If you’ve read my first post on the Fuel EX9, then you you already know that it’s my new Dirt Rag test bike. That first post was made on November 3rd, but I’ve actually been riding the EX9 since October 5th, so I reckon it’s high time for an update.

A look at the geometry chart below reveals that Trek offers two different "medium" sizes. That may seem odd to you, but it’s seems like brilliance to me. I’ve always been a bit of a tweener—able to ride either a medium or a large bike, but often feeling that neither size fit me perfectly. The larger of the Fuel EX9′s two medium sizes (18.5") fit me like a glove! Needless to say that went a long way to making me feel right at home on this bike. I hope this "multiple medium" sizing is a move that is copied by other bike companies.

geometry

I’m a big fan of tubeless tires on mountain bikes, and I’ve racked up a many, many miles on UST tires, and regular tires converted to tubeless via sealant (including Stan’s, Bontrager, DT Swiss and Hutchinson flavors of the juice). The Fuel EX9 comes with tubes in the tires, but both the wheels and tires are tubeless compatible (additional purchases required). After getting a flat tire on each of my first two rides, I ended up calling Trek and asking for the goods required to go tubeless (i.e., Bontrager tubeless rim strips, tubeless valve stems and Super Juice sealant). It’s a pretty simple conversion. Ditch the tube, replace plain rim strip with a Bontrager tubeless strip, insert the valve stem in rim, mount one side (bead) of tire, pour in recommended dose of Super Juice, mount the other side of the tire, inflate, and ride away a happy man. Many rides later, I’ve had no more flats. I should note that the Bontrager Race Lite tubeless compatible tires have a bead that is designed to seal tightly with tubeless rims, yet they’ve got lightweight casing, not the heavy UST casing. Yes, they require sealant to hold air, but I always use sealant with tubeless, including UST, because you’d be stupid not to. For my money, the Bontrager tubeless compatible "hybrid" design is a winner.

On my first few rides, the Fuel EX rear suspension was making nasty squeaking and squawking noises—and it didn’t feel as supple as I’d remembered during my test rides during the Trek Press Camp in June. Throw in a healthy dose of ghost shifting, and my Spidey Sense was tingling. I threw the bike on my workstand and double checked the suspension set-up, and made sure the rear derailleur was properly adjusted. Closer inspection revealed that something in the rear suspension didn’t look quite right (see photo below). There was a washer visible between the rocker link and the frame on the right side, but not on the left side. I emailed the photo to Trek and they they guessed that somebody might have forgot to insert the left side washer during assembly, so they sent me a washer. But when I started to unbolt the rocker, so I could put in the washer, I discovered there already was a washer on the left side. It turned out that the cavity in the rocker (that the washer sits inside) was machined too deep on the left side, and this caused the washer to "disappear" completely inside the rocker body. This meant that the rocker and frame were in direct contact and binding, which caused my aforementioned problems. Another call to Trek produced a brand new rocker. With that installed everything was fine and dandy with the rear suspension: smooth as buttah, no squawking, no ghost shifting—All good. Chalk it up to a bit manufacturing variation as Trek gears up production (note that I got one of the first EX9′s to roll off the production line).

left rockerright rocker

Did I say buttah? I believe I did. And with good reason—it’s an honest description of how the Fuel EX9′s suspension feels when bombing a technical downhill, or hammering through a rock garden. For a bike sporting 120mmm of rear travel, this should come as no great surprise. What makes this on-demand coosh worthy of comment is that it comes on a bike that feels efficient under pedaling power. By itself, the Fuel EX rear suspension does a decent job of canceling out pedal-induced bob. Flipping the Fox Float RP23 to the Pro Pedal position gives the bike a racer-boy feeling. Match that Pro Pedal rear with a locked-out Fox Talas RL fork up front, and you can hammer the pavement, or crank up those fire road climbs, and not feel like you’re wasting all your energy bobbing along. On a recent excursion to the rocky-as-heaven Laurel Highlands trails (download 912K PDF trail map) I had the opportunity to experiment with suspension set-up on some technical-rocky trails. This place is chock full of sections where you really have to stay on the gas to make it through clean. Under those conditions, I really learned to appreciate the beauty of the Pro Pedal setting—efficient transfer of pedal power to the rear wheel, suspension ready to kick in and absorb blunt force trauma. Had three and a half hours of fun that day.

That ought to do it for this edition. More to come….