ASUS Oxiis E250G1 Adds Electric Assist to Compatible Bikes With Seatpost Friction Drive

August 26, 2026: ASUS is moving beyond its familiar world of computers and electronics with the Oxiis E250G1 Intelligent Bike Booster, a compact friction-drive system designed to add electric assistance to a compatible conventional bicycle without replacing the wheel or modifying the bike’s gears or brakes.

Unlike a typical hub-motor or mid-drive conversion, the Oxiis mounts near the seatpost and presses a powered roller against the rear tire. If you are considering electrifying a bike you already own, my beginner’s guide to DIY electric bike conversions explains how conversion approaches differ. You can also follow the latest Electric Bike News for more new motors, batteries, bikes, and e-bike technology.

Current Status: ASUS Has Revealed the Oxiis, but Price and Retail Availability Are Still Unclear

ASUS now has an official product page and technical specifications online for the Oxiis E250G1.

What the company has not announced is just as important.

As of August 26, ASUS has not provided an official retail price, exact general on-sale date, or a clear country-by-country retail rollout, including confirmed U.S. availability.

Regional ASUS product pages exist, and independent reporting indicates testing has taken place in Germany, but that does not establish broad retail availability.

For now, I would treat the Oxiis E250G1 as an announced and demonstrated product rather than something U.S. buyers can necessarily order today.

How the ASUS Oxiis E250G1 Works

The Oxiis uses a friction-drive system.

Instead of placing the motor inside a wheel hub or connecting it directly to the crankset, a motor-driven roller contacts the bicycle’s rear tire and transfers power through friction.

ASUS says installation does not require modifications to the bicycle’s gears or brakes.

That could make the Oxiis appealing to someone who already owns a bicycle they like and does not want to replace a wheel or install a conventional mid-drive system.

There is a tradeoff, though. Friction drive depends on good contact between the roller and tire, which makes tire compatibility especially important.

ASUS specifically says heavily knobby tires are not recommended.

ASUS Oxiis E250G1 Key Specifications

• Motor: 250W rated, 500W peak
• Battery: 158.4Wh, 36V removable battery
• Claimed Eco range: Up to 50 km, or about 31 miles
• Claimed Sport range: Approximately 10 km, or about 6 miles
• Maximum listed speed: 32 km/h, about 20 mph
• Regional speed setting: ASUS says some markets will be limited to 25 km/h
• System weight: 3.7 kg, about 8.2 lb, including the battery
• Charging: 100W USB-C Power Delivery
• Claimed charging time: About 2 hours with a compatible 100W PD charger
• Water resistance: IPX4
• App support: Android and iOS
• Wheel compatibility: 16 to 29 in. plus 700C
• Maximum tire width: 60 mm
• Seatpost compatibility: 25.4 to 34.9 mm

These are manufacturer specifications and claims. I have not independently tested the Oxiis E250G1.

The 158.4Wh Battery Charges Over USB-C

One of the most interesting parts of the Oxiis is its battery.

Instead of requiring a conventional proprietary e-bike charger, ASUS says the removable 158.4Wh battery can charge through 100W USB-C Power Delivery.

The company lists an approximately 2-hour full-charge time when using a compatible 100W PD charger.

That is a small battery compared with the 500Wh, 600Wh, and larger packs commonly found on complete e-bikes, but the Oxiis is trying to solve a different problem. It is designed as a compact add-on rather than a long-range integrated e-bike system.

ASUS claims up to 50 km, or 31 miles, in Eco mode, but that should not be treated as guaranteed real-world range.

The company says range depends on factors including rider effort, terrain, and assist mode. In Sport mode, ASUS lists approximately 10 km of expected range.

If you want to understand why a 158.4Wh battery behaves differently from the larger packs on complete e-bikes, my guide to e-bike battery capacity and watt-hours explains the basics.

Three Assist Modes and Automatic Hill Support

The Oxiis includes three assist modes: Eco, Normal, and Sport.

Eco prioritizes efficiency and range. Normal is designed as a balanced everyday setting, while Sport provides stronger assistance for hills and higher-demand riding.

ASUS also promotes what it calls Adaptive Boost Technology, which is designed to detect inclines and adjust assistance as terrain changes.

Pedaling is monitored with a wireless cadence sensor, avoiding the need to run a sensor cable along the bicycle frame.

That wireless installation is part of the Oxiis pitch: add electric assistance while leaving as much of the original bicycle untouched as practical.

A Smartphone App Controls More Than Assist Level

The Oxiis connects to an ASUS app for Android and iOS.

ASUS says riders can use the app to switch between Eco, Normal, and Sport modes and view riding information.

The unit itself also includes controls, so basic operation is not described as entirely dependent on keeping a phone mounted to the bicycle.

For a first-generation cycling product from a major consumer-electronics company, the software experience is one of the areas I will be interested in watching once more production units reach riders.

It Also Includes a Brake-Sensing Taillight

ASUS has integrated a smart taillight into the Oxiis system.

The company says the light detects braking and increases visibility accordingly.

That is a useful addition on a conversion system because an ordinary bicycle being electrified may not already have an integrated brake light.

It does not replace the need for appropriate front lighting, reflectors, or other equipment required where you ride.

Compatibility Is Broad, but It Is Not Universal

ASUS markets the Oxiis as broadly compatible, but riders need to read the fit requirements carefully.

The company lists compatibility with city bikes, road bikes, gravel bikes, folding bikes, hybrids, and hardtail mountain bikes.

However, ASUS specifically says the Oxiis E250G1 is not compatible with full-suspension bicycles.

It also says the system should not be mounted to a carbon-fiber seatpost.

Compatible seatposts need to measure from 25.4 to 34.9 mm in diameter, and ASUS supplies spacers covering several sizes.

Tires can range from 16 to 29 in. plus 700C, with a maximum width of 60 mm. ASUS lists slick, semi-slick, and textured tires as compatible but says knobby tires are not recommended.

So although the Oxiis could work with a wide variety of conventional bikes, saying it “fits any bicycle” would be inaccurate.

IPX4 Means There Are Weather Limits

The Oxiis E250G1 has an IPX4 water-resistance rating.

ASUS says that means the unit can tolerate splashing water and may be used in light rain.

The manufacturer warns against exposure to heavy rain or submersion.

That is worth considering for commuters who ride in all weather. IPX4 is useful protection, but it should not be interpreted as unrestricted wet-weather durability.

Can You Take the Oxiis Battery on a Plane?

This requires more caution than ASUS’s marketing language may initially suggest.

ASUS describes the 158.4Wh removable battery as suitable for carry-on air travel subject to airline approval.

For travel governed by current U.S. FAA rules, lithium-ion batteries between 101Wh and 160Wh require airline approval. The Oxiis battery is rated at 158.4Wh, placing it close to the top of that range.

Individual airlines may impose stricter requirements or decline to carry the battery.

So riders should not assume that buying the Oxiis automatically means they will be allowed to board a flight with its battery. Check both the airline’s current battery policy and applicable aviation rules before traveling.

Does the Oxiis Legally Turn a Bicycle Into an E-Bike?

That depends on the jurisdiction and the market-specific configuration.

ASUS lists a 250W rated motor and a maximum speed of 32 km/h, or about 20 mph. The company also says the system is limited to 25 km/h in certain regions.

Those specifications do not automatically determine the bicycle’s legal classification everywhere.

E-bike definitions can depend on assisted speed, motor power, throttle capability, operable pedals, labeling, and other requirements.

Riders should check local law after installing a conversion system rather than assuming the original bicycle automatically qualifies as a legal e-bike.

My guide to Class 1, Class 2, and Class 3 e-bikes provides a starting point for understanding the common U.S. class system.

The Biggest Question Is Still Price

The Oxiis makes an interesting technical case.

It adds about 8.2 lb, avoids replacing a wheel or modifying the bike’s gears and brakes, offers a removable USB-C battery, and adds app connectivity and a brake-sensing light.

But whether it makes financial sense depends heavily on a number ASUS has not announced: price.

Conversion kits compete not only against other conversion systems but also against increasingly affordable complete e-bikes.

If ASUS prices the Oxiis low enough, it could appeal to people who already own a good bicycle and only want occasional electric assistance.

If the price approaches that of an entry-level complete e-bike, the tradeoffs become harder to ignore.

Who Might Be Interested in the ASUS Oxiis?

I can see the Oxiis making the most sense for riders who:

• Already own a conventional bike they like.
• Prefer an add-on conversion that avoids replacing a wheel or major drivetrain components.
• Ride primarily on smoother, compatible tires.
• Need modest electric assistance rather than a large long-range battery.
• Like the convenience of USB-C charging.
• Own a bike with a compatible frame, seatpost, tire, and suspension setup.

It looks less suited to riders using full-suspension bikes, carbon seatposts, heavily knobby tires, very wet conditions, or riders who regularly need the range of a large integrated e-bike battery.

My Take

The most interesting thing about the Oxiis E250G1 is not its 500W peak number. Friction-drive conversion systems are not new.

What makes this worth watching is ASUS entering the category with compact hardware, USB-C charging, wireless sensing, adaptive assistance, app integration, and an integrated brake-sensing taillight.

I also like the basic idea of adding electric assistance while keeping more of the original bicycle intact instead of replacing a wheel or installing a conventional mid-drive system.

But I would not make a buying recommendation yet.

Price and confirmed retail availability are still missing, ASUS’s range figures remain manufacturer claims, weather protection is limited to IPX4, and the system has meaningful compatibility restrictions.

Once ASUS announces where the Oxiis will actually be sold and what it will cost, we will have a much better idea whether this is a clever niche accessory or a serious competitor in the e-bike conversion market.

📰 How This Story Was Verified

This report is based primarily on ASUS’s official Oxiis E250G1 product page and technical specifications, with independent technology coverage used for additional context. Manufacturer specifications and range figures are identified as claims, and details ASUS has not clearly announced – including retail price, exact on-sale date, and confirmed U.S. availability – are left unresolved rather than estimated.

Sources

• ASUS – Oxiis E250G1 Intelligent Bike Booster
• ASUS – Oxiis E250G1 Technical Specifications
• GIGAZINE – ASUS Oxiis E250G1 coverage
• Netzwelt – ASUS Oxiis testing and availability report
• FAA – PackSafe guidance for lithium batteries