Stromer ST1 S Review

Compared with the ST1 T, the S (which stands for sport) has a more aggressive geometry due to its flat bars vs. the low-rise bars, it has thinner ergonomic grips and no extra racks. The two models are very similar electric bikes and aside from color differences, could be easy to confuse. Both deliver impressive power and speed (maxing out around 28 mph with the POWER 48 motor) with responsive output thanks to a custom tuned TMM4 torque sensor and both offer a unique Schlumpf drive bottom bracket shifter effectively doubling the nine speed cassette… That’s the biggest upgrade from older ST1 Elite and Platinum models… or even the ST1 Limited which is metallic blue. While there’s no true throttle mode on any of these ebikes, you can enter one of the special codes to unlock a low-speed boost mode that allows you to hold the plus button on the display for power boost up to 12 mph (great for starts or crossing a puddle without putting your feet in harms way… or even as a zippy walk mode if you’re willing to jog). The ST1 S is more affordable than the ST2 and still delivers premium features and higher top speeds but does produce a bit more noise under operation, lacks some of the fancier display features (like the touch screen on the ST2) and has a smaller 36 volt battery verses 48 volts).

Enlarged two inch road tires cushion the bike at high speed which is a big deal given the lack of suspension. The rigid frame and thicker heavier build quality (with custom thru-axles front and rear) give this and other ST1 models a fluid, solid ride quality. It feels more substantial this way and there’s very little frame flex. The head tube is tapered 1 1/8″ at the top to 1 1/2″ at the base if you felt like replacing the fork. The fork that ships with the bike is rigid but made with Carbon fiber to cut down on weight while simultaneously improving ride feel by dampening vibration. The ST1S weighs around 62 pounds (varying slightly by frame size) and in my book that’s heavy… but I understand why and am happy to make the trade off here. A lot of the weight comes from the powerful gearless direct drive hub motor made by Ultramotor which is very satisfying. It powers you quietly and it also helps to slow you down while recouping energy. This is one of the few ebikes that offers regenerative braking… but you have to squeeze the right lever to make it work as the left is not wired in. Alternatively, you can arrow down using the display interface to one of the two “recoup” levels which are great for long hills or moments where you actually want to challenge yourself and get a workout. The display panel features integrated buttons that can be reached while holding the grip but aren’t quite as close as the independent backlit buttons on the ST2 models.

Powering the bike and its integrated LED ligtset is a beautiful, custom designed, Lithium-ion battery pack. The look is awesome, with a colorful aluminum casing and a slide-in door mechanism that nearly completely hides the pack (just a black rubber outline remains on the right side of the frame). You can charge the battery on or off the bicycle but unfortunately the plug adapter is different depending on whether you’re plugging into the side of the frame (circular) or into the base of the battery off the bike (rectangular) so Stromer gives you a dongle with the charger to switch between the two… The charger itself is rated at 4 Amp output which is pretty fast and there’s an integrated fan to keep it cool, the casing and circular plug adapter are both metal so they’re sturdy and should hold up if you toss them into a backpack while riding. The charger weighs around 2.3 pounds.

Aside from a couple little quirks like the single-lever motor inhibitor activation and the dongle adapter for the battery pack this is a really polished electric bike. The full length aluminum fenders are silent and hug the oversized tires closely which reduces toe clip and just looks cool. On the back of the rear fender you’ll find a plastic mounting point which is used for license plates in Europe where speed pedelecs are more heavily regulated. The lights are both very high quality with the front being a Supernova that offers adjustable angle and is housed in aluminum. It’s the same one used on some of the Specialized Turbo models. Part of me wishes the lights could be controlled through the display panel (and that the display was metal, center-mounted and removable) but the flip side is that the lights work independent from the control systems and can be used while the rest of the bike is turned off. The display panel itself is sleek enough and backlit for easy viewing at dawn or dusk.

There are only a handful of consumer level, legal, electric bikes that really feel thrilling and satisfying on pavement and the Stromer lineup definitely makes the list. The TMM4 torque sensor it relies on is responsive at start but purposefully delayed when you stop pedaling to reduce the feeling of surge. It’s also designed to operate at lower levels and more slowly if you decide to push gently (regardless of your assist level setting) and that’s cool. It feels more like an extension of your body but does require increased effort to achieve the highest top speeds and zippiest feedback. Again, this can all be adjusted by entering codes into the display which is mentioned in the pro’s section below. I’ll close by saying that riding above 20 mph, while fun, significantly shortens range due to air resistance. As far as speed-pedelec Class 3 ebikes go, Stromer is a trusted name with a big following. You pay a premium for their designs but for a limited time it sounds like they are tossing in a second battery pack with purchase (a slightly smaller 36 volt 11 amp hour pack) and the 2+ year warranty is hard to beat.

Pros:

• For a limited time you get an additional (smaller) battery pack for free with the purchase of ST1 models, the battery is 36 volt 11 amp hours for 20+ miles of additional range and weighs 6.6 pounds so you could toss it into a backpack with the charger
• Custom thru-axles (15 mm front and 12 mm rear) for added strength and stiffness, performs better at high speed and with the heavier weight, the rear spokes are also larger 13 gauge to support the added power of the motor
• Unique drivetrain with a 9 speed Shimano Deore XT cassette and 2 speed bottom bracket gearset by Schlumpf delivering 18 gears total… requires fewer shifters on the handlebar and requires less maintenance than two derailleurs
• Larger 2″ tires improve traction and add comfort when riding at high speed, built in puncture protection to reduce flats, the specs show tires with reflective sidewall stripes but the model I tested didn’t have them (perhaps they were replaced for demo purposes?)
• The integrated Aluminum alloy fenders look amazing, they hug the tires closely and have struts for added strength and reduced rattling
• Premium Supernova headlight is bright, tough and mounted on an adjustable swivel… both it and the back light run off the main battery for convenience but you have to switch them on with a rubber button on the back of the front light vs. using the display panel
• There’s a unique “start mode” built in that works like an under powered throttle (just hold the up button for several seconds), this could be used for walk-assist or to get you going without pedaling, it has to be enabled by entering a code into the display console
• I love the nice little extras you get with this bike including large alloy platform petals, bottle cage mounting point on the downtube, neoprene slap guards on both chain stays (to hide wires), a flick bell, Ergon ergonomic locking grips and the upgraded spring kickstand
• Powerful oversized hydraulic disc brakes offer excellent stopping power and are ebike specific so the right lever cuts power to the motor when activated and activates energy regen mode to recapture and store power (~10% efficient but this also reduces wear on the brake pads)
• The fork is custom Carbon fiber vs. Aluminum alloy which reduces weight slightly and improves ride comfort… this is really nice at high speeds along with the larger tires
• Purpose built frame is available in two sizes for improved fit and the unique slide-in battery stays very hidden while keeping weight low and center for improved handling
• You can enter special codes to change setting in the LCD display… hold the power button and the plus button for a few seconds then arrow up or down to change the four digits (press power to move to the next digit) then hold power to submit the code, the full list of codes was shared in the EBR Community here

Cons:

• Both wheels require tools to take off, an adjustable wrench for the rear and 7/32″ allen key for the front which makes changing flats and doing maintenance more involved but also deters theft
• This is a heavier electric bike… the gearless direct drive motor is powerful and fast but it weighs ~16 lbs and the larger 14.5 amp hour battery, fenders and rack add even more (but at least the battery is removable so at least ~6.4 lbs can be taken off, the rear wheel would require tools)
• Only available in one color with these specific features, you could consider a standard ST1 in black or white as well as the ST1 Special Edition in metallic blue or the ST1 T in metallic brown
• One of the more expensive electric bikes at close to $5k but you get premium components like the Schlumpf + Shimano Deore XT drivetrain and a solid 2+ year warranty
• Only available in high-step “diamond” frame style for now, if you want a step-thru Stromer for easier mounting and stand over consider the ST1 Platinum or ST2 models
• I love that the bike offers regen and has a motor inhibitor built in but wish that both levers had that vs. just the right

Resources:

• Official Site: https://www.stromerbike.com/en/us
• More Pictures: https://goo.gl/photos/kRsF7dzV4PPYtdX77