Bike Nerd,
I am also in Colorado and one of my all-time favorite bikes was a 2008 Pivot Mach 429 with several “downcountry” upgrades.
· Shorter stem and wider bars – This is pretty much required on any older bike and the 50mm stem and 725mm bars did improve the fit and handling of the bike.
· Bigger fork – Going from a 100mm Fox 32 to a 120mm Fox 34 totally changed the character of the Mach 429.
· Wider rims – Replacing the 21mm rims with a 27mm rear / 30mm front combo provided a significant increase in all-around traction. I ran 29 x 2.3 Specialized tires (Grid rear / Control front) but if I still had the bike I’m sure I would be on something a little wider on the front.
· Dropper post – This was one of my last upgrades and is not a must-have for me. I had a Fox DOSS on the bike and having 3 settings was really nice on the Mach 429.
I rode the Mach 429 on at least 20 of the Singletracks Top 100 trails, always had a blast, and never felt like I needed more bike. The upgrades I made moved the bike from XC toward Trail, which seems to be the point of “Downcountry.”
The new crop of more capable 100mm 29ers is pretty sweet but for Colorado, I would probably choose a 120mm Trail bike.
There are some interesting videos comparing the new Ibis Ripmo and Ripley. Perhaps Jeff can give us a back to back comparison between the Epic Evo and the Stumpjumper ST.