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First Ride: BMC Speedfox

BMC's Trailsync dropper post takes control

When they first started putting lights inside refrigerators, I wonder if they had to be switched on manually. I'd bet some people would forget to switch them off, and others wouldn't bother using them at all. Eventually, someone must have realized that you only need the light when the door is open, and voila! System integration. It was only a matter of time before the same thing happened between our dropper posts and our rear shocks.

Trailsync: The Post

The Trailsync dropper post is integrated into the new Speedfox frame (we’ll get to that) and offers the bigger diameter, larger hardware, stronger bushings, and cleaner look you can only get with the forward-thinking integrated approach. But other aspects of Trailsync are a bit of a throwback. The three-position system is similar to that of mechanical posts of yesteryear, and you'll only get 80 millimeters of travel on the small, 100 on the medium, and 125 on the large and extra large.

That panel under the top tube hides the mechanism that locks the post in place.

The travel is limited in part because all the action needs to fit within the short distance between the top of the seat tube and just below the top tube where the locking mechanism sits. It keys into a track along the front of the post and holds it in place with a spring-loaded pin. Everything above that track has to be smooth and round to seal inside the dust wiper that takes the place of the seat clamp.

The seat mast topper offers plenty of adjustability after you’ve made the cut.

No traditional seat clamp means no traditional height adjustment. You'll actually be doing your initial sizing with a hacksaw. Similar to integrated posts found on road bikes, the fine tuning is then done with an adjustable "topper" which clamps over the cut end of the post. That end happens to serve as the air spring, so after cutting the post to size, you install an expandable plug with a schrader valve to seal off and then pressurize the chamber. The seal at the bottom of that chamber sits on top of a shaft that attaches to the inside of the seat tube just above the bottom bracket with two externally accessible bolts.

It’s that easy!

Trailsync: The Shock

Following so far? Good. We're almost finished. But if you want to skip ahead, here’s an animation of what makes Trailsync tick:

Affixed to the bottom of that shaft is a cable housing stop. The rear shock's remote cable housing loops up into the seat tube and rests in that housing stop, and the cable end rests in a clip just above it. Through that clip runs a spoke (yes, a spoke) which is affixed to the seatpost. Just before the seatpost reaches max height, that spoke pulls up on the clip, the clip pulls up the cable, and the cable pulls your rear shock into "firm" mode.

This is where the magic happens, or at least most of it. The shock actuation mechanism can be accessed through a window in the seat tube.

Simple, right? Actually, yes. Disassembling the system just takes a couple allen wrenches. The only special tool you'd need would be to replace the bushings. Aside from cleaning under the seal once in a while, it'll rarely need service, but it's completely user-serviceable when the time comes.

Trailsync’s guts aren’t as complex as they seem.

And most importantly, it works. I expected the force needed to pull the cable might occasionally prevent the seat from reaching full height, which could be a problem on three-position posts. But even when I intentionally slowed the momentum that helps pull the cable, the post always hit its mark, and the locking pin always locked.

BMC Speedfox Frame and Suspension Updates

I hate to keep you in suspense, but before I cover my ride experience with Trailsync, let's talk about the rest of the new Speedfox. Most notably, that it's no longer a 130 millimeter bike. It's been scaled down to 120. The fact is, above a certain travel range and price point, e-bikes are quickly coming to dominate bike sales overseas. The new Speedfox is adapting to stay relevant to BMC's local customers that still don't want motors.

The geometry got scaled back a tad as well. The head angle and bottom bracket height remained almost unchanged, but, and I thought I'd never write these words, the reach got shorter and the chainstays got longer. This would be a surprise in any other trail bike's march to modernity, but the new Speedfox isn't meant to be a slasher. It's meant to combine versatility, stability, and comfort into a package that does most of its slashing uphill.

Ride Impressions

I was eager to test its mettle, and I had a long day to do it. On my first day on the Speedfox, our route traversed out of the town of Leukerbad through a narrow valley in the canton of Valais in southern Switzerland, catching ancient rooty paths up the steep Alpine foothills, then catching even more ancient rocky ones back down. Having spent the previous days on a shorter travel marathon bike, the mid-travel Speedfox offered a welcomed respite.

During the first ascent of the Matterhorn, four of the seven mountaineers never made it home. We had much better luck on our rail-assisted shuttle.

Descending on the new Speedfox is a very different experience than on its predecessor. The last Speedfox we knew was as supple and planted as a 130 millimeter bike could be. It didn't ride beyond its category, but it was willing to give up all its travel to be on the edge of it. This Speedfox, on the other hand, sits high in its travel and stays light and punchy. Well suited for its long-legged cross-country potential, but not as eager to plow. And in moments when I wanted to get creative, I wished I could give back the extra 10 millimeters added to this year's chainstay, but when I would calm down and ride like a normal person, I welcomed the extra stability.

Valais, Switzerland is dotted with singletrack gems, but it’s absolutely saturated with vistas like this.


In some ways, I sensed hints of the Scott Spark 900 in the new Speedfox, and not just because of the similar travel and similar continent of origin. Like any race-inspired trail bike, the Speedfox is meant to be pedaled. At and above 120 millimeters of travel, BMC's APS linkage comes into its own on the climbs. They were early adopters of parallel link suspension, and it shows. No pedal kickback, and nearly no squat. And though I'll always hesitate to praise long-ish chainstays, they did help keep the front wheel on the ground.

BMC rider Ludo May checks out the slopes on the Matterhorn

Trailsync: The Ride

I was skeptical of Trailsync before the ride even started. You pay a high price for that technology. The short drop was quite an adjustment, as was going back to a three-position system. And given how well a mid-travel BMC will climb without even using the rear shock's firm setting, Trailsync seemed like an answer to a question I didn’t ask. And I'll admit it, I'm a bit of a control freak. Whenever I'm riding a bike with remote control rear suspension, I'm constantly making decisions whether or not to flip the switch, based upon what type of climb I'm approaching.

Trailsync always makes that decision for you, and as long as your seat is up, the decision is always 'on.' I spent the first half of my day with Trailsync thinking about every rooty climb and the slight edge I was losing because my shock wasn’t responsive enough. But eventually, I stopped thinking about it and just rode. That's rare for me to do with a remote lockout. I was able to put it out of my mind, which is exactly the reason Trailsync was invented.

BMC-Switzerland.com/mountain

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