Under-bed spare tire mounting questions

[dsy1]

I just got a '71 longbed fleetside with the mount under the bed for the spare. It didn't have a spare, so I picked up a used 16 inch rim and tire, but I'm not sure how it fits in the mount. The cross-strap has two brackets riveted onto it, but they don't seem to line up with the size of the spare (they are closer together than the inner diameter of the spare wheel). Do I grind off the rivets and move the brackets? How are the brackets supposed to fit inside the wheel rim? Pics would be great, or an explanation of how the spare is supposed to be secured in this mount.

Thanks.

[Zeke]

Its been awhile but if I remember the brackets don't really hold the tire, install the tire with the outside of the rim down, push the cross strap up ajusting position of tire so it is somewhat centered until it catches the bolt and tighten with a tire iron until it is snug between the cross strap and bed cross rails. The reason for having the outside of the rim face down is so you can check the tire pressure without removing the spare. if it goes flat the brackets should keep the spare from falling out.
Unlike newer truck with the winch type carrier these trucks require you to crawl under the truck to get to the spare. If you have my luck the only time you get a flat is when its cold, raining and dark, always carry something to lay on.

[68gmsee]

Yeah, it's a pain to get to the tire. Not sure about your truck or if it makes any difference but most I've seen have 15 in. tires. Did yours come with 16 in. tires?

As Zeke mentioned and as I also recall: What you have to do to remove tire.

Crawl under the bed and with a large scew driver or tire tool, loosen the long retainer bolt. Lift tire slightly to disengage long bolt while insuring tire doesn't come down on you.

Lower to the ground (it will be at an angle) and slide out.

Reverse the procedure to install.

[Sinister]

I have the repop tire carrier that LMC sells. IIRC, There were 2 different positions to mount the brackets. I chose the wider for my 16" rims. I mount the spare with the backside of the rim face down.