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Post by dh0081 on Jan 30, 2012 8:32:32 GMT -6
My son placed second in his pack race and will be going to district. My question, the back end of his car started wobbling after the curve, when the track straightened.
Not sure if it was the weights not centered or the axles. Right now it is not a rail rider. I think it would be best to buy the press and turn it into a rail rider for the stablity.
Should I run the risk of taking the weights out and making sure it all centered, or can i just make FDW on the heaviest side and not mess with the weights? If the weights are off center its not by much.
any thoughts?
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Post by squidhead on Jan 30, 2012 8:56:50 GMT -6
Let the experts answer this one for sure, but this year we had absolutely no wheel wobble. I noticed that 53 out of 58 cars that entered our pack derby this year had wheel wobble.
What we did differently was shaved the outer hub step down to at least level. You can actually modify the outer hub shaver to make a cone shape similar to the inner hub shape. We tapered the nail/axle heads and canted the back and front axles with the rail rider tool. The car was/is a straight runner and the wheels stayed put and rode on the axle heads all the way down the track. I don't even think it ever touched the rail. This car was actually our back up to the back ups car. We still took first in the den and 3rd over all. Believe me it was .001 of seconds separating 1st, 2nd & 3rd.
We also upgraded our procedure for just about everything. Lets put it this way we now own every Derby Worx tool available. Thank God my sons car was so successful and he was just in awe of the whole thing. If not I would have been sleeping in the shed this weekend. Ironically the credit card bill was in the mailbox when we got home from the derby.
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tkp
Pine Head
Posts: 65
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Post by tkp on Jan 30, 2012 9:39:47 GMT -6
Yes- if possible center weights. RR would assist as well.
Alignment on rears and adjusting drfit are most likely root cause. However, being too light on the front end also can produce a shimmy. Also ensure the spacing between wheel hub and body are tight.
It appears best practice would be more drift, check front end weight, ensuring tight wheel spacing to stop potential shimmy in the first place and lastly rear wheel alignment. For rears, you can try a skid test. Only have the rear wheels on the car and put tape (outside slick edge out) on the nose. Then use an incline plane and run it down to see if it runs straight. Also ensure that the wheels go out to the axles heads- going frontwards and backwards. Lets start with rear alignment and determine if your sons front end is heavy enough. Lastly, what is wheel spacing?
Let us know,
TKP
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Post by dh0081 on Jan 30, 2012 12:08:55 GMT -6
The spacing on the rear wheel to the side of the car I made slightly wider. I did that so if the front wheel touched the guide rear wheels wouldn't. I might have over compensated on this. Moving forward the wheels do go out, but going back one wheel does go toward the car. I will try and rotate the axle to see if that fixes it.
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