First Ride: Pivot's Third Generation Mach 4 SL (2023)

The Takeaway: Pivot’s new Mach 4 SL shaves 300 to 400 grams from the previous version, along with updated geometry and a revised suspension. Offered in two versions—a 100mm-travel fork with 95 or 103mm rear travel and a 120mm fork with 106 or 115mm rear travel—the new Mach 4 is the lightest dw-link frame on the market and one of the lightest dual-link frames, period. It offers refined rear suspension performance in a category where many bikes are little more than glorified hardtails.

Price: $6,200 to $11,600 (as tested, $11,600)
Weight: 24.4 lb. (Medium, Team XX SL)

The first World Cup Cross Country Olympic (XCO) race of 2023 recently took place in Nove Mesto, Czech Republic. As if to celebrate the return of professional mountain bikers riding absurdly fast up and down hills, Pivot dropped the latest version of its Mach 4 SL XC race bike.

Now in its third generation, the new Mach 4 SL is lighter (of course), with revised geometry (longer, slacker—of course), and refined suspension that both pedals more efficiently and improves its capability in rougher terrain (say it with me, of course).

While the Mach 4 SL comes in a reduced travel cross-country race-tuned variant with remote front and rear lockout and other lightweight parts, it’s also offered in a slightly longer travel version that’s more suited to marathon racing and riders who prefer a light bike for their everyday mountain biking.

No matter which flavor you prefer, the new Mach 4 SL is available at Pivot dealers starting today.

Suspension Details

From the beginning, the new Mach 4 SL was designed to satisfy the needs of a World Cup level cross country racer. Even though this bike comes in two travel variants—95 and 103mm rear travel with a 100mm fork or 106 and 115mm rear travel with a 120mm fork—the shorter travel version led the way during design. However, Pivot’s president Chris Cocalis says there was some “give and take” between the variants as they finalized the frame designs to ensure appropriate geometry for both.

As you’d expect for an XC race bike, weight is of utmost importance. And on that front, the Mach 4 SL is impressive. Pivot claims they’ve pulled three to four hundred grams out of the frame compared to the previous version: a painted size small frame with shock weighs 1,930 grams (4.3 pounds and that’s an actual weight on a Feedback Sports scale). That’s lighter than the other race frame with dw-link suspension, Ibis’s USA-made Exie (2,026g, 4.47 lb. for a size medium with shock).

Notably, Cocalis says Pivot cut significant weight from the previous generation while making the bike more capable and without any loss of frame stiffness.

A complete Mach 4 SL World Cup build with SRAM XX SL Transmission, front and rear remote lockout, dropper post, and 2.4-inch tires weighs 10.4kg (22.9lb.). Again, that’s a real weight on a Feedback scale. And Cocalis says bikes for Pivot’s professional racers can get closer to 20 pounds. The medium size bike I rode—the longer travel version with the most expensive Team XX SL build—weighs 24.4 pounds.

I imagine the Weight Weenies forum alight with comments like, “Yeah, but the new Specialized Epic World Cup is lighter.” Indeed, it is. That frame comes in at a claimed 1,765 grams (3.9 lb., medium frame painted with shock and all hardware) with complete bikes in large weighing around 9.8kg (21.7 lb.) though notably without a dropper post.

There is an important distinction between the Mach 4 SL and the new Epic (and many other World Cup race bikes, too)—the suspension. The new Epic has just 75mm of rear travel actuated by a single pivot suspension system. Trek’s Supercaliber (which heavily, um, “inspired” the new Epic) uses a single pivot to achieve 60mm of rear travel and a frame weight of 1,933 grams (4.3 lb., size medium).

1,933g (size large) is also the claimed weight of Santa Cruz’s Blur XC frame, which features 100mm of travel and single pivot suspension. Allied’s 120mm travel BC40 frame has a “target” weight of 1,950g (large, with shock) and, again, single pivot suspension. And Scott’s single pivot 120mm travel Spark RC SL frame has a claimed weight of 1,870 grams (with shock).

As you can see, these XC race frames come in around 1,800 to 2,000 grams and use a single pivot suspension layout. And a quick scan of the bikes used by the professionals at World Cups reveals that almost all of them are on bikes with a single pivot system. The Pivot, however, uses dw-link suspension: a dual-link design with cartridge bearings in the pivots. It’s a heavier system but offers more control over the kinematics, which—in theory—results in more refined suspension.

I asked Cocalis why he stuck with dw-link for his World Cup XC bike, “Even if we could have shaved a few more grams [by using a single pivot system], frame stiffness and suspension performance would have been compromised,” Cocalis told me, adding, “The dw-link along with the one piece triangulated swingarm provides a more efficient pedaling platform and enables that rider to maximize their power output. We avoid the inconsistency in handling and wind up that is common among single-pivot flex-stay bikes.”

I followed up by asking him what advantages, in his opinion, the dual link system offers compared to a single pivot system used by so many other XC race bikes, “Even at XC travels, the rearward wheel travel path of the Mach 4SL can take the hits better [than a single pivot frame] without being knocked offline. However, everyone already knows that single-pivot bikes make some compromises for simplicity and lightweight. In the case of the dw-link, there’s also the pedaling performance side of the equation. We can really get the power down and do it while keeping the chassis in line and doing what it is supposed to do,” Cocalis said.

Frame Details

You’ll see that Pivot continues to use a BB92 press-fit bottom bracket. While this stands apart from the many brands returning to threaded bottom brackets, Cocalis—who helped develop the press-fit BB92 standard with Shimano—argues that a properly-executed press-fit system is “A shit ton” lighter than a threaded system and presents “No issues if done properly.” Every frame is placed in a CNC machine to clean up and prepare the cable ports, pivots, head tube, and bottom bracket for assembly. As a result, Cocalis claims a press-fit, “bottom bracket will not wear out early or creak in our bikes.”

Sticking with a press-fit bottom bracket is against the grain. And so is the Mach 4 SL’s hose and housing routing. Pivot sticks with its clamping port system in the downtube, not routing hoses through the upper headset bearing. While not as clean aesthetically—to be clear, the ONLY reason brands are switching to a more hidden hose and housing routing scheme is aesthetics—Pivot’s arrangement does make things like headset, brake, and drivetrain maintenance, replacement, and repair much (MUCH!) easier, and will cost you less in labor fees at the bike shop.

Pivot also eschews full-length routing tunnels, stating that adding them adds weight and removes some routing options for riders with different control setups. Pivot keeps things quiet in the downtube by over-wrapping hoses and housing with foam tubes.

While Pivot gets credit for “inventing” Super Boost Plus 157mm rear spacing (it’s essentially the DH 150mm standard that predates Boost 148), the Mach 4 SL sticks with Boost 148, which allows fitting the lowest Q-factor cranks offered by SRAM and Shimano.

A notable absence from the new Mach 4 SL frame are provisions for Fox’s Live Valve system. Pivot is one of Live Valve’s biggest cheerleaders, offering it as an option on many models (it was a popular upgrade for buyers of the outgoing Mach 4 SL). While the lack of provisions might seem like Pivot is stepping away from the system, it appears there is a more exciting reason (cryptically suggested by Cocalis): a new and wireless Live Valve system on the horizon. Plus, by eliminating compatibility with current Live Valve systems, Pivot was able to make the frame lighter.

The Mach 4 SL’s vertical shock arrangement eliminates the possibility of seat tube water bottle placement. But Pivot still worked up a two-bottle solution for most sizes. All sizes fit a large water bottle on the downtube, and the three-pack mount under the top tube provides a second, albeit less conventional, bottle mount option for riders of medium and larger frames. That three-pack mount can also be used for a cargo plate or to mount one of Pivot’s Phoenix Mount accessories (tools, CO2 systems). There’s an additional mount under the downtube which can be used as a bottle mount, for a cargo plate or one of Pivot’s Phoenix Mount products.

Rounding out the frame details are rubberized chain slap guards, two ISCG ’05 tabs for a chain guide, a UDH derailleur hanger for compatibility with SRAM Transmission, and clearance for up to a 38-tooth chainring.

Two Travels

The Mach 4 SL comes in two travel variants. World Cup trims 95 or 103mm rear travel with a 100mm fork, while all other trims (Team, Pro, Ride) run 106 or 115mm rear travel with a 120mm fork.

World Cup builds have less rear travel because they use a shorter stroke shock: 40mm versus 45mm for the other builds. Eye-to-eye length, however, does not change. So the bike’s geometry is the same with either shock. As you’ll see below, World Cup builds have different geometry than the others, but this is solely down to a change in fork travel.

The 95/103mm or 106/115mm travel setting is achieved with a flip chip in the rocker that changes the overall leverage ratio on the shock. It does not alter the geometry, and because leverage at sag is about the same in both settings, riders shouldn’t have to change shock pressure when they change travel.

Geometry

The Mach 4 SL comes in sizes extra-small through extra-large: all roll on 29-inch wheels.

Compared to the outgoing generation, the new Mach 4 SL features a steeper seat tube angle, slacker head angle, and a longer top tube and reach.

Regardless of rear travel, all models use the same frame and a shock with the same eye-to-eye length (190mm). That means all geometry changes are down to a change in fork travel.

The head angle is 68 degrees (100mm fork) or 66.7° (120mm fork). On paper, all sizes have either an effective 76°(100mm fork) or 74.7° (120mm fork) seat tube angle. However, those effective angles are measured at a different saddle height for every size, so this frame does feature size-specific actual seat tube angles.

All sizes use a 432mm chainstay length. The seat tubes are on the shorter side and straight, meaning many riders can fit longer-travel droppers if they desire.

Build Kits

There are four build tiers—in order of price from lowest to highest: Ride, Pro, World Cup, and Team—and each tier has two kit options. Complete bike prices begin at $6,200 (Ride SLX/XT) and top out at $11,600 (Team XX SL). You can find all of the build details on Pivot’s website.

All builds have dropper posts—the World Cup builds getting Fox’s new two-position Transfer SL dropper—and most builds (the two Ride level builds excepted) get remote lockouts.

World Cups get a single remote that locks both front and rear, while Pro and Team builds have only a remote rear lockout. The World Cup’s lockout tune is race firm, while the Pro and Team get a softer platform instead of a rigid lock.

Another differentiation for the World Cup models is the fork itself: a smaller diameter 10omm travel Fox 32 instead of the 120mm Fox 34 on the other builds.

No matter the build, the frame is the same. Besides the five sizes, riders can choose Seafoam Green or Ice Blue paint.

First Ride Impressions

I took my first rides on a new Pivot Mach 4 SL (the 106/115mm frame with 120mm fork in the Team XX SL build) over the course of two days. In a twist from the usual press trip boondoggle, this event took place at the Phil’s World trail system in Cortez, Colorado—just down the road from my home in Durango.

I know these trails very well, giving me a better-than-usual first taste of a new bike. Even so, I’m withholding my final judgment because the Phil’s World trails which—while an extremely good time—are medium speed, flowing, not very technical, lack extended climbs or descents, and are less demanding than current World Cup XCO or XCM racecourses.

As such, there were few opportunities to push this new bike as hard as I like to before making any declarations. I have the bike in my possession and will ride it on home trails (and in the high country when those trails dry), and I will let some trusted testers bound around on it as well.

Embarking on the first ride, I quickly noticed my seated position was further aft of the bottom bracket than I prefer. This was surprising because I don’t like a particularly forward riding position, especially on an XC-style bike. But I did stop and push the seat almost all the way forward, which felt much better. I’ve never vibed with the stock WTB Phoenix saddle (especially in the narrow width that Pivot uses). So, perhaps I was sitting on the back of this saddle for comfort, and the too-rearward sensation will abate when I install a favored saddle.

The other thing I quickly felt was some lateral give in the back end of the bike. Whether this comes from the frame, the Reynolds Blacklabel 289 rear wheel, or the 120TPI Maxxis Rekon Race rear tire—or some combination of the three—I don’t yet know. I am 180 pounds, which is on the heavier side for a lightweight XC setup, so that needs to be considered as well. But the flex was never detrimental to the bike’s performance, or my ability to hit the lines I wanted. It was simply noticeable, or perhaps more noticeable that it is on the longer travel bikes I more frequently ride.

With the seat in a better place, and familiarity pushing the give from the front of my mind, I began to settle in with the Mach 4 SL and started to feel out its qualities.

What has impressed me most about the Mach 4 SL so far is its speed. It doesn’t take much effort to get this bike up to speed. And once you’re going, the superb rear suspension and the bike’s handling lets you hold on to that speed with ease. It is a super-efficient bike, and not just in its pedaling performance. Everything about this bike’s being seems to let the rider extract as much speed as possible in cross country conditions.

Head angles are now, and forever will be, a topic of debate. I think there’s as much a case to be made that the Mach 4 SL should have a slacker head angle as there is a steeper head angle. That’s because there is no perfect head angle or handling feel, only what an individual rider likes.

I do like the Mach 4 SL’s steering which I find light and reactive enough to give it a zesty feel and plenty of front-end traction, yet it never gave me a reason to fear that the front-end might tuck either. As I noted above, the terrain at the launch was not steep or challenging but even so the Mach 4 SL so far strikes me as a bike that, although very reactive, maintains healthy balance and predictability which allows the rider to confidently push the bike hard.

Although it seems almost a given for a Pivot with dw-link, the rear suspension impressed. The Mach 4 SL gets a lot of nuanced performance out of a little bit of travel. Unlike many XC race bikes, the Mach 4 SL does not ride like a hardtail with extra give: It is a real suspension bike with real suspension performance.

That may not be what all XC riders want—for them, many other options exist—but my initial impression is that the Mach 4 SL is a truly lightweight cross-country bike with true suspension performance. And that’s a fearsome combination.