Review: PinkBike - Fox Transfer SL Dropper Post

PinkBike has reviewed the Fox Transfer SL Dropper post. Here is what they had to say:

Fox have long had the Transfer dropper post in their line, but the Transfer SL that was released last spring is quite unlike its longer travel sibling. The SL is a different post from the ground up - a pared-down, lighter-weight, and shorter travel option designed for the likes of XC racing, gravel riding, or riders who place a priority on lightweight rather than having the most drop possible.

The Transfer SL weighs a mere 327g for the shortest travel 27.2mm diameter Kashima coated Factory Series model and there are lever options for various types of mounting, including drop bars.

Construction and Features

Starting at the top, the seat clamp looks more like a throwback to previous versions of the Transfer, but a bit more refined. This departure from the standard Transfer clamp, which Fox had heralded as a crucial innovation to maximize post drop, was done to keep the weight down. With the post only needing to accommodate up to 100mm of drop for XC applications, maximizing the post's travel and keeping the stack height low wasn't as much of a constraint during development.

Moving down, the post has an entirely new mechanical spring, rather than an air-sprung, cartridge-style post, as more commonly seen these days. Additionally, the mechanics and function of the spring system give the post only two positions, up or down, rather than the infinite adjustment we've grown accustomed to. The reasoning behind this is again weight. The team at Fox claims that for XC racing, the post is typically either up or down and few riders tend to use it in a mid position.

While the aforementioned mechanical spring is an additional mass of metal, according to the engineers behind the design it allows for weight savings because the sealing mechanism does not need to be as robust as it would if there was a sealed air chamber.

The spring is only used for the extension of the post and it doesn't support the rider's weight - it has a very low spring rate that is highly preloaded. Locking it all in place, and supporting the weight of the rider, is a mechanism with hardened steel balls that engage through grooves in the upper post in either the raised or lowered position. There is a mechanism to prevent rotation between the upper and lower post composed of two preloaded bushings designed to prevent any angular free play. In the smaller diameter 27.2mm post, there are traditional anti-rotation pins which Fox claim allow a little saddle angular play when in a harder rotational stop.

Internally routed is the only option for the Transfer SL. The post has a window in the lower half that allows the cable to be run in either direction for compatibility with various dropper levers. Fox engineers said this also minimizes extra cable housing length to, you guessed it, save more weight. With the lower post walls being thinner than usual, torque spec does have to be considered as over-clamping the seat post binder can cause the post to incorrectly function or cause damage to the post.

So, how's that compare to other similar offerings? The post that first comes to mind as a lightweight, XC-style option is DT Swiss' D232 ONE. The D232 is polarizing in its look thank to its inverted design. The D232 has 60mm of travel and comes in two sizes, 27.2 and 30.9, with a claimed weight of 369g for both sizes. With a similar lightweight spring system, it is able to keep weight down, but the inverted design only allows the post to go so low in the seat tube. It sells for $566 USD, significantly more than the Transfer SL, has less travel, weighs more, and has fewer size, travel, and setup options than the Fox post.

Looking at many of the more standard length dropper posts just for sake of comparison, the Transfer SL, at 346g, is far lighter than the 595g average weight of the 13 posts tested in our past Ridden & Rated article. While those posts are all longer travel options, which inherently means they will weigh more, 346g for a 100mm dropper is pretty darn light.

Ride Impressions

I've had the Transfer SL for several months now, enough time to put it through the wringer in a full range of weather conditions, from wet to dry and hot to cold. The post is undoubtedly light, coming in at about 25% less weight than a standard Transfer, depending on what length you're comparing. While you've read the word "light" plenty of times already, I'd say that it's the best way to describe how the post operates and functions.

Similar to a standard post, the Transfer SL has a smooth and consistent action and feel at the lever, but that is where the similarities split as the minuscule amount of effort required to push the post down was quite a departure from the norm. It's strange saying that it takes some getting used to, but it really does take a different style of operation. The Transfer SL may be aimed at the XC racing crowd, but one potential benefit is that the post works really well for kids or very light riders who may have trouble compressing and lowering a more traditional dropper post.

Upon dropping the post, it's key to ensure that it's fully dropped, as it doesn't have the infinite travel adjust many of us are accustomed to. It was surprising to me how often I didn't quite fully drop the post until I was more mindful to ensure it was fully down. It didn't take too long to adapt to the different style, though; I'd imagine it's similar to someone getting used to a different style shifter from what they've always used. Do a ride and you're good to go.

I did miss the infinite travel adjustment, but I can't really knock the post for that as the two-position design was intentional. As for that, it works precisely as it should.

Another thing worth noting is that there is a slightly more noticeable amount of play at the top of the post than I've grown accustomed to. Again, this is a difference in design and while it's quite noticeable off the bike and with the post at full extension, it was merely an afterthought while riding.
 

Overall, I was very happy with the performance of the Transfer SL. It's light and functions exactly as it should. While I wouldn't recommend the post for the modern-day trail rider looking to slam their seat and ride varied terrain where having some selection in drop is truly beneficial, it does give XC racers and connoisseurs of gravel sports an option many will appreciate. As sure as the sun rises in the morning, XC racers will be counting those pesky power-robbing grams, and more often than not, I feel that those bikes and those riders can appreciate a little skill boost when the going gets more technical, which is where the Transfer SL helps level the playing field and truly shines as the best option available for this application.

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