Dual Wheels on the M-37

52 M-42 · Post by **52 M-42** » Sat May 26, 2012 4:40 pm

I have acquired a set of dual wheels and new tires (9.00 X 16.00 NDTs) for the M-37. The set is four wheels & tires.

Before using them, I thought I'd ask if using these will damage (break) the rear axles? I remember seeing a few of these set ups in the military (parked) but I never saw them used, so I'm a little nervous about actually using them. They look very cool on the truck and trailer, or both axles dualled up on the truck, but I'm just not sure about the effects of actual use.

Does anybody out there have any actual experience using duals or know of a documented (manual / TB) source of information?

Charles, maybe?

I really don't want to learn by breaking something. A sissy, I know, but I've broken enough stuff through stupidity without adding to the list.

Thanks!

52 M-42

MSeriesRebuild · Post by **MSeriesRebuild** » Sat May 26, 2012 5:40 pm

My take is this; if you are doing it for the look and don't really intend to load the truck, I don't have much concern about axle shaft issues.

If you intend to install duals with the intent of hauling a bigger load in rough terrain, I'd have a spare shaft stash on hand, and finding a source for some heavy duty custom shafts would be a good idea.

52 M-42 · Post by **52 M-42** » Sat May 26, 2012 7:19 pm

Mostly it would be to increase traction in snow and mud, and maybe sand. Not really doing any excessive load work. The brakes are just too under powered to exceed their design limits.

Thanks for replying, Charles. I was hoping to benefit from your knowledge and experience.

I wish I knew more about this whole dual set up. It is never mentioned in PS Magazine that I've seen (so far anyway; I'm up to 1963 and no mention yet) and there is nothing in the manuals, that I know of.

Thanks again, Charles.

52 M-42

52 M-42 · Post by **52 M-42** » Sat May 26, 2012 7:23 pm

BTW, Charles, any suggestions on who to talk to and where to look for those custom heavy duty shafts? That sounds like a good idea in general, or do you just start breaking other stuff (third members, twisting drive shafts, etc)?

powerwagontim · Post by **powerwagontim** » Sun May 27, 2012 3:04 am

You can physically mount 2 900-16 tires/rims as duals, using the budd hollow studs and nuts, but the tires will be touching each other. They will quickly chafe and you will soon have 2 flats! To do it properly with 900s, you need to install a spacer. The budd hollow studs and nuts were made to dual up rims with 750-16s. Then they work without spacers.
Tim

MSeriesRebuild · Post by **MSeriesRebuild** » Sun May 27, 2012 4:16 am

52 M-42 wrote:BTW, Charles, any suggestions on who to talk to and where to look for those custom heavy duty shafts? That sounds like a good idea in general, or do you just start breaking other stuff (third members, twisting drive shafts, etc)?

We actually have a source that is supposed to be building some right now, and should be seeing some very soon if he has followed through on the schedule he gave to me. I need to follow up on it. Will try to look into that this week.

52 M-42 · Post by **52 M-42** » Sun May 27, 2012 11:30 am

powerwagontim wrote:You can physically mount 2 900-16 tires/rims as duals, using the budd hollow studs and nuts, but the tires will be touching each other. They will quickly chafe and you will soon have 2 flats! To do it properly with 900s, you need to install a spacer. The budd hollow studs and nuts were made to dual up rims with 750-16s. Then they work without spacers.
Tim

These are special off set military rims used by the military. I've mounted them up and they do not rub. I use the hollow nut/stud combination. These were obviously designed as duals. I wish I knew the history of this mod, or could find some documentation somewhere.

Oh well, I'll just keep looking.

If I could ever figure out how to get photos to post on this website, I'd post pics, but so far that is just an exercise in frustration.

52 M-42

52 M-42 · Post by **52 M-42** » Sun May 27, 2012 11:38 am

[/quote]We actually have a source that is supposed to be building some right now, and should be seeing some very soon if he has followed through on the schedule he gave to me. I need to follow up on it. Will try to look into that this week.[/quote]

Could you please post something about these axles when you get them, or PM me, please? I'd be interested in upgrading to stronger axles if possible. The stock ones seem as fragile as glass. The rear ones can break in the blink of an eye if the front hubs are not locked. Ask me how I know.

I just do not want to start breaking other stuff (third members, twisting drive shafts, etc).

Thanks, Charles!

52 M-42

MSeriesRebuild · Post by **MSeriesRebuild** » Sun May 27, 2012 12:34 pm

If you are having an excessive shaft breakage problem for seemingly no apparent reason; you probably should look into your differential spider / side gears and thrust washers being badly worn. That is the most common cause of frequent breakage. Can also be related to loose motion elsewhere in the drive line, most likely a combination of issues. If excessive wear is present in these areas, even a premium quality shaft will be fatigued to the point of premature breakage.

I'll post it here when we have some in hand.

52 M-42 · Post by **52 M-42** » Sun May 27, 2012 2:46 pm

I haven't had any breakage for "no apparent reason". I know the reason, and it wasn't the truck's fault; it was the nut behind the wheel. Stronger axles just seem like a good idea (the old "When in doubt, make it stout" refrain).

Thanks for your help and I'll be watching for a post about the axles.

Thanks again,

52 M-42

CSCameron · Post by **CSCameron** » Sat May 23, 2015 11:42 am

52 M-42 wrote:I haven't had any breakage for "no apparent reason". I know the reason, and it wasn't the truck's fault; it was the nut behind the wheel. Stronger axles just seem like a good idea (the old "When in doubt, make it stout" refrain).

Thanks for your help and I'll be watching for a post about the axles.

Thanks again,

52 M-42

I know this is an old post but I was wondering if you were still running the duals? Any troubles? If not, do you want to sell them? Have you ever figured out how to post pics? Would love to see them.

Thanks,
Clark

52 M-42 · Post by **52 M-42** » Sat May 23, 2015 12:42 pm

I have figured out how to post pictures (thanks to Robyn)!

Here are a few pictures of the dual wheels / tires mounted on the front. I just did enough to be sure they would work.

I have never installed them on the truck for driving around because I don't have the proper fenders fabricated yet ( I just got a set of extra rear fenders to start that project a couple of weeks ago). It is not at the top of my project list, but will probably be done (or at least started) within the next year. I will be sure to post a thread on that project when it gets completed.

I'm not interested in selling my set, but I saw a dual wheel the other day on Ebay under Dodge Military M37 Parts. You might also try Supply Line if you belong to the MVCC or just search the usual vendor suspects.

Good Luck.

CSCameron · Post by **CSCameron** » Sat May 23, 2015 1:31 pm

Thanks for posting the pics. It looks like your tires are touching in the pic, is that correct?

Nice M

Clark

w30bob · Post by **w30bob** » Sat May 23, 2015 5:05 pm

Hi 52,

Not sure where to start.........I understand wanting to make the rear duals.....but I don't understand wanting to do that to the fronts. It's hard enough steering a stock M, adding another tire per side is sure not going to make it easier. Actually, I'm not sure how the truck will respond. Whenever you turn the steering wheel the inner front tires will pivot, but the outer tires will have to drag, as they're moving in a bigger circle than the inside, but can't rotate any faster because they're bolted to the inner tires. I got a feeling turning won't be much fun.

As for traction....I've got a dually pickup.....and it depends on what you're on. Mud and very thick snow......yes, you'll get an improvement as surface area counts. Snow over pavement you'll be losing traction as the force pushing down on the tires to make contact thru the snow to the pavement will now be distributed thru 4 tires per axle and not 2.....you know, less contact pressure per tire. On dry ground the duals will provide better traction, but that means more torque before they break lose.....which your axles aren't designed for and will not like.

A very interesting project for sure. Looking forward to seeing how it turns out (no pun intended).

regards,
bob

52 M-42 · Post by **52 M-42** » Sat May 23, 2015 5:50 pm

O.K., just to be clear:

I did not put an inside dual wheel and tire on the truck in the photos; only the outside tire & wheel combo to see if it would fit. Also I just used the front because it was easier. You can dual-up the truck all the way around, but unless you are in some nasty mud (Russia comes to mind) i don't know why you would.

My reason for the dual set up (only in the rear) would be sand.

Dual Wheels on the M-37

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