Rock the Bike

Rock the Bike manufactures and sells its equipment and also runs full-service events and rentals; the Pedal Power Utility Box has been documented since a blog post of 21 April 2011 that is still current, and the Generator Pro, the Roll-Up stand and the Event Power Box are live product pages as of 2026. The Generator Pro is a purpose-built fixed-gear bicycle whose dedicated rear wheel contains a large brushless hub generator driven by chain from the crank; the hub's three-phase output is rectified to DC through a 20-foot cable. For a rider's own bicycle, the Roll-Up stand presses an external six-inch composite roller against the tyre. The active status rests on shop and blog pages current through 2025–2026.

Specifications

What do these labels mean?

Field	Value	Confidence	Sources
System voltage (Generator Pro line)	24 V nominal DCThe company states all its systems are 24 V; output is 'pegged to the load you connect'. The Roll-Up stand and the Event Power Box are separate cases — see the rows below.	Documented	^4,3
Ultracapacitor brick voltage (Utility Box)	30 VDescribed by the company as 30 V ultracapacitor 'bricks'.	Documented	^1,5
Roll-Up stand output voltage	0–30 V DC, or three-phase AC	Manufacturer rating	⁶
Generator Pro drive type	Brushless three-phase hub generator, fixed-gear rear wheelCorrects an earlier 'bottom-bracket flywheel drive' description; power flows crank → chain → generator hub.	Documented	³
Generator Pro rated output	not disclosedVoltage (nominally 24 V) is published; no wattage rating is.	Not disclosed	⁴
Roll-Up generator rating	300 W continuous (nameplate)Manufacturer rating, medium confidence per the research (Table 2.1); the product page itself qualifies it: 300 W sustained is very challenging for most pedalers. Rock the Bike's own expectation for a public-event rider is about 50–75 W.	Manufacturer rating	⁶
Pedal Power Utility Box buffer	2–5 minutes (ultracapacitor bridge, load-dependent)Withdraws an earlier circulating figure of 60–120 seconds, found in no Rock the Bike document.	Manufacturer rating	^1,5
Pedal Power Utility Box capacity	up to 5 bikesThe company's blog documentation separately describes ten pedaler inputs; the product specification is five bikes.	Manufacturer rating	¹
Pedal Power Utility Box inverter	1,000 (2011 box); 1,500 US / 1,200 EU (current) W pure-sineThe 1,000 W figure belongs to the original 2011 product; the current model is rated higher.	Manufacturer rating	¹
Event Power Box capacity	2.5 / 5 kWh (standard / extended version)Only the 5 kWh option is published as a capacity; the standard 2.5 kWh is implied by the product page's own worked example (a 300 W PA for about eight hours), not printed.	Manufacturer rating	²
Event Power Box inverter limit	1,500 WProduct-page rating; no independent measurement exists.	Manufacturer rating	²
Event Power Box battery chemistry	not disclosedNot printed on the product page; the '48 V LiFePO4' combination sometimes attributed to it appears only in the company's separate DIY outage-preparedness guidance.	Not disclosed	²
Event Power Box bus voltage	not disclosed	Not disclosed	²

Technology

The Utility Box's ultracapacitor "stabilizes the spiky DC power coming from bicycle generators"; continuous pedalling is needed to keep devices on, and the bridge is "a 2–5 minute buffer of power (depending on consumption levels)" ahead of the pure-sine inverter ¹. Rock the Bike's expectation for a public-event rider is about 50–75 W of continuous output, against the Roll-Up stand's 300 W continuous nameplate ^7,6.

Two-lane line diagram comparing Rock the Bike's ultracapacitor bridge of two to five minutes with its battery box of two and a half or five kilowatt-hours — Energy-flow diagram A and B: Utility Box (2–5 min ultracapacitor) vs Event Power Box (2.5/5 kWh)^4,1,2,3 Image: BicycleCinema.org, drawn from the research corpus

Rock the Bike pedal-powered lighting rig at night — Photo: Rock the Bike (rockthebike.com) — via rockthebike.com

Line drawing of the Generator Pro fixed-gear bike showing the brushless generator inside the rear hub, correcting the bottom-bracket description — Generator Pro correction card: chain to rear hub generator, not bottom-bracket^4,1,2,3 Image: BicycleCinema.org, drawn from the research corpus

Rock the Bike pedal-power event with stationary bikes — Photo: Rock the Bike (rockthebike.com) — via rockthebike.com

In their own words

"The magnets and coils inside the hub never touch each other." ³

"It stores energy in a battery, accepts renewable inputs like solar and bicycle generators, and delivers standard AC power while showing the energy story on a daytime-visible display." ²