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I was having a discussion on another Slot Forum, about the Magnetic downforce of Stock Aurora T-Jet Chassis vs. that of Cars with Neo Traction magnets. And I said, a stock T-Jet chassis, has little downforce attraction of the magnets to the track. And the one fellow(RichD) countered that I was WRONG, and stated that the Lowered FRAY and SS Chassis, when using Strong Ceramic magnets -does INDEED have Magnetic down force ! Soooo, I proposed a little experiment, and although my pix here don't prove anything- since my FRAY/SS Chassis is just sitting there...I was trying to point out, that my AW Ultra-G Chassis, even with Taller Drag tires, will stick to plastic sectional track held upside Down. BUT, I couldn't get my FRAY Chassis, with Matched/Very Strong DASH Magnets, to stick to the track upside down, even with no body, and No TopPlate/Armature/Gear assembly ! For Reference, the Track I used for this experiment is a single lane of Marchon Track, which has the same highly magnetic rails as does the Original Aurora Lock & Joiner Track, which I don't really have any pieces of- except for a Few Cobblestone tracks. Anyway, the Fray Chassis is as low as I go, and I am using .348" rear Sili-sponges in this shot, and very strong magnets, and I COULD feel some magnetic downforce when held on the track up-right, but not enough to hold the bare chassis (w/mags) when held upside down.

And before anyone comments, I use .348" Sili-Sponges on my FRAY "Type" chassis, because I only run on section plastic track, and rail height is an issue.
And btw- when doing this experiment, I tried all the brands of track I had on hand, and found the strongest magnetic pull came from Aurora L & J (but didn't have old original A/FX to try), and Marchon was just as Strong, and funny thing- I noticed Lionel track was ALSO just as strong a pull- BUT, Atlas track DIDN'T hold well...neither did Tomy, AW, Tyco, Mattel, or Life-Like !

Someone misunderstood what I was saying, I did not intend to say that you were wrong in any case.What I wanted to say was that magnetic downforce is indeed a factor with Fray type cars. If you run a Ultra-G car or just glue a small neo magnet to the bottom of a regular chassis obviously you will get a lot more downforce, provided that you run on a track with magnetic rails of course. The one Ultra-G car that I have turns faster lap times than my best Fray style car, about the same times as a good Manatraction or X-Traction car. On another thread someone was using a Magnet Marshal to take some actual measurments. What really counts is what the car will do on the track. Adding a magnet will probably be faster and cheaper than buying a lot of expensive speed parts and spending hours building a car. Adding a magnet is not an option with the cars that I race, but it can be fun to experiment.

That's cool RichD, I just used our little discussion as the means to create a New thread :text-thankyouyellow:

Btw- I just did another small test(no pix this time, but I can if requested). In this test, I merely set up a bare Aurora T-Jet chassis tub, and again used very strong DASH Magnets, but this time the chassis had no pick-ups, and no wheels/axles or tires either. And guess what, the bare chassis DID stick to the rails upside down ! :D

Here's a NEW Surprise ! ....I wanted to shoot a photo of my latest test with the bare chassis tub with just DASH Mags sticking to the track upside down, then I thought to myself, I wonder how it will do with a complete Top Plate(Arm & Gears) installed ? Well....here's the Result- SUCCESS ! It Sticks upside down, albeit minus the axles, wheels, tires, crown, pickup shoes w/springs, and comm brushes !



Obviously, the closer to the rails you get, the stronger the down force !

The amount of downforce varies with the square of the distance between the magnets and the rails, so changes in ride hieght have a bigger effect than you would expect. Decreasing the distance by a half would increase the downforce by 75%.
The shoe springs do tend to lift the front of the car, for the best performance you need to find the lowest spring pressure that still gets you good contact. You can buy a set of springs with incremental increases in tension. If you run a car that is lower than stock you should check to see if the shoe springs are fully compressed, if they are a joint with even a slight mismatch in the rail height can flip the front of the car up.

Here are a few down forces I came up with

Some interesting comparison data!
Thank you for sharing! :)