Feedback Needed for Yellow Snow Wiggle

Feb 2, 2013
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So we just got Yellow Snow back, it was not actual yellow snow but our BASX car rom the Feb Race. I am wondering if the setup was just not right for the type of car. It had a lot of rear end wiggle. It is my wife's car but I don't think that was the cause of the shake. Her rear end movement is much different.

The makeup of the car is it is 3 flat but the rear wheels cant enough to migrate out. The front also is drilled to ride on the bodyand has around 12"+ steer in 6 feet. Weight is 12 cubes in back and 6, 2, and 2 in front. The 2 rows of 2 being on the DFW side with around a cube worth of weight of putty to bring it up to 5oz. It had BASX type wheels and small axles. The rear wheel gaps were pretty tight. The front also tight but not as much as the rear. Standard Wheel prep with red rocket and oil. Axles were polished using the DD4hire kit. It rolled good on the tuning board, was quiet, and tracked good.

I expected it to not be very fast but not so much wiggle. I wonder if the weight was too aggressive or if the looser wheel bore and less cant may need more gap on the rears. The front looked like it was planted very well in the video but the rear end was all over.

The first run was really bad but the next 3 were decent and improved each time but the rear was always really loose.

Blue 3.0188
White 2.9999
Black 2.9982
Red 2.9934

We have a very similar car my son used for his scout race. The body is thicker, it has Gee Fenders, and is graphite but similar wheels and axles. It also has about the same steer. It ran on a Best track and was very stable with no rear wiggle. It probably had more gap but was overall very close to the Yellow Snow configuration. Based on how it ran I did not expect all the wiggle Yellow Snow had. I expected it to be slow but stable.

It will be a one and done car for league racing but will be my wife's car for an open race. It will get Gee fenders and converted to graphite. The open class also allows up to 8 ounces so it will get more weight. It will end up a really different car for that race but I am still looking for feedback on the rear end wiggles and if I was off on my initial setup.

Thanks,
KP
KPendle Racing
 
I'm sure others will have more ideas, but you can start to look at:

weight on the FDW too light
more steer (every car is different)
too much rear gap
bias the weight differently in the rear
rear drill out of alignment

Search on "wiggle" and you will find more information than you can shake a stick at.
 
To B_Regal's list I would add:

Rear axles too small in diameter
Not enough rear cant
One or more rear wheels that didn't spin true
 
If you have an aggressive CoM the steer probably needs to be tweaked more. If it is getting more weight the guys that have experience with that say you start getting diminishing returns after 6.5-7oz.