual trans?
 
With stock tire size I wouldn't do a D. Go up to a bigger tire that has 3195+ max load as a D will work fine since you don't haul. You will want to weigh the truck an get load tables for the tire so can set pressure based on loading.
 
No...it's an automatic. I saw an '05 in a parking lot the other day and it caught my eye because of the look. The guy had 315s on the factory polished aluminum rims and it looked really nice. I forgot to see what load range the tires were. I will probably just go up one notch....to the 285 and stay with the E rated tires. I haven't priced the 315 size in load range E. Probably quite a bit more than 275s or 285s.
 
285/75/17 (not 285/70) is the best proportionate tire you can run on these trucks IMO. Tall enough to fill the wheel wells nicely and not too wide.

Also I would not run a LRD tire just because the larger tires have a higher rating. The tire structure is still weaker than a LRE and you can only inflate to 50-60 psi. BARELY marginal on an empty truck, when you start loading it up even moderately it becomes a safety issue.
 
I'm sorry I don't buy the resistance to a Load Range D tire. For example
LT245/70-17E is rated for 3195@80psi and at 2740@70 psil load.
LT285/75-17D is rated for 3195@65psi and at 2755@50 psi.
No real difference in load ratings.

Now with the current TRA guidelines the 285 isn't rated any higher in a Load range E as all new 17" designs are limited to 3195; however, going back to a older Toyo AT load table shows the E could go to 3750 in a E. The 245 was already topped out in the older tables so no improvement there. So while i agree that there is extra margin if you are hauling going to the E, it is not unsafe running the D in the specified load rating with the bigger tire.

I run a 295/70-18 so I can get a 4080lb load rating and need it when carrying the cab over camper but the op never carries a load so going up in tire size and down in load range would be fine. IMO. The important thing is to try and not have to run max pressure at your maximum load as you have no safety margin.
 
The extra load capacity comes from the increased footprint but at the end of the day an 8 ply tire is an 8 ply tire no matter how you slice it and the sidewall will feel soft even lightly loaded. You don't buy a truck that's capable of towing a trailer based on its empty weight, you buy one that's adequate to tow the trailer based on its max gvw. Your argument of how it will feel empty should not be a factor in considering tires for many reasons.
Your giving an opinion to a complete stranger to run a weaker spec'd tire than the factory recommends. That's not a good habit to get into.
 
I don't buy I'm giving a recommendation for a weaker tire. The bigger tire has the same weight rating it just needs less pressure to make that weight rating.
 
OK fair enough, next set of tires you need pick up a set of LRD's and report back with some honest feedback. I already know what the answer will be, I've been down this road before with my former truck that had LRD's mounted by the PO. I couldn't get those POS's off fast enough.
 
I did it on my F250 without a problem. It worked fine and was actually more stable than the stock tires.

On this truck I barely make it in a E125 rating which is why I have E129 tires on it.
 
Great conversation, guys......appreciate all of your answers. I want to discuss this also with a couple tire dealers for their input.
 
Try calling Toyo tech support also. I've found them very nice to deal with and they are were I got the TRA load tables from.
 
OK fair enough, next set of tires you need pick up a set of LRD's and report back with some honest feedback. I already know what the answer will be, I've been down this road before with my former truck that had LRD's mounted by the PO. I couldn't get those POS's off fast enough.

X2.

You'll wish you'd stayed with "E's".

But, then again, who are we to say JR? All we've done is actually try it, right?
 
Im with the stay with the 10 ply crowd. Buddy bought a 02 a while back and was fighting driving issues felt soft took almost a month till we noticed the 8ply tires swapped my tires on to his truck all the handling issues gone.......and my truck drove like Shi--never thought about it as it had new tires.
 
I did it on my F250 without a problem. It worked fine and was actually more stable than the stock tires.

Was this Ford a diesel? Sorry, no way can a lighter tire with a weaker sidewall be "more stable". Maybe they weren't as stiff a ride when empty, but that's going to be the extent of it.
 
Your rear GAWR is rated around 6000-6200 lb isn't it? If so, all you need are tires that will support that load.

x2

I'm sorry I don't buy the resistance to a Load Range D tire. For example
LT245/70-17E is rated for 3195@80psi and at 2740@70 psil load.
LT285/75-17D is rated for 3195@65psi and at 2755@50 psi.
No real difference in load ratings.
Snip....

Agreed.

I have many posts/articles on my (currently defunct) blog about tires, including one a about sidewalls and load ranges. Needs and desires vary based on application and usage.

The original poster was clear that he was not going to haul heavy with his truck, so it sounds like he would have plenty of load capacity and stiffness with a LR D tire.

When lightly loaded, or not loaded, if truck owners are not running their tires at the max psi for the maximum carrying capacity, yet running lower pressures, there will be less if any observed difference in most applications at lower pressures. Running enough is the key. I am very against running my tires at GAWR psi (60-80) when running light as I have no desire to have 80 psi tires bouncing around offering less traction and wear.


I did it on my F250 without a problem. It worked fine and was actually more stable than the stock tires.

On this truck I barely make it in a E125 rating which is why I have E129 tires on it.


Another specific example- My recently sold '96 F-350 came with the then standard 235/85R16E size, rated for 3,042 pounds each (SRW) at 80 psi. They were replaced with a larger size that lived on the truck for most of its 18 years, 255/85R16D. Only relatively recently did the 255/85 size start to be made in a LR E, they were always a LR D tires, and some still are.

The 255/85R16D is rated for 3,000 pounds (SRW) at 65 psi. The 84 pound capacity difference (per pair) is so small it's a non-issue for me, the GAWR on the truck was 6,084, obviously because that was the capacity of the tires. That old Ford hauled and pulled plenty of weight during my 18 years of ownership, at max. 65 psi. Of course if one needs maximum stiffness (not the example given), chose a different tire. When not running a load, psi was much lower, appropriate for the load (or lack of load). Your mileage, usage and needs may vary.

There are/were some stout LR D tires and some weak LR E tires, all depends.

But, because many drivers are terrible about tire maintenance and safety, and the times we live in, you may have a hard time finding a tire shop that will mount a LR D tire on a truck that came with LR E. Even if they are rated to carry more weight than the OE tires.
 
Load range E tires are the best bet, BUT there are many many truck with load range D tires, Ive had 37x12.5x17 LR D tires for over 5 years with no issues, no DW, no handling issues. With that said not all tires are equal either, Ill take a good quality D rated tire over a crappy E rated tire any day. The softer sidewalls can make worn components more obvious and If I was hauling alot I would want E rated tired but D rated tires will not cause the earth to fall off its axis and all life to vanish as some would leave you to believe.
 
Was this Ford a diesel? Sorry, no way can a lighter tire with a weaker sidewall be "more stable". Maybe they weren't as stiff a ride when empty, but that's going to be the extent of it.

It was a IDI 7.3. I ran the tires at around 6000lb axle weight in both cases which is right at tire capacity of 6400lb. The bigger load range D did just as stable as the smaller load range E.
 
The Fords are a lighter truck with a different suspension, crappy as Dodge but different. The ply ratings are a joke because they don't mean anything anymore with the supposed changes in structure and composition. Load rating of the tire and tire weight is what will make the biggest difference in certain tires, in other it is an outright lie. They won't perform on a these trucks even at 80 psi.

Staying with the lighter E rated tire and lower air pressures works far better than any D rated tire. That becomes obvious when a mistake is made. Admitting the mistake is a rare occurence.
 
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