X-Fusion HiLo SL Seatpost

It’s only taken a few years for dropper seatposts to go from something that was seen as a gimmick, to an almost essential component on any mountain bike other than a pure XC racer. The extra clearance and confidence provided through fast corners and steep descents is very difficult to relinquish once you’ve had a taste. Not surprisingly most suspension manufacturers have had a go at making one as the technology involved is not inherently different to what goes into a suspension fork, and X-Fusion is no exception.

They brought out the first HiLo post a few years back and whilst it wasn’t horrible, it was a little heavy, had a less than ideal one-bolt head, was a tad short on travel and weighed more than its competitors. With the new HiLo SL (Super Light), X-Fusion is looking to gain a substantial chunk of the ever-growing dropper post market by addressing the shortcomings of the previous version. With premium options from other manufacturers often retailing for $400 to $500, it’s great to see that the HiLo SL can be bought in Australia for a little over $300—X-Fusion continues to produce quality parts at very reasonable prices.

The construction quality is up to the high standard we’ve come to expect from X-Fusion with all metal parts, tight tolerances, and excellent machining and finishing throughout. Unlike the competition the HiLo uses an open bath damper which is completely user serviceable—you can download a full service video or instructions from their website. Any reasonable home mechanic or bike shop should have no problem doing a full strip down and rebuild when required, which is much better than the extended downtime required by many other posts which must go back to the factory for maintenance.

The damper design means that the post will extend if you lift your bike by the saddle; much of the competition have now managed to prevent this from happening, but it’s only a minor annoyance and it doesn’t affect the post’s operation in any way. At this stage there’s no internally routed option (although we hear that one is in the works). The HiLo is still actuated from the post head, which means there’s a loop of cable when the saddle is dropped, however the slightly offset cable entry point helped to keep this loop from getting in the way on the two different frames we tried.

X-Fusion certainly got the SL part right; including the 95g cable and remote the 30.9mm HiLo SL (31.6mm is also available) hits the scales at 559g, which puts the weight within a few grams of the lightest hydraulic droppers on the market. There are perhaps a couple of mechanical posts which are slightly lighter, but they either feature less travel or fixed drop positions, unlike the HiLo which can be stopped anywhere within its 125mm of travel.

Design Updates

Gone is the old seat clamp too, replaced by a far more secure two-bolt design. It has a reasonably long lower cradle, which is much gentler on lightweight seat rails. Also gone is the ‘crotch grab’ under seat lever option; remote activation is the only way to go with the new post. The remote itself is an interesting design; its relatively long trigger can be pulled or pushed in any direction to actuate the post, can be run on either side of the bar, and the split clamp makes it easy to install. If you’re running a 1X setup it works very well under the handlebar on the left side, but it was much harder to find a comfortable position in and around the extra shifter of a multi-ring drivetrain. In the end we settled on mounting it above the left grip and inboard of the shifter and brake. This worked but you need to lift your thumb a long way to hit it and it’s also quite exposed to crash damage.

On trail the HiLo works consistently and smoothly, but the post’s action is not linear like on most other droppers we’ve used. It gets moving easily enough, but there’s a strong ramp-up as you approach full compression, which makes it hard for flyweight riders (sub-70kg) to get the last 10-15mm of drop from the post. Even by bouncing quite hard on the saddle we could never get the last 5mm; the saddle is still well out of the way so it’s not a deal breaker, but it does mean that using the HiLo isn’t as effortless as its competitors. At the very end of our test we noticed the post not returning to full height; somewhere along the line it had started to lose air pressure. It was a quick fix with a shock pump, but you need to invert the post and let it settle for around half an hour before adding air or you’ll end up spraying suspension oil everywhere and loosing damping control. We’d suggest checking the HiLo’s air pressure once a month would be a good idea.

Safe Returns

Return speed is also a bit slower than we’re used to; much better than being slapped in the undercarriage but slightly quicker extension still wouldn’t hurt. You could add slightly more air pressure to increase the return speed, but that only makes it harder to drop the post all the way down. There’s also marginally more rotational play at the saddle than the best droppers on the market, and there’s around 2-3mm of saddle drop when you first weight the HiLo. Neither of these is noticeable when riding, but we still think it warrants a mention.

All in all, the HiLo SL is a vast improvement on the older HiLo, and despite its quirks we still think it well worth a look if you’re in the market for a dropper post. It’s not champagne on a beer budget, but good domestic sparkling instead. The HiLo SL isn’t perfect; it’s a little reluctant to deliver all of the advertised travel, there’s a little more play than some, the air pressure needs checking regularly, and the remote won’t work well with every cockpit setup. That said, it is very well made, about as light as dropper posts get, completely user serviceable, and ours worked smoothly through the mud and filth of a very wet test period. Add to that the very reasonable price and we think X-Fusion’s new post is a welcome addition to the market.

DIY MTB (02) 4446 4636 / www.diymtb.com.au