A runnel is a narrow channel in the ground that water flows through. A bike runnel is a narrow channel on the edge of a stairway that helps
dismounted cyclists with bikes, e-bikes or e-scooters negotiate stairs. Cyclists place their wheels on the runnel and hold the handlebars and
seat to push or hold their bicycles as they ascend or descend the stairs. Runnels are used in bike-friendly cities around the world and known by various names including bicycle stairway channels, wheel ramps, tracks, gutters, push ramps and/or access ramps. While bicyclists use of stairs is no replacement for ridable paths and routes, sometimes stairs provide a more direct route.
While a fairly simple concept, bike runnels can be deceptively complex and require careful attention in design to address intended users. This requires specific efforts to minimize adverse impacts to people using the stairways. Stair use by those with mobility limitations, older persons, or young children who depend upon access to the handrails, requires the stairway tread to be free of any possible tripping hazard. Trends in modern bike design include bulkier, longer bikes with larger tires which require wider runnels.
Additionally, creating an extended skateboarding grinding edge is probably not the intention when looking to improve bicyclist access. Here are a few tips to consider when considering bicycle runnels:
- Material: can be formed in concrete or metallic channels (typically L-shaped).
- Position: should be on both sides under the hand railing, out of the walking area of the stairway.
- Width: typically, 2-4 inches wide (.05 to .10 m) for runnel surface which may be flat or channeled. The outer edge can be typically less than 12 inches (0.3 m) from the wall but needs to be no more than 8 inches (0.2 m) from the outer face of the railing.
- Height (lip): typically, 1.5 to 2.5 inches height to control the wheel position (.04 to .06 m).
- Non-slip: gripping runnel surfaces are important for safety, particularly in the downhill direction (avoid smooth metal or polished granite or adhesive tape which can become a maintenance issue).
- Handrails2: wall-mounted to avoid pedal obstruction with posts, when possible.
- Two-way traffic: consider stair width space for two-way/passing travel (this may lead to stair widths above 8 feet (2.5 m).
- Transitions: smooth transitions at top and bottom of stairs as well as at landings to avoid pedal catching on stairs (may require a slight hump).
- Landings: space for cyclists who pause on a landing should not impede pedestrian use of stairs; to prevent pedal strikes, runnels should continue to rise across landings.
- Skateboard guards: anti-skateboard grinding clips/stoppers/devices may need to be considered on open edge of any open runnel.
- Debris: consider maintenance requirements of leaf, debris, and trash removal, particularly if the runnel is added to existing stairs; to avoid accumulation issues, any added texture should focus on wheel rolling surface.
- Signing/Marking: consider signing and markings (anti-slip) for runnels to call attention to them in setting where not all stairways are similarly outfitted.