CUBE SUV Hybrid SL 27.5 Review

The CUBEW SUV Hybrid SL is one of the first cadence matching electric bikes I’ve tested. It uses an electronic shifting system to match the “gears” to your desired pedal speed… but instead of using gears it relies on a NuVinci H Sync continuously variable transmission (CVT). The drivetrain is extremely tight, clean and quiet but there is some servo noise produced by the shifters and the geared Bosch mid-drive motor. For a refined city/urban style bike the drivetrain is wonderful and it completely opens up the handlebars. I actually felt confused a couple of times when accelerating because there were no shifters to rest my thumbs on. I’m so used to banging through gears when testing ebikes to see how the drive system will respond and in this case… it all just sort of works and the only thing to focus on is ride quality and the surroundings. The frame is aluminum alloy but the fork is carbon fiber and this reduces weight, dampens vibration and provides efficiency. I love that the fork is color matched to the rest of the frame (a sort of glossy gray) but miss fender mounts, especially for locations where it rains a lot. Thankfully, there are four bosses and a center hole on the seat stays so you can add a fender there as well as a rack. This would be a fun commuter bike because it’s extremely efficient. The tires are a bit squishy (if you don’t overfill them) and that adds a bit of comfort but I think I’d still lean towards a Body Float or NCX suspension post (make sure it fits 30.9 mm or use a shim). I could definitely see more e-bikes with a fully integrated motor and shifting setup like this but it doesn’t come cheap. CUBE, which is known for offering more affordable Bosch powered bike, still charges $4,799 for this model and I’m sure a lot of that cash goes straight to Bosch and NuVinci.

Driving this bike is a 250 watt geared centerdrive motor from Bosch (there might be some 350 watt versions depending on your location). It offers 60 newton meters of torque and responds to the rear wheel speed, your pedal cadence and pedal torque to switch on and off smoothly and quickly. It also has shift detection built in but I’m not sure that functions here because of the CVT auto-shifting… I’m not sure it’s necessary because there aren’t huge drop offs and banging associated with cadence changes like there are with a chain and sprockets. While most other mid-drive electric bikes use traditional sized chainrings, Bosch systems use smaller sprockets up front that rotate about 2.5x for every pedal stroke. This allows the motor to operate at a higher RPM and gain a mechanical advantage while pulling the chain. I think it also allows for faster chain stop as the motor disengages. As shown in the video review above, at higher RPMs there is a distinct whining noise produced by the motor but it’s not that noticeable if you’re operating at a lower cadence (I was at 60 RPM for most of the video). Note that I was also in the highest level of assist for most of my ride in order to accentuate motor noise and illustrate the speed with which the Bosch system starts and stops. The outer casing on the motor is purely aesthetic and designed to protect the metal-encased drive unit inside which bolts directly to the motor plate (joining the downtube, seat tube and chain stays). It’s a great system that feels powerful and natural until it cuts out as you reach the top speed and then pedaling becomes much more difficult :)

Powering the CUBE SUV LS is a Bosch Powerpack 400 battery that mounts just above the motor, along the downtube. It’s positioned well for both weight distribution and protection in the event of a crash and it’s removable for transporting and charging off of the frame. You get 36 volts of power and 11 amp hours of capacity here which is a touch above average in terms of size but the way this power is used and the quality of the cells inside is well above average. Inside the pack are 18650 cells made by Samsung, they use an energy dense Lithium-ion chemistry designed to be light weight and long lasting. The pack only weighs ~5.5 lbs so you could conceivably buy a spare and toss it into a backpack for extremely long rides… the charger only weighs ~1.5 lbs and is fairly small as well so brining it along would be lighter if you’ve got a place to plugin. Reaching ~80% takes just one hour but completely filling the pack is closer to three due to cell balancing. I like that the pack itself has an LED readout on the left side for showing your charge status (handy if you’re storing it inside and can’t remember if it’s already full or needing a top-off). It locks securely to the frame when mounted and uses an ABUS core and key set which is definitely higher quality. I noticed that mounting the pack on this particular bike felt a bit tighter and required more effort than other Bosch ebikes I’ve tried… not sure why. The pack has a sort of built in handle that makes it convenient to carry around when off the bike, dropping it could crack the case and potentially damage the connections inside so this little touch is actually a big deal in my opinion. To really care for this pack and help it reach 1,000+ charge cycles I recommend storing in a cool, dry environment and maintaining a 20% to 80% fill at all times. If you haven’t used the bike for several months time, top off the battery. You can easily charge the pack on or off the frame using the same unique connector plug and it fits securely with a nice click.

Operating the CUBE SUV Hybrid SL is comfortable (physically speaking) but a bit less intuitive than traditional Bosch powered electric bikes. That’s because you use the display panel and button pad to select a power level and cadence level… there are no shifters. For a brand new rider, someone who has never ridden a traditional bicycle with gears, this setup would probably feel fine but for me it took a bit of getting used to. I found myself feeling around for shifters with my thumb on the right grip and I had the desire to shift into higher gears while accelerating… even though my cadence didn’t require it. The one definite drawback to this Bosch+NuVinci system is that you rely more on the screen and might be tempted to adjust more settings while riding than if it had shifters. Normally I’d be able to ride without looking down at all but with this bike I found myself distracted by the LCD trying to see which mode I was in (power select or cadence select) and it can take up to seven clicks on the “i” button to get to the correct area. If you simply choose a power level for your entire ride and then use the up and down arrows to select cadence you’ll be fine… and the opposite is also true. I’m not sure which I’d prefer and maybe it isn’t a big deal but it’s definitely more involved than shifting gears with one hand and changing power with the other.

The display panel itself is backlit and has a lights on/off button, you could actually wire in lights to run off the main battery if you wanted to. It’s removable (but also comes with a set screw if you want to secure it more permanently), swivels forward and back to reduce glare and powers on fairly quickly. There’s also a small micro USB port on the top right-side edge that could charge a portable electronic device (or update the firmware and charge the display itself) just note that it only offers 5 volts, 500 ma of power. I like having the display in the center and appreciate the separate control pad that’s mounted near the left grip. These two interfaces put you in full control of the drive systems and offer multiple ways to do the same standard things. The “i” button lets you explore everything from trip distance to ride time, max speed and estimated range (which is my favorite). You can fairly accurately predict how far you’ll get with pedal assist using the range estimator and this is one of the more efficient builds I’ve tested so 60+ miles is definitely possible on moderate terrain in Eco mode.

I’ve been excited to test the CUBE brand for some time now and was really impressed with the style… they have a vast lineup of models in Europe that offer a wide range of ride experiences and each bike looks distinctly cool. the SUV SL felt sharp and professional, there aren’t any stripes or colorful patterns going on, just a shiny gray and black that envelops every tube, component and drivetrain element. This is clean bike that feels responsive and looks aerodynamic, cables are all internally routed and there’s no chain bouncing around… just a short flat belt (the Gates Carbon Drive CDX). The one branding element I did see was a raised metallic outline of the brand “CUBE” along the downtube. Well done! Even though I’m still warming up to the auto shifting CVT thing it was definitely fun to try out. I’m not sure if the electronic shifting runs off of the same battery as the motor but that would be cool. If you like racing around town or plan on commuting and want a bike that looks awesome, comes in a few different sizes and uses state of the art technology then this is an obvious choice. If I could change one thing it would be to add mounting points for a front fender but part of me doesn’t want to tarnish the sleek looks, quiet operation and light weight of the stock setup… maybe a slim black backpack would be better.

Pros:

• Carbon fiber fork is light weight and helps to absorb some road vibration (more so than aluminum alloy)
• The Gates Carbon Belt drive system is super quiet, clean and tight which means it won’t slap your chain stays or require the same sorts of tuneups as a chain running a cassette
• You can shift at standstill (or approximate shifting by changing your cadence with the Bosch Intuvia system)
• Smooth, powerful hydraulic disc brakes front and rear require less hand strength to activate
• Removable display panel, battery pack and quick release on front wheel for more compact storage, lighter transport and maintenance and easier charging
• Excellent range thanks to the efficient centerdrive motor that leverages the rear CVT and high performance Lithium-ion 396 watt hour battery
• Great torque output, this bike can climb very well in Turbo mode when you’re pedaling along, try the higher cadence settings for very steep terrain
• Battery pack locks to the frame for security and uses a quality ABUS core with in-cut routed key, the pack can be charged on or off the frame for convenience or to reduce weight if you’d like to ride unpowered, the pack also includes an LED charge level indicator
• Intuitive display panel is large, easy to read and removable – the stand alone button pad is easy to reach without taking your hand off the left grip and “clicks” when pressed for tactile feedback (you don’t have to look down when riding), it’s neat that it controls power level and cadence so you don’t need any additional switches, buttons or shifters
• Larger Schwalbe Super Moto-X tires offer a bit of cusion without increasing drag, the slick pattern is fairly quiet but also grippy, kevlar lining reduces flats from stickers
• Three frame sizes offer better fit for a wider range of riders (16″, 18″ and 20″)
• Nice paint and raised metal branding on the downtube, all cables and wires are routed through the frame which reduces the potential for snags when riding or hauling this bike
• Good weight distribution (motor and battery centered and low on the frame), one of the lightest Bosch powered ebikes I’ve tested

Cons:

• No quick release system on the rear wheel despite being a mid-drive ebike, this is likely due to the Nuvinci H Sync
• When the tires are filled to capacity the ride can become stiff when rolling over bumps, consider a Thudbuster, Body Float or Suntour NCX suspension seat post
• When I hit the top speed of the drive system the motor cut out smoothly but pedal cadence changed, it became slower than what I had set in the menu
• As with all electronically shifting bicycles, if the shifter battery runs out you can no longer change gears
• More difficult to add a front fender with the custom carbon fiber fork, I didn’t see an eyelet for mounting at the top or sides
• The battery pack takes up the space where a water bottle cage might otherwise mount and there isn’t one on the seat tube due to the rear suspension setup, consider and aftermarket accessory for the saddle rails or grab a CamelBak
• No throttle mode, this bike only offers pedal assist (like all Bosch powered systems) but will get a better range than if it did
• The brake levers do not include a motor inhibitor but the drive system is more responsive than others I’ve tested so it hasn’t been an issue… also, normally the Bosch system utilizes shift detection but I don’t think that’s active here with the CVT, maybe it’s not necessary since there aren’t big jumps, just more of a slide

Resources:

• Official Site: http://www.cube.eu/en/bikes/hybrid/suv-hybrid/cube-suv-hybrid-sl-275-glossyngrey-2015/
• More Pictures: https://goo.gl/photos/qkJ4eFo1BrzdJGFN8