Field Test: BMC Fourstroke LT - Gorgeous in Green

The Fourstroke LT is a thing of beauty, especially with the sparkly green paint and exceptionally clean lines. I don't know about you, but there's something about it that makes me believe it's from the future while also looking uncluttered and classy. The internal cable routing is tube-in-tube and the cables enter at the fork bumper on the downtube. Other notables include room for a single bottle inside the front triangle (nothing on the downtube), a minimalist molded chainstay protector, and the cutest little rubber fender to keep rocks and gunk from getting trapped between the frame and lower link.

The most interesting part of the BMC? That has to be the integrated dropper post.

There are some obvious reasons to be wary of an integrated anything, but the Race Application Dropper is certainly neat and has been around since 2018. Two bushings are pressed right into the bike's seat tube, and the post itself is oval-shaped which, according to BMC, "reduces weight while improving strength for reduced flex and uncompromised functionality under load." The whole thing is said to weigh just 345-grams, which is much less than most other droppers, and especially those with more travel than the 80mm all-mechanical, two-position RAD design offers.

I suspect that many of us would prefer more stroke, but on a 120mm-travel rig intended for marathon racing and fast riding some riders will be okay with less rather than none at all. Speaking of less, you only get 90mm of seat height adjustment in the frame, with the post-clamping bolt near the bottom of the seat tube rather than the top.




Bicycle Manufacturing Company uses a dual-link suspension layout that they say allows them to, "design complex kinematics that could not be achieved using weight-driven solutions like flex stays and single-pivot suspension systems." The upper link is carbon while the captured lower link is aluminum, and it's actually the same frame as the 100mm-travel bike, but it gets a longer stroke shock to deliver the added travel. If you're looking to downsize for some reason, all you need is a spacer from Fox to reduce the stroke.

The Fourstroke LT might have a bit more travel than a pure race bike, but the other numbers still point towards quick, responsive handling and a snappy ride. The 66.5-degree head angle is a degree slacker than the standard Fourstroke, and all sizes get short 429mm long chainstays and a 74.8-degree seat angle. Reach is conservative, with our medium-sized test bike sitting at 440mm, a large at 456mm, and an extra-large at only 476mm.

All of the above adds up to a respectable 25.2 lb (11.4 kg) after we installed the Specialized Ground Control tires that we put on all six of our test bikes.





Trailforks Regions Where We Tested

While we spent time at Massif de Charlevoix, the Empire 47 trail center, and both Sentiers du Moulin and Vallee Bras du Nord, most of my saddle time on the BMC took place at Mont-Sainte-Anne's cross-country park. You'll find plenty of short loops to smash out, all of which are easy to access from the trailhead and a good match for our short-travel test bike fleet. You can choose to climb singletrack or the gravel road up, while a mix of berms and flow or more natural, rooty trails take you back down to do another lap.

It may be "just" a blue square, but don't sleep on La Bouttaboutte, a fun route that traverses across the hillside, or La Lisière if you're looking for more of a challenge. There are also plenty of other lesser-known trails worth checking out in the same area, including a few freshies just waiting for your tire tracks.

Mont-Sainte-Anne XC Park

Climbing

If you ask me, the Fourstroke looks fast while it's just leaning up against a wall. The clock backs it up, with the BMC tied for the quickest uphill time during Sarah's laps. You wouldn't be surprised with that result if you pedaled the Fourstroke LT around for more than ten feet, though; both the riding position and relatively firm suspension are dead giveaways that this thing is all about speed, regardless of it having 20mm added room for fun.

Much like the BMC hardtail we reviewed at last year's Value Bike Field Test, the Fourstroke's front-end came slammed from the factory. For some reason, that's like dangling a still-warm glazed donut in front of me when I'm on a climb. Or a flat section. Or anywhere really, even though I'm fully aware that donut is hanging from a string off the front of my own helmet and that'll no amount of mashing on the pedals will let me taste it. I know that doesn't sound like "fun" to everyone, but riders nodding their head right now are the ones most in line with the Fourstroke's intentions.

There's an obvious efficiency to the suspension, and that goes well with the riding position to make for a bike that's always eager for your watts. There's also a lockout to firm up both the fork and shock, but I never once felt like I needed to activate Europe-mode, even when chasing that donut up the paved climb to the trailhead before the ride actually started.

The Swiss missile loves getting into the tight and twisties, too, easily carrying good speed through switchbacks versus longer, softer bikes like the BC40 and Wildcat that needed an extra second or two and a bit more elbow room. It's not all PRs and KOMs for the BMC, though, as both of those bikes had far more grip and success whenever climbs got really muddy and slippery. The Allied in particular rewards you for staying seated, carrying more momentum when possible, and tractor-ing straight up through that patch of shiny roots, whereas the firmer Fourstroke is more likely to get knocked offline and less likely to find any traction after that happens. It's still a monster on the climbs, and especially when watts are more important than line choice, but it won't do you any favors if you're trying to keep your dab count low.




Descending

If you've gotten this far, I probably don't need to tell you that the Fourstroke LT isn't focused on descending... But the Fourstroke LT isn't focused on descending. That's important to stress because sometimes I think we forget that not every bike is trying to be your trail bike, even if it has 120mm rather than 100mm of travel. This BMC is a cross-country weapon, through and through, and is a ton of fun on most downhills once I got that fact through my thick skull.

The bike comes alive when you realize that no, you don't need a 300mm dropper post or handlebars higher than your nipples to have fun, just a willingness to cartwheel through the rhubarb when you go past the BMC's very well-defined edge of control. With a short-ish wheelbase and firm-ish suspension, that edge comes much sooner than it does on all the other short-travel bikes we have in Quebec, aside from the Lapierre that wants to live its entire life over the edge. Having just 80mm of seat drop didn't help, of course, and neither does the fact that you literally can't install any other post on the bike due to the frame's oval-shaped tube and proprietary design.

Now that I've got all that out of my system, I can also say that the Fourstoke is fast as hell on the right kind of descent, which is obviously anything not steep or technical or rough. On flowier sections of trail that ask you to pump and carry speed it can feel like an oversized BMX bike of sorts, especially if it's tighter than faster. Ride the bike with precision and stay engaged, and it'll easily get through anything and everything I'd consider cross-country-able. I may have even accidentally pointed the BMC down some chutes that were more suitable to that other-country that we won't mention here and it more than held its own, even if I did quickly realize that baggy shorts and short-travel droppers can be a sketchy combo.

As for the Fourstroke LT's 120mm of suspension, it didn't do anything wrong but also didn't wow any of us in any way during testing. Both Matt and I made similar notes about it feeling a bit more supple and active than the Lapierre, but also that both bikes were more chattery and less forgiving over fast rough ground than the others. You'll likely find yourself standing more when riding the BMC than on the Allied or even the Ibis for that reason.




Back to that clever proprietary seatpost before we wrap this up: I broke it. Actually, I only broke the bolt at the bottom of the seat tube that clamps the whole thing in place, and while I likely could have found something by taking a trip to the local Quincaillerie Limoilou, the correct bolt includes an O-ring seal and would be the right fix. It snapped when I was tightening it by holding onto the very short end of my tiny multi-tool and I very definitely wasn't using a torque wrench. Just being honest.

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Pinkbike's Take

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