Scientific tire traction testing

[mattb]

When I built the new wood track, I rolled two coats of gray latex gloss paint on it. Nice and smooth like I wanted, but all the imperfections in my work jumped right out. So I put a coat of flat finish on it, but with silicones it didn't have the traction I wanted or I had with my last wood tracks. I figured to try some other paints and see what worked best. I tried flat epoxy, spray rustoleum with some kind of grit in it, a coat of clear polyurethne, a coat of the gray with some aluminum oxide (from my bead blast cabinet) in the paint and a coat of gloss latex gray. I then put a car on each type of paint and angled the track piece till the car started to slide. The clear coat and the gloss latex were the best, so I brushed a coat of gloss gray over the flat. Now traction is fine and brushing seemed to not highlight the un-eveness in the wood.

With urethane tires, I think it would have rubbered in, not sure the silicone would have.

Here is the scientific testing.

[slothead]

Love it when this sort of experimentation is used to do comparisons.

My 'dirt' oval is made from 1/4" hardboard (aka Masonite) with nothing done to the surface. I wanted it smooth and slippery to make getting 'slideways' a part of driving, which it is, but found out it's too slick for anything but silicone tires.

My road course is made from MDF with errors and screw holes patched with wood filler, then a coat of primer, and a top coat of flat grey latex paint. I was too anxious to get the track running and only did one top coat before applying the copper tape and after awhile light brown spots where repairs had been made started to show through. Urethane tires (PGT's) work best on this track as is, but when I get to work on the scenery I think the track surface needs repainting and I'll want to use something that has similar traction characteristics. So maybe I need to replicate what you did using various paints, application methods, and cars with PG tires.

[HomeRacingWorld]

It is a good test.

My recent track rebuilds/repaints used SATIN latex. Not too much gloss, not as chalky as pure flat. It allows the rubber to wear in over time, yet Quick Slicks work on it well as it has almost zero chalk/dust.

Thanks for the time and effort taken here.

[mattb]

If you plan to run urethane, I would just duplicate what Harry and many others have done. Seems the urethane will rubber in a track and traction will only get better, with silicone I'm not sure it's the same. Silicone tires like a clean and smooth track. I used to clean my wood track with Windex and a towel. Dust is a big problem.

[slothead]

Dust being a big problem at a dirt track is nothing new, it just usually doesn't effect traction. I clean my oval with a feather duster or Swiffer when it hasn't been used for awhile. If it wasn't for fear of damaging scenery stuff I'd use the shop vac. I've thought about building a track prep truck pulling a battery powered dust buster on a trailer behind it, but never got the parts to do it.

[chappyman66]

Matt,
Cool and interesting test. Any time you finish wood, at least two coats are normally required. I normally sand after the first coat with 120 grit or so and use a tack cloth before the second coat. The surface is much better after two or three coats.
I also used satin or semi gloss. Silicones have great traction on my track when it's clean. I have a 4" wide silicone roller for cleaning the track...made from the same stuff as tires it works pretty well.

[RichD]

When you paint MDF with a water based paint little fibers pop up, for the best grip those should be removed before you apply a second coat. Our expert track builder likes to scrape the surface with a razor blade, but a light sanding with a medium grit paper should work as well. Most of our tracks have a flat latex finish and we get plenty of grip, however a final coat of semi gloss polyurethane will add a little more grip. A new track will need to be run in no matter what tires you use. Different types of tires may not play well together if you are looking for maximum performance. In a club racing type setting you would be better off picking one type of tire and running all of your cars with that. We got away from using rubber tires because they often give inconsistent results due to batch to batch variations. Rubber tires wear more quickly and can turn rock hard or turn to goo after a year or two. Another issue with rubber tires is that you can enhance their grip by various treatments, and that tends to make racing with a level playing field more difficult. Silicone tires do like a clean track, once they get coated with dust they loose much of their grip. We do not find that cleaning our tracks is a big deal. Wiping the track down first if it has not been used recently is helpful. You need to use something that actually picks up the dust, rather than just push it around. Vacuuming is not that effective in my experience unless you have a lot of stuff to remove. Vacuum cleaners are not very good for removing fine dust. Running the cars and cleaning the tires often will condition the track rather quickly.

[HomeRacingWorld]

Down here in the Ye Olde Skunkworks, it can get rather dusty. I do use a Shop Vac to clean up first (a small one with filters). I do this to make sure there are no larger objects like the occasional body screw, or in my case down here, a small moth/bug.

Then I use masking tape. Nothing has proven to work better than this method as it actually picks up the small particles, not just move them around.



It leaves no residue and is simply a very inexpensive and effective method. I run about 4 or 5 laps and change the tape, repeat. Done.

Then just racing the track. I do this before any product review road testing and before our major race events.

Both the MIDMO and Show-Me tracks used Satin. After the first coat has dried, I use a tack cloth to clean, then two more coats.

We race it all here. Rubber, Fish Foams, Standard foams, PG urethanes, Quick Slicks silicones. From 1/24 vintage thingies to stock 1/32 cars. What tiny amount of "rubber" silicone might pick up or clean isn't hurting a thing. The rubber that is worn in, stays in. This isn't necessarily improving the grip surface and removing loose portions of it isn't really a bad thing. It is more related to the smoothness your surface becomes over time by racing. The smoother it is, the more tire contact to the track. And in just a few laps with the stock or rubber tires and what small amount has been cleaned, just gets "baked" back in again.

Some clubs have all sorts of rules and restrictions for tires, tire cleaning/treatments, etc. These simply do not exist here. Anyone that has watched the race videos of our Showdown Series, or driven here will attest that there is no grip issue. Each year since the Show-Me rebuild, the lap times are just getting faster. The more action this track sees, the smoother it gets.

Again this was a good testing and appreciate the effort. I hope your track serves you and your racers well.

[mattb]

This is a good thread to get input from so many people. That's how you learn something new every day.
I agree with the 2 coats in principle, but the piece I painted had 1 coat of gray epoxy rolled on it and 2 coats of flat latex applied the next time and one coat of polyurethane semi gloss last. This was all applied before I painted the stuff I tested. Everything had a good primered base coat underneath.

I will put up a better picture of the test piece. I will try to re-size it so it fits the window. That track piece was my first experiment with 2 4 lane sections and how the joint would work between them.

Harry, if I re-size and I found a program that will do that, what size do I want to go to?
Matt

[HomeRacingWorld]

Photo sizes are max size at 900 pixels wide. I will take that attachment and resize/post for you.

[mattb]

Here's a little more on the science experiment testing tires and paint! This un-used piece of mdf was painted with satin
polyurethane with some oxide particles sprinkled on it, some plain old alkyd enamel and some spray ACE enamel.
The old oil based enamel was probably best of all.

P1010002.JPG

this picture shows my attempt to see if I could put two pieces of 4 lane track together and how good the joint and electrical connections would be. This piece you can see I tried several different paints and the gloss latex was the best with the clear poly about the same. I put the ruler next to the track and then just raised the side till the car started sliding and looked to see how high I raised it. Real scientific! The gloss latex immediately gave me great traction on the new track. I have some vintage cars with urethane tires and I will run a few of them to see if oe rubber affects the other good they do. I expect they will be as good. I also think on a flat finish urethane would also rubber in the track and work just as good.

P1010001.JPG

[Broman62]

Thanks for the in-depth report MB!! :auto-layrubber: :auto-layrubber: