Scott have entered the race to build an ultra-light electric mountain bike. The Lumen is closely based on the Spark
, the brand's XC/trail bike. It uses the innovative and lightweight TQ motor seen in Trek's Fuel EX-e
, but Scott undercut Trek on the scales as their lightest model has a claimed weight of just 15.5 kg (34.2 lb).
The Lumen's other party piece is the ability to fit two water bottles or a bottle and a range extender battery inside the frame. Scott pitch the Lumen as "an e-bike for a mountain biker," with weight and handling much closer to a Spark than their other e-bikes and a serious focus on reducing noise to an absolute minimum.
Scott Lumen Details
• Claimed weight from 15.5 kg (34 lb)
• TQ HPR50 motor, 200% assistance, 50Nm
• 360 Wh battery + 160 Wh range extender
• 29" wheels, 130 mm travel F&R
• Headset cable routing
• Two bottles or bottle & range extender
• 77° seat angle, 65.5° +/-0.6° head angle
• Price: TBD
Motor & Battery
After considering alternatives from Fazua and others, Scott settled on TQ as the motor supplier for its low weight, noise, and ride feel. It provides 50 Nm of torque (that's 10 Nm less than Orbea's RS-tuned motor and 35 Nm less than a full-power ebike) and assistance goes up to 200% of rider input. That means if you pedal at 100 watts, the motor will add up to 200 watts.
There are three assistance modes to choose from, which Scott tunes to their liking, but these can be adjusted by the rider with an app.
The 360 Wh battery is fully integrated into the downtube - it's not designed to be removed easily. This helps Scott save weight by keeping the downtube structurally uncompromised. The optional 160 Wh range extender mounts to the downtube bottle bosses via a custom mount which can be swapped to a water bottle cage without tools. It plugs into the charging port just in front.
The Lumen shares all the unique features of the Spark, including Scott's TwinLoc remote that firms up or locks out the fork and shock with an under-bar remote. Like all of Scott's recent bikes, the shock is hidden in the downtube, which Scott say is the most structurally efficient place to put it and leaves space for the two water bottle mounts in the main triangle. There's an extended air valve on the shock to make adjusting it more accessible and a sag indicator on the side of the frame.
Like the Spark, the Lumen also uses a flex-pivot rear suspension system to save weight, but it delivers 130 mm of travel to the Spark's 120 mm.
The headset is the entry port for all the Lumen's cables. It's also an angle set, allowing +/- 0.6 degrees of adjustment.
The geometry is very similar to the Spark. The Lumen has a 12.5 mm longer chainstay length to fit around the motor and a slightly steeper seat angle. The head angle is similar in the neutral setting, but the headset cups offer 0.6 degrees of adjustment in either direction, from 64.9 to 66.1 degrees.
Models and specifications
There are four models in the range including the Contessa women's version (pictured above). Pricing is yet to be confirmed.