There has been disputes over silicon verses rubber or urethane tires.

In their own environment silicon tires work well as do the rubber tires. The silicon tires have the advantage that they don't wear. The grip offered by both is similar. Except when you try to run both on the same track.

The silicon tires clean and pick up anything that is laying on the track surface.

So dusty tracks with rubber left on the surface will have to be vacuumed to remove the loose particles other wise the silicon tires will attract the dirt. Rubber tires do not pick up particles on the track as easy so the effect of the dirty track is less and traction more constant.

Below is my experience with the problem of running silicon and rubber tires on the same track!

I have recently painted over my Ferrodor surface with Cabothane a product made by Cabots Paints and is a urethane based paint. So effectively I have a thin layer of rubber over the track. Traction has been really good since applying the Cabothane paint.

I thought that the Cabothane surface may be able to hold traction and we could run both silicon and rubber tires. My testing has proved to me that we can't do that. This is because the silicon tires remove, very effectively, the inlaid rubber laid on the track from rubber tires.

Even though the surface was rubberized by the Cabothane it still relies on the process of rubber being inlaid on the surface from the car's rubber tires to get high traction.

I experimented by selecting the following cars after running on the "rubbered up" Cabothane surface to get their average lap time. Here are the times:

NSR Mosler with MJK tires - 8.9 seconds

Slot-It Sidewinder Porsche 926 - 9.3 seconds

Scalextric F1 Renault - 9.1seconds

Fly Porsche Sports - 9.4 seconds

Scalex. Camero - 10 seconds

I have 2 Ninco Indy Cars fitted with Indy grips Silicon tires - I ran them on the track for about 200 laps until they had cleaned the lane and were lapping at 8.9 seconds with out sliding .

I then tried the other cars with rubber or urethane tires. The traction for them had definitely reduced. They were all about 1 second a lap slower. I decided to run them for a while to see if they could get back to the traction I had before running the silicon tires.

I did a total of 100 laps between the rubber tire cars until the traction started to come back. At 150 laps the Camero achieved 10 second laps again . It took between 150 to 200 laps for the other cars had regained the lap times they had before the silicon tires hit the track.

All except the NSR Mosler though! It manged to record 9.2 seconds. I then sanded the tires on the Mosler and it came back to 8.9 seconds. The Mosler was the quickest car therefore the most reliant on good traction.

The inlaid rubber and corresponding traction took around 200 laps total by the five cars to return to the level it was before the test.

My conclusion is that silicon tires should not be used when rubber or urethane tires are being used on a track. This is did surprise me as the surface is painted with urethane and I thought they may be able to be used together. This is proved that we must be diligent to see that silicon tires must be kept away from the track surface if we are running rubber tires .

This is unfortunate but that is the conclusions I make from my tests.

CABOT PAINTS' CABOTHANE - a great racing surface

I am very pleased with the Cabothane surface and it has equivalent traction to Ferrodor at its best. And that applies for all atmospheric conditions. The Cabothane surface reduces roll over damage and only needs a blow off to get full traction.

That is if you don't mix silicon tires with rubber tires on the track. Cabothane does not seem to get effected by the moisture in the air or by dust as much as Ferrodor. The surface is sealed and impervious. This was of benefit to me because my shed has large double lift doors so it is exposed to the atmosphere more than some tracks would be.

Cabothane is available as water mixed and a satin finish. It is clear and very thin and can be applied with a brush retaining texture of what is under it (if you want to). It is also available in Gloss and as a oil based paint

As Cabothane is designed for coating floors It is hard wearing and can be easily re-coated if necessary. I believe It could save commercial track operators hours of maintenance. It even retains the appearance of what is under it ( e.g. Ferrodor) except for a slight sheen.

Rubber tires should not require treatment with CRC 2.26 before a race meeting as they often are when racing on Ferrodor. – (especially when it wears.)

Cheers – John - Fulham Park Raceway - www.slotcarsadelaide.com