Spare Tire Mounting

[adf5565]

I’m looking to mount a spare tire under the bed of my M1008. It has been missing whatever the original setup was so I’ll need to purchase or fabricate a mounting system. LMC sells what seems like the complete original mounting, however I’ve never used this setup before and not sure how easy it works. Is it worth getting parts from them? Or has anyone come up with a better way to mount the tire under the bed?

 

[Mullaney]

I’m looking to mount a spare tire under the bed of my M1008. It has been missing whatever the original setup was so I’ll need to purchase or fabricate a mounting system. LMC sells what seems like the complete original mounting, however I’ve never used this setup before and not sure how easy it works. Is it worth getting parts from them? Or has anyone come up with a better way to mount the tire under the bed?

View attachment 879290

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You might look for a Chevy spare holder on a square body truck.
Item #5 in the picture is a "must have" and clean is really nice to have.
Item #3 is pretty important too.

Word Of Caution: A flat on the rear can be dangerous. You just about can't get the spare off the under-bed cradle with a rear wheel flat. Then you use the factory jack with about a six inch square pad on the ground - and lift the flat off the ground - and it wobbles (or worse, the jack slips) and you get mashed.

Nobody carries a jack stand or cribbing. So you are depending on that jack to do its job. To lower the spare to the ground, you have to get under the truck. You REALLY NEED to Think Safety before you put yourself under that truck on a jack. Your squishy parts will become smashed parts if something goes wrong...

 

[Keith_J]

I carry 2 Jack's and 4 jack stands in my M1031 SECM but it is set up as a mechanic vehicle .

In the picture, 2 is left front pivot for the carrier, 1. Goes into a hole in the frame rail.

The securing bolt 4 and lockable nut 5 are in the right rear. Carrier is diagonal to the frame opening.

The carrier only works with 31" diameter tires and fit gets tight with some receiver hitches. I had to remove item 7, riveted onto carrier 1 due to hitch.

 

[adf5565]

That does bring up a good point on tire size for the spare which I still need to look into. I’m not lifting the truck but do plan on putting slightly larger rims/tires on (~32.5”s). With the Detroit in the rear, is that tire size discrepancy enough that if I used the original tire/rim as a spare on the rear it would cause issues with the differential?

It sounds like the original carrier setup isn’t the best. I’ve debated mounting a hoist style spare tire carrier like this instead but not sure if it’s been done before. It may just need a new crossmember between the frame rails and as long as the lug is accessible it should work.

 

[Keith_J]

With a Detroit Locker, running a smaller spare can cause wear. This differential allows a faster coasting wheel to ratchet over the driven, no different than driving in a circle with identical diameter wheels.

If you have a sub diameter spare, drive gently to prevent wheel spin as torque will be on the smaller diameter. If this wheel slips, the larger wheel will engage with a clunk. This is where damage can happen, especially on hard, dry surfaces.

If driving longer distances, put the spare on the front axle. So a purchase of a cordless impact wrench would be great along with a decent jack and stands. My SECM has two air impact wrenches, air compressor and hose, a 3/4" 24 volt Robo Tool and a cordless 1/2" impact wrench. Plus 4 jack stands and two hydraulic jacks.
Running 255 85 16s on 8 inch wide rims, with stock size spare.

 

[Mullaney]

That does bring up a good point on tire size for the spare which I still need to look into. I’m not lifting the truck but do plan on putting slightly larger rims/tires on (~32.5”s). With the Detroit in the rear, is that tire size discrepancy enough that if I used the original tire/rim as a spare on the rear it would cause issues with the differential?

It sounds like the original carrier setup isn’t the best. I’ve debated mounting a hoist style spare tire carrier like this instead but not sure if it’s been done before. It may just need a new crossmember between the frame rails and as long as the lug is accessible it should work.

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Tojo has a wire rope that the spare tire hangs from under the truck. (Picture Below and it looks like your picture as well) There is a hole - generally above or beside the license plate that allows you to lower the tire to the ground. Size of the tire is only limited by the space you have below the frame rails and left to right. Less chance that you can't get the spare out from under the truck...



If you use the Chevy factory mounting or the Tojo, you will be much happier if you have the tire with the valve stem pointed down - and generally near the back of the truck. That will make it easy for you to check the air pressure in your spare maybe once a month.

 

[cucvrus]

Just putting this out there. I have the OEM used parts for that carrier.