Hello all, I joined this forum to learn some of the tricks of the trade with mountain biking, just picked up a new specialized rockhopper 29er and have loved every minute of it! I'm originally from central florida but the Air Force has taken me all over the world. I'm currently in San Antonio for aircrew school and then on to many more schools after that so the bike will be my enjoyment along the way I currently live when not traveling in Clearfield Utah with my wife and 2 dogs and we will be finding out where the AF will send us next in about 3 weeks!

Main reason I joined TODAY was due to my bike having gone through 4 tubes in 7 days of grass/street and dirt road riding... I'm dumbfounded and have no Idea what I'm doing wrong... the bike shop gave me 4 kenda 29' tubes and they just fall havn't been able to take more than a few hours ride time before they are flat. the stock tubes lasted until I got to TX and now I have blown both of those... Help me!

Some diagnostic questions for you:

1) Assuming you located the hole(s) in the tube, are they on the tire or rim side?

2) Do you pump up your tires to the recommended minimum pressure?

3) Did you inspect the tire to see if there is a thorn/nail/staple in the tire that is causing the repeated flats?

4) How many holes in the tube per flat? (Look close, often two holes can me a few mm apart, referred to as a snakebite) .

5) Are goat heads or other thorny plants ubiquitous to the area? (LBS or other local riders would know).

6) To help future diagnostics, you might want to index the rim's valve stem hole to a fixed feature on the tire, like the center of the tire's label. Then, in the future, you notice a pattern like "the flat is always at the 3:00 position", and item #3 may apply.