The Mach 4 is hardly a new name for Arizona-based Pivot Cycles. The XC race rig was one of their first bikes and has been in the line-up ever since, going through myriad updates. The latest is this 27.5in wheel, 115mm rear travel XC race bike with trail bike versatility.
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Pivot Mach 4 highlights
- Full carbon frame
- 115mm travel dw-link suspension with race and trail tuning (XS size has 100mm travel)
- 27.5in wheels
- Fits tires up to 2.6in
- Available in either trail-oriented or XC racing-focused complete bike builds
- XS, S, M, L & L(long) sizing, with X-Small featuring super low stand-over clearance
- Claimed frame weight from 5.1lb/2.3kg
Pivot Mach 4 build details
The Mach 4 in for test features the trail-focused Team XTR 1x build and as you might expect, there's very little room for want. The carbon frame is loaded with a Fox 34 Factory with 130mm of travel. Rear end action is handled by a Fox Float Factory DPS shock yielding 115mm.
The 27.5in wheels are gorgeous DT Swiss XMC 1200 carbon hoops that I have high expectations for. The same can be said for the Shimano XTR 11-speed (XT cassette 11-46) with Race Face Next SL cranks (30T) and Shimano XTR Trail brakes.
Maxxis Ardent Race 2.35in tires are on board, although I will be testing other rubber since the Mach 4 can swallow 2.6in widths. I was also pleased to see a Fox Transfer dropper post fitted.
Pivot Mach 4 first ride impressions
Spinning up the trail on the Mach 4, for whatever reason I kept reminiscing back to when I was much more XC obsessed. Back then it wasn't really a conscious decision, XC was all there was, so it was the only riding I knew. What I did know was I wanted to go fast and ride loose. It was too bad the bikes sort of sucked.
But now there are bikes like Pivot's Mach 4 Carbon.
Granted, it's rare nowadays to find an short-travel XC bike rolling on 27.5-inch wheels, but as my ride progressed I began to wrap my head around why this bike had the smaller wheels.
Here's why. When it comes to cross country racing and riding, the old adage is everything is won or lost on the climbs. That's true, but now that almost every bike company has a featherweight XC rig, it's sort of equal. The other spot to grab a lot of time is in and out of the corners. 29in wheels, due to sheer size, are slower to gain speed. That means a 27.5in bike can get back up to race pace quicker in the tight stuff. Less gyroscopic effect also means it's a bit more playful.
I was impressed with the sheer acceleration of the Mach 4. I did a decent climb the day before so I assumed my legs would be a bit hollow, but with every flick of the cranks, the whooosh of the air rapidly got louder in my ears. With the stiff carbon frame and wheels, and responsive rear suspension, getting up to speed felt effortless and really, really fun.
With the 27.5in wheels it felt like I could just live in the high end of the cassette, especially since the bike I have has a paltry 30T ring. This is one thing I might change in favor of a 34t or 36t chainring depending on the situation.
On the uphills, I initially left the Fox Float rear shock open. There was a tiny bit of movement so I nudged the lever over to the middle setting which tamed the movement even more. Being that the dw-link rear end is super efficient and the trails I ride are loose and techy, the firmest shock setting is of little to no use for me.
With gravity's assist, the Mach 4 surprised me by feeling a bit deeper than its 115mm travel. Sure, that can be taken as cliche, but I think it's more a testament to a well-sorted rear suspension. The front end complimented the back. I'm a huge fan of the Fox 34 and its 130mm of travel didn't disappoint here.
I did notice the smaller wheels getting hung up a bit more through chunky sections and the Ardent tire's knobs getting a bit overwhelmed in some corners, especially on the front. I'm very interested in seeing what happens when I throw on larger, wider tires.