tires again

2deuce

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I have read too many tire threads trying to get info, I don't know what to think.
I bought some 16" 6 lug steel wheels and I have 1100 xzl tires. Will the 6.2 blow the 10 bolt rear end with freeway use? I see that 35" tires are what many think is the limit but I will only use this M1009 for street use and if I happen to go on logging roads I can go into low range. Nothing more hard core than that.
With this tall of tire I'm sure I'll have the throttle mashed in the mountains, will the 10 bolt have a short life? or is off road where they break? I'm trying to keep the revs down for freeway speeds of 70-75.
Thanks,
Greg
 

jimmy-90

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You should be good to run 1100X16s on the street and do some light wheeling too. I ran a set of 36X14.50-R15s on my civilian blazer for a couple years. I used that truck to commute from way out in the sticks all the way into the city every day with no major issues. You may want to get good at changing wheel bearings and hubs though. Other than that your axles should be fine since the 6.2 diesel does not power up like a super charged big block. To answer your other question YES!!! off roading will break them if you try to rock crawl or do some extreme stump-jumpin!!! Long muddy trails with light or no real obstacles should be fine though. Would make a good truck to cruse around muddy job sites n stuff. Also if you are gonna put like 6 or 8" of lift on it to clear the big tires make sure you put shims under your springs to aim your pinion towards your t-case and check your driveshaft length. All that street driving I did with mine did tear up the rear seal in my t-case because I just said ta **** with it and ran it with a bad drive line angle for a long time.
 
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2deuce

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portland, oregon
I want to lift it as little as possible and don't mind alittle trimming. Getting it up high might catch too much wind, which would kill mileage along with speed. I saw where guys moved their front forward and used a 2wd steering box to use a crossover and gain clearance. I want to do the same but didn't want to do that with a 10 bolt if it wouldn't last. I don't think that 3.08 gearing is available with a stronger rear if it did break and then I'd have to change the front. I mainly want to cruise at 70 with lower rpm's. That's my goal, and no breakage.

Thanks,
Greg
 
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dmc-4359

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Chapin, SC
To me it seems the easiest way to lower the rpms is to switch out the th400 with a well built 700r4. 30% decrease on the interstate in 4th and a little bit more leverage in 1st gear to get going.
 

2deuce

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I don't have a 700r4 + the cost to beef it. I'm going to need tires soon anyway and I like big tires, if they can stay in the fender well. I think I'm going to try running the 10 bolt.

Greg
 

4bogginchevys

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you can get a 14 bolt with 3.07s, rare but they exist. Crossover steering usually requires a minimum of a 6" lift, but you could probably figure it out with a 4" lift and a custom block to raise the steering arm. good luck
 

dmc-4359

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Chapin, SC
I don't have a 700r4 + the cost to beef it. I'm going to need tires soon anyway and I like big tires, if they can stay in the fender well. I think I'm going to try running the 10 bolt.

Greg
I see. I didn't catch that part when I read your post the first time. Makes sense.
 

truck0590

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I guess I don't understand. Most M1009 do fine on RPMs with 31-33 in tires and 3.09 gears. It is the M1008 w/4.56 gears that do not do well on the street. I would think if you put 1100 xzl on there w/3.09 gears you wouldn't hardly be able to get it moving.

Truck
 

2deuce

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portland, oregon
I know acceleration won't be good and pulling hills will be poor. Anybody know the torque curve for the 6.2? I'd like to cruise at 70 at the peak if there is one.
 

Croatan_Kid

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New Bern, NC
3.08s and an 11.00R-16 (just a hair over 38" tall) won't be good at all. Those tires weigh 120 lbs a piece with no rim, plus they're simply too tall for 3.08s. The 6.2 produces it's torque about 1800-2200 rpm IIRC and I've always head the "sweet spot" for cruising is 1850 rpm or so.

With that setup at 70 mph, you'd be running 1900 rpm and at 55 you'd be at 1500 rpm. However, it would be entirely gutless and would probably slow down if you put your hand out the window. Not to mention your fuel milage would likely be in the single digits. I ran my M1008 with 11Rs for a while with 4.56s, it was decent on the highway. I was getting around 14 mpg on a good day. Also, take into account windage, a much larger rotating mass, and more rolling resistance. 4.56s put you at about 2800 rpm @ 70 mph. Some 33s and the stock 3.08s at 70 mph would be right at 2200 rpm. 33s are much cheaper, you won't have to lift it much (if at all) and it'd make life easier for you.

You have to sacrifice some things when you chose your gearing. Too high and it will work the motor too hard to get it to move and you'll run to engine out of it's RPM range for good power and milage. Too low, and it'll just over-rev and have no speed.


As for crossover and such, you can run crossover with 4" of lift. It's more difficult and involved on a 10 bolt since you need a flat-top Dana 44 knuckle on the passenger's side. Stock steering will work for street use, just get a droped pitman arm or raised steering arm. Don't use a steering block, it adds leverage to a critical point and makes it very easy to sheer off the steering arm bolts.
 

jimm1009

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Louisville, KY
ALL M1009 CUCV trucks had 15 x 8 6-bolt wheels from GM.

If you go from a 10:50 x 15 OEM Military stock tire to a 33 12:50 x 15 all terrain tire you don't have to do any fender trimming or any lifting for moderate
off roading and you have a heck of an improvement on the road.
You want bigger tires then 33 12:50 x 15's you get into gearing changes and / or different engines depending on what you want to do.
Your truck then do what you want but this is the cheapest way for drastic improvement with the stock wheels and gearing.
I've put over 200,000 miles on my M1009 like this in the last 15 years.
jimm1009
 

AJMBLAZER

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Croatan pretty much covered it.

You could make the 11.00R16's fit easily enough. Just cut to fit and maybe 1" of front lift. That said...don't even think about it. You'll end up with a tired engine, broken axles, and a dead transmission. You're making too many comprimises with that setup trying to get to a very fuzzy goal.
 

2deuce

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portland, oregon
I appreciate all the input. Sometimes there is no answer. As to my fuzzy goal, it sounds like most of you feel its a pie in the sky and your convincing me not to try it.
With 3.08's and 31" tires 65 feels like the engine is turning too fast. I didn't think 33" tires would cut the rpm that much. Back to the drawing board.
Greg
 

Sgt Hulka

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I'd like to be another bandwagon jumper and advise against this. I'm having more confidence everyday that the stock M1009 running gear components are a really good reliable set up for intended use. And I really don't see the benefit from the risk of going to an ultra tall tire set up. You could go to 33s with no problem and from seat no loss of performance in any environment from those big 16" set ups. Something folks forget a lot, not just around here but in general, is that weight is your enemy. And unsprung weight is even worse...
 

danochamp

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Columbus, IN
I'm also thinking that 33 or 35 inch tires would be nice. I would only want to lift it about 4-6 inches and am thinkin I might have some trouble clearing the tires. Also what size tire would fit the stock rim? And what would do the least damage to the truck, a 33 inch set of tires right?

What would be the least amount of lift necessary to acheive 33 inch tires, 35 inch tires?
 

Sgt Hulka

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As far as I know, you don't need any lift for 33" tires. That doesn't mean you don't want a lift, but it's just not necessary. I may go to 33" tires sometime myself and I believe in stock generally...
 

AJMBLAZER

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33's can be fit on a M1008 with no lift, especially if you go with a narrower tire like a 285/75R16 or a 255/85R16 (33x11.25ishR16 and 33x10ishR16). A wider tire like a 305/70R16 (33x12ishR16) may give you slight rubbing problems.

A 35" tire is a 315/75R16 but will require a lift or trimming/cutting. I'm running narrow 38's with 1" of front lift and a decent amount of cutting. Lifts aren't necessary but if you put on 4" of lift you can probably fit the 35's without much rubbing. Lifting opens up a can of worms though as most lift springs aren't as heavily rated as the factory springs so you loose capacity while at the same time gaining travel which then puts the tires into the fenders more when flexed. Also, obviously, your truck gets taller and doesn't fit into standard garages as easily. Meanwhile you need good steering correction, longer brake lines, extended driveshafts, new u-bolts and stuff, maybe alignment shims, etc.

33's won't help the top end much and 35's will only a little. You don't see much gain until you're around a true 36" tall tire but then the weight of the tire starts to work against you.
 
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