It now sports 165 mm of rear travel, the option to run a 27.5″ back wheel and downtube storage. But the big story is the use of a sliding shock mount and a two-pivot suspension system, which Arc8 debuted with the Essential, their XC& Trail bike. They say it makes even more sense in a long-travel application.
• 165 mm travel rear, 160-170 mm front
• Mullet or 29″ wheels
•Slider system suspension
• Storage box
• Non-headset cable routing
• Sizes: S,M,L / 440, 470, 500 mm reach
• 2,225 g claimed frame weight (without shock)
• Price: 5,999 € – 8,999 €
• arc8bicycles.com
Frame Details
In place of an upper rocker link with two pivots, Arc8’s solution involves a pivot connecting the seatstay to a carriage that slides along a pair of rails parallel to the top tube and the shock. This is teamed with a flex pivot at the seatstay that takes the place of a rear pivot. The linear rail taking the place of a link means the shock does not rotate around its eyelets as the suspension compresses. The main advantage, according to Arc8, is that they can achieve a gradually changing leverage curve typically seen with long rocker links while keeping things compact, stiff and lightweight like a short rocker link.
The frame is available in carbon only and has an impressive claimed weight of 2,225 grams including hardware but excluding the shock. Arc8 have moved away from headset cable routing as seen on the first Extra in favour of traditional cable ports, which no doubt make the frame harder to make. They’ve also added a storage compartment in the downtube.
There’s a threaded BB, UDH and substantial frame protection. Another interesting feature is the flip chip that moves the main pivot forwards or backwards. This adjusts the bottom bracket drop to tweak the geometry or to (partially) compensate for switching 29” for a 27.5” wheel, while simultaneously shortening the chainstay length with the latter.
Suspension
The Extra 2.0 has a continuously progressive leverage curve, with none of the ups and downs of the previous bike’s kinematic. There’s a 20% drop in leverage over the shock from 0 to 100% travel. That makes it moderately progressive, but not especially so. However, most of that change happens after sag, which means it should resist bottom-outs well and play nicely with coil shocks.
According to Arc8, the anti-squat remains just above 100% throughout the sag window (30-35%).
Geometry numbers with a 170 mm fork.
Geometry
The new Extra is significantly longer, lower and slacker than its predecessor, but still isn’t outlandish by current standards. The three-size range covers 440 to 500 mm reach, and this is combined with generous stack height in the large size, which will make it feel bigger relative to the reach. The chainstay length grows by 12 mm when going from the 27.5” to the 29” setting. It also changes by 3 mm per size or 6 mm across the size range, which is probably too small a difference to notice. But if you combine the wheel size and frame size effects, there could be up to 18 mm between the shortest and longest combination, which is significant.
The BB drop in the above chart is measured relative to the front wheel with a 170 mm fork. According to my calculations, that corresponds to a BB height of around 322 mm, whether in the high setting with a 27.5″ wheel or low with a 29″ rear wheel.
Specs & price
There are two main flavours of Extra: coil or air. Aside from the obvious difference, the air-sprung builds use a 160 mm fork (instead of 170 mm) and 36 mm stanchions instead of 38 mm. All use the same carbon fibre frame. There are three air-sprung build kits, ranging from 6,499 € to 8,999 €, plus two coil-sprung options, costing 5,999 € or 7,499 €. Framesets start from 3,399 €.
Full price list
Laura Adams is a tech enthusiast residing in the UK. Her articles cover the latest technological innovations, from AI to consumer gadgets, providing readers with a glimpse into the future of technology.
