Guide axle on 3 wheel cars

[JCovert]

Could anyone provide some feed back on the thought process behind the "4th axle"? It appears to act as a guide. I'm building an eliminator class car and was wondering what the proper method is.

 

[DerbyDad4Hire]

It is just a guide pin keeping the car from jumping the track.

 

[OPARENNEN]

Normally, if the car's veer is set up properly, it will seldom touch the track on the pin side, However, too often turbulent air, vibration from other cars, etc. will cause a car to drift back towards the pin side. so it is definately needed, especially if something causes it to drift to the wrong side, AND if it jumps the track, goodbuy to 75 dollars worth of bearing wheels. This can also happen if the pin is not secure, touches the track and rotates to the rear (I know this, because it happenned to me during testing), be sure the pin's entrance into the body is very firm. Occasionaly, I put a tiny piece of Teflon on the end of the guide pin. But many very good car builders don't do this. About the only time I do this last item, is when my time is off a tiny bit (maybe only 1/1000) and I am looking to increase my time a tiny bit (doesn't work all the time.) Look at last month's Unlimited results. Less than 1/1000 is the difference between several of the top cars, some be only a few 1/10,000th, meaning that a decrese of 1/1000 would move a car up five or six places.