Unno Bikes has updated its long-travel Burn mountain bike, opting to replace the 27.5″ with a mixed-wheel platform. While the previous Unno Burn had 160mm of rear wheel travel delivered via a dual-link platform optimized for use with air shocks, the new mule setup with its VPP link has greater versatility, with a curve of lever capable of accommodating both air and coil shocks.
2022 Unno Burn
The Unno Burn carbon frame is made by VIP in China. Unno took their standard carbon layer and did 5-6 loops of refinements to get to the layer they were happy with.
- Intent: Enduro and Bike Park Riding
- Wheel Size: Mule (29″ front, 27.5″ rear)
- Fork travel: 170mm
- Rear wheel travel: 160mm
- Size range: S1-S3 (range 435mm to 510mm)
- Starting price: €7,995 for Race Spec
Like all Unno bikes, the Burn 2022 was developed in Barcelona with input from former World Cup racer Cesar Rojo. Fun fact: it’s named after Mount Blackburn, the highest peak in Alaska’s Wrangell Mountains at 4,996 meters. Unno tells us the new Burn is designed to be ridden hard, with an aggressive set of geometric figures and dual-row 7mm EnduroMax bearings supporting articulation at every linkage pivot.
The Unno Burn gets a post-mount rear brake mount with spacing for a 203mm rotor; neither smaller nor larger. The bike uses a 73mm threaded BSA BB.
The frame is surprisingly different from its predecessor. With the shock now mounted low in the frame, it sits in not one, but two shock tunnels; the first is a regular shock tunnel formed by a slot in the seat tube, while the second is created by two additional carbon fiber spacers that connect the bottom bracket area to the top tube, reinforcing the front triangle in the direction that the shock is driven when the bike is pushed through its 160mm of rear wheel travel.
The shock absorber is mounted on bearings at the lower end, rings at the upper end; it does not turn more than 2° on the stroke
Sound familiar? It is because it is; the Unno Boos eMTB uses the same VPP linkage design and frame layout.
The new layout seeks to place more weight closer to the bottom bracket region, and is also said to provide a leverage curve more suited to the linear rate of a coil shock. Unno tested coil shocks from Fox, RockShox and Ohlins, all of which fit with ample clearance. While the linkage may look more complicated than the link seen on the previous Burn, it is still that, with two co-rotating linkages, the lower of which now hinges around a pivot concentric to the bottom bracket.
The Burn is designed to operate at 35% sag
What about geometry? Well, with the head tube sitting at 64° supporting a 170mm travel fork, the Unno Burn doesn’t seem to mind. The chainstays are 445mm, consistent across the S1-S3 size range, with the boost rear (12mm x 148mm) capable of accommodating a maximum tire size of 27.5″ x 2.6″.
The bottom bracket drops 30mm from the axle of the 29-inch front wheel and 10mm from the axle of the 27.5-inch rear. Seat tube angles are listed at 76.5° (effective) for all three frame sizes. For the S2, this angle was measured at a seat height of 750mm.
Although it may look like a flip-chip, the bolt you see here is simply a design to keep the pivot axle from loosening during use.
The litter 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, accommodating rider heights of 160cm to 200cm. These numbers are generously long and up to date, but with only three frame sizes covering this wide range, there can be a lot of people finding themselves in no man’s land, so to speak.
The low-slung top tube makes the seat tube lengths feel quite long. Well, they come in at 435mm on the S1, 465mm on the S2, and 490mm on the S3. The maximum seat post insertion lengths are 235mm, 250mm and 280mm respectively. That’s quite a bit longer than comparable VPP-linkage mixed-wheel bikes on the market that fall into this travel bracket.
The new Burn benefits from integrated storage in the downtube under what appears to be the bottle cage mounting panel; we’re looking for confirmation on that, but it looks like the front triangle should be able to hold a full-size water bottle here. It comes with a zipped pocket to prevent the contents from clashing too much.
The Burn runs an IS52 – ACROS Aix540, allowing the cables to run straight through the head tube, rather than flapping around the sides before entering further back. The cockpit has a pretty sleek and clean aesthetic thanks to that internal cable routing and integrated tiller stem in the form of the carbon Two Enduro tiller. It has a width of 800mm, a rise of 20mm and a reach of 40mm.
Price and availability
The Unno Burn will only be available in size S2 in about 3 weeks, with sizes S1 and S3 due in August 2022. Only one build model is available at this time; it’s the Race Spec retailed at €7,795 including VAT. VAT This money gets you a Fox 38 Factory fork with GRIP2 shock, Fox X2 Float Factory shock, SRAM GX AXS drivetrain, Formula Cura 4 brakes, Crankbrothers Synthesis alloy wheelset and a Fox Transfer dropper post. For more details on pricing and availability, head to the Unno Bikes website.
Unno.com
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