Fair Wheel Bikes FSE ("Filament Spun Evolution") and Carbon-Ti X-Hub Clincher Wheelset Review
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The Lowdown: Fair Wheel Bikes FSE Carbon-Ti X-Hub Clincher Wheelset
Fairwheel Bikes has always been a bellwether of weight-weenie goodness. They sort of blur the line between manufacturer and retailer by sourcing and assemblying great parts to create customized offerings. They have a knack for finding somewhat esoteric equipment that is always lightweight and generally an excellent value. I've written about various products from them before including KCNC quick release skewers (an incrediblly light 45 grams for the set at just $70), 1334 gram alloy clinchers (built with TUNE hubs for $875), and sub 1500 gram, 24mm wide clinchers for under $400. Recently I clicked on one of their newsletters which mentioned "wider is better", nearly 26mm wide carbon clinchers that weigh just 1225 grams with rims from a brand that I'd never heard of. I thought the weight was a typo and clicked through to read more. Sure enough, that's what they claimed; there was some marketing text in there that said the rims, made by a company called FSE, were stronger and lighter than other carbon rims because they used a new kind of manufacturing process. At $1470, the price was much lower than what I would have expected for the weight. As Fairwheel Bikes says, these may be the "proverbial 'Holy Grail' of carbon wheels".
But...this seemed to good to be true. I assumed there had to be a catch and I had to find out more.
Fortunately, I was able to get a wheelset to test.
Going in to this test, I had three goals:
- To see if these wheels were as light as claimed.
- To see if carbon rims could really brake reliably. By now I am a broken record, but ever since having kids, my descending skills have regressed dramatically. I'm an extremely cautious descender and I tend to ride the brakes. Living in the SF Bay Area, we have a lot of big climbs which means long descents. To say I've been spooked hearing stories about carbon rims delaminating and failing on long descents is an understatement.
- To see if wider vs narrow rims really make a difference. There have been a lot of claims about wider rims being "better" but what exactly does that mean; what does it feel like? How do you know they are "better"?
Fair Wheel outfits these rims with Italian-made Carbon-Ti hubs. Despite the brand name, they are actually made of 7075-T6 aluminum. At a combined weight of 224 grams, these hubs are impressively light and offer easy access external preload adjustment and durable and serviceable high quality steel cartridge bearings. The hubs are laced with high-end straight-pull Sapim CX-Ray spokes (~4.5 grams each) on the non-drive side and stronger CX-Sprint spokes (~6 grams each) on the drive side to ensure long term durability with only a slight increase in weight. Moving on to the rim, the manufacturer, FSE, claims they use a new "filament spun" process which precisely adds just the right amount of epoxy resin to the carbon fiber strands by bathing the fiber in a well of epoxy as the carbon fiber "yarn" gets spun with very tight tolerances on to a mandrel (mold). This process precision coats each strand and because just the right amount of epoxy is applied, overall weight is reduced and there is little waste. In fact, because of the precision of this manufacturing process, FSE claims the rims to be "40% stiffer, 40% stronger, and up to 200 grams lighter than comparable carbon rims". You can check out their claims with this video here.
While I can't substantiate the "40% stiffer, 40% stronger", a wheelset weight comparison makes the "up to 200 gram weight savings" claim plausible.
Comparable clincher wheelsets weigh as follows:
At 1225 grams, this wheelset is, indeed, extremely light, and, in some cases truly 200 grams or more lighter.
So how they ride?
Frankly, my expectations were reserved prior to riding these wheels. I was still skeptical about this unknown brand, the claimed weight, as well as braking performance. That said, when they arrived, at 1270 grams with the rim strips installed, I was amazed. Sub 1300 gram clinchers? These wheels really lightened up my bike. In fact, even running wider 700x26mm tires, I was able to get my 2011 Cervelo S3 under 14 pounds! As a bonus, the rims were also easy to work with; installing the Specialized S-Works Turbo tires required just moderate thumb pressure.
Once under way, I was immediately impressed by the stiffness of the wheels; it was a palpable difference. Not sure if it was 40% stiffer, but these wheels accelerate incredibly quickly. The feeling was in part due to the rear hub which seemed to engage instantly, but the overall lateral stiffness of the wheel was the most noticeable factor. With regard to "wider is better", the wheels are surprisingly comfortable and the ride is now much more supple. Perhaps this is because the footprint is 34% wider than a traditional 19mm rim. Think of it like low-profile tires on wider car rims; effectively the wheel does more to contribute structurally to the bike's handling by creating a laterally stiffer contact patch with a more responsive sidewall. This 30%+ increase in width is why a lot of folks who used to run 120psi now dial it back to 80psi (myself included).
So what about the braking?
As said, I am cautious about braking. But I rode these down long mountain descents and through the rain and they were impressive. As with the acceleration, the braking was remarkable; the brake feel was secure and confident and well modulated. That said, the rims do affect the brake pads. Using Swisstop "Black Prince" pads, there is some whine from the wheels while scrubbing off speed. And the brake pads do wear quicker than what we are used to on aluminum rims, but they felt confident and secure regardless. To see if there was any hint of the rims delaminating or failure under braking, I did a test, comparing one bike with the carbon wheels to another with aluminum rims. I rode down a very steep hill, accelerating to 37mph, then hit the brakes and kept them applied for two-tenths of a mile down the hill, likely longer than most cyclist would apply the brakes on a descent. Using a digital thermometer, I measured the carbon rim at 101 degrees, while the aluminium rim hit 98 degrees. The results were much closer than I had expected and, interestingly, both cooled off quickly at what seemed like the same rate. In any case, FSE claims their epoxy resin is good for 240 degrees celsius so it seems that there is plenty of margin for safety.
A great upgrade
With this wheelset, my "old" 2010 bike felt transformed. The Cervelo S3 is meant to be an aero road bike and because of this, the frame is vertically pretty stiff. While this is good for accelerating and climbing, it can be fatiguing to ride longer distances. To be honest, I have always appreciated the bike but didn't always relish riding it because of it's harsh ride. But with these wheels and 26mm wide tires, the bike has been transformed. The ride is now positively plush. Even after a 70 miler with over 6700 feet of climbing, I felt great on the climbs, confident descending (rare for me) and, more importantly, didn't feel beat up at the end. The wheelset even helped me to my second fastest benchmark climb of the year on a dreary cold December day, at the end of the season! Overall, the wheelset made the bike so much more fun to ride; they seemed "frisky" - light, but stiff and responsive, charging along; it feels like my bike is a hot rod! I found myself looking for excuses to ride more, and did, having already put in over 700 miles on them. Downsides? Besides brake pad wear, the only other minor nit is the rear hub is a bit noisy while coasting; not Chris King hub noisy but slightly bothersome.
Don't just take my word for it
To make sure my findings weren't anomalous or too caught up in the moment, I loaned out the wheels to my friend Dave. He is somewhat legendary as a climber and insane descender in this area and, no joke, has over 520 Strava KOMs (!). On his test ride, we used 28mm wide Donnelly Strada LGG tires.
Here are his words:
"I’m not a Cat road rider, but have raced Pro in MTB in the past, and have competed in many hill climb races on my road bike. I have two sets of road wheels that are tubular, Zipp 202s and Easton Aero 90s. I mainly ride the Eastons, the Zipps feeling a little less stable and flimsy in the steep descents, but they climb well. The Eastons brake better too. I am very critical on braking! I put the FSE wheels on my 2009 Cervelo R3, the 28mm tires barely cleared my fork, but cleared the rear pretty easily. The rims were fat! And I like that. Since the tires were 28mm, and I wanted to be safe on the turns on the downhill, I set the front tire pressure to 60 psi and the rear to 70 psi. Pretty low pressure by most people’s standards. I’m 165lbs. I thought I’d pedal the wheels up something steep, then down something steep, so I headed up Los Trancos, Old Spanish, then down Joaquin and Alpine. Those hills are pretty steep, up to 16% in a couple spots and I could tell the FSE were pretty efficient. I’m used to my Easton Aero 90s, which I thought were stiff, these FSEs were more stiff. Even when I stood and pedaled hard, I could tell then they were well designed and built. Wheels were super straight, btw. Then came the DH, down Joaquin (note - Dave nabbed the KOM that day). The braking tract was awesome! Almost felt like my disc brake bike. Very controlled. I can’t believe it, but it didn't rub! No flexing, even through the hard braking tight turns. All in all, very impressed with these wheels."
These wheels have helped me fall in love with my seven year-old bike all over again. They've added a whole new experience of better handling, increased responsiveness, much improved comfort, and fun. They accelerate quickly, feel great in the turns, and brake with confidence. On the weight-weenie side, the bike is now even under the magic 14 pound mark; imagine what shaving 200 grams or so of rotating weight would do to your bike!
By far, this has been the best upgrade to my bike. They are a great value that seems pretty much unmatched in the marketplace right now.
Many thanks to Fairwheel and FSE for pushing the envelope with low weight, high quality, performance, and a reasonable price point.
To learn more about this wheelset, check Fairwheelbikes here.