The other night I got a text from Brian at JRA Cycles about a secret Pivot Cycles demo at The Fells. We’d spent all day Saturday at a Pivot demo shredding Mach 6s and whatnot but there was one bike that was conspicuously absent from the lineup—the new Mach 4 Carbon. The old Mach 4 is an aluminum bike with 100mm of rear suspension travel and 26” wheels. This bike is carbon with 115mm of travel and 27.5” wheels. A totally new beast.
Brian told me they were going to have a small and a medium. I’m a solid large so I resigned myself to spending some more time on one of the other Pivot models I’ve already ridden extensively (I’m a big fan of the Mach 429 Carbon and the Mach 6) and shooting video of Brian riding the Mach 4. But when we got there it turned out that they actually had a Mach 4 in a large and I was like, oh hell yes!
My first impression was: that looks wicked hot. My second impression, upon picking it up, was: wow, that’s wicked light. My third impression, after stomping around the parking lot briefly was: damn, this thing is wicked fast.
But when we started riding things changed…
Right out of the gate we shot up a steep climb into a tricky, technical traverse. It definitely climbed well like DW Link bikes tend to do and the lightness was apparent and appreciated but the front end was all over the place. I really couldn’t control the bike at all. I was dabbing like crazy and I even went over the bars on a section (let me put my jerk hat on for a second here) that I may or may not have the Strava KOM on.
This was very different from any other experience I’ve had riding Pivots. Usually I hop on them and feel like I could ride off into the sunset and clean every obstacle on the way there but the Mach 4 and I were not getting along.
I set about trying to figure out what exactly the issue was. The thing that jumped out was the bar/stem combo. Brian’s medium bike had a 70mm-ish stem while mine had a 100mm stem. A stem that long coupled with the very wide (for an XC bike) 740mm bar meant I had a whole lot of leverage going on. Too Much. The front end was super twitchy. Apparently the Mach 4 has the same head angle as the Mach 429 (which I’m wicked comfortable and confident on). I assume the forks have the same offset. I’m wondering if the smaller wheel size still makes for less mechanical trail.
Any engineers are welcome to weigh in on that one. Weagle? DeFrancisco? Anyone?
Another issue could have been that I’ve been riding 29ers for ten years and the only other 27.5 bike I’ve ridden is the Mach 6, which has a lot more travel and a way slacker head angle. Adapting back to a smaller wheel size may have been part of it.
As the ride went on I kept tweaking things—little pressure out of the tires, little pressure out of the fork and shock, adjustments to my body position and expectations…and the bike and I gradually began to sync up better and get along. Brian, he was killing it pretty much the whole time, having zero issues. You should have seen his wheelie up the entire road to Bear Hill. He even did a drop that I only feel comfortable doing on the 155mm travel Mach 6.
I’ll be honest, when the ride started out I was like: I hate this thing! Can we go back and swap bikes? I am going to DIE. But, by the end of the ride, I was like: What? This is over so soon? I want to go ride this thing all day long! In fact, we went back to shoot some more video on the first trail we did (the one where I was dabbing up a hurricane and flipping over the bars) and I absolutely smashed it with full confidence.
After a couple hours on the Mach 4 Carbon my thoughts are that this bike would be an ideal XC race or recreational bike for a more conservative rider. It’s an efficient machine that wants you to get from point A to point B as quickly and safely as possible. It doesn’t say “Hey, go hop off that thing, jib that rock, then point it down that chute…y’know, go nuts, kid!” That’s more for its crazy older brother the Mach 6. I don’t think we’ll see guys slapping bigger forks on this bike and Enduro-ing it like they do the Mach 429. We probably will see it winning some XC races and smashing all the Strava KOMs in your neighborhood. This bike is fast.
That said, and I am saying that said, I would like to try the Mach 4 in an XL and throw a stubby-ass stem on it to see if that eliminates my control issues. I have a feeling it might seem more trail-worthy and less XC-leaning. The large does run a little small and I was showing a lot of seatpost. I haven’t ridden an XL frame since 1991 when I bought my first mountain bike and a sketchy sales dude foisted off a 21” closeout Specialized Rockhopper on me. Funny, I never did grow into that thing. The 150mm stem didn’t help either.
We shot some video during the ride. Watch for that on DirtWireTV soon.