Tire pressure and balancing

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RockHillWill
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Tire pressure and balancing

Post by RockHillWill » Thu Dec 07, 2017 10:06 am

I'm just getting used to the Humvee in the road, its an M998. Current tire pressure is 25 PSI @ front and 30 PSI at rear. Rides like crap! Local motor pool guys are telling me put 50 PSI in both front and rear for civilian highway use. What are current owners thoughts? What is the preferred method(s) of balancing these tires. I currently have 12 bolt wheels with new Goodyear MT's, but will soon be switching to 24 bolt w/Baha's. Thanks!

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Re: Tire pressure and balancing

Post by DockRocker » Thu Dec 07, 2017 10:46 am

RockHillWill wrote:I'm just getting used to the Humvee in the road, its an M998. Current tire pressure is 25 PSI @ front and 30 PSI at rear. Rides like crap! Local motor pool guys are telling me put 50 PSI in both front and rear for civilian highway use. What are current owners thoughts? What is the preferred method(s) of balancing these tires. I currently have 12 bolt wheels with new Goodyear MT's, but will soon be switching to 24 bolt w/Baha's. Thanks!

If you think it rides like crap now wait until you put 50lbs in the tires!

Can you describe what “rides like crap” feels like to you? That would help with a diagnosis.

FYI these trucks are never going to ride good. They are always going to have a harsh ride especially over big bumps.



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Re: Tire pressure and balancing

Post by RockHillWill » Thu Dec 07, 2017 12:14 pm

I truthfully don't mind that 'it rides like crap', as that is one of the reasons that I like owning one. As it is now, I have three new tires and one very poor tire on the right front. The feel that I am concerned with is that at slow speed, about 15-20 MPH it feels like the left rear tire has a flat spot, or is out of round. At the same tire pressure, the poor RF tire looks as though it is low on air. The camber at the front wheels does not seem the same left to right, nor does the rear tires seem to have similar camber from side to side. I have read that there is toe in at the front, and toe out at the back, but the motor pool guys say that they set both the font and rear to straight ahead. I am reasonably familiar with setting toe in/out and caster/camber from the years in racing, but have no idea how these should feel. Even the pace cars ran well over 100 MPH. The steering seems to be tight and I am not experiencing any wandering.I do seem to feel that balance is an issue. In the stock cars, tire diameter from side to side caused many issues. What about the Humvees?

What say you guys concerning tire balancing, tire diameters, toe in/out at the front and the rear.

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Re: Tire pressure and balancing

Post by lkgindy » Thu Dec 07, 2017 12:29 pm

I have always set my front at 1/8” toe in and the rear 1/8” toe out. I use balancemasters on both of my trucks and have never had a balance issue. As far as air pressure I use 40 psi all around. I have put many thousands of miles on my trucks over the years and these settings have served me well.

Larry
1987 M-998 Project
1995 Hummer HT
2006 H3

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Re: Tire pressure and balancing

Post by JuanPrado » Thu Dec 07, 2017 1:51 pm

Many opinions out there but I will share my experience.

I have a stock m998 with original springs. I have added mods which added weight and I feel have made the ride better. It seems to like some weight on the springs. Front winch and front underbody cage / rear airlift bumper, reinforcement plate, pintle extension, tire carrier with tire. Ride height is level and looks ok. I thought about adding m1038 springs but felt it would ride higher and more harsh. Nothing wrong and rides well so why mess with it?

Originally had 12 bolts with Gooodyears and ran 30psi. Some rims did show lead on inside so the military did balance some of them.

I upgraded to the baja D range with 24 bolt even spaced rims. I picked this tire as the sidewall felt softer than the E range. The Newer current goodyears are very hard with no flex. I felt it would ride much harder. I run city/highway and occasional dirt road and no true offroad. No rocks or rock climbing here in the swamp. I run 30 front and rear 35. Truck drives very well and not harsh at all. Drives like any big pick up/suv.

I brought them to and old school tire guy who balanced them for me on the inside. I have a small fortune in lead if the prices go up :-) One was perfectly balanced and he told me it had beads. Not sure how that works with the runflat grease but I made that one my spare. I hand picked all 5 from a surplus military tire dealer ouside OKC and know they all have runflats because the weight. They are heavy! I do find when first started and run on the interstate they like a few miles for the runflats/tires to smooth out. Just a little more bumpy and then all is good.

Military uses the higher PSI with all the weight of the armored trucks. I would stay away from 50 psi. My 5 when I picked them had from 5 psi to 50. None leaked and that just gives you an idea on how many variations of psi out there. BTW, none had the same amount.

YMMV


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Re: Tire pressure and balancing

Post by Kurt Lesser » Fri Dec 08, 2017 9:33 am

I've got to agree with Juan here. I'm running an M996 ambulance and the ride improved dramatically when I dropped the ambulance body onto the truck. The basic 998s need a couple hundred pounds in the back to pre-load the springs to a comfortable position for use on the road. Remember these are rated as 5/4 ton trucks and empty they're right at the top of the springs. The truck has Wrangler MTs on 12 bolt wheels running at 40 pounds. All wheel weights were removed years ago and I run BalanceMaster dynamic balancers. These tires seem to need balancing on a regular basis and the BalanceMasters continually do the job perfectly.
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Re: Tire pressure and balancing

Post by RockHillWill » Fri Dec 08, 2017 3:43 pm

Gentlemen, I appreciate the replies. I understands the concept of more weight making these things ride better. My current configuration is as an M998 two door soft top with nothing on the back. I just got the tag and am driving it because I can. The plan is to add the 'top stuff' to have an M1026. I already have the Baha 24 bolt wheels and tires as well as the airlift bumper, bumper pintel extension and the Rhino spare tire items. I have just received the front frame extensions so I can get started on installing the front winch and bumper plate. You guys give me optimism that the ride will be some better with the added weight. I had a friend help me today and we got the oil and Dextron III fluids replaced as well, as the belts and hoses and new antifreeze. That friend works at a front end and tire shop and has offered to balance both my Goodyear MT's and the Baha sets of tires, so I will be going that route initially. It looks like I will also start with 40 PSI front and rear. THANKS!

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Re: Tire pressure and balancing

Post by lkgindy » Sat Dec 09, 2017 7:28 am

I think the reason the tires never seem to stay balanced with lead weights is that the runflats seem to rotate slowly over time inside the tire. Since the runflats are big pieces of unbalanced rubber, the initial balance does not stay accurate very long. That is why I never waste time and money to balance the tires and just let the Balancemasters constantly conform to what is needed.

Larry
1987 M-998 Project
1995 Hummer HT
2006 H3

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Re: Tire pressure and balancing

Post by Kurt Lesser » Sat Dec 09, 2017 10:34 am

Your 100% correct Larry. I fought with runflats for years and finally just gave up on them and went with the BalanceMasters. There is another company, Centramatic that sells a similar product and both continuously balance the wheels while you drive. They will compensate for the run flats rotating but another way to handle this is with Hutchinson beadlocks. They insert in the wheel after removing the runflat to keep the bead seated.

For those of you who are new to the HMMWV the wheel AMG uses isn't like the one on your civy car. There is no bead around the perimeter to keep the tire bead seated against the it so inflation pressure is critical if you pull the runflats out. Beadlocking is done by the runflat so if you remove it you should put something back in to keep the bead seated if you lose air pressure. I have also seen beadlocks made from sections of PVC pipe cut to 6.75" lengths.

RHW, as a test throw a couple bags of sand in the back over the rear axle and see what a difference it makes.
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M274A2 Mule
M151A1 Mutt w/M416B1 Trailer
M890 Crew cab

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Re: Tire pressure and balancing

Post by RockHillWill » Sat Dec 09, 2017 1:38 pm

Gentlemen, I do understand what your saying. I will have to give this some SERIOUS consideration, but it sure looks like the lead weight balancing is a waste of time. I looked at the BalanceMasters website and they are quite expensive. Are there alternatives, or should I just 'bite the bullit'?

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Re: Tire pressure and balancing

Post by Action » Sat Dec 09, 2017 2:56 pm

lead has worked on mine for the past 4 years. I wonder if we can balance the runflat?
the road force touch tire machines will tell you if the tire is out of round.

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Re: Tire pressure and balancing

Post by JuanPrado » Sat Dec 09, 2017 3:13 pm

I thought the centramatic set at $279 was high. I had not heard of the others; geez, the balance masters are $450 :shock:

I can't justify those numbers when my ride is not that bad. I paid $15 labor for each tire and including unlimited lead. Did not have to pay for the one with beads already. I also did not have to load/remove them from my trailer :D So far so good. I know it is a YMMV and I would start simple and see how things go.

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Re: Tire pressure and balancing

Post by RockHillWill » Sat Dec 09, 2017 4:28 pm

Again, I am new here, but what about using some of the 'green' or equivalent flat tire sealing cans. Apply and rotate the tires very slowly for a few minutes. Would that seal the run flats to the wheels so that lead balancing might be a more dependable option?

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Re: Tire pressure and balancing

Post by Action » Sat Dec 09, 2017 5:07 pm

If you want to glue the runflat to the tire, why not just put some screws in them?

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Re: Tire pressure and balancing

Post by RockHillWill » Sat Dec 09, 2017 5:54 pm

I'm not knowledgeable enough to make that decision. Can you run the screws in without dismounting the tires?

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