2020 PINKBIKE FIELD TEST
Pivot Mach 4 SL
There's no hiding this bike's World Cup XC pedigree.
Words by Sarah Moore, Photography by Trevor Lyden
Pivot’s Mach 4 SL replaces the long-running Mach 429 SL as the company's premier cross-country bike. Given how that market is now firmly in the 29er camp, Pivot decided to shed the "29" part of the name and revert to the simpler Mach 4 moniker since wagon wheels are basically a given in that category these days.
The updated geometry aims to help racers win World Cups while making the bike more versatile. Pivot says that "the new school geometry also lets this cross-country race bike flirt with trail bike versatility outside of the course tape." Building on that theme, riders can choose between a cross-country build with a 100mm fork or the Trail version of the bike that comes with a 120mm fork and a dropper post.
Pivot Mach 4 SL Details
Travel: 100mm (r) / 120mm (f)
Wheel size: 29''
Frame construction: carbon fiber
Head angle: 67.5° (geometry
Chainstay length: 431 mm
Reach: 427 mm (size Medium)
Sizes: XS, S, M, L, XL
Weight: 26.6 lbs / 12.07 kg (as pictured)
Price: $10,399 USD
More info: www.pivotcycles.com
The suspension on the Pivot Mach 4 SL is a variant of the dw-link layout that has marked every Pivot full-suspension bike since the inception of the company in 2007, but the shock is now oriented vertically instead of horizontally, tucking in front of the seat tube instead of residing under the top tube. This allows for a lighter and more compact front triangle. It also means that there is room for a water bottle to fit in the main triangle on every frame size, and the XL size can even handle two bottles.
The Mach 4 SL uses Boost hub spacing, a PF86 press-fit shell, and while it is built solely for 1x drivetrains, it does have ISCG tabs if you’d like the security of a light-duty chain guide. All frames are compatible with Fox Live Valve, but not Shimano Di2.
Prices for the complete bike range from $5,200 USD for the Race XT 12-Speed to $11,999 USD for the fully electronic AXS and Live Valve build. We tested the Mach 4 SL Trail XTR model which comes with Shimano's top-tier mechanical group and brakes, DT Swiss XRC 1200 Spline wheels, and Fox's Live Valve suspension. All of that will cost you $10,399 USD. Climbing
Chloe Woodruff won a World Cup Short Track on the Mach 4 SL earlier this year and finished in the top-ten almost every race, so we had a feeling that the Pivot Mach 4 SL wouldn't be a slouch on the climbs with that kind of pedigree. It turned out to be an accurate assumption, and the Mach 4 SL did a great job of keeping the rear wheel stuck to the ground; I was able to make it up steep and technical climbs that really tested the limits of grip. While the suspension wasn't quite as plush or comfortable as the bikes with more travel, it didn't skip around or feel uncomfortable harsh.
Less commendable was the 73.5-degree seat tube angle on the Pivot Mach 4 SL, which was the slackest of all the bikes in the down-country category. It's 74.5-degrees with a 100mm fork, but as the head tube angle slackens slightly with the more travel, the seat tube angle does the same. The effect was noticeable as soon as you pointed the bike uphill. I slid the saddle all the way up on the rails and still wanted to be more forward, especially when it got steep.
Speaking of steep climbs, the 34-tooth chainring also felt pretty specific to cross-country racing, as did the 75mm stem. There were no complaints about the weight, though. Even with the slightly heavier Live Valve setup (adds 220g / 0.5lb), this was one of the lighter bikes in this category, which was nice on the longer climbs and made that 34-tooth ring more manageable. Descending
One downside of riding the Pivot Mach 4 SL with the 120mm fork was that the reach was a paltry 427mm. It has a 440mm reach when ridden with a 100mm fork, but when you over-fork the bike it ends up shortening it by 13mm, which reduces some of the benefit of that extra suspension. You get more travel up front and a slacker headtube, but you’re moving the rest of the geometry in the opposite direction of what you want.
Both James and I felt that we were constantly fighting to hold lines on Pemberton's chunky, steep terrain, and it was the most nervous of the five bikes we rode. The suspension on the descents was not the most predictable or supple, and instead of being able to relax into the descents and catch your breath, you had to really hang on and focus on the task at hand.
On the trails in Pemberton, it felt like the Live Valve-equipped Mach 4 SL had a hard time keeping up with the terrain at times, especially when faced with repeated hard impacts.