Wig Wag

[jjackrash]

Greetings. First time poster.

The boy's race was last night on a wooden track.

He had a pretty fast car (it actually turned the fasted lap of the night, but he took third overall), but it had way more wig way than any of the fastest cars. COG is right on 1 inch. Rear axles were drilled at 3 degrees cant and rear alignment looked good on the tuning board. It also constantly hit 4" drift over 4 feet on the tuning board. We didn't have a test track pre-race that we could use to test.

What are the main causes of wig wag? I'd like to diagnose the problem so we can improve next year.

Thanks in advance for your help.

 

[Kinser Racing]

http://www.pinewoodderbyonline.com/post/rear-of-car-going-back-and-forth-7900384?pid=1290657293

 

[TRE]

some cars need more steer, but if it needs much more than 5 inches there is a problem bad drill too much wheel gap..just have to play around with it

 

[jjackrash]

Thanks for the link.

 

[Kinser Racing]

some cars need more steer, but if it needs much more than 5 inches there is a problem bad drill too much wheel gap..just have to play around with it

Depends on the slope of the tuning board.

 

[derbychip]

some cars need more steer, but if it needs much more than 5 inches there is a problem bad drill too much wheel gap..just have to play around with it

Depends on the slope of the tuning board.

Can you explain this Chris? Wouldn't it not matter being the wheels have to take same number of rotations to cover same distance no matter what angle, increased angle will only speed up the time in which the distance/rotations are covered?

 

[Kinser Racing]

It'll also increase the slide of the steer wheel on the smooth glass surface.

 

[Ballistic Racing]

Not to get too far off the subject, what's a good slope for a tuning board? My board is 5' long with 1 1/2" lift at one end. Seems about right, just enough to self start but not too fast at the other end.

 

[GravityX]

My tuning board is raised about 3/4", it starts a little slow, but within a few inches it's up to speed. This will vary with each racer here. Also make sure the tuning board is level side to side.

 

[jjackrash]

Thanks for all the input folks. I appreciate it.

 

[Choo Choo]

A pool cue ball works well to verify the tuning board is level side to side.