Yes. Many existing tunnel car washes can be converted from an over/under conveyor to a belt conveyor. A retrofit belt system is designed to make use of an existing facility. Whether it is the right choice depends on your building, conveyor layout, utilities, and the vehicles you want to wash.
For an owner with an established location and a sound building, the first step is to evaluate what can be retained and what needs to change. The goal is a conveyor that fits the operation and protects the value already invested in the property.
How does a retrofit belt conveyor work?
In the retrofit configuration described here, a moving belt carries the vehicle’s driver-side tires through the wash. The passenger-side tires continue to roll on the tunnel floor.
This differs from a full dual-belt conveyor, which supports both sides of the vehicle on moving belts. That distinction matters: with a retrofit belt, the driver can still influence vehicle movement by braking or steering. Loading instructions and operating procedures must match the particular system.
A retrofit belt and a dual-belt conveyor serve different needs. The retrofit approach helps owners modernize an existing over/under installation while making efficient use of the available conveyor space. A full dual-belt system may be a better fit when the site and project goals support a more extensive conversion or new construction.
Why available loading space matters
One of the most useful differences is where the conveyor begins moving the vehicle. An over/under system needs room for its rear-tire roller engagement. A retrofit belt engages the front tire sooner, which can reduce the loading distance needed at the entrance.
In Understanding Car Wash Belt Conveyor Systems, Lawrence S. Stovall, II illustrates this with a tunnel layout that might require approximately 125 feet with an over/under conveyor but approximately 105 feet with a retrofit belt. Those figures are an example, not a guaranteed reduction for every wash. The actual layout must be evaluated for your site.
If limited tunnel length has made an upgrade seem impractical, it is worth having the loading arrangement reviewed before ruling out a conversion.
When is an existing wash a good candidate?
A retrofit belt is worth considering when:
- Your existing building is structurally sound and you want to keep using it.
- You are replacing or modernizing an over/under conveyor.
- Available tunnel length or construction space is limited.
- You want to manage renovation costs while updating vehicle transport.
- Your intended vehicle mix fits the proposed conveyor and the rest of the wash.
Some retrofit systems can accommodate wider tires than older conveyors. Confirm the actual tire and vehicle limits for the proposed configuration. Conveyor capacity alone does not establish that a vehicle will clear the entrance, wash equipment, and exit.
What should you check before requesting a proposal?
Prepare these details so the equipment team can evaluate the project:
- Existing layout: Tunnel length and width, entrance and exit dimensions, and the current conveyor make and configuration.
- Building and foundation: Available drawings, the condition of the floor or conveyor pit, and any known structural limitations.
- Drainage and utilities: Existing drainage, electrical service, and utility locations that could affect installation.
- Vehicles and loading: The cars, pickups, or commercial vehicles you intend to serve, along with your preferred loading method.
- Equipment integration: The wash equipment, controls, sensors, and customer guidance systems that will need to work together.
- Project scope: What you want to retain, what needs replacement, and the business goals driving the upgrade.
Photos of the entrance, current conveyor, tunnel interior, and exit are also useful starting points. They help frame the discussion; final fit and installation requirements still depend on a site-specific evaluation.
What determines conversion cost and downtime?
A useful proposal covers the complete installed system. Compare the conveyor equipment alongside foundation work, electrical work, control integration, freight, installation, startup assistance, and training. Ask which items are included and who is responsible for each part of the project.
The amount of construction and integration required will affect both cost and the installation schedule. A single price or standard shutdown period cannot describe every existing wash.
Also look beyond the initial purchase. Frame materials, corrosion resistance, maintenance access, replacement parts, and service support all influence long-term ownership costs. An upgrade should make sense for the years you plan to operate the wash.
Start with the wash you have
A belt conveyor conversion can be a practical way to modernize a successful location. Start with the existing building, the customers you serve, and the operation you want to run. Then evaluate the conveyor options against those needs.
Explore AutoBrite’s belt conveyor systems and installation examples, or contact AutoBrite about your retrofit project. Call (210) 736-1892 to discuss your existing wash and the next steps for a proposal.
Adapted from Chapters 7 and 9 of Understanding Car Wash Belt Conveyor Systems: A Practical Guide to Selecting, Installing, and Protecting Your Car Wash Belt Conveyor Investment, first edition (2026), by Lawrence S. Stovall, II. The book draws on his decades of experience designing, installing, servicing, and evaluating car wash conveyor systems.