This page details in one place all the Osa parts and specs, plus replacements/alternatives if possible.
The information on this page started out as list of Osa specs from CAKE’s website, and is being enhanced with additional details we learn more about the bike and its components.
This page was initially documented and discussed in the “Osa parts and specs” thread on Discord.
¶ Photo
¶ Specs
¶ Battery
¶ Battery specs
- Capacity:
- Osa Flex (Battery L) 50 Ah / 2.5 kWh
- Osa+ (Battery XL): 70 Ah / 3.5 kWh
- Voltage (nominal):
- Osa Flex (Battery L): 50.4 V
- Osa+ (Battery XL): 51.8 V
- Cells:
- Premium 21700 lithium cells
¶ Battery charger
- Cake-1000 battery charger (same as Kalk)
¶ Brakes
- Motorcycle brake system, four piston calipers
- Hand levers for both front- and rear brake
- Combined brake system (CBS) on newer Osa+ models
- Disc: Stainless steel, 220 mm diameter, 3.2 mm thickness
- Pads: Elig HK31C (possible alternatives)
¶ Controller
¶ Display
- Most Osa have Display v1
- Newer Osa have Display v2
¶ Drivetrain
Specs according to CAKE:
| Model | Peak power | Nominal power | Torque (wheel) | Torque (motor axle) |
|---|---|---|---|---|
| Osa flex | 5 kW | 4 kW | 151 Nm | 42 Nm |
| Osa flex :work | 6 kW | 4 kW | 151 Nm | 42 Nm |
| Osa+ | 9 kW | 6 kW | 151 Nm | 42 Nm |
| Osa+ :work | 10 kW | 6 kW | 151 Nm | 42 Nm |
- Electric motor: Dana TM4 IPM-200-33 AD01
- Final drive: See Belts, chains & sprockets for information about the final drive of each model
¶ Measurements and materials
- Handlebar interface: 31.8 mm
- Ground clearance: 220 mm
- Seat height: 795 mm
- Wheel base: 1340 mm
- Frame and swingarm: 6061-T6 Aluminium, Extruded, Forged, CNC machined, welded and painted
- Fenders & bodywork material: PC/ABS plastic
¶ Speed & range
The numbers shown in tables below are from CAKE; real world usage can vary. The Range is for mixed city riding (WMTC-II).
| Model | Top speed (km/h) | Top speed (mph) | Range (km) | Range (miles) |
|---|---|---|---|---|
| Osa Flex | 45 km/h | 28 mph | 92 km | 57 miles |
| Osa Flex :work | 45 km/h | 28 mph | 120 km | 74 miles |
| Osa+ | 90 km/h | 55 mph | 111 km* | 69 miles* |
| Osa+ :work | 90 km/h | 55 mph | 111 km | 69 miles |
* Osa Plus is also listed as having a range of 52 km (32 mi) for high speed riding (70km/h).
¶ Suspension
- Front: Upside-down spring fork by RacingBros
- Osa flex: Single crown, 100 mm travel
- Osa+: Dual crown, 120 mm travel
- Rear: 260mm shock with adjustable pre-load, custom "Shicane" line by RacingBros (source)
¶ Weight
- Dry bike:
- Osa flex: 70 kg
- Osa+: 72 kg
- Battery:
- Osa flex: 17 kg
- Osa+ (and :work models): 25.5 kg
- Max. permittable load: 260 kg (bike + battery + rider + passenger + carry-on items)
¶ Wheels & tires
- Hubs: Forged and CNC aluminium CAKE hubs with 25 mm axle
- According to ridecake.com/spare-parts, Osa and Kalk share the same rear hub: SKU SP0044
- However, Osa and Kalk have different front hubs. Osa front hub is SP00435 (whereas Kalk front hub is SP0045)
- Rims: 14"x2.15" custom designed lightweight motorcycle rims
- Tires: Custom-designed Town & Trail tire 100/90-14" for the Osa (source)
- Width: 100mm / 3.9"
- Height: 90mm / 3.5"
- Inner diameter: 355.6mm / 14"
¶ Alternative tires
Other potential options:
- Early Osa models came with Anlas SC-500 Winter Grip 2 tires (source, photos)
- Michelin Anakee Street 100/90-14 (source)
- Hookie use Bridgestone Rectangle 5.4-14 on their bikes, but you cannot run them with the stock fenders (source)
¶ Miscellaneous parts
¶ Wiring schematics
Main wiring schematic:
12v wiring schematic:
¶ Known issues
¶ Steering column recall
Osa flex models originally had an aluminium steering column which may fatigue and break on impact (e.g. crash, potholes). A recall was issued in late-2023 (NHTSA ID: 23V803000). CAKE replaced the aluminium steering column with a reworked steel version. The image below shows the aluminium version on the left and the stainless version on the right. It also shows a broken aluminium steering column.
Please check your steering column is the steel version which can be identified by its shiny surface compared to the aluminium version which has more of a matte texture. The reworked steel version can be purchased from CAKE Service Co or from the sellers on the #marketplace on Discord. Installation can be done by following this guide: Osa flex: Replace triple clamp assembly (PDF).
¶ Misc issues
- Weld failure on early center stands, see Zach's thread on HackCAKE. CAKE later revised the center stand design with a more substantial bracket.
- Forks clunk when riding over sharp drops (like potholes). This seems to be a permanent "feature" of Osa, rather than something becoming faulty. See thread on Discord for more discussion.
- Front fender rattles. DIY solutions involve reinforcing the fender with a DIY stay, or raising the mudguard to provide more clearance between it and the tire. See Discord forum thread for more info.
- Osa with v2 display randomly switch to ride mode R1. See Facebook thread for more discussion.