# When Magnets Don't Match



## Grandcheapskate (Jan 5, 2006)

You never stop learning in this hobby.

A few weeks back I purchased an assortment of about 20 T-Jets and original AFX, plus a couple Tyco Pro. The cars looked to be in pretty rough shape but after going through the method I use to clean up the bodies and chassis, the bodies look pretty good, the chassis look great and they all ran fairly well with a minimal amount of tuning (more tuning and they might really fly). Amazing how these things come back to life even after decades of neglect.

Anyway, here's what I discovered for myself. One of the AFX seemed to have a problem somewhere in the drive train - anywhere from the pinion gear to the crown gear. When you manually turned the rear wheels, you could feel the armature kinda clicking/snapping into place. I then noticed that the armature always wanted to stop with one of the arms pointing directly at the front magnet.

This got me to thinking that maybe one magnet was way stronger than the other and sure enough, when I took a better look at the magnets, it seems the front magnet may have been from a Super II (it had the little dimple). I replace it with a regular AFX magnet and the problem went away.

Of course, I now had to disassemble every other Aurora car from that lot looking for the matching magnet, but came up empty.

So what I learned today is that if I have an armature which wants to always stop (or come to rest) in a certain location, that is an excellent indicator that the magnets are vastly different in strength.

Thanks...Joe


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## slotking (May 27, 2008)

yep

I have done that on purpose for some races I have been to.


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## Grandcheapskate (Jan 5, 2006)

slotking said:


> yep
> 
> I have done that on purpose for some races I have been to.



Why would you do it on purpose?


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## alpink (Aug 22, 2010)

there are classes of drag races that DRHOE runs with a neo mag on one side and a poly mag on the other side. 
inline motors.
they use different strength traction mags in some classes too. 
the E stands for Extreme, so those rules are for inbetween classes. have a look ate their site sometimes, very interesting.
i have raced with them using the really radical fastest cars
grenades just waiting to go off LOL


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## slotking (May 27, 2008)

I play with different setups to see what works best for racing a car.
sometimes it is matched, or a little different or a lot different.

A lot = 300 or 400 gauss


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