On the Wash Front - May 2007

The Spin
on Cleaning Side Vehicle Surfaces
By Anthony Analetto

Like most things in life there’s more to it than meets the eye — cleaning the side of a vehicle is certainly no exception. Different brushes rotate in different directions, at different speeds, at different angles, and all for different reasons. Some are obvious: tire brushes rotate toward the ground to prevent throwing debris onto painted surfaces. The problem is that I’ve seen botched equipment installations with brushes rotating in the wrong direction. It reminds me of a grade school teacher I had who once asked the class, “What color is the chair you’re sitting on?” Very few could answer with confidence. Unfortunately, in a car wash, the first assumption will often be that the equipment is inadequate for the chain speed or road-grime conditions. Many operators will then resort to costly manual labor to prep vehicles. Before you run out to check the rotation of all the brushes in your wash, take a minute to read through to the end of this article. Side surfaces don’t get nearly the amount of attention we give to getting wheels and front grills clean, but present many challenges that I’ll review below.


It is nearly impossible to clean a car in a tunnel wash without at least one set of wraparound washers. Every wash should have at least one set installed. At the same time, they cannot deliver enough cleaning performance to be the only wash action to clean side surfaces. Unlike side washers, wraps rotate with the vehicle, allowing them to “walk” smoothly off the front of the car and down the sides before crossing back to clean the back. While they do clean side surfaces, their true claim to fame is an unparalleled ability to wash the front and back of a car or truck. By “walking” down the side, wraps are very safe, but much of the cleaning energy is lost because the vehicle is moving in the same direction as the wash material. This effect is greatly exaggerated as conveyor speed increases, making it difficult for any wrap to consistently clean all side surfaces — especially lower rocker panels, since there are thousands of different vehicle profiles. Even if your wraps appear to be cleaning all side surfaces, it is inevitable that a drastically angled rocker panel will be missed. As important as they are, wraparound washers absolutely can not clean the rear wheel well of every car that will enter your wash.


Unlike wraps, side washers rotate against the direction vehicles travel. Contact time will still be reduced as conveyor speed increases, but not as dramatically as a wraparound. Every wash should have at least one set of side washers for consistent results.

Side washers are available with either electric or hydraulic motors mounted on the top or bottom of the hub. Some operators prefer the motor mounted at the top for ease of maintenance. Bottom mounted motors offer greater installation flexibility and shorter brushes can often be mounted underneath a mitter curtain, an important consideration for operators looking to increase wash performance without major construction. Another advantage of this design is that the motor is hidden, and customers only see soft materials near their car, not the mechanics of what’s powering them


In the face of changing weather and new vehicle designs, there is one thing a car wash operator can safely predict — the bottom of the car is consistently dirty. Yes, there are still differences caused by tire tread designs and splashguards, but in our business, this is about as close as we get to a sure thing. With that said, when addressing side cleaning it’s best to work from the bottom up.

If you only have room for one side washer, use it to concentrate cleaning on the lower rocker panel with a short brush — normally 18 to 28 inches. This brush will often be slightly angled to accommodate a wider range of lower body types and feature a tapered wash material for maximum penetration. Ideally, this short brush will be placed early in the wash process immediately following detergent and CTA applications. When properly lubricated with foamed detergent, more and more operators are having success with crushed feather tip bristle brushes spun at a higher rpm on lower rocker panels — yes, bristle, the material practically banned from car washing for decades. No one ever questioned its ability to clean, and when used with a proper lubricating detergent it delivers spectacular results — fast and safe. Flat soft-cloth materials also work excellently on lower surfaces with a proven track record of reliable performance.

A single set of wraparound washers and a single set of rocker panel washers will meet side surface cleaning needs for most car washes running a chain speed less than 80 cars per hour. Additional performance can be found by introducing different wash media, such as closed-cell foam or high-loft tufted wash material on the wraps. Except during extreme weather conditions involving snow, ice, or mud, it is unnecessary and costly to pre-wash vehicles with high-pressure before entering the first friction wash cycle. Regions with these characteristics will want to examine a supplemental application and pre-cleaning process. Prior to entering the foaming pre-soak applicator arch or system, vehicles should be cleaned with a high-pressure wash system emphasizing wheel wells and lower surfaces. It is imperative that the water is infused with an alkaline detergent that matches the pH of the first detergent application. This will prevent excessive dilution of the first pre-soak application which could otherwise disrupt the wash quality.


In my opinion, all hybrid washes need at least one set of wraparounds and a short rocker panel brush concentrating on low vehicle surfaces. The question is where you go from there once chain speed increases above 80 cars per hour. The answer is — it depends. Once you move above the bottom 10 inches where cars are consistently dirty, you introduce numerous variables that influence equipment selection. Understand that as you increase the speed at which a vehicle travels through the tunnel, you must add additional wash components since each one will have less contact time with the vehicles surface.

Difficult Conditions
Locations with heavy mud, snow, or other road grime, usually related to periods of high precipitation, will want to add an additional tall side washer. Different wash materials and detergents work better in certain situations, but all demand more equipment to clean the side of the vehicle. How tall the brush needs to be is related to the average vehicle height in your market and other equipment in the wash that may overlap to clean top side surfaces. Typically, a brush of approximately 50 inches will accommodate the widest range of vehicles and standard SUVs. Markets with a significant number of vans and large SUVs will want to consider a taller hub of 60 or more inches, and some urban markets can get away with a shorter brush, commonly 35 inches. Avoid automatically adding the largest side washer you can find. It is not only more expensive up-front, but also increases the cost of replacement cloth, and the heavier hub can put some additional strain on replaceable bearings and other components.

Good Conditions
Some operators are fortunate enough to be located in geographic regions without any of the difficult conditions that warrant a high side washer rotating at the vehicle for maximum cleaning. Still in need of supplemental side cleaning as chain speed increases, these tunnels can consider adding a second set of wraparounds in lieu of a tall brush. Although not as effective on top side surfaces, if conditions dictate that they are sufficient, you’ll get the added benefit of a second pass at cleaning front and rear surfaces.


Sides are no different than any other vehicle surface. Whenever possible, you want to incorporate a hybrid wash process that uses a combination of chemistry, friction wash, and touch-free high pressure for optimal results.

A good high-pressure wheel-cleaning system will provide some cleaning to side surfaces but this is often not enough. Many pivot or track the wheel for increased contact time. Although great for getting a clean wheel, they become ineffective for side cleaning. Washes with faster chain speeds, or difficult road grime behind the wheel wells, will want to consider adding a dedicated high-pressure blaster that oscillates, sized for the conveyor speed, after the first friction wash for supplemental cleaning.


A dirty mirror will stick out like a sore thumb and destroy a customer’s satisfaction with an otherwise great wash. Wraparounds work well for cleaning mirror glass, especially when outfitted with foam or tufted wash materials. The opposite rotation of a tall side washer works well to clean the outside of the mirror, making them a must for nearly any wash in an area with a heavy bug season. Adding a supplemental high-pressure blaster focused directly at mirrors is becoming increasingly popular. These blasters not only clean, but also do an excellent job flushing any residual foam from behind the mirror — a great benefit for any wash offering triple-foam conditioner.


There’s a lot involved with getting the side of the vehicle clean. Resorting to manual labor even during the worst weather conditions should be avoided at all costs. If you’re struggling to get the sides clean, evaluate the correct performance, type, and placement of your equipment, and consider using different wash media. Have your detergent supplier recommend different products better suited to loosen the road grime you’re trying to remove. Whenever possible, invite others to help identify solutions. Too often, as operators, we’re so close to our wash that we assume we know everything about it. I can illustrate this from personal experience. I recently installed a beautiful flashing sign next to my triple-foam applicators to promote the service. I positioned it just right. I installed the bulbs myself. It wasn’t until the spouse of a friend going through the wash asked me, “What’s polshing?” that I realized it’s always good to get a second opinion.

Anthony Analetto is the chief operating officer of SONNY’S The Car Wash Factory and one of the company’s driving forces behind new car wash equipment innovations. Prior to joining SONNY’S, Anthony was the director of operations for a national car wash chain featuring 74 locations across the country. He has over 25 years of experience in the car wash industry and can be reached at (800) 327-8723 or via e-mail at Aanaletto@SonnysDirect.com.

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