Having just put a rock through a treadblock of an OEM BFG Rugged Trail tire with less than 9000 miles on my 2005 Nissan Frontier Crewcab Nismo, I'm in the market to replace tires. I've decided on BFG All Terrain T/A KO, because most of my travel both on- and off-road is in semi-arid and desert regions. I have a separate set of winter tires on rims for winter. The truck is not my daily driver. It is used for local truck transport-related actiivites (central Washington State), driving to local trailheads for hiking, and driving long-distance (ca. 1300+ miles) to the desert Southwest for backcountry driving/hiking/climbing. Any recommendations regarding the D- versus E-rated versions of the BFG tires sized LT265/75-16?
D- vs. E-rated BFGoodrich A/T KO
- Thread starter FJPeryea
- Start date
granitex1
Adventurer
D rated is going to be more than enough tire for you, the only way that you would need e rated is on a 3/4 heavy or a 1 ton. All that you would be getting is a stiffer sidewall with a harsher ride. D is the exact tire that I am running in the same size and I could not think of going any heavier duty.
Both the D and E range BFG AT's are 3-ply, not 10 ply. I would agree that the D range is sufficient. I don't agree that one would be noticeably harsher riding than the other since both will be aired at under 40psi to match the weight of the crew cab. If aired at the placard pressure of 35psi, both tires will be over-rated for the GVWR of the vehicle, and should provide about the same ride as your Rugged Trails. I have been using this size BFG AT D range on my F-150 for about 3 years now with no noticeable signs of wear really, I rarely air above 38 pounds because I rarely carry a load in it, and the F-150 weighs 4,900 pounds without a load, which I believe is heavier than the Nissan. I don't find the ride harsh at all. Actually it is somewhat plush for a truck, and quiet as well.
mauricio_28
Adventurer
Ditto here. Just installed a set of E-rated Pirelli Scorpion ATR LTs on my Navara. At 40psi and below, they are not at all harsh. Yes, they are more tire than is warranted by the car's weight, but that excess sturdiness translates into increased durability and peace of mind on "expeditions".
Last edited:
Guinness44
Adventurer
D, E: The E tire is rated to run more psi, for more loadrating. If you air them both lets say 35 psi, they probably both "carry" the same load at that pressure. (Some tirestores have charts, just ask).
I got this chart (sorry wrong size) but to give an idea:
37 x 12.5 R 17/D 124 Q
35 psi = 2245 lbs
40 psi = 2465 lbs
45 psi = 2680 lbs
50 psi = 2910 lbs
55 psi = 3085 lbs.(max psi, load)
If you travel offhighway, airing down also helps with puncture resistance, as the tire "folds" over a sharp rock, instead getting poaked into.
I got this chart (sorry wrong size) but to give an idea:
37 x 12.5 R 17/D 124 Q
35 psi = 2245 lbs
40 psi = 2465 lbs
45 psi = 2680 lbs
50 psi = 2910 lbs
55 psi = 3085 lbs.(max psi, load)
If you travel offhighway, airing down also helps with puncture resistance, as the tire "folds" over a sharp rock, instead getting poaked into.
For LT265/75/16 at 35psi, the load is 1,910 per tire. (source: Toyo). At that pressure value, the tires are both rated in the "C" range of use, even though either would be "D" or "E" in fact. I would also expect either a D or E to carry identical weight for a given pressure as long as the pressure in question is at or below the stated maximum pressure and load for the "D" range tire. That is, the load ranges of the D and E overlap in part, but the E ranges higher in both pressures and loads. For those pressures that are common to both tires, the load should be about the same if not exactly the same. The tire load chart from Toyo makes no differentiation, and I expect that there is none to make.
What we run into here is that we are using for a light duty truck tire that is designed to serve a one to two ton utility truck of medium to heavy duty, which explains why load charts for these tires also show pressures and loads for the tire used as a dual, not just as a single tire. The E range tire can be used on the back of a 14,000 GVWR dually, while the standard P-metrics can't. There is no problem inherent in using such a highly rated tire for light duty.
An extreme example in this instance would be my use of the BFG AT in LT235/85/16 (E-range) on my 1968 CJ5, which only weighs around 2,500 pounds. The lowest pressure/load entry I can find for this tire size is 1,700 pounds at 35 psi. Since for the CJ5 each tire needs to carry only 625 more or less, you would have to say the tire is over-rated for the vehicle. But there are no light duty tires in this size range, so we use what there is, and air down accordingly. I would expect that my vehicle would need no more than 18 to 20 pounds of pressure with these tires, but as this is really far down in the load range for these tires, there may be an economy of scale factor to take into account (minimum structural highway pressure), and I will need to test the tires for contact and driving habits to know where to air them to. The nice part is that it is very unlikely that I will break them in the desert. Off road, my only concern will be keeping them on the rims at low pressures.
What we run into here is that we are using for a light duty truck tire that is designed to serve a one to two ton utility truck of medium to heavy duty, which explains why load charts for these tires also show pressures and loads for the tire used as a dual, not just as a single tire. The E range tire can be used on the back of a 14,000 GVWR dually, while the standard P-metrics can't. There is no problem inherent in using such a highly rated tire for light duty.
An extreme example in this instance would be my use of the BFG AT in LT235/85/16 (E-range) on my 1968 CJ5, which only weighs around 2,500 pounds. The lowest pressure/load entry I can find for this tire size is 1,700 pounds at 35 psi. Since for the CJ5 each tire needs to carry only 625 more or less, you would have to say the tire is over-rated for the vehicle. But there are no light duty tires in this size range, so we use what there is, and air down accordingly. I would expect that my vehicle would need no more than 18 to 20 pounds of pressure with these tires, but as this is really far down in the load range for these tires, there may be an economy of scale factor to take into account (minimum structural highway pressure), and I will need to test the tires for contact and driving habits to know where to air them to. The nice part is that it is very unlikely that I will break them in the desert. Off road, my only concern will be keeping them on the rims at low pressures.
Last edited:
Comments from thread originator
Based on the discussion, it would appear that, properly inflated, both the D- or E-rated tire can easily carry my expedition load, which I estimate to be around 1100 to 1200 pounds (people, hiking/camping/personal travel gear, recovery equipment, 8 gal+ water (minimum), fuel in fuel tank plus 5-10 gal extra fuel in containers, Shrockworks rock sliders and full skidplates, three large storage boxes filling bed). I do not appreciably exceed the speed limit on roads except temporarily when passing, and I slow down and air-down off-road and on backcountry/primitve roads. Sharp angular basalt and granite rocks embedded in or laying directly on stretches of bedrock or severely compacted soil appear to be the predominant deleterious situation that I encounter. Mud and snow are much less of an issue for me.
My impresssion from the available literature is that both ratings of BFG All-Terrain T/A KO tires have identical Triguard sidewalls, and that they differ by:
D-rated: S speed rating, dual-compound rubber allowing M&S rating, deeper tread blocks (16/32"), thinner belt (5-ply) beneath tread blocks, overall diameter of 31.7";
E-rated: Q speed rating, single-compound perhaps harder rubber (?) that precludes M&S rating, shallower tread blocks (15/32"), thicker belt (7-ply) beneath tread blocks, overall diameter of 31.8" reflecting the thicker belt.
My interpretation is that both T/A KO tires should give a firmer ride than the OEM BFG Rugged Trails because of the street-orientation of the latter tires and the requirement for higher pressure in LT tires for equivalent load-bearing capacity. The E-rated tire may be slightly firmer at an equivalent inflation pressure as the D-rated tire (although sidewall flex should be similar?) with perhaps somewhat greater protection against perforation through the tread. and possibly greater treadlife because of the harder rubber. Does this sound right to you experienced expedition off-roaders?
I apologize for focusing on such small details but feel that this sort of information may be useful to other readers as well as to me.
Based on the discussion, it would appear that, properly inflated, both the D- or E-rated tire can easily carry my expedition load, which I estimate to be around 1100 to 1200 pounds (people, hiking/camping/personal travel gear, recovery equipment, 8 gal+ water (minimum), fuel in fuel tank plus 5-10 gal extra fuel in containers, Shrockworks rock sliders and full skidplates, three large storage boxes filling bed). I do not appreciably exceed the speed limit on roads except temporarily when passing, and I slow down and air-down off-road and on backcountry/primitve roads. Sharp angular basalt and granite rocks embedded in or laying directly on stretches of bedrock or severely compacted soil appear to be the predominant deleterious situation that I encounter. Mud and snow are much less of an issue for me.
My impresssion from the available literature is that both ratings of BFG All-Terrain T/A KO tires have identical Triguard sidewalls, and that they differ by:
D-rated: S speed rating, dual-compound rubber allowing M&S rating, deeper tread blocks (16/32"), thinner belt (5-ply) beneath tread blocks, overall diameter of 31.7";
E-rated: Q speed rating, single-compound perhaps harder rubber (?) that precludes M&S rating, shallower tread blocks (15/32"), thicker belt (7-ply) beneath tread blocks, overall diameter of 31.8" reflecting the thicker belt.
My interpretation is that both T/A KO tires should give a firmer ride than the OEM BFG Rugged Trails because of the street-orientation of the latter tires and the requirement for higher pressure in LT tires for equivalent load-bearing capacity. The E-rated tire may be slightly firmer at an equivalent inflation pressure as the D-rated tire (although sidewall flex should be similar?) with perhaps somewhat greater protection against perforation through the tread. and possibly greater treadlife because of the harder rubber. Does this sound right to you experienced expedition off-roaders?
I apologize for focusing on such small details but feel that this sort of information may be useful to other readers as well as to me.
I believe your impressions are correct. As for ride quality, I don't know of a standard for testing. I suppose it would have to do with sidewall and belt deflection in response to a known force at a given pressure and load, all of which sounds like a technical test facility would be needed. Left to our own devices, how a vehicle rides is subjective, and the differences could be very subtle. I would say run them and see if you like them.
Correct about the rubber content having to do with BFG not recommending the E tire for severe snow. Not they don't work in snow, but that there is a measurable difference in tire response in cold weather with cryophilic rubber compounds. Winter blend rubber compound also tends not to wear as well in summer and on abrasive roads as a rule, but so far I have had very good service from D rated BFG AT's in the same size as you are contemplating, and I could not say that they are wearing any faster due to the dual compound rubber. Driving on these tires so far includes a loaded trip down the Alcan in spring weather (no snow dry roads), so they have around 8,000 or 10,000 miles and you can still see the molding tits on the tread blocks.
Correct about the rubber content having to do with BFG not recommending the E tire for severe snow. Not they don't work in snow, but that there is a measurable difference in tire response in cold weather with cryophilic rubber compounds. Winter blend rubber compound also tends not to wear as well in summer and on abrasive roads as a rule, but so far I have had very good service from D rated BFG AT's in the same size as you are contemplating, and I could not say that they are wearing any faster due to the dual compound rubber. Driving on these tires so far includes a loaded trip down the Alcan in spring weather (no snow dry roads), so they have around 8,000 or 10,000 miles and you can still see the molding tits on the tread blocks.
Keep in mind about using LT tires over P-metric, you will need to increase your tire's air pressure for the same load, i.e. a P-metric tire might require 35 psi at 2500 lbs load while an LT tire could require 45 psi. So, your ride will get more harsh. Running a lower tire pressure on an LT tire will give you a better ride but could cause the tire to overheat and running an LT tire underinflated will not offer any benefit of being "heavy duty."
Cary over at mud wrote a good post on this:
http://forum.ih8mud.com/80-series-tech/111671-tire-inflation-ultimate-answer.html
Cary over at mud wrote a good post on this:
http://forum.ih8mud.com/80-series-tech/111671-tire-inflation-ultimate-answer.html
The observation is true only when discussing identical loads. Since none of us is running a 10,000 truck, we don't need to pressurize the tire to handle 2,500 pounds per tire. The relationship between P-metrics and LT's remains the same, but it is simply not true that one "needs" to run 45psi in an LT if we were running 35psi in a P-metric if 35psi in the P-metric was not required to start with.
Running underinflated tires does generate heat due to increased flexion in the tread and sidewall. But it is not necessary to assume that reducing inflation pressure to compensate for light loads will generate excessive heat. Example: today I inflated my LT235/85/16 BFG AT's to 30psi front and 28psi rear on my CJ-5, then ran down the mountain into town on the county blacktop at moderate highway speeds, 35 to 55mph. Turned around and drove back, then checked the tire temperatures with a digital IR reader. Ambient temperature here at the time was 84 degrees. After the 14 mile run on the blacktop, the sidewalls of the front tires were 83 degrees, one degree less than ambient, and the rears were 94 degrees, 10 more than ambient. Tread temperatures in the center of contact were 101 degrees on all 4 tires.
I can't explain why the front tires would actually have less than ambient temperatures in the carcass, and will have to repeat the experiment (possibly they were not outside long enough to reach ambient temperature to start with). Nor do I yet know why the carcass temperatures would be different by 10 degrees unless my assumption about weight distribution is incorrect, or because the driven wheels get more action. Having a locker in the rear might also contribute to tire scuffing, which could cause slightly higher temperatures in the rear.
Point is that although the tires are E range tires and were inflated to 30psi or less, they did not overheat. Actually, they didn't heat all that much at all. I would not consider a 10 degree rise in tire temperature abnormal for any vehicle driven on pavement.
I also watched for tire deflection in corners, and took some of the mountain roads at a stiff pace to see if the tires would act as if they were underinflated. They didn't appear to be abnormal at all. I observed very little tire roll during hard corners, and the front tires are easy to see from an open early CJ, so I don't feel that the tire pressures are under a safe working pressure. In fact, I intend to try lowering pressures a bit, as I am not getting full contact on the tread. Close, but not full contact.
Final observation - the ride on these E range tires is smooth and plush, not harsh at all, even on my lightweight car. No doubt if I ran them up to 45psi as some have suggested, it would ride like a farm wagon, but then at 45psi they would have sufficient pressure to support 2,030 pounds per tire according to the TRA load capacity charts, and the vehicle weighs only about 2,500 pounds tops, so 45psi would be far too much anyway.
Running underinflated tires does generate heat due to increased flexion in the tread and sidewall. But it is not necessary to assume that reducing inflation pressure to compensate for light loads will generate excessive heat. Example: today I inflated my LT235/85/16 BFG AT's to 30psi front and 28psi rear on my CJ-5, then ran down the mountain into town on the county blacktop at moderate highway speeds, 35 to 55mph. Turned around and drove back, then checked the tire temperatures with a digital IR reader. Ambient temperature here at the time was 84 degrees. After the 14 mile run on the blacktop, the sidewalls of the front tires were 83 degrees, one degree less than ambient, and the rears were 94 degrees, 10 more than ambient. Tread temperatures in the center of contact were 101 degrees on all 4 tires.
I can't explain why the front tires would actually have less than ambient temperatures in the carcass, and will have to repeat the experiment (possibly they were not outside long enough to reach ambient temperature to start with). Nor do I yet know why the carcass temperatures would be different by 10 degrees unless my assumption about weight distribution is incorrect, or because the driven wheels get more action. Having a locker in the rear might also contribute to tire scuffing, which could cause slightly higher temperatures in the rear.
Point is that although the tires are E range tires and were inflated to 30psi or less, they did not overheat. Actually, they didn't heat all that much at all. I would not consider a 10 degree rise in tire temperature abnormal for any vehicle driven on pavement.
I also watched for tire deflection in corners, and took some of the mountain roads at a stiff pace to see if the tires would act as if they were underinflated. They didn't appear to be abnormal at all. I observed very little tire roll during hard corners, and the front tires are easy to see from an open early CJ, so I don't feel that the tire pressures are under a safe working pressure. In fact, I intend to try lowering pressures a bit, as I am not getting full contact on the tread. Close, but not full contact.
Final observation - the ride on these E range tires is smooth and plush, not harsh at all, even on my lightweight car. No doubt if I ran them up to 45psi as some have suggested, it would ride like a farm wagon, but then at 45psi they would have sufficient pressure to support 2,030 pounds per tire according to the TRA load capacity charts, and the vehicle weighs only about 2,500 pounds tops, so 45psi would be far too much anyway.
Last edited:
Guinness44
Adventurer
Dont forget to watch the rims max. pressure rating also.
We had a lifted TJ and run 285/75/16 tires. The same tire as the Cummins Ram. We really had to guess, and just to town and back (no freeway) we left them at 18, to run farther we went to 22/24. The Ram with the heavy nose is at 55 front, 40 rear (or 45 when more load is carried). I found that not all brands are totally the same. Hopefully your tirestore has a chart for the tire you buy.
We also use a infrared temp gun to check on the "guts" when something feels wrong, or were not sure. (tires, brakes, TCase, tranny, diffs, hubs.......)
We had a lifted TJ and run 285/75/16 tires. The same tire as the Cummins Ram. We really had to guess, and just to town and back (no freeway) we left them at 18, to run farther we went to 22/24. The Ram with the heavy nose is at 55 front, 40 rear (or 45 when more load is carried). I found that not all brands are totally the same. Hopefully your tirestore has a chart for the tire you buy.
We also use a infrared temp gun to check on the "guts" when something feels wrong, or were not sure. (tires, brakes, TCase, tranny, diffs, hubs.......)
madizell, my E load Toyo MT's at 45psi are not comfortable but at 35-38psi, it is fine. So, actually, I am hoping you are correct. But did you look at the Nitto link:
http://www.nittotire.com/assets/saf...ht Trucks.pdf#search="p-metric lt load range"
From their tire temperature pictures, they make it seem like a 10 degree difference would be a big deal. They went from ~104 degrees (green) at 50 psi to ~112 degrees (red) at 30 psi but they do not say at what load. The temperature they were most concerned with were the main plies under the rubber tread. Would your IR gun be able to measure that?
I can't think of any reason why they would try to mislead as it is a tech/safety article and nothing to do with tire sales.
http://www.nittotire.com/assets/saf...ht Trucks.pdf#search="p-metric lt load range"
From their tire temperature pictures, they make it seem like a 10 degree difference would be a big deal. They went from ~104 degrees (green) at 50 psi to ~112 degrees (red) at 30 psi but they do not say at what load. The temperature they were most concerned with were the main plies under the rubber tread. Would your IR gun be able to measure that?
I can't think of any reason why they would try to mislead as it is a tech/safety article and nothing to do with tire sales.
dieselcruiserhead
16 Years on ExPo. Whoa!!
There is a famous particular road in central Nevada that is nutorious for killing tires. It is a dirt road and for some reason the rock it is built out of and that surrounds the area is quite sharp. What it comes down to here is simply keeping your speed down though the road is smooth graded (which is a bummer). The roads kick off the front tires and kick in to the rear tgires and kill sidewalls. There are two mines on the road and truckers with 10-12 miles that need to routinely go out there also experience it heavily, many have been stranded from more than one or two tire failures beyond their spares.
So, this is a unique situation, but it appears that load rating has little to do with tire punchures (particularly between D and E rating), it is largely related to velocity of those rocks and nothing really potentially stopping it (other than simply slowing down). Secondly, if D will do weight rating wise (you really only need D or E for a heavy truck). In regular wheeling scenarios I think either option would be fine in either situation.
Just my $.02...
So, this is a unique situation, but it appears that load rating has little to do with tire punchures (particularly between D and E rating), it is largely related to velocity of those rocks and nothing really potentially stopping it (other than simply slowing down). Secondly, if D will do weight rating wise (you really only need D or E for a heavy truck). In regular wheeling scenarios I think either option would be fine in either situation.
Just my $.02...