So I was riding the other day and tore the valve stem on my rim strip. Instead of spending more money I really don't have and waiting a miserable week for the UPS truck, I decided to take a crack at the D.I.Y. option. The whole process went off without a hitch and saved me approx $20. I don't know if it's overkill or not but I used a double thickness of tube. I peeled a 20" tube in halve, stretched the top side around the rim, trimmed it to fit, bored a hole for the valve stem, mounted the other half, trimmed that to fit, then put on the tire, added sealant, then aired it up. It took a little coaxing for the bead to seat, but all in all it was pretty straight forward and painless.