At this point, Fair Wheel Bikes’ custom builds should need no introduction. The small outfit out of Tuscon, Arizona is one of the go-to local bike shops for service and high end bikes, but they also put together some incredible custom builds. Builds that often challenge for the title of “world’s lightest”. For their latest build, Jason Woznick of Fair Wheel Bikes says that they didn’t set out with the goal of building the world’s lightest disc brake road bike, rather they simply wanted to build a race worthy bike that also happened to be light. Very light.

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

Starting with the Factor O2 Disc fuselage in a 52cm Stealth Black finish, the frameset includes a number of parts – which were mostly swapped out in favor of even lighter pieces. Actual weight on the frame came out to be 853.2g. Not bad for a disc brake bike.

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

In typical Fairwheel fashion, the build includes exotic speed parts from Thm, Schmolke, Carbon-Ti, Tune, Extralite, Pillar, and more. But key to the build is that none of the parts are so light that they can’t be trusted for race use. In fact, Fairwheel says that they could drop another 340g from the build with parts they have on hand, but instead opted for trusted parts.

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

For the shifters and derailleurs, the bike uses a mostly stock SRAM Red eTap set up. The only modification is the addition of Extralite derailleur pulleys to the back. The crank definitely not stock, and a THM Clavicula SE with Carbon-Ti chainrings and KCNC SL chainring bolts.

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

The brake calipers are standard SRAM Red, though Ashima Ai2 160mm rotors were used with Rainbow ti bolts.

Fair Wheel Bikes sub 5.1kg Factor takes aim at world's lightest disc brake road bike

Add in a custom set of wheels made from FSE tubular 25mm rims, Extralite SPD road disc hubs, Pillar Xtra Titanium spokes, alloy nipples, and Vittoria Corsa Speed Graphene tires in 23mm, and you have the complete build – just 5.092kg (11.2 lbs). As mentioned, Fairwheel has done the math with parts available and they could get it down to 4.76kg if they really wanted to. So while they may not have been intentionally going after the world’s lightest disc brake road bike build, that may be what they just built.

For the play by play of the build process, check out the Fair Wheel Bikes blog at the link below.

fairwheelbikes.com

35 COMMENTS

  1. if they really wanted to have the lightest build, why use the heavy eTap groupset and the Factor frameset? The mechanical shifting RED and Emonda Disc are far lighter.

      • Which makes the title “takes aim at world’s lightest disc brake road bike” kind of silly.

        Regardless, they keep saying how they want it to be reliable so they don’t care about super ultra-light; both the mechanical RED and emonda disc would still be just as reliable.

        • The Emonda may be a lighter frame, but as a bike it’s a heavier package. The BB90 isn’t compatible with the lightest cranks, the seat mast is quite a bit heavier than a light post, the stem restrictions from the steerer prevent use of the lighter stems, the proprietary thru axle sizes are incompatible with lighter thru axles…. When you do the math you just can’t build it as light as some other framesets.

        • Here’s a mind bending paradigm to ponder: a bike can be the worlds lightest disc brake road bike, and not use absolutely the lightest parts!

  2. Pretty cool and pretty jelly, those wheels are trick and would drop my disc bike right into sub 5 kg range. Wish I had enough spare funds to go that route without compromises like Recon cassette or shallow tubulars. One day, one day.

  3. Brake hose and fluid is lighter linearly, but since discs are located at the hub instead of at the perimeter of the wheel, the weight savings is a wash because you need roughly twice as much. I’ve compared some hydro disc calipers with rim calipers, and typically, they are slightly lighter. I haven’t weighed Sram calipers, but Shimano Ultegra’s are a few grams lighter than their rim brake counterparts. The big savings are the pads, disc pads, especially aluminum backed ones weigh about 1/3 of rim pads. Add the rotor back in and it’s slightly heavier. Realistically the hydro disc compared to mechanical rim is nearly a wash. If you use disc specific rims sans brake track, there is a tiny savings in hydro. (but in the most important place, at the perimeter)

    • There is also the factor of the hub. Disc hubs are generally heavier.

      The hubs on this build are extremely light, as are the rotors, but I would not trust either as a daily driver.

  4. I can’t take my eyes off the crank, it’s gorgeous and if the data still holds true, they are the stiffest AND lightest cranks on the market. All the money SRAM and Shimano have and they cannot whip Clavicula.

    • Perhaps ‘whipping’ a boutique producer of bleeding-edge parts isn’t high on the list of factors that contribute to mass-market profitability…
      Weight weenies just tolerate things like cranks falling off and pedal inserts pulling out and still sing the praises of those parts online. If the failure rate of Dura Ace cranks were 1/10 that of the Clavicula, Shimano could kiss the mass market goodbye.

      • all true, and furthermore the DA (at full retail, which who buys that?) is 1/2 the cost of the THM. It’s gorgeous, for sure, but don’t think it’s apples-to-apples and THM is just wiping the floor with Shimano/SRAM

    • You’re comparing the brands that dominate the global market with a questionably reliable part that’s more than 2x the cost and most have never seen in person?

      I’d rather pedal a 14lb bike than push or carry an 11.5lb one. ll take Shimano D/A all 7 days a week.

    • “Man a custom tuned Supra with Nitrous and custom engine is so much faster than the BMW M5 if a super old Toyota built up by a few pokey tuners is faster than a stock high end Beamer How does that bode for one of the worlds largest automakers?” this is basically what you’re saying.

  5. OK, I’m missing it. Cool components, but anyone can piece together equipment someone else makes. I’d consider this news if they actually manufactured something that makes one of their bikes lighter than what can be accomplished otherwise

    • So this is a bike that is going lite just to go lite. Factor so you know does make in house their own frames, forks, seat-posts, stems, bars, and wheels. Yes they do not make a component group but they make just about everything else in a factory they over-see. You cannot say the same about many other brands. I have a Factor O2 and it is a rocket ship. In a 58cm with their parts and Shimano Di2 it comes in a 14.2.

    • I would agree. Please stop calling this building when really they’re just assembling a bike with boutique components something any home wrench can do. Nothing wrong with that but it’s not the same thing as making a bicycle frame or components.

    • They work pretty well on ice, actually. With that many cutouts they pulse like anti lock brakes.

      This bike will see tons of conditions like that, believe me.

    • I disagree as well. Have been using the Ashima rotors for a few years now and regularly see high speed-hard braking descents, even when hot there’s absolutely no fade. Started using them in the Rockies now in the Cascades. But I digress, BR charlatan trolls know best. Isn’t that right, ChrisC?

      • The rotors are fine. I have 160mm one on the back of my mountain bike and I’ve done mile plus descents on it with no issues. Never used one on the front so I can’t comment on that.

  6. “says that they didn’t set out with the goal of building the world’s lightest disc brake road bike”

    Sure. That’s 100% believable. Because racers value weight much higher than durability, performance, and (especially) saddle comfort.

  7. I think I may have found my next bike. The only thing I’d do is a wider tire, but that’s just a personal preference, otherwise it’s a pretty ideal build for climbing.

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