22/08/2013 | 20 comments
Ever since reading a Kirk Pacenti (frame builder/designer and general innovative guru) interview and his rationale for the 650b or 27.5 wheeled mountain bike some three years ago I’ve been hooked on the ‘tweener’ wheel size. Riding and experimenting with all sorts of 27.5 contraptions to varying degrees of effectiveness, trying to find the sweet spot between 26″ handling with 29″ rolling…
The one breakthrough product I’ve been waiting for has been a ‘good’ long travel 27.5 fork.
2013 saw Fox release the Float/Talas fork with 34mm stanchions and 160mm travel, but I’ve always thought it best to have a little choice in life so I’ve been waiting for the launch of a rival to it.
Like buses you wait and wait, then two come along
2014 is going to be a great year for front suspension, as there is not only one new 27.5 fork in the shape of the re-invented RockShox Pike, but also a brand new dedicated 27.5 fork from X-Fusion called the Sweep.
Like the Pike, the Sweep is aimed at the all-mountain and ‘enduro’ rider who wants reliability and performance at a lighter weight than a 36mm fork.
For those of you who are unfamiliar with X-Fusion, they’re an American company that has a steadily growing reputation for producing well-made, effective suspension, which is also very low maintenance.
In the world of 27.5, X-Fusion have also been slightly ahead of the game with their previous 26 forks; the Velvet and Vengeance being internally adjustable to either 26 or 27.5.
For 2014 X-Fusion have changed their game slightly and are offering forks designed with specific offsets for your preferred wheel size – either 26”, 27.5” or 29”.
Joel Smith from X-Fusion puts it like this: “We believe that dedicated offsets based on wheel size provide better overall performance. The offsets are based on standardizing trail: 42mm offset for 26, 46mm offset for 27.5 and 51mm for 29. Sweep is 46mm, Slant is 42mm and Trace is 51mm”.
Anybody interested in getting a better ride out of his or her bike will understand the importance using the correct fork offset for the frame’s wheel size. Riders like me who have been running ghetto 27.5 set-ups should therefore feel the benefit of a dedicated 27.5 fork with the correct offset.
Out of the box the Sweep look very similar to the Velvet and has a distinct X-Fusion style. Available in 160mm travel they have beefier 34mm stanchions and 15mm bolt up axle. The Sweep is also available in a variety of other smaller travel options and in black or white.
The Sweep forks claimed weight is 1905 grams, and our test pair weighed in more or less bang on, at 1890 grams with a full length tapered steerer.
Internally, the Sweep uses the proven X-Fusion RL2 sealed cartridge damper. The RL2 damper uses a mid-valve compression circuit, which helps control the fork over rougher terrain.
New on the Sweep forks is X-Fusion’s Nvolve seal that improve seal-life and reduce friction.
I asked Joel to give me some background on the Nvolve seals:
“The reality of bicycle suspension forks is that stiction is a major factor in limiting performance. But since we need long term durability, you can’t just open up the tolerance on the seal to reduce stiction because you will get contamination and premature wear. Since I started working with suspension some 16 years ago, the seal manufactures have made great advances in materials, and we as a company have learned a lot about seal design. The new Nvolve seals use a proprietary internal design and material. There’s a lot of technical detail, but the bottom line is that it does an excellent job of retaining the lubricant in the seal and wiping away contaminants while limiting both short and long-term stiction.”
Finally, I asked Joel why there’s no ‘Kashima’ coating or black stanchions like the Fox and Pike as this seems to be the current trend.
“It’s coming, but slowly. We have been producing small batches of products with Gold Slick Ano coating, but we are taking it slow to ensure we have the process down 100%.”
The set up
For the first quick test ride I put the Sweep forks on a long travel hardtail, the frame was designed for all-mountain use with 27.5 wheels, but the lack of a specific fork meant I’d been running a 160mm travel fork in a 26/27.5 ghetto set up.
Literally the first thing I noticed about the Sweep was the longer 46mm offset, it complemented the 27.5 wheels and gave the bike more balance and composure, the handling was more precise in general but especially in tight corners.
The suspension action was pretty stiff out the box, but massively improved as the ride progressed. Even after the short 32km loop I could feel the travel becoming plusher and starting to feel much smoother on the smaller trail chatter.
The mid-travel RL2 valve is the real key to Sweep forks, as this really helps to keep them firm and where you want them. On repeated medium/large roots or rocks this increased control on descents.
The forks will need some fine tuning to get them working right for me, as I found the recommended factory setting of 60PSI was generally a little to soft for my tastes, especially on some out-of-the-saddle shorter climbs.
I have found X-Fusion forks to have a tendency to need breaking-in, but after a few rides they really ‘plush up’ and remain that way for a long time, with very little need for servicing too. Later this week I’ll be taking the X-Fusion Sweep forks to Hafjell in Norway (host to 2012 and forthcoming 2013 World Cup downhill), for some head-to-head testing against another much-hyped new enduro fork, the Pike.
I’m looking forward to some longer-term testing on the Sweep and giving them some more serious punishment in Norway.
In the meantime, here’s some technical specifications:
X-Fusion Sweep RL2
Weight: 4.2 lbs/1905 grams
Wheel Size: 27.5 inch
Travel: 120, 140, 150, 160mm (other custom travels achieved with travel spacers)
Stanchion: 34mm Aluminum
Damper: Sealed RL2 Cartridge w/ Mid Valve
Adjustments: Lockout, Rebound, Air Spring
Axle: LockX 15mm
Options: DLA, Remote DLA, Quick Flip Remote Lockout
Dedicated 27.5 offset: 46mm
Seals: New Nvolve low friction custom seals
Then Sweep is also available in on-the-fly travel adjust DLA model with 130mm-160mm and with a 120mm option with a remote.
The expected retail price of the RL2 Sweep is £454.99 and £489.99 for the DLA option.
What X-Fusion says about the Sweep fork:
“The Sweep is the latest addition to X-Fusion’s 34mm line of forks. Joining the Slant (26inch) and the Trace (29inch), the Sweep is a dedicated 27.5inch wheel fork. What sets it apart from other forks as a dedicated 27.5inch fork is the offset. Its 46mm offset provides precise, yet smooth handling characteristics matching the trail found on the 26inch and 29inch forks.”
Jumping the gun
I got my sample Sweep forks direct from the manufacturing factory (with help from my international network of connections…) and, as I understand it, expected delivery of Sweep forks into the UK will be in the next few months, although there is no firm date set.