First Impressions: KFX i28 Wheels Are A Massive Upgrade For FSA Cross Country Line 

Full Speed Ahead (FSA) claimed a cross-country World Championship with Alan Hatherly and Cannondale Factory Racing this summer. That expertise and technical know-how have been instrumental in developing the new FSA KFX i28 Wheel wheelset.

FSA Athletes have been riding and training low-key on KFX i28 prototypes all year. Now, we finally get the full scoop on FSA’s best-looking cross-country wheelset. 

FSA KFX i28 Wheelset – What is it? 

For those unfamiliar with the FSA lines, KFX is the top-tier racing line. The Cannondale Factory Team and other cross-country specialists use KFX bars, stems, and super-light (Cannondale SiSl2-looking) KFX cranksets. It’s the top choice for FSA when it comes to cross-country, and it’s seen a steady refresh over the past five years. 

The wheels for the KFX line have always been slightly lighter than the second-tier SL-K models. Most of the weight has been lost by upgrading spokes and slight tweaks to the rim layup. This new KFX model, however, is a sharp departure from the typical FSA cross-country build. 

When you look at the new KFX i28 wheels (if you’re familiar with the previous model), it looks like an entirely new line of wheels. The rim is a different shape (not only wider), and the hub is a complete change (much better). The only remaining piece is the classic monochromatic FSA KFX styling with a slight pop of metallic silver. 

Variable Height Rim 

The rim is the first piece that caught my attention for the KFX i28 wheels. It’s a variable-height rim with a classically round shape. The rim itself is about 22mm deep, with a bump up to 24mm near the spoke nipples. FSA chose to keep the rims asymmetrical like previous versions of the wheel. The rims measure 28mm internal and 33mm external and have a 3mm hookless bead. 

PRS X900 Hubset

After departing from their go-to 6-pawl design, FSA updated the new KFX i28 wheelset with a PRS (Power Ratchet System) X900 hubset. You’ll find the PRS system on the newest Vision road wheels, like the Metron SL40, and so on.  The PRS system boasts a 72-point ratchet system, similar to the DT-Swiss star ratchet but larger. 

The PRS hub is a straight-pull spoke, 6-bolt design with an oversized clutch ratchet and helical freehub driver. Its internal workings are much easier to service and maintain than the previous 6-pawl model.

Plus, the PRS mountain bike version employs large, easy-to-service cartridge bearings. The freehub is available in SRAM XD or Shimano Mircospline.

FSA KFX i28 Wheels Weight and Dimension: 

• Rim Depth: 22/24mm 
• Inner: 28mm  
• Outer: 33mm 
• Sizing: 12 x 148mm, 15 or 12 X 110mm
• Freehub Options: Shimano HG or Mirco Spline, SRAM XD (tested)
• Weight: 1580g 
• Pricing: $1810.00
• Warranty: Lifetime
• Available: Now 

Setup Impressions 

For most, if not all, of their tubeless wheels, FSA/Vision supplies tape, and valves with the package—the KFX i28s are no different. The wheels arrive with 35-mm-wide tubeless tape that flexes to fit the contours of the rim. The tape fits the inner channel of the rim well, but requires some extra muscle to get that bubble-less fit.

I’ve used this FSA-branded tape with other mountain bike wheels for many years with great success. I see no reason to search for another tape as an “upgrade.” 

I went with a pair of WTB Marco 2.4 tires as my treads and had zero issues mounting and seating them. The Marco 2.4 tires have an optimized rim width of 29-35mm, but the 28mm worked fine. 

Ride Impressions 

My rides were mostly on cross-country single track with a mix of roots and rocks. I like to ride on the trails and took this opportunity to feel out the wheels without trail interruptions. On the road and gravel tracks leading to the trails, the KFX i28 wheels are springy. They spin up on the open road and feel nice on the climbs, like a much lighter wheel.

The weight of 1580g (with valves and tape) had me thinking they would be slightly sluggish on the climbs compared to the Roval Control Team Editions they replaced. The KFX i28 wheels seem to carry most of the weight at the hub. Even when picking up the wheels for the first time, you can feel it. FSA says, “The target weight is 420g per rim,” solidifying that the hub carries most of the weight.

The lower profile rim (compared to the 30mm previous version) has a nice feel over the trail. The 28mm rim width provides enough tire contact for extra suspension from the 2.4 Macros, and keep the tread integrity.

Powerful and Sturdy

I hardly noticed the wheels on the trail, which was a great thing for me. They slotted in the right after a very high-end (and expensive) wheelset and performed well enough that I couldn’t tell the difference. Now, thats not to say these are identical performance wheelsets, but they have a similar feel on the trail. For most mountain bike riders, thats all that matters.

The straight-pull spokes are conventional—non-bladed, tapered, and not carbon—resulting in stiff and responsive handling. In the corners, the KFX i28 wheels feel sturdy and robust. Some super lightweight wheels can feel slightly “mushy” in corners; conversely, they feel rock solid—like cornering on an excellent road wheel in a crit. 

Engagement-wise, the PRS ratchet system offers a very competitive feel to the higher-end DT-Swiss hubs. The bearings look to be built for the long haul (crappy weather, power washing, dumb east coast winters), but only time will tell. Plus, the hubs have an easy to scan “service” QR, this will pull up what you need for your wheels and how to service them.

Lasting Impressions 

I’ve ridden nearly every version of FSA cross-country mountain bike wheels released in the past seven years. They improve incrementally with each iteration, but the KFX i28 wheel seemed to have leapfrogged a few. 

The KFX i28 wheels are by far the best-riding and most serviceable cross-country wheelset FSA has released. The design is competitive with the top-tier cross-country wheels, and when you throw in the lifetime warranty, they are at the pointy end of the value. The $1810 price tag also makes the KFX i28 the most expensive wheelset in their mountain bike line, but in our opinion, also the most refined. 

Look for a long-term review coming in a few weeks, but until then, if you’re curious about the FSA KFX i28 wheels, you can find them at Fullspeedahead.com