Need help understanding all the Humvee tire choices

[Enforced_Leo44]

I currently own a 1988 M998, 6.2L 3 speeds, the original deal, with some 36s and 8 bolt rims (I think I also have the original magnesium run flat ring in them)
From what I understood, those are the bias ply tires, better for heavy loads but worse for every day use
Then there are the 37s, which are radial ply tires, which should be better for "standard" every day use, which is what I'm looking for

Now, the question is, can put the 37s on my 8 bolt rims? Or are those rims only for bias plys and I need to get 12 or 24 bolt rims?
Don't know if I'm overcomplicating things, but I can't find any definitive answer online, so here we are

Thanks in advance for the replies!

 

[Coug]

The 36" bias ply are lumpy until they warm up, so the first few miles of driving isn't exactly what you would call "smooth". After that through they are fine.
The 8 bolt rim is only rated for 25psi. I suppose if you were running your tires below that you would be okay, but I don't know of anyone that recommends it with the radial tires as it's too easy to forget the rim is rated so low, and if you overinflate you're asking for catastrophic results. So I'd say it's not recommended.

12 bolt rims are rated for 50psi, same as the MT tires, and the load range "D" MTR and Baja.

There are 2 versions of the 24 bolt rims. One has the bolts evenly spaced all around the rim, and the other has the bolts set more as pairs.
The 24 bolt evenly spaced are also only rated for 50psi, so load range "D" tires.
The 24 bolt paired bolt rims are rated for 65 PSI for the load range "E" Baja and MTR.

Unless you're running your truck VERY heavy, as in more than 14k lbs weight, you don't need the load range "E" equipment. You're better off without the load range E tires anyway as the stiffer sidewall makes for a harsher ride and don't flex as well aired down.

 

[Enforced_Leo44]

The 36" bias ply are lumpy until they warm up, so the first few miles of driving isn't exactly what you would call "smooth". After that through they are fine.
The 8 bolt rim is only rated for 25psi. I suppose if you were running your tires below that you would be okay, but I don't know of anyone that recommends it with the radial tires as it's too easy to forget the rim is rated so low, and if you overinflate you're asking for catastrophic results. So I'd say it's not recommended.

12 bolt rims are rated for 50psi, same as the MT tires, and the load range "D" MTR and Baja.

There are 2 versions of the 24 bolt rims. One has the bolts evenly spaced all around the rim, and the other has the bolts set more as pairs.
The 24 bolt evenly spaced are also only rated for 50psi, so load range "D" tires.
The 24 bolt paired bolt rims are rated for 65 PSI for the load range "E" Baja and MTR.

Unless you're running your truck VERY heavy, as in more than 14k lbs weight, you don't need the load range "E" equipment. You're better off without the load range E tires anyway as the stiffer sidewall makes for a harsher ride and don't flex as well aired down.

This gives quite a lot of answers so big thanks for that!

I definitely noticed the bumpy ride for the first few miles, and also a pretty significant wobble at around 30mph, if I go either faster or slower than 30mph the wobble completely disappears, both with cold or warm tires, so I guess that's a balancing issue

 

[Enforced_Leo44]

The 36" bias ply are lumpy until they warm up, so the first few miles of driving isn't exactly what you would call "smooth". After that through they are fine.
The 8 bolt rim is only rated for 25psi. I suppose if you were running your tires below that you would be okay, but I don't know of anyone that recommends it with the radial tires as it's too easy to forget the rim is rated so low, and if you overinflate you're asking for catastrophic results. So I'd say it's not recommended.

12 bolt rims are rated for 50psi, same as the MT tires, and the load range "D" MTR and Baja.

There are 2 versions of the 24 bolt rims. One has the bolts evenly spaced all around the rim, and the other has the bolts set more as pairs.
The 24 bolt evenly spaced are also only rated for 50psi, so load range "D" tires.
The 24 bolt paired bolt rims are rated for 65 PSI for the load range "E" Baja and MTR.

Unless you're running your truck VERY heavy, as in more than 14k lbs weight, you don't need the load range "E" equipment. You're better off without the load range E tires anyway as the stiffer sidewall makes for a harsher ride and don't flex as well aired down.

Also, another question that I forgot to add in the original post, can I use a inner tube? I have a spare set of new 36s bias that I wanna use, but I don't plan on re-installing the runflat and I don't have the o-rings that go between the two halves of the rim

 

[Coug]

Also, another question that I forgot to add in the original post, can I use a inner tube? I have a spare set of new 36s bias that I wanna use, but I don't plan on re-installing the runflat and I don't have the o-rings that go between the two halves of the rim

That I have no idea. The main concern I'd have is the inner tube valve stem lining up properly in the same location as the inflation valve location on the rim. I find it unlikely that you'll get a perfect match, which would cause strain on the inner tube, leading to premature failure.
You will probably be okay if you keep them at max recommended inflation even without the run flat beadlock assembly installed, though if it's a set of the military 36" bias tires, they might be unused, but as they stopped making them over 3 decades ago they will be old tires and not sure if I'd trust them for road use.

 

[Enforced_Leo44]

That I have no idea. The main concern I'd have is the inner tube valve stem lining up properly in the same location as the inflation valve location on the rim. I find it unlikely that you'll get a perfect match, which would cause strain on the inner tube, leading to premature failure.
You will probably be okay if you keep them at max recommended inflation even without the run flat beadlock assembly installed, though if it's a set of the military 36" bias tires, they might be unused, but as they stopped making them over 3 decades ago they will be old tires and not sure if I'd trust them for road use.

I see the concern... I'll need to find a set of o-rings for the rims if I'm not gonna go for the inner tube, and, being in Italy, it's gonna cost me about 150 bucks for said 4 o-rings

 

[MarkM]

I always had a saftey concern removing the run flats with the 37s. If cruising down the road and having a blowout without the run flats that wheel is going to abruptly drop over eight inches. That is a tad concerning.

Mark

 

[mgFray]

I see the concern... I'll need to find a set of o-rings for the rims if I'm not gonna go for the inner tube, and, being in Italy, it's gonna cost me about 150 bucks for said 4 o-rings

From a safety perspective, I'd recommend ordering a couple sets of the wheel o-rings and ship them in. It's a small price to pay to ensure you have the wheels assembled properly, and they won't lose air (and are thus safe to drive on the road.)

As for the inserts, I removed the run-flats from mine, but I did put the PVC bead locks in though. I have a concern that if I were to puncture a tire, I want it to ride on the rubber (even if it destroys it) long enough for me to get off the road. Without an inner beadlock, you run the real risk of the tire coming off the rim due to the way the rims are formed. (My personal belief, others may disagree with my assessment.)

I'm not concerned with a "blow-out" at speed, but I am concerned about a slow leak.

 

[springer1981]

The run flats also supply a bead lock. The stock rims don't have regular beads on them so if you remove the run flat you need to get aftermarket bead locks (large PVC spacer) so the beads will seal. A tube won't work for that. Here is the bead lock https://www.ebay.com/itm/134350481890

 

[Coug]

There is some debate about the necessity of the bead lock.

There is nothing inherently different about the military 16.5" HMMWV rim bead seating area compared to any other 16.5" rim. As long as you keep the tires inflated properly, the tire will stay on the rim.

The issues mostly come in when people don't check their tire pressure regularly, or try deflating the tire to drive off road. At lower pressures, there is a greater chance of the bead coming off of the rim compared to a modern wheel bead design.

 

[Retiredwarhorses]

There is some debate about the necessity of the bead lock.

There is nothing inherently different about the military 16.5" HMMWV rim bead seating area compared to any other 16.5" rim. As long as you keep the tires inflated properly, the tire will stay on the rim.

The issues mostly come in when people don't check their tire pressure regularly, or try deflating the tire to drive off road. At lower pressures, there is a greater chance of the bead coming off of the rim compared to a modern wheel bead design.

the split rim is entirely different than a standard rim from a solid rim, the shoulder of the split rim has a soft shoulder that is kept on via the bead lock, in this case…the-run flat.
There is Tire TM that discusses all the various rim types.

 

[Retiredwarhorses]

Check out TM 9-2610-200-14

 

[Enforced_Leo44]

There is some debate about the necessity of the bead lock.

There is nothing inherently different about the military 16.5" HMMWV rim bead seating area compared to any other 16.5" rim. As long as you keep the tires inflated properly, the tire will stay on the rim.

The issues mostly come in when people don't check their tire pressure regularly, or try deflating the tire to drive off road. At lower pressures, there is a greater chance of the bead coming off of the rim compared to a modern wheel bead design.

Oh damn I didn't see this reply and made another post about this
As you said, there's a major debate over the need for runflat/beadlocks in Humvees, and I can't really decide on what to do


I don't think my Humvee will ever see heavy off-road or cross any trail that requires to air down a tire, but I also don't know if keeping them at a proper pressure (~20psi), would completely eliminate the risk of the tire coming off the rim or breaking the bead while driving

 

[Coug]

Oh damn I didn't see this reply and made another post about this
As you said, there's a major debate over the need for runflat/beadlocks in Humvees, and I can't really decide on what to do


I don't think my Humvee will ever see heavy off-road or cross any trail that requires to air down a tire, but I also don't know if keeping them at a proper pressure (~20psi), would completely eliminate the risk of the tire coming off the rim or breaking the bead while driving

no worries; we try to have as few threads started as possible; especially when it's the same basic issue/discussion.
I did reply on your new one, but don't be surprised if a moderator moves it over into this one.

 

[Enforced_Leo44]

no worries; we try to have as few threads started as possible; especially when it's the same basic issue/discussion.
I did reply on your new one, but don't be surprised if a moderator moves it over into this one.

They did delete the thread without moving the reply, so if you could re-write it here I’d be glad!

 

[Coug]

My personal opinion is it's better to have the bead lock run flat installed. It's a bit of extra work, but adds a lot of safety in case of tire issue while driving. Especially because you're talking about installing tires that the military stopped using 3 decades ago, so even if they are "new" condition, they're still old.
The only reason I would use them is if you are keeping this truck as historically accurate as possible, and only using it for special events (parades and display) and not for everyday driving.

if you aren't going to use the runflat/beadlock, you need to take extra care checking the tires every time before you drive to make sure the pressures are good. All it takes is one small leak while driving for the tire to get to low pressure, then hitting a pothole or bump hard enough to shift the tire.

The question is, if you already have all the runflat/beadlock stuff to install into the new tires, is the risk of a catastrophic tire failure and the possible resulting accident at whatever speed this happens at worth the amount of time and effort saved by not installing them?

My primary suggestion is to only run these wheels/tires until you can afford to replace them with the newer versions. Even with runflats and beadlocks in my radial tires, I never aired down below 30psi even off road because of their age. My tires were 15 years old and my truck is typically around 7k lbs or more with all the gear I keep in it and other stuff I've done to it. I recently replaced them all because even with 30psi they were starting to show issues in them. I can only imagine 30 year old tires being worse.