Orbea's Rise is a sleek and ultralight e-MTB

Orbea's latest ebike is said to be less "e" and more "bike".

This sleek-looking machine is one of the new breed of minimalist electric mountain bikes. Just like the Lapierre eZesty and Specialized Levo SL, it's designed to offer subtle assistance, while retaining the lightweight, agile ride feel of a regular mountain bike.

The lightest version weighs just 16.5kg, according to Orbea, making it the lightest full-suspension ebike, as far as we know. Most full-power ebikes weigh well over 20kg.

Orbea Rise motor and battery

The Rise is built around a custom-version of Shimano's brand new EP8 motor.

Using custom electronics, Orbea's RS (Rider Synergy) motor has a less aggressive assistance profile than the standard motor. It's torque (the twisting force it can supply to the chainring) is limited to 60Nm, rather than 85Nm for the standard motor.

While an earlier version of this article stated that the claimed weight of the RS motor is 100g less than the stock version, we've since learned that the weight of the motor its self is exactly the same. Shmano's claimed weight for the motor (2.6Kg) was just a slightly more conservative estimate than Orbea's (2.5Kg) claimed weight.

According to Orbea, its RS concept is designed to prioritise efficiency over grunt, thereby allowing a lighter battery, while providing intuitive and proportionate assistance. The assistance offered is highest with pedalling cadences between 75 to 95 RPM (revolutions per minute), with less assistance outside this range than the standard EP8 motor.

This should help to save energy because the motor operates most efficiently in this RPM range. According to Orbea: "full assistance comes in the right places at the right times, responding naturally with no lag or drag."

There are two assistance modes, Profile 1 and Profile 2, that can be customised in Shimano's E-tube mobile app.

The Rise uses a fully-integrated 360Wh (Watt-hour) battery – that's the amount of electrical energy it contains – which is claimed to weigh just 2.1kg. For comparison, the Specialized Levo SL makes do with a 320Wh battery. Most "full-power" ebikes have batteries of 500Wh and up. Bosch's 500Wh external battery weighs 2.6kg (500g more than the battery in the Rise).

The slim, fully-integrated battery is housed in the down tube. This helps to save more weight because the down tube is structurally uncompromised, compared to removable batteries which require a large opening to be built into the down tube for removal.

As a side note, one of the most important battery measurements is the specific energy, or the number of Watt hours of energy stored per kilogram of battery. The Rise's battery pack works out to 171Wh/kg, while Bosch's plastic-covered 500Wh external battery boasts 192Wh/kg. The very best lithium-ion batteries used in electric cars have specific energy as high as 265Wh/kg.

Orbea's 360Wh battery uses 21,700 cells (which measure 21mm in diameter by 70mm tall). According to Orbea, these can retain 80 per cent of their original capacity after 500 full charge and discharge cycles, while smaller 18,650 cells (18mm x 65mm) will retain just 60 per cent capacity.

According to Orbea, the Rise's subtler assistance and greater reliance on rider power, combined with greater efficiency and less weight, means range is extended by around 50 per cent compared to a conventional ebike with a similar size battery. So, it says, the 360Wh battery is equivalent to a 540Wh unit in terms of range.

If that's not enough, there's the option to add a 252Wh external battery, which slots into the bottle cage. This brings the total capacity to 612Wh and should be enough for epic rides.

Orbea Rise frame

The Rise is only available as a full-carbon affair, using Orbea's finest "Orbea Monocoque Race" (OMR) carbon layup. The frame has a claimed weight of just 2,300g, that's for a medium without shock, battery or motor. Unlike the Orbea Rallon or Occam, there's no shock strut to help stiffen the frame because the slightly fatter down tube that was needed to contain the battery makes the frame plenty stiff without it.

The Rise uses Orbea's concentric rear axle pivot suspension design to deliver 140mm of travel. The linkage is fairly progressive (around 17 per cent), so it shouldn't be bottoming out too easily. It offers around 115 per cent anti-squat at sag, so it should pedal efficiently, too.

To keep up the normal bike feel, the power button is located out of sight near the bottom bracket. There's no display either (unless you choose to add one through Orbea's MYO programme), but you can see all the ebike data (range, speed, assistance level etc.) on a Garmin or other Bluetooth device.

Orbea Rise components

Like more and more ebikes, the Rise is 29er only. It's not designed to be run as a mullet (with a smaller rear wheel).

The build is designed around lightness. All four models have a custom ethirteen alloy chainring (most ebikes use steel), with 32 teeth to allow easier unassisted pedalling.

The tyres are custom too, 29 x 2.4in Maxxis Rekons, and use the moderately-tough EXO+ casing which is usually reserved for more aggressive tyres. The Rekon is more fast-rolling but less grippy than the tyres usually seen on ebikes, presumably to help eke out more range.

Two of the builds (the cheapest and the priciest) use the Fox 34 fork and inline DPS shock, while the other two use the burlier Fox 36 fork and piggyback Fox DPX2 shock. One of our main criticisms of the Specialized Levo SL was the 34 fork, so the 36 is a good choice from Orbea.

The 34 fork on the other models can be swapped for a 36 if buying online through Orbea's MYO programme.

Orbea Rise geometry

On paper, the geometry is pretty much what you'd expect from a modern trail bike. Gone are the days when ebikes had longer chainstay than front-centre lengths.

From studying the geometry charts, the Rise's geometry is a little more modern and aggressive than its closest competitor, the Specialized Lovo SL.

Size-for-size, it's a little longer in both reach and wheelbase, the effective seat angle is slightly steeper, and with the 150mm Fox 36 fork, the head angle is a touch slacker too.

*With 140mm Fox 34/With 150mm Fox 36

Orbea Rise models

All four build options use the same carbon frame, battery and motor. Orbea's MYO programme offers the possibility to upgrade or swap many of the components if buying online, including the saddle, brakes, fork, shock, wheels, seatpost and display.

Orbea Rise M-LTD

• Fork: Fox 34 Float Factory 140mm FIT4 3-position
• Shock: Fox Float DPS Factory 3-position adjust
• Brakes: Shimano XTR M9100
• Drivetrain: Shimano XTR M9100
• Wheels: Race Face NEXT-SL TLR
• Price: £8,899 / €9,899 / $10,499

Orbea Rise M-TEAM

• Fork: Fox 36 Float Factory 150mm Grip2
• Shock: Fox DPX2 Factory 3-position adjust Evol
• Brakes: Shimano XTR M9120
• Drivetrain: Shimano XTR M9100
• Wheels: Race Face TURBINE-R30 TLR
• Price: £7,999 / €8,999 / $9,499

Orbea Rise M10

• Fork: Fox 36 Float Factory 150mm Grip2
• Shock: Fox DPX2 Factory 3-position adjust Evol
• Brakes: Shimano XT M8120
• Drivetrain: Shimano XT M8100
• Wheels: Race Face TURBINE-R30 TLR
• Price: £6,799 / €7,599 / $7,999

Orbea Rise M20

• Fork: Fox 34 Float Performance 140mm 3-position
• Shock: Fox Float DPS Performance 3-position Evol
• Brakes: Shimano M6100
• Drivetrain: Shimano SLX M7100
• Wheels: Race Face AR 30c tubeless ready
• Price: £5,399 / €5,999 / $6,499