What have you done to your 5 ton this week?

a truck with dual tires weighs more than a truck with singles on all M939 models except a 923 or 925 in which case the A1 trucks weigh more than the A0s. Pretty screwed up chart.

An 809 series truck runs better IMO with dual 1100s on it. Maybe 1200s if you could get them. Super singles are ok but eh they have their drawbacks. You have one flat you are stuck. I wouldnt even think about going to 1600s on an NHC250 truck cause they just don't like all the weight. Tires are 330 plus whatever weight in the choice of wheel you want to run. Plus on an 809 series truck with 1600s if you chose to run HEMTT wheels you would have to install longer studs or get the recessed lug nut which are both cost consuming.

74M35A2 said:

Ummmm, nothing:

View attachment 754770

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I did the same thing with my truck

75%+ tread Michelin XL 14.00R20, on combat wheel, with bead lock, NOT runflat.

Eventually I would like to go to 395s like Toby to gain a little flotation, tire capacity, and hopefully a little bit of fully loaded starting torque, then crank the governor up to get back to 70mph cruise speed.

Will first see how it goes after I get a few issues resolved, pyro added, and then start monkeying with the pump and maybe timing...

simp5782 said:

a truck with dual tires weighs more than a truck with singles on all M939 models except a 923 or 925 in which case the A1 trucks weigh more than the A0s. Pretty screwed up chart.

An 809 series truck runs better IMO with dual 1100s on it. Maybe 1200s if you could get them. Super singles are ok but eh they have their drawbacks. You have one flat you are stuck. I wouldnt even think about going to 1600s on an NHC250 truck cause they just don't like all the weight. Tires are 330 plus whatever weight in the choice of wheel you want to run. Plus on an 809 series truck with 1600s if you chose to run HEMTT wheels you would have to install longer studs or get the recessed lug nut which are both cost consuming.

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I'm more of a caretaker owner than a tweaker or modifier. I briefly entertained upgrading to 12.00X20 simply because they should fit and the M819 had them but decided that it was a lot of effort for zero gain. Mainly, I was just curious if everyone who jumps up to massive tires was aware of the tradeoffs, or if perhaps I was overestimating the effect of larger tires and wheels.

I was recently informed that NDT's don't have a very long service life on pavement which is another reason I've been pondering tire choices. I know about the driving performance of NDT's on pavement but I didn't consider that they would wear faster.

Jbulach said:

View attachment 75477775%+ tread Michelin XL 14.00R20, on combat wheel, with bead lock, NOT runflat.

Eventually I would like to go to 395s like Toby to gain a little flotation, tire capacity, and hopefully a little bit of fully loaded starting torque, then crank the governor up to get back to 70mph cruise speed.

Will first see how it goes after I get a few issues resolved, pyro added, and then start monkeying with the pump and maybe timing...

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Weird, I tried to hit the "Thanks" button instead of wasting a post, but it's not visible in your post. So, 400# for that mounted tire.

simp5782 said:

a truck with dual tires weighs more than a truck with singles on all M939 models except a 923 or 925 in which case the A1 trucks weigh more than the A0s. Pretty screwed up chart.

An 809 series truck runs better IMO with dual 1100s on it. Maybe 1200s if you could get them. Super singles are ok but eh they have their drawbacks. You have one flat you are stuck. I wouldnt even think about going to 1600s on an NHC250 truck cause they just don't like all the weight. Tires are 330 plus whatever weight in the choice of wheel you want to run. Plus on an 809 series truck with 1600s if you chose to run HEMTT wheels you would have to install longer studs or get the recessed lug nut which are both cost consuming.

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I liked the stability of the duals on the M817 dump truck. I would have liked the super single up front, but the 365 or 14.5 does not fit the combat rim (metric VS industrial). 12.00 would be nice, like you say Wes.

If I were not running a load a lot, the super single in 395 size on an 809 series would seem to be a nice setup. It's bigger than the 11.00 and not as tall as the 14.00.

Edit....please leave the 819 wrecker out of that SS recommendation for SS. I was thinking cargo.

I've been pondering this exact SS vs dual decision for my m813 for months. Many guys who went 16.00s mention lower stability or feeling like the tires are driving the truck. I hear 14.00s feel better and you can chain them up but they are about $200 more per tire and getting harder to acquire.

Do many guys regret going with 16.00s?

I did not like it on My 923 with the modified NHC250, 16spd and T1138 transfer case. Yes i had a double overdrive but i couldn't pull crap. I mean it was horrible trying to get into 16th with anything on my trailer. The 1600s last longer and are alot tougher than 1400s. they do not get eaten up by the road as much. I have a set of 1600s with around 60/65,000 miles on them on the rear. For most people they would last the life of the truck they will use it for aside from the dry rot.

Now with 500hp. It doesn't care what tires it has on it. and I only have a single .83 OD so i need the road speed from the bigger tires.

NTC-500....twice the output would be fun

Are 1400s out of production? What tires do the 7-tons come with?

US6x4 said:

NTC-500....twice the output would be fun

Are 1400s out of production? What tires do the 7-tons come with?

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Michelin hasn't made them since 2014. Goodyear does on SO.

7 tons run 16.00s. They also have 550 kitty's under the hood

US6x4 said:

I've been pondering this exact SS vs dual decision for my m813 for months. Many guys who went 16.00s mention lower stability or feeling like the tires are driving the truck. I hear 14.00s feel better and you can chain them up but they are about $200 more per tire and getting harder to acquire.

Do many guys regret going with 16.00s?

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Can't answer the 16.00, seems Wes did.

Here is an 813 with what I think are 395 Goodyears. Nice.

https://www.youtube.com/watch?v=4NPk0ATb2SI

7 tons (MTVR's) have a CAT C12 as delivered 425 hp and they run 16R20's. They don't notice the meat of the tires, they have more than enough power and could likely be turned up with a simple computer modification / tune.

The USMC upgraded their M809 series fleet to 1400 from the 1100s. I have one of those trucks and I did not take it for a long ride before I stripped it down, but it wasn't bad on the 5 mile test runs I did. M813RC has more experience with them then I do.

Here is something I didn't do to my 5 ton...

https://youtu.be/qEL3kyygSXw

US6x4 said:

I've been pondering this exact SS vs dual decision for my m813 for months. Many guys who went 16.00s mention lower stability or feeling like the tires are driving the truck. I hear 14.00s feel better and you can chain them up but they are about $200 more per tire and getting harder to acquire.

Do many guys regret going with 16.00s?

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16.00 are great for stability and ride smooth. They are much better than the 11.00's when I made the swap on my A0. I swapped 14's to 16's on my A2 and same result, more stable and ride smooth. I tow big with my A2 and no complaints or issues.

I have 14.00's on my 817 dump and hate them. Not very stable and a little to much tire with the 3rd to 4th jump on the manual trans. 16.00's would be too big and kill power even more unless swapping trans to a direct drive 5th. 11.00's are too skinny on front. 12.00's or 395 singles would be perfect. I haul lots of rock in my dump and would like to swap the 14's for 395's or 12.00 duals.

My top tire picks
16.00's or 395's on an 939 truck
12.00's or 395's on 809 series




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I'm surprised that going from 11.00 to 12.00 on an 809 series makes much difference. Interesting.

When you say 11's are too skinny on the front, how do you mean? You don't like the way it steers or...?

Ajax MD said:

I'm surprised that going from 11.00 to 12.00 on an 809 series makes much difference. Interesting.

When you say 11's are too skinny on the front, how do you mean? You don't like the way it steers or...?

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Yes. Some of my customers run 11R20s on the rear and a wide 425 65 22.5 on the front.

AjaxMD.... both the way it steers and the flotation. The reversed bud wheels make the stance with the center of the tire narrower and the 11.00 is thin compared to the SS tires, giving less contact area. They make a rut really easy. A combat rim with SS puts the center further out + has about twice the area in contact as an 11.00. I had the feeling that (loaded 817) I could roll the steer tire off the bud rim while turning on pavement (never did).

On a wrecker, I'd stay with the 11.00 Goodyear radials (not NDT) on the rear and change the front to what Wes recommends above (425 65 r22.5).

Gotcha. Visually, the front just looks "smaller" to me but I think that's a visual trick of the front being singles.

New question: I want to transport 10, mounted, 11.00X20 NDTs. An 11.00X20 is 41" tall. How *wide* is a mounted, inflated 11.00X20 NDT?

Also- How accurate is my weight guess at 200 lbs. per mounted tire on standard, M809 series steel wheels?

XM820 w/Hyd. tailgate. Got it closed up and ready to ship it out after removing fifteen 1400 and 1600 tires and nine HEMTT NOS Wheels plus two big block Chevy heads. Just glad the wires/rigging was working or I would have gotten it closed up.