I want to report in on something that I've found works great and is cost effective: "Ghetto Tubeless"
I have always had problems with flatting on my MTB, especially with my new found love of urban assault paired with my current inability to hop my rear tire properly in key situations. Flatting also cost me some positions in two MTB races this year, boo.
So here's the instructions for ghetto tubeless!
Pt1 - http://www.youtube.com/watch?v=WRM7gq1fcoQ
Pt2 - http://www.youtube.com/watch?v=PwON2VxZL0g
Also, Sponge has the sealant you need to do this... so go harass him for some.
1 year ago