Is this the ultimate full-suspension bikepacking rig? Before we answer that somewhat provocative title, it’s worth discussing why we built this… In 2023 SRAM released their engineering masterpiece – Eagle Transmission. This new drivetrain has a rear derailleur that mounts directly to the frame without the need for a hanger. It offers the promise of perfect shifting and the ability to take rock strikes like a boss. Why is this relevant to Tailfin? Well, since we mount all our Racks and AeroPacks on our Tailfin axle, we needed to develop a new part to make the Tailfin system compatible with SRAM Transmission.
In simple terms, our SRAM Eagle Transmission Adaptor makes any Tailfin Rack or AeroPack compatible with SRAM Eagle Transmission
Although we had a variety of bikes in the Tailfin stable that would enable testing, this seemed like a perfect opportunity to build up a new ‘Ultimate’ bike to celebrate this compatibility. With a history of building up intriguing Tailfin bikes, it was hard to pass up this opportunity.
As you might imagine, at Tailfin, we’re always tinkering, testing, and trying out the latest and greatest gear. For this build, we wanted to see what an ultra-lightweight, full-suspension XC/Downcountry/Trail bike could be. This was the brief we gave ourselves:
- Capable of long days in the saddle
- Slacker than an XC but more purposeful than a Trail bike
- Large frame triangle
- Lightweight
- Efficient
Choosing frames, wheels, parts, components, and accessories is always a drawn-out process. Let’s just say that spreadsheets were made, conversations were had, and lots of reviews were read before we finally pushed the button.
The frame: Arc8 Evolve FS
What drew us in first of all was this quote from MBR magazine: “The ARC8 Evolve FS is a sub 10kg XC race bike that rides like a trail bike”. Given that this will be less of a race bike and more of a trail/bikepacking bike, we liked what the few reviews said about it; it definitely ticked some boxes. We really like ARC8’s take on what the geometry of a cross-country-focused bike should be. The head tube angle is 65 degrees, more in line with 130mm/140mm travel trail bikes and, by comparison, is 1.5 degrees slacker than Specialized’s Epic Evo, which was our second choice for the frame. We also love that the incredibly compact rear shock allows us to maximize frame bag size. Lastly, it’s super light, and even though it won’t make much of a difference for our uses, it’s always fun to see how light something can go.
ARC8 Evolve FS build sheet and reason for choosing:
| Bike Part | Component | Reason For Choosing |
|---|---|---|
| Frame | Arc 8 Evolve FS (Large) Carbon fibre, 110mm travel | We wanted a short-travel XC/Downcountry bike but really liked the head tube angle that’s 1.5-degree slacker than found on the Specialized Epic Evo. Plus, it’s nice to try new upcoming brands with interesting histories (the designer came from BMC) |
| Fork | RockShox SID Ultimate Race, 120mm | With 35mm diameter stanchions (as opposed to 32mm) it offers a great combo of stiffness and weight. The lower leg diameter also works perfectly with Tailfin SFMs. |
| Shock | Fox Float DPS Performance, 110mm | This was the shock specced with the frame! Does it matter that the cuffs don’t match the collar? |
| Drivetrain | SRAM XO Eagle Transmission, 32T, 10-52T cassette | The bike was somewhat built around this to test out how the Tailfin system works with it. We love the concept of a bulletproof, perfectly-shifting rear derailleur. |
| Brakes | SRAM Level Silver Stealth, 180mm F, 160mm R | Stealth was chosen to minimize the impact on bar bags. NOTE: Rear brake calliper swapped to SRAM Force flat-mount – this was a cunning hack to get a SRAM flat-mount calliper on the back of an MTB |
| Wheels | HUNT Proven Carbon Race XC 29 Wheelset | With Josh Ibbett and many of our athletes using these – it almost seems like a no-brainer. Lightweight, strong, Proven. |
| Tyres | Maxxis Ardent Race, 29×2.35″, Max Speed, EXO, TR, 3C | Highly efficient, fast rolling but still grippy. |
| Handlebar | Ultimate Sports Engineering Nail Carbon Bar, 20mm Rise, 800mm (trimmed to 760mm) | We love the wide mounting area to add aerobars or other hardware on either side of the stem. |
| Grips | SQ-Lab Grips 711 Tech & Trail 2.0 medium | So far, we love their non-round features, and the rubber compound is super comfortable whilst being pretty grippy. |
| Barends | SQ-Lab 410 2.0 | These might be our favourite components on the build. It’s great being able to change hand position. |
| Stem | Ultimate Sports Engineering Vyce Stem, 31.8mm, 40mm length | Such a clever stem at an incredible weight. |
| Seatpost | OneUpComponents Dropper Post V2, 150mm drop | It comes in at a great price, is fully user-serviceable and has the lowest stack height in the industry. Wish we had the new V3 that came out after the build! |
| Dropper Lever | OneUpComponents V3 Remote, SRAM Matchmaker clamp | It has reliable performance, and the new soft grip is great. |
| Saddle | Ergon SMC Core Saddle | So far, this is a new favourite saddle. We were nudged in this direction after reading the glowing review on Bikepacking.com from Miles Arbor. |
| Pedals | OneUpComponents Alloy flat | Great all-rounders – thin, grippy, wide base |
| On-board Tools | OneUpComponents EDC Tapped Fork | It’s a game-changer having quick access to tools on the go. Means never forgetting them! |
Join us on this journey as we embark on our ASMR-inspired full-suspension Bikepacking dream build. Thanks to Sterlands Cycles, Bristol for the build:
Find out more about ARC8 bikes here.