They don't appreciate the synergy of cleaning created by placing high pressure before the cloth. Doing it this equals an automated vehicle prepping system. The reasoning is that high pressure prepping (however it is applied - manually or automatically) produces a cleaner car and more satisfied customer. If they didn't believe that they, would not do it? Prepping takes time and costs volume. Auto Prepping lets you limit manual prepping to only vehicles that present the greatest challenge (heavy mud, heavy bugs, bird droppings, snow and ice), instead of every vehicle you wash.
I prefer front wheel pull for several reasons. First, you set your equipment up the same way as you would in a rear wheel push layout with the first arch some 27-30' from roller up. Now you need to get only 6' of the vehicle on line instead of the entire vehicle. once loaded, the roller is called for, and the vehicle starts down the conveyor. This gives you some 18-20' of area to perform any prepping you feel necessary while the vehicle is moving. In rear wheel push you cannot start the vehicle until the prepping is finished. In front wheel pull this vehicle is moving while being prepped and the next vehicle loaded as soon as the rear safety roller comes up behind the back wheel. On busy days, this allows you to keep your line of cars always moving. If on a busy day you have gaps between cars of one car length or more, the your wash volume suffers mightily. An 80 car per hour conveyor speed translates to only 50 actual cars washed each hour instead of 75-80. Then what operators usually do, is turn up the line speed to compensate for the lack of volume. Thus to do 75 cars an hour a conveyor speed of 110 is required and all of a sudden cars are not coming out as well cleaned, rinsed or as dry.
