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Living Hinge Rub Rail

hinged screw cap cover on white passenger bus

The Customer & Goal

A shuttle bus manufacturer is dedicated to achieving performance and safety for the countless passengers who enjoy its vehicles. The transportation vehicle provider prides itself on using a 16-gauge tube-galvanized steel cage on each bus, ensuring theirs are some of the safest and strongest buses in the transportation industry.

Rail cap tearing off commercial bus

The Challenge: Performance & Supplier Issues

The shuttle bus manufacturer was having issues with its rub rail, the aluminum strip used to conceal joints covered by a soft vinyl compound to protect against impact. When bus speeds exceeded 45–50 miles per hour, the vinyl strip in the aluminum channel dislodged and fell off or dragged on the ground. This issue was not only a safety hazard but also threatened to undermine the company’s reputation for high-quality vehicles.

At the same time, the shuttle bus manufacturer also learned that its aluminum supplier was struggling to provide the product it needed for its shuttle bus rub rails. This, coupled with the defective vinyl strip, indicated that the company needed an alternative rub rail that would be cost-effective, reliably sourced and durable at high speeds.

Trim-Lok l11434-BW living hinge rub rail and screw cover with snap-in-cap diagram

The Solution: TPO Hinged Screw Covers

Not long after the shuttle bus manufacturer discovered issues with its rub rail, Trim-Lok took a living hinge prototype to their head engineer. A living hinge is comprised entirely of a single piece of flexible material. Similar to a door hinge, Trim-Lok’s living hinge is designed to move easily to simplify installation. Plus, the hinged cap design means it’s guaranteed to stay in place.

This feature was very important for them, because its original rub rail was blown out of place while on the road. Made of Thermoplastic Polyolefin, a blend of polypropylene and ethylene-propylene rubber, the living hinge would eliminate the need to purchase two separate parts from two different suppliers.

The shuttle bus manufacturer decided to partner with Trim-Lok, and now they can order one-piece hinged screw covers for an added element of protection and to hide the panel seam on their shuttle buses.

Build a Living Hinge Rub Rail Screw Cover



Trim-Lok’s hinged screw cover offers a much more lightweight option that is easier to ship and takes up less space in transport. The durable rub rail is about 5 lbs. per rail, while the shuttle bus manufacturer’s former aluminum rub rail was about 17 lbs. per rail. The new lightweight TPO option reduces the weight of each bus, helping the vehicles achieve better gas mileage.

Weather & UV Resistant

The new rub rail is completely weather resistant and holds up to shifting temperatures as buses travel widely or seasons change. With UV resistance and non-fading properties, it is durable enough to withstand all-day sunlight as buses carry passengers to and from their destinations.


The TPO material that Trim-Lok uses for its hinged screw covers is paintable, making it easy and convenient to alter the color of the product at any time. Trim-Lok also offers color matching to ensure that living hinges meet specific brand or color requirements for their application.

Trim-Lok black with white cap living hinge rub rail and screw cover

The Result: Cost Savings & Efficient Rub Rail Installation

By replacing the ineffective aluminum and vinyl rub rail with a lightweight, durable one-piece product, Trim-Lok helped the transportation provider decrease installation time by three minutes per bus. The all-plastic living hinge screw cap cover also produces cost savings, as TPO is less costly than aluminum and allows the shuttle bus manufacturer to order from just a single supplier.

Interested in replacing an efficient, heavy aluminum rub rail with a living hinge? Find a rep near you, and we will work with you to customize a bus or RV screw cover trim for your application.