Does anybody make a speedo and ABS calibrator such that 20 inch wheels may be used on a 2005 GMC 2WD Sierra?

 

There are several 20" tires that are close to the same height as stock tires...or, you could check out the Jet SCU2000. It will correct the speedo for tire and gear size changes. I didn't see it listed on their website, so you might wanna call them to make sure it's still available.

www.jetchip.com

 

a 275/45/20 will get you VERY close to stock height. close enough I don't think your speedo will tell a difference. don't put 32" tires like mine has. you will notice a decrease in acceleration from a grunt and it will be harder to stop. stay close to factory height as possible.