Unno Bikes has updated their long-travel Burn mountain bike, opting to replace the 27.5″ with a mixed-wheel size platform. While the previous Unno Burn ran 160mm rear wheel travel delivered via a twin-link platform optimized for use with air shocks, the new mullet configuration with its VPP-linkage has greater versatility, with a leverage curve able to accommodate both air and coil shocks.
2022 Unno Burn
- Intention: Enduro and Bike Park Riding
- Wheel Size: Mullet (29″ Front, 27.5″ Rear)
- Fork Travel: 170mm
- Rear Wheel Travel: 160mm
- Size Range: S1-S3 (Reach 435mm-510mm)
- Starting Price: 7,995€ for Race Spec
Like all Unno Bikes, the 2022 Burn was developed in Barcelona with input from ex-world cup racer Cesar Rojo. Fun fact: it is named after Mount Blackburn, the highest peak in the Wrangell Mountains of Alaska standing at 4,996 meters. Unno tell us the new Burn is designed to be ridden hard, with an aggressive set of geometry figures and double-row 7mm EnduroMax bearings taking care of articulation at each pivot of the linkage.
The frame is strikingly different to its predecessor. With the shock now mounted low in the frame, it sits within not one, but two shock tunnels; the first is a regular shock tunnel formed by a split in the seat tube, while the second is created by two additional struts of carbon fiber that bridge from the bottom bracket area to the top tube, bracing the front triangle in the direction that the shock is driven as the bike is pushed through its 160mm of rear wheel travel.
Looks familiar? That’s because it is; the Unno Boos eMTB uses the very same VPP linkage design and frame layout.
The new layout looks to place more weight closer to the bottom bracket region, and it is also said to deliver a leverage curve that is more amenable to the linear rate of a coil shock. Unno have tested coils shocks from Fox, RockShox and Ohlins, all of which fit with sufficient clearance. Though the linkage may seem more complicated than the twin-link seen on the previous Burn, it is still just that, with two co-rotating links, the lower one of which now articulates about a pivot that is concentric to the bottom bracket.
What about geometry? Well, with the headtube sat at 64° supporting a 170mm travel fork, the Unno Burn doesn’t appear to be messing about. Chainstays come in at 445mm, consistent across the S1-S3 size range, with the boost (12mm x 148mm) rear-end able to accommodate a maximum tire size of 27.5″ x 2.6″.
The bottom bracket drops 30mm from the axle of the 29″ front wheel, and 10mm from the axle of the 27.5″ rear. Seat tube angles are quoted as 76.5° (effective) for all three frame sizes. For the S2, that angle was measured at a saddle height of 750mm.
The reach figure was the determining factor for the size range; the S1 has a reach of 435mm, the S2 a reach of 470mm, while the S3 comes in at 510mm, accomodating rider heights from 160cm to 200cm tall. Those figures are generously long and bang up to date, but with only three frame sizes covering that wide range, there may be a lot of folk finding themselves in no man’s land, so to speak.
The low-slung top tube gives the impression that seat tube lengths are pretty long. And, well, they are, coming in at 435mm on the S1, 465mm on the S2, and 490mm on the S3. Maximum seat post insertion lengths are quoted as 235mm, 250mm, and 280mm, respectively. That’s a fair chunk longer than comparable VPP-linkage mixed-wheel bikes on the market that sit within this travel bracket.
The new Burn gets integrated downtube storage underneath what looks to be the bottle cage mounting panel; we are seeking confirmation on that, but it does look like the front triangle should be able to house a full size water bottle here. It comes with a zippered pouch in an attempt to keep contents from rattling around too much.
The Burn runs a IS52 – ACROS Aix540, allowing cables to run directly into the headtube, rather than flapping around the sides before entering further back. The cockpit has a pretty sleek, clean-looking aesthetic thanks to that internal cable routing and the integrated bar-stem in the form of the carbon Deux Enduro Bar. It comes at 800mm wide, has a 20mm rise with a 40mm reach.
Pricing & Availability
The Unno Burn will be available in size S2 only in around 3 weeks time, with size S1 and S3 due in August 2022. Only one build model is available right now; that’s the Race Spec retailing at 7,795€ inc. VAT. That cash gets you a Fox 38 Factory Fork with GRIP2 damper, Fox X2 Float Factory Shock, SRAM GX AXS drivetrain, Formula Cura 4 brakes, Crankbrothers Synthesis Alloy Wheelset and Fox Transfer dropper. For full details on pricing and availability, head to the Unno Bikes website.