Stromer’s $11,000 ST5 Ebike Packs A Punch And Scores A First: ABS Braking On A Bicycle

Nov 17, 2023

Powerful, comfortable, sophisticated and now with ABS, the Stromer ST5 has been the company's halo ... [+] bike for several years.

Some ebike 101: For the most part, ebike makers selling bikes in the U.S. have to slot their creations into specific performance classes, currently delineated as Class I, which allows pedal assist up to 20mph but no throttle, or Class II, which is also limited to 20mph but does allow for a throttle for pedal-free riding, and Class III machines, which do away with that throttle but allow pedal assist up to a speedier 28mph. In Europe, the idea is the same while the speeds are a bit lower.

Who made up the classes and why those figures were chosen is fairly irrelevant (and complicated), and to be honest, there are more than a few ebike makers that see them more as guidelines than hard and fast rules.

Switzerland-based Stromer is committed to playing within the rules, and they created a sensational Class III ebike, the ST5, way back in 2019, and now offer a major update to the ST5 in the form of the ST5 ABS, which includes, as you probably suspect, an Anti-lock Braking System, aka ABS. (Note: The ST5 ABS is now just called the "ST5" on Stromer's website).

For the past few months, I’ve been tearing around Portland on the ST5 ABS, and it is one of the most impressive ebikes I’ve ridden to date. With a price tag topping $11,000, it would be easy to say "well, for that money, it should be great," and honestly, you’d be right for the most part, so it's fortunate that Stromer packs in a ton of value with this top-tier, tech-infused two wheeler. Let's take a closer look.

Stromer ST5 ABS Tech Overview

It's not light, but it's built like a truck, has the power to match and should last for years.

Where to start? The Stromer ST5 ABS is packed to the brim with tech goodness, much of it tucked away inside its wide aluminum frame. What, no carbon fiber frame? Not for this beast, which clearly prizes durability over light weight, seeing how it rings in at 72 pounds. Even the fenders are aluminum. The ST5 ABS has no suspension as stock, but it can be had with a suspension fork if desired for an additional $1,100. My review bike had no suspension, and really, I didn't miss it, as the special Pirelli Cycl-e 27.5-inch beach bike-style skins do a good job of soaking up small bumps and no suspension keeps the ride more precise. This is not an electric mountain bike, it's a full-on city bike for commuters who need speed, comfort, long range, high performance and reliability. If you must have some bounce, the optional fork can be teamed with an optional suspension seatpost.

Got speed? In top "S" mode, yes you do. I found assist level 2 to be the most flexible, but S is fun ... [+] to be sure.

Stromer's OMNI user interface works through a small backlit touchscreen (above) frenched into the upper frame spar, and the lower spar holds a massive 48-Volt, 983 Watt-hour battery that's also removable. There is an OMNI companion app, of course, which allows tweaking of many settings on the ST5 ABS and can also help track it down via GPS since the bike will connect to 4G cell networks, no phone required. The connectivity also allows for remote locking of the bike and over-the-air (OTA) firmware updates via the app. A phone mount is hidden under a panel on the top of the stem, but you’ll need to get an appropriate matching Quad Lock case for your specific phone. A USB charging port is hidden under the front logo - very clever.

Stromer uses a Syno Sport hub motor instead of a mid-mount for simplicity and quiet operation.

Battery power flows to a SYNO Sport 650-Watt motor in the rear hub, which can pop up to 850 Watts for short boosts. It's rated at 48nm of torque, which seems conservative. An 11-speed Shimano XTR Di2 rear cassette with one-way clutch and electronic shifting is controlled by two electronic buttons on the right handlebar. The system requires power but does not draw from the bike's battery and must be charged on occasion with a small included USB-type charger. The ST5 ABS is a Class III ebike with a top pedal assist speed of 28mph, and it does not have a throttle for free-wheeling. The assist has a total of five levels, including a "zero assist" mode that keeps the lights on as it were, standard 1,2 and 3 levels of assist, and an "S" or Sport mode for maximum assist. A torque sensor adds more gallop to the motor if you pedal harder, which is great for ascending hills and aids in efficiency.

Adjustable regenerative braking feeds power back into the battery to extend range.

Unusual for an ebike, the ST5 ABS also includes regenerative braking with five levels of "recup" as Stromer calls it. The system puts power back in the battery while braking or coasting, and it can be turned off as well. Under ideal conditions (likely maximum regen and pedal assist at 1), Stromer says the ST5 ABS will roll over 100 miles with assist. Crank assist up to Sport mode and the battery is good for 40 miles. A full charge from zero takes about 5 hours using the large appliance-like charger that comes with the bike.

The central Supernova headlight is hugely bright day or night, and even has a high beam.

The steering stem and handlebars are proprietary Stromer items, and they are well-positioned and comfortable. Stock lighting includes a horseshoe of LEDs around the Stromer logo on the front of the frame, and a retina-searing 1,250-lumen Supernova M99 Pro LED headlight with an LED halo - and a high beam. A Supernova M99 LED taillight sits out back. The lights come on automatically as darkness falls and have manual operation as well. Light control buttons are on a nifty backlit pod on the left bar, and the electronic horn (different choices for the sound are in the app) also gets a button next to the light controls. Booting up the bike requires knowing that the power button is stealthily hidden UNDER the LCD screen on the bottom of the top frame spar. Good luck, bike thieves.

Bright red four-pot calipers have a nice pop. Central slotted ring is part of the Blubrake ABS ... [+] system.

Stout TRP hydraulic disc brakes with 203mm carbon steel rotors and swank lipstick red quad-piston calipers are activated by three-finger levers on the bars, with the absolute minimal amount of brake lines showing before they disappear into the frame. The front brake is augmented by a Blubrake ABS system running off the bike's battery, the back brake does not have ABS. A slotted ring within the brake disc (shown below) tells the ABS system if the front wheel is locking up. The system then modulates the brake to keep the wheel rotating while still applying braking power. This system is very similar to how ABS systems on motorcycles operate, except motorbike ABS typically works on both wheels using a more elaborate dual-channel setup.

While the ABS system does require battery power to operate, the draw is very minimal. Also, if the battery on the ST5 ABS were to run down to the point where the bike's electrical systems shut off completely (which would be exceedingly rare), the front brake continues to work like a "normal" brake but loses its ABS capabilities.

Ride Impression

A quick pause for a photo on scenic Springwater Corridor, a rail-to-trails path that is popular in ... [+] Portland.

After a quick seat height adjustment at Lakeside Bicycles in the Portland suburb of Lake Oswego, I set out for home on the ST5 ABS, about 12 riding miles away. Right away, I could tell the ST5 ABS was on another level in terms of performance, precision and capability. First off, it's big (I requested a Large frame), which suits me fine at 6-foot-1 and 200+ pounds. And while some ebike makers tempt riders by cheating a bit at speed limits, the Stromer ST5 ABS keeps all of its assist cutoffs and such within the legal bounds of that Class III 28mph limit. The difference between the ST5 and many other ebikes is how powerful and precise it is within those limits. 28 is a very rapid clip on a bicycle, and while I like to see bike makers experiment with ebike speed limits to some degree, I’m all for capping things at 28mph in cities. It's plenty fast.

Remember summer? It was made all the better with long rides on the impressive ST5 ABS.

Transitioning from surface streets to Portland's reclaimed Springwater Corridor rail byway, now paved for riders and walkers, I set the ST5 ABS to "S" (Speed? Sport?) mode and dug into the pedals a bit, and the bike launched forward until the assist tailed off at 28mph, but the moment I dipped below 28, the power eased back on, and I blasted down the tarmac for miles on end at top speed. Yes, I was pedaling, but it wasn't a peloton-level workout by a long shot. The pushbutton electronic Di2 shifting system is precise, quiet, lightning fast and a joy to use. It's the equivalent of a top-spec dual-clutch transmission in a sports car, and I got used to it very quickly.

Back on city streets, I found pedal assist level 2 to be the most effective, with a bit of regen, er, recup mixed in for soft automatic braking once I stopped pedaling. But even at assist level 1, the power is evident, and in the flat, I often ticked assist to 1 and just rolled along at 20mph, which is plenty fast on a bicycle.

Backlit buttons on the left bar control assist level and lights. Horn sound is programmable.

Hills are a different matter of course, and I slipped away early on a Sunday morning to tackle my local elevation test. Set to 3 and then S mode, the ST5 ABS fairly flew up the road to the summit of the butte, often at well above 20mph, which is likely a record for bikes I have tested, with rare exception for some models that don't exactly hew to the legal ebike limits. Going down the deserted roads on the back side of the 700-foot rise, the ST5 ABS easily topped 40mph with some enthusiastic pedaling in top gear and a gravity assist abetted by the weight of the bike and rider. It felt planted and secure at speed, even railing through a series of sweeper turns with pavement undulations, the tires howling a bit as I increased lean angle. I have no way of knowing for sure, but whoever is in charge of design at Stromer may be a motorcyclist, and I wouldn't be at all surprised if that was the case.

I was hoping some rain might come my way while I had the bike so I could test the ABS system, but Portland was graced with dry summer weather during my review window, and I didn't want to chance a crash or damage the bike in repeat attempts to trigger the system. Circumstances intervened.

Coming down a sidewalk at a good clip near my home, a car suddenly emerged from a driveway obscured by a concrete wall on my left. I instinctively grabbed both brakes and crushed the levers in a panic, instantly locking the rear wheel into a skid. But the the front wheel continued to turn as the lever rapidly pulsed, and I was able to stop a few inches short of the car's passenger side door, behind which a woman was bracing for impact. The relieved driver mouthed "I’m sorry" and I nodded acceptance, and we both went on our way, uninjured.

Was I going too fast down the sidewalk? Probably. Did she not look before exiting the driveway? Likely. But thanks to the Blubrake ABS and that big front rotor, my ham-handed braking didn't result in a collision. That's what ABS and other "nanny" tech does best: Helps us out when our instincts take over and possibly lead us into injury. If the ST5 had not had ABS, the most likely outcome in that situation would have been a bike-breaking collision with a ride over the hood of the car for me, or a front wheel washout followed by a collision and a lot of road rash. Instead, we walked (well, drove and pedaled) away to ride and drive another day. ABS tech adds weight and complexity to a bicycle, but I’m happy to have it, and there's more of it coming from brands besides Stromer. I say bring it on, and at both wheels, in due time at least.

Conclusion

Expensive? You bet. Worth it? For riders wanting the best in a Class III ebike, it ticks most every ... [+] box.

Ten large (or more) is a very big ask for any ebike, but while riding the Stromer ST5 ABS, one phrase that kept coming to mind as I confidently blitzed down streets was "this is totally worth it." The massive but finessed power, top-level build quality, top-spec components, confidence-inspiring ride, burly design and all the small but useful touches add up to a bike that, while undeniably expensive, was also eminently practical, and above all, a joy to experience. It's pretty easy on the eyes, with smoothed welds, internal cable runs and a tough but tech-forward style. It got a lot of compliments.

Nits? It is a bit on the heavy side. The LCD screen requires a quick glance down and takes your eyes off the road, but it's highly legible and this was not a big issue for me. And sure, it doesn't have a throttle, but there was never a time I took a pass on a chance to ride the ST5 ABS because of that. Indeed, the excellent powertrain - especially that ultra-precise rear derailleur - and the fat power envelope makes the ST5 ABS a joy to pedal, especially up a steep hill. And coming back down an incline, there was never a point that the Stromer ST5 ABS felt the least bit overwhelmed by velocity, even above 40mph.

While the ST5 isn't a motorcycle, it often felt like one at speed, with a confident demeanor at any pace, and almost no motor noise. The ABS tech in the front brake is a very welcome step forward in bike tech. The Stromer ST5 ABS is a true game changer for rider safety, but overall, it's just a consistently fantastic riding experience.

While some might think of it as another toy for the wealthy, it should be seen as a workable replacement for a car (or motorcycle or scooter) in many situations. Able to access bike lanes, sidewalks and split through traffic, I was able to reach destinations either as quickly or very close to the speed of driving my car or riding my motorcycle, and have fun doing it. And in heavy urban traffic, the Stromer ST5 ABS was the winner every time.

Highly recommended.

Stromer ST5 ABS ebike: MSRP (as of October 25): $11,180

Hits

Misses

• Very expensive

• No suspension as stock

• Touchscreen requires a glance down

• Bars and stem are proprietary

Gear:

Bell XR Spherical MIPS Helmet