Pivot Cycles’ new Mach 4 SL replaces both the Mach 4 and Mach 429 SL, designating it the only dual-suspension, cross-country offering in Pivot’s lineup. The roster isn’t the only thing that’s been streamlined while producing this flagship XC bike. The new Mach 4 SL has shed some weight and lost some curviness through the makeover process. The svelte new frame is still designed around the highly-praised DW-link platform, but now has revised geometry – featuring an upright shock configuration. Company founder, Chris Cocalis, has always had a no-compromise philosophy with his designs, prioritizing function over form. While the performance was always there, the unconventional shapes and sizes didn’t suit everyone, myself included. That’s old news though, as every bike released from Pivot recently is absolutely jaw-dropping. No longer the runner up at the pageant like its step sisters were, this fabulous new Mach 4 SL is both beauty and beast.
What’s New with the Mach 4 SL
The Mach 4 SL is only available with 29” wheels. No surprise there, as this is a bike with World Cup winning heritage and aspirations. Sure, there are still riders grinding out cross-country laps on 27.5” wheels but climbing onto the steps of a World Cup podium will most certainly require the 29” variety. While there is no denying the pace and proficiency of bigger wheels, they can be cumbersome for smaller riders. Pivot athlete Chloe Woodruff stands 5’2” tall and worked in tandem with the engineering team to design a bike that meets their needs. The frame is available in sizes XS-XL and comfortably fits riders between 4’10” and 6’7”.
Repositioning the shock from its horizontal position under the top tube to a vertical configuration in front of the seat tube, was fundamental in solving other design objectives. Pivot was able to produce a frame with greater standover than the outgoing 27.5” Mach 4 frame afforded. The new Mach 4 SL frame also has a shorter seat tube, increasing options for riders wishing to run longer dropper posts. These modifications make it cleaner to choose a frame size based primarily on the reach measurement. Riders will also be happy to hear that the frame can now accommodate a water bottle inside the main frame. The mounting location also includes auxiliary anchoring options to install the bottle higher or lower along the top of the down tube. My size medium frame has three bolting options to choose from. The XL frame has even more and can run two water bottles using these add-ons. While after-market options such as Wolf Tooth’s B-Rad system facilitate this, a built-in solution is always cleaner.
Refinements in the mold and carbon layup have allowed Pivot to produce a frame that is roughly 300 grams lighter than the previous Mach 4. A Mach 4 SL kitted with Pivot’s top tier World Cup build is reported to weigh 21lbs. Affixing a horizontally oriented shock to the top or down tube requires more material be added to neutralize forces focused there. A vertical shock, which is fastened above the bottom bracket, takes advantage of being mounted were the frame is already optimized for added stiffness. Another notable revision is the integration of full carbon bearing cups. Tube shapes have also been enhanced to add clearance and reduce weight. The stiff, one-piece rear triangle now incorporates double uprights that join the stout aluminum links to the main triangle. The frame incorporates a press fit bottom bracket. I’m not a fan, but my experience with other Pivot bikes have revealed that they pay close attention to tolerances. They were a co-developer after all. I haven’t had any issue to warrant my aversion to press fit bottom brackets – on Pivots anyway. Though I remain partial to the threaded variety. Cable routing is fairly straightforward, with easy access using Pivots Cable Port System. I have encountered some cable rattle on other Pivot bikes, but the ride on the Mach 4 SL has remained rattle free. I still feel this port system could be improved with some rubberized backsides at the port to better clasp and dampen cables.
Pivot Cycles Mach 4 SL Team XX1 & Fox Live Valve Details
Fork: Fox Factory Stepcast Live 34 29”, 44mm offset, FIT LIVE – 120mm
Shock: Fox Factory Live Valve
Shifters: Sram XX1 Eagle AXS 12-Speed
Rear Derailleur: Sram XX1 Eagle AXS 12-Speed
Cassette: Sram XG-1299 10-50t
Brakes: SRAM Code RSC
Wheels: DT Swiss XRC 1200 w/ DT Swiss 240 hub & 36t Star Ratchet, 25mm – 29″
Crankset: Sram XX1 Eagle DUB SL 32t
Tires: Maxxis Ardent Race 29″ x 2.2″ TR, EXO, 120 TPI, Maxxis Ardent Race 29″ x 2.2″ TR, EXO, 120 TPI
Stem: Race Face Aeffect R 50mm
Headset:Pivot Precision Sealed Integrated Cartridge
Handlebar: Phoenix Team Flat Carbon
Saddle: Phoenix WTB Team Volt
Seatpost: Rock Shox Reverb
MSRP: $11,999.00 US
Weight: 11.75kg / 25.90lbs (with XTR Trail pedals)
More details, geometry charts and build options can be found here: https://www.pivotcycles.com/en/bike-mach-4-sl-1
Is The Mach 4 SL Down-Country?
Short-travel trail bikes such as the Pivot Trail 429, Giant Trance and Santa Cruz Tallboy fill the demand of most riders looking for an efficient daily-driver. These bikes are at home on chunky trails, perfect for long days in the saddle or multi-day stage-races. These ultra-capable bikes have pushed the limits of what short-travel bikes can do. I’d go so far as to say that many of the bikes within the 120-140mm travel offering are closer to mini-enduro bikes than traditional trail or all-mountain bikes.
Developing these bikes to be nearly as capable as their long travel siblings has come with a noticeable weight penalty, however. While there is still a considerable gap in ultimate potential between a trail and enduro bike, that spread is much tighter on the scale. Sometimes only a few pounds separate the two significantly different classes of bike. While lightweight used to be a major selling point, the trend has certainly moved towards capability and reliability. Riders in the market for a contemporary trail bike appreciate the trade-off required to achieve that performance. For purebred cross-country riders however, that’s not the performance they’re after and these bikes are still an uncalled-for compromise.
The newly defined “down” or “fun-country” category spans a narrow but critical junction between current XC and trail bikes. Its genesis is from racers challenged by shorter, more technical circuits and non-racers missing a lighter trail bike option. Within that newly established spectrum, some bikes are more down than country. I think it’s a negligible and highly subjective distinction, similar to the one that divides the all-mountain and enduro race classes. If you’re at the top of your game, those subtle differences could make or break your season. For everyone else, it’s a matter of preference over performance. The distinction between down and cross-country is so subtle in fact, that a slight change in the build can alter the bike’s characteristics enough to reclassify it. Both Pivot and Santa Cruz offer trail build options that achieve this very thing. Moving up to a 34mm stanchion fork, with a 20mm bump in travel, is sometimes enough to bridge the two classes. Adding a dropper post further declares down-country intentions. Do these minor mods really make a bike down-country though, or is it just a ploy to have the bike appeal to a broader customer base? Can a bike designed around a 100mm travel, 32mm stanchion fork really achieve down-country performance, whatever that is?
My dream down-country setup blends a lightweight chassis, built around an efficient suspension platform and modern geometry. I’m not a fan of the terms “under” and “overbiked”, which often comes across as a judgment on others’ bike choices. In building a case for my down-country bike however, I wanted to be as “underbiked” as possible before needing to bust out the Bic. Butting right up against the cutting edge of cross-country performance, while benefiting from all the recent advances garnered from modern-day trail bikes. Anything more would quickly nudge me into short-travel trail bike manners and weight.
I’ve had the pleasure of owning a few Pivot bikes now. The Les Fat, Phoenix DH and Firebird 29. While these aren’t fully representative of Pivot’s top tier cross-country models, I’ve always appreciated Pivot’s application of the DW-Link suspension platform. This placed Pivot at the top of the list, right out of the gate. Also in the running were the Santa Cruz Blur, Yeti SB100 and Trek Top Fuel.
Officially, the Mach 4 SL is predominantly positioned and promoted as a World Cup winning race bike. When kitted in Pivot’s full off-road package however, the Mach 4 SL ticks most of the boxes on my down-country bike checklist.
Now that I was settled on the Mach 4 SL, the only choice remaining was whether to indulge completely and opt for the Fox Live Valve upgrade. Pivot has worked closely with Fox during Live Valve’s development and I was keen to see what such a sophisticated system could do for a hack like me. Could it make up for the five watts lost by not shaving my legs? Live valve is also available on certain models from Rocky Mountain, Scott and Giant. I don’t want this review to turn into a Live Valve assessment but it definitely deserves more than a mention in the spec list. It’s a component of the bike that is so interdependent, it’s difficult to isolate it from the rest of the bikes performance.
What is Fox Live Valve?
Fox Live Valve is an electronically controlled suspension system that integrates a central controller and sensors to read and react in real-time to ever changing terrain. Live Valve provides automated, faster than humanly possible, on-the-fly adjustments to the suspension system. Fox claims this is the fastest valve they have ever produced for mountain bike applications.
The Fox Live Valve system is made up of a controller, battery, three sensors and Live Valve valves in the fork and rear shock. The accelerometer sensors are positioned at the fork, chainstay and main triangle. These sensors measure bump force independently at the front and rear wheel, evaluating the terrain and informing the system at a rate of one thousand times per second. The sensors can also detect whether the bike is going uphill, downhill or is mid flight, and apprises the controller accordingly.
More information about Fox Live Valve can be found here: https://www.ridefox.com/content.php?c=livevalve-bike
Riding the Mach 4 SL
Setting up the Mach 4 SL was easy as pie. The bike arrived directly from Pivot and the final assembly was a pleasure. For no reason other than personal preference, I swapped the brakes, dropper post, bar and stem. The Live Valve system came pre-installed, which I believe could have been the only element to present a challenge. Like with all Pivot bikes, a sag indicator takes the guesswork out of setup and I have been completely satisfied running Pivots recommendations. I am operating at roughly 18% sag in the fork, sometimes bumping it down to 15% depending on the terrain. I am running the low speed, open-adjustment setting in the stock configuration. I’m an obsessive knob turner when it comes to suspension. I can spend weeks bracketing settings to get things just right. The very fact that I have ridden the bike all this time without fiddling with the dials, says a lot about how good the base Live Valve tune is. The Live Valve shocks come with a slightly lighter tune than the shocks without Live Valve.
On the trail, it’s hard to not be instantly blown away by the snappy pedaling feel the Mach 4 SL delivers. A phenomenon achieved jointly by the responsive and supportive feel of the DW-Link platform combined with the seamless integration of Fox Live Valve. The DW-Link suspension on the Mach 4 SL is so optimized that lockout or Live Valve isn’t required to put power to the pedals. Organically, the suspension is firm with just enough activation to maintain optimal traction. The entire stroke has a predictive and supportive feel. The platform provides crisp, positive feedback to the terrain. When faced with roots and rocks, the rear suspension opens without hesitation. What I love most about the suspension is that even while it’s damping a blow from below, I’m able to drop my heals and drive the bike. Traction remains composed at times when most bikes would be left scrambling. This raw, reactive attribute is absolutely addictive and makes you want to smash things most XC bikes would have you avoid.
The balance of the bike is on point. Only minor tweaks in air pressure were required to hone in on the sweet spot. It’s easy to sit in the pocket and rally the Mach 4 SL. The bike can just as easily be pulled up from the ground, as it can be pushed into it. It’s got plenty of pop and doesn’t flinch when things get choppy. With only 100mm of travel out back, the Mach 4 SL can get out of its depth when things get big and burly. Though I must say that my time on the Mach 4 SL revealed that it could handle much more than I expected it would.
Digging into the geometry chart reveals that the Mach 4 SL’s has a fairly relaxed 67.5-degree head tube angle. While that wasn’t the slackest among the bikes I considered, it proved to be well suited to the rest of the Mach 4 SL’s manners. The bike has a precise, responsive feel at the bars, with no wheel flop on climbs. The 73.5-degree seat tube angle provided a confortable pedaling position. The DW link platform provides above average support and sits higher in its travel than most other suspension designs. For this reason the actual seat tube angle is steeper in practice than it appears on paper. Short, 430mm chain stays add to the already snappy, go-cart-like ride the Mach 4 SL offers. Pivot was able to achieve this with standard Boost spacing on the Mach 4 SL.
My only real gripe with the Mach 4 SL has to be the stunted reach. With 100mm fork, the size medium Mach 4 SL has a 440mm reach. That number drops to 427mm with the 120mm travel fork option. There are times during my testing that I wished for a slightly longer, slacker front end. However, the bike rides so well that my little voice kept pleading with me not to mess with the special-sauce, because it clearly works. In retrospect, I should have gone with a size large. That choice is on me, though I will say that I find Pivot’s sizing to be inconsistent across models. With most brands I am a size medium, across the board. With Pivot, I can span three sizes depending on the model.
This is a bike that really has to be measured as a whole though. A reductionist look at the bike might reveal one millimeter or degree that seems off but the entire bike is a finely tuned machine. On one of my early rides aboard the Mach 4 SL I was inspired to charge a local segment. I dropped into the trail with no intention of “going for it” that day but the Mach 4 SL demanded it. I was with a seasoned XC racer who typically has me in the hurt locker on these sorts of rides. When he caught up to me at the end of the trail, he commented that all he saw were claw marks were that bike had dug in on the climbs. That echoed how I felt, which was insane traction and power transfer. I crushed my previous best time on that day and broke into the top three for that segment. I should punctuate this by saying that I don’t ride for segment results, or any result. This did however help to provide a metric to what I was feeling on the bike. Which is that is just wants to go. Go fast!
Fox Live Valve in Action
We have no mountains in Ontario, but that doesn’t mean we don’t have peaks and valleys. They just aren’t very big. What they lack in vertical, they make up for in sheer volume. We’ve got more ridges than a rippled potato chip up here. The climbs are short and punchy, with abrupt transitions. Every ride profile here looks like a nasty interval.
This ever-undulating terrain is one of the primary reasons I have never really taken to lockout for suspension. There are certainly times when it’s welcomed, but for the most part, I found all it added was bar clutter with less tuning potential. I prefer Fox’s Grip2 damper, which allows independent control of the low and high-speed circuits. I love the idea of my suspension being firmer when needed, but I don’t feel like playing thumb wars or performing finger gymnastics to achieve it. The crux is hitting the lever or turning that dial at the exact moment when it can actually make a meaningful enough difference to warrant it. While the window to hit the trigger on a long fire road climb stays open for a while, it gets slammed shut pretty quickly here. The moment you’re down, you’re going back up again. My philosophy has always been to optimize my suspension the best I could and leave the rest to timing and fitness.
I was excited but still remained unconvinced about the claims made with regards to Fox Live Valve’s performance. I suspected it would be just another lockout gadget that was always a bit off and caused more mistakes than it prevented. I was so wrong. After only one ride, it was clear that Fox Live Valve is the real deal. The integration and performance is completely seamless on the trail.
The controller has five settings. These settings determine the amount of force required to open the valves, as well as how long the valves remain open. This is a very smart concept that makes it dead simple to adjust your entire ride platform based on the terrain. I’ve tested all five settings and found the third position to be best for my riding style and needs. Another nod to how well Pivot and Fox have this tuned for the Mach 4 SL.
There are hundreds of opportunities to make use of lockout on a typical ride here. With a mechanical lever, I’d estimate that I take advantage of 25% of them. Past experience with lockout and selectable compression modes reveals that I’ll be in the wrong setting for a good chunk of my ride. That margin of error has to be factored into the equation to determine a technologies’ worth. Not only does Fox Live Valve remove the guesswork and potential blunder, it takes advantage of every possibility to optimize the suspension. Where I perceive dozens of times to adjust the suspension on a ride, Live Valve sees thousands. My greatest revelation was how many times it came on and off, ever so briefly, and what that added to my ride. It never took away from anything, only added. It’s hard to go back once you’ve felt the advantage it offers. If you’re considering this over carbon wheels, get Live Valve, hands down.
Where it really shined for me was putting power down out of a corner. I did encounter the odd clunk when confronted with oddly spaced ledges and chunky terrain: mostly when you’re doing trials-style efforts. It still worked but the transition could be felt and was a bit clunky. Riding Live Valve feels like AI for your suspension. It’s either that or Fox has placed a miniaturized version of their supreme World Cup Tech Jordi Andres Cortes in your suspension and he’s in there, with tunes cranked, working his magic.
While I haven’t had any issues with Fox Live Valve, I wouldn’t want to have to troubleshoot it or send it in for repair.
This is a very high-end bike and its price tag certainly reflects that. That said, whether you’re a weekend warrior or World Cup cross-country racer, this bike will deliver. In my opinion, given my down-country dreams, the bike is exactly what I was after. In true Pivot fashion, the Mach 4 SL is all about performance. It pedals amazingly well with or without Live Valve, and is more than capable to tackle anything in front of it. It’s a blast to ride and certainly inspires me to push my limits. The ride is supple, well-balanced and ready to charge – if you are. While not easily measured, I felt much fresher after long rides on the Mach 4 SL. At times, even choosing it for my gravel rides.
I don’t think it could be my personal quiver killer but I am certain that it could be for most riders in Ontario. I’d recommend double-checking the reach based on your style and what length stem you’ll want to run.
Is the Mach 4 SL down-country? I think that will come down to how it fits a rider’s individual needs. During my time on the Mach 4 SL, I never really felt like I was on a purebred XC bike. For my needs, it most certainly was full on, fun-country. But it most certainly is a top-tier cross-country dominating machine. The fact that, under a better rider, with a different build, it can lay waste to a field of elite racers indicates that this bike is very much wolf in sheep’s clothing.