New Tires For Big Blue

[85lebaront2]

😈. Well here I am, poking the sleeping tiger again

Gary I think that GVWR's from the factory are cooked up to put your vehicle just at the 8,600# emissions cutoff, or in Bills case right at 10k where one pound heavier Darth would be a whole 'nother class of vehicle.

I picked up on the linear tire pressure formula and ran with it to some absurd extreme.

I certainly shouldn't have taken their example number and applied it to your tires and fringe off-road use case.

Bill has the slightly narrower tires less likely to pinch a rock between the duallies, but that narrower sectional profile wants to roll over even more.

Steer axles are going to be affected by that, and by how much weight is behind them.

You need them to track.

I'll bet that Blue's wider rims and different factory tires are why he has a lower recommended front tire pressure.

Tires are pretty complex.

Street tires sold to the general public operate in many dynamic environments and no one wants to be Firestone in the '90's

.

BB's rims (stock) are the same diameter/width as Darth's, 16X6 K which tells me that as long as the rear duals don't (a) rub the sidewalls loaded or (b) get rocks wedged between them I could go to wider tires.

On the 215/85R16 LR D, I could crawl under Darth and look at the spare sidewall.

 

[ArdWrknTrk]

BB's rims (stock) are the same diameter/width as Darth's, 16X6 K which tells me that as long as the rear duals don't (a) rub the sidewalls loaded or (b) get rocks wedged between them I could go to wider tires.

On the 215/85R16 LR D, I could crawl under Darth and look at the spare sidewall.

But would you want the bigger contact patch of a 235 width tire?

Darth and his ilk were designed almost exclusively to tow heavy loads.

This might make the steering slightly heavier but it would certainly change the applied pressure of the rear contact patch(es)

You have much more experience driving one but my limited time makes me feel like traction is very marginal when unloaded.

Is spreading that same weight across three more inches of width going to help?

 

[Nothing Special]

BB's rims (stock) are the same diameter/width as Darth's, 16X6 K which tells me that as long as the rear duals don't (a) rub the sidewalls loaded or (b) get rocks wedged between them I could go to wider tires...

"They say" (but who are they and what do they know?) that 235s will rub sidewalls when mounted as duals on stock rims without spacers. And it's not as easy as mounting them up and looking. you already mentioned the extra bulge when loaded. You also need to factor in higher dynamic loads as you hit bumps and take corners. You might also want to factor in a tire being under-inflated.

[Gary Lewis]

BB's rims (stock) are the same diameter/width as Darth's, 16X6 K which tells me that as long as the rear duals don't (a) rub the sidewalls loaded or (b) get rocks wedged between them I could go to wider tires...

"They say" (but who are they and what do they know?) that 235s will rub sidewalls when mounted as duals on stock rims without spacers. And it's not as easy as mounting them up and looking. you already mentioned the extra bulge when loaded. You also need to factor in higher dynamic loads as you hit bumps and take corners. You might also want to factor in a tire being under-inflated.

Wow! I spent several hours working on Big Blue and y'all had quite the conversation. I've read all of it, but it appears that there's not much to say or ask at this point.

But if I get the seat situation nailed down, or maybe bolted down, then I can take the truck in to get new tires.

[Rusty_S85]

Load rating and load index are not the same. (see above)

Yes, I would, and MANY other people do too.

See that original quote where a D rated tire carries more weight at less inflation pressure than an E rated tire.

If you want a compliant ride you should get a tire with a more compliant carcass (within reason!)

Also consider that tire pressure is essentially an undamped spring that supports your entire vehicle.

The ideal gas law (shown above) explains the relationship between pressure, volume and heat.

Load Range is a classification that describes how much weight a tire can carry. Same thing as Load rating as youa re calling it, its based on an older measurement called ply rating. The KO2s I run are a C1 load range which is 6 ply rating with a max load carrying air pressure of 50 psi.

Load Index is another way to describe in more detail a tires carrying capacity, in the case of the KO2s I run it has a load index of 109 which translates into 2,271 lbs carrying capacity.

Yes they are not the same but you keep talking about load rating which I believe you mean Load Range and talking about pounds it can carry yet the Load Range is just the rating of the tire, ply wise and pressure wise and has nothing to do with the weight carrying capacity of the tire. That falls under the Load Index.

As far as ride quality goes, you want to get as low a ply tire that can carry your load with a cushion for safety. Sure you can go with a 10 ply tire and run lower pressure but that 10 ply tire is a stiffer side wall than a 6 ply tire hence why you can run lower pressure. It would negate the purpose of seeking a softer ride to go with a stiffer side wall tire with the goal of running less air pressure to achieve the same carrying capacity. I am running 6 ply tires at 35 psi and the carrying capacity at 35 psi exceeds the total gvw of my truck by a good 1,100 lbs which means I would never hit that weight on my truck without doing serious damage to not only my suspension but over loading the trucks designed capacity. So the belief that you will get better ride quality with a 11 ply sidewall tire running at 35 psi vs a 6 ply sidewall tire running at 35 psi is laughable. Sure the 11 ply will carry more weight at 35 psi than the 6 ply but you dont need that carrying capacity if the 6 ply at 35 psi already exceeds the design capacity of the truck by 1,000 lbs.

[Gary Lewis]

Load rating and load index are not the same. (see above)

Yes, I would, and MANY other people do too.

See that original quote where a D rated tire carries more weight at less inflation pressure than an E rated tire.

If you want a compliant ride you should get a tire with a more compliant carcass (within reason!)

Also consider that tire pressure is essentially an undamped spring that supports your entire vehicle.

The ideal gas law (shown above) explains the relationship between pressure, volume and heat.

Load Range is a classification that describes how much weight a tire can carry. Same thing as Load rating as youa re calling it, its based on an older measurement called ply rating. The KO2s I run are a C1 load range which is 6 ply rating with a max load carrying air pressure of 50 psi.

Load Index is another way to describe in more detail a tires carrying capacity, in the case of the KO2s I run it has a load index of 109 which translates into 2,271 lbs carrying capacity.

Yes they are not the same but you keep talking about load rating which I believe you mean Load Range and talking about pounds it can carry yet the Load Range is just the rating of the tire, ply wise and pressure wise and has nothing to do with the weight carrying capacity of the tire. That falls under the Load Index.

As far as ride quality goes, you want to get as low a ply tire that can carry your load with a cushion for safety. Sure you can go with a 10 ply tire and run lower pressure but that 10 ply tire is a stiffer side wall than a 6 ply tire hence why you can run lower pressure. It would negate the purpose of seeking a softer ride to go with a stiffer side wall tire with the goal of running less air pressure to achieve the same carrying capacity. I am running 6 ply tires at 35 psi and the carrying capacity at 35 psi exceeds the total gvw of my truck by a good 1,100 lbs which means I would never hit that weight on my truck without doing serious damage to not only my suspension but over loading the trucks designed capacity. So the belief that you will get better ride quality with a 11 ply sidewall tire running at 35 psi vs a 6 ply sidewall tire running at 35 psi is laughable. Sure the 11 ply will carry more weight at 35 psi than the 6 ply but you dont need that carrying capacity if the 6 ply at 35 psi already exceeds the design capacity of the truck by 1,000 lbs.

I pulled the trigger on the Falken WildPeak A/T3W's today. The local tire company, Tate Boys, has them on order and expects them to come in on Monday. So I'm set up to take the truck in 1st thing on Tuesday.

Thanks for all the input. I really appreciate it and it certainly helped me think through things, including tire pressures. I'm planning on running much more pressure, but I don't know how much just yet. I've found a scale that is somewhat local where I can weigh the truck for $13 and then weigh just one axle for another $3. So I'm going to do that in order to have a better idea of what weight the tires are carrying, which will let me work out what the minimum pressure(s) should be.

[Rusty_S85]

I pulled the trigger on the Falken WildPeak A/T3W's today. The local tire company, Tate Boys, has them on order and expects them to come in on Monday. So I'm set up to take the truck in 1st thing on Tuesday.

Thanks for all the input. I really appreciate it and it certainly helped me think through things, including tire pressures. I'm planning on running much more pressure, but I don't know how much just yet. I've found a scale that is somewhat local where I can weigh the truck for $13 and then weigh just one axle for another $3. So I'm going to do that in order to have a better idea of what weight the tires are carrying, which will let me work out what the minimum pressure(s) should be.

Let us know how the weight aligns with the door tag. It should be considerably lower than the door tag unloaded. Its been a while since I did the scales on mine when I bought flagstone some 20 years ago but I seem to recall it was some where in the neighborhood of 3,800 - 4,000 lbs with a 5,250 gvw.

[Gary Lewis]

I pulled the trigger on the Falken WildPeak A/T3W's today. The local tire company, Tate Boys, has them on order and expects them to come in on Monday. So I'm set up to take the truck in 1st thing on Tuesday.

Thanks for all the input. I really appreciate it and it certainly helped me think through things, including tire pressures. I'm planning on running much more pressure, but I don't know how much just yet. I've found a scale that is somewhat local where I can weigh the truck for $13 and then weigh just one axle for another $3. So I'm going to do that in order to have a better idea of what weight the tires are carrying, which will let me work out what the minimum pressure(s) should be.

Let us know how the weight aligns with the door tag. It should be considerably lower than the door tag unloaded. Its been a while since I did the scales on mine when I bought flagstone some 20 years ago but I seem to recall it was some where in the neighborhood of 3,800 - 4,000 lbs with a 5,250 gvw.

I'll for sure come back with the weight of the truck awa each axle, plus what I decide to run for tire pressure.

[Gary Lewis]

I'll for sure come back with the weight of the truck awa each axle, plus what I decide to run for tire pressure.

Yippee!!!!!!!!!! The new tires are wonderful!!!

Compared to the old tires these Falken A/T3W's are dead silent. So far I've not heard them at all. In fact, I can now hear the exhaust slightly where before I couldn't. And they are so smooth. No balance issues and no flat spots like the ones which caused the old ones to jiggle the truck.

Speaking of balance, I watched the guy do that and the most weight it took was 2 oz on the outside and 2 oz on the inside - and he told the other guy to put that one on the RR. And the tire that took the least took .75 oz on the inside and none on the outside, so he put that tire on the LF. When I asked why he said they put the best balanced tire closest to the driver and the least farthest away.

As for the alignment, it was dead on. No adjustment needed whatsoever as the needles where right smack in the center of the recommended range. But the guy did say the steering box is a bit worn, so some day I'll put a Blue Top on.

They asked me what pressures I wanted to run and suggested 65 psi, but I said 60 front and rear. And on the drive down to the scales and back, probably 25 miles round trip, I could feel the bumps a little bit more, but nothing to worry about. In fact, the only downside is that there's a little less "feel" in the steering. But the truck rolls much easier, like when coming up to a stop, so I think I can trade feel for MPG.

As for the weight, with me out of the truck and the front tank at 1/2 and the rear full plus all the recovery gear:

Front: 3720 lbs 57%

Rear: 2840 lbs 43%

------------------------

Total: 6560 lbs

Going back to the lb/psi equation that says each psi can carry 47 lbs. So that says that the minimum inflation pressure for the front tires would be 40 psi, although when you add a driver and a passenger you could easily add 400 lbs to the truck. And then there's the extra equipment we'll be carrying, which weighs who knows how much. So we could easily add another 1000 lbs with passengers and equipment, for a total GVW of 7560. And with the 57/43 split that puts 4309 lbs on the front axle and requires at least 46 psi in the tires. But I don't know that the 57/43 ratio will hold so I think 50 psi is a better minimum - and 60 may actually be about right.

Anyway, I am really, REALLY thrilled with the new tires.

 

[JimJam300]

Gary, I'm glad you found yourself a good tire. I'll look into them myself when I get a chance.

However with so much discussion about the BF Goodrich KO2s I have to throw in my experience. They just didn't do enough for me. I had a set of 31" KO1s on a 90 Ranger and a set of 33" KO2s on a 00 4Runner. They did not clean out well in mud and they refused to grip on ice. Snow, dirt, and sand performance were acceptable. At work my vehicle is an 08 F-250 4x4 with Goodyear Wrangler Duratracs. They are a bit noisy but they do well in the mud and I haven't got stuck yet, fingers crossed. At this point I just don't believe in a compromise with tires. Either they're quiet and low rolling resistance or they are good off-road. That's just my opinion.