Suggestions about finding a 20" rim for a GMC Sierra?

If you want a new quality rim. Contact one of the Les Schwab stores in Reno and have them do the ordering and get the rim and tire when you get to Reno.

Junk yard?

find a 17"

Try Craigs list und car parts for your area. Always seeing wheels and tires on there.

Why do you want a 20" rim for the spare? Why not get the same as the factory spare? The rim size doesn't matter, it's the overall diameter of the tire that does. For example my stock truck has 275/55R20 tires which are 31.9 inches in diameter, the spare is 275/70R17 which is 32.2 inches in diameter or a 0.3" difference which is close enough for the trucks computer. The manufacturers do this to save weight and cost. (tires for 17" rims are much cheaper than 20s)

Keep an eye out on Craigslist or visit a GM forum and check the buy/sell forums. Quite often you can find original full sets or singles for way less than new.

Car-part.com should have what you need.

JKaz

What size are you looking for 17" or 20"? I have the same setup and using the 17" on the ground was no problem, just do not use 4x4 when it is on the ground. I had ours on for about 100 miles when we had a blowout. There are NO plain Jane steel 20" rims for our trucks, so don't keep looking. The cheapest 20" aluminum I could find was through Discount Tire @$128/ea. Several tire stores said they get them in trade once in awhile, when someone wants to upgrade from the factory wheels and I have 2 stores looking for me. Reno has several new Discount tire stores, so that may be your best bet. Also, try any GM dealer for takeoffs, they may have them.