I have a build that is driving me nuts. It is running nice and smooth on the tuning board and drifting just the way I want it to. But once it is on the track it is bouncing back and forth killing the speed. What causes this?
Car bouncing off the rails, need help
- Thread starter DerikX Racing
- Start date
It could be lots of things, but the two that first come to mind is a fender is rubbing the rail. The other possibility is the rear wheels are not drilled right.
1, try swapping axles. 2, try different wheels. 3, check the weights. 4, if 1-3 don't work scrap it and start over or re-drill new holes /images/boards/smilies/smile.gif I know you have built 100's of cars and know your stuff. Maybe somebody else will give an answer. Maybe take a video or show some pics. If you have fenders on it, check for clearance as 1 touch will set it off into multiple wobbles.
mxquad said:
I’ve built hundreds of cars yes, but sometimes I feel like I don’t know what the heck I’m doing. By no means am I an expert, that’s why I’ve spent so much time on this site.
pony express said:
The fenders seem to be clearing just fine. I will try different wheels and axles, if that don’t work I guess I will scrap it and start over.
- Nov 24, 2011
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It could be that the rears are toed out. When my car ran on the tuning board, everything was ducky. On the track however, it was shaking its rear like a cat in heat.
Check to make sure that the body will sit flat on all four corners when placed on a flat surface.
We had a Scout car that we built that acted the same way as you described. It turned out that I put too much CA glue in the weight pockets to reinforce the wood that was thin after the weight pockets were cut. When the CA glue dried it caused the body to have a twist in the back by the weight pockets which caused the car to wiggle regardless of weight placement and COM.
We had a Scout car that we built that acted the same way as you described. It turned out that I put too much CA glue in the weight pockets to reinforce the wood that was thin after the weight pockets were cut. When the CA glue dried it caused the body to have a twist in the back by the weight pockets which caused the car to wiggle regardless of weight placement and COM.
Check your axles shaft to make sure there is no CA glue on them (if the same axles were used while fixing fenders some CA glue might have dried on to the axles), if so then dip them in alcohol, clean with a clean cloth and razor blade. Flared out rear wheel bores could also cause rear end to sway/wobble.
Derik, have you tried biasing the weight MUCH heavier to the NDRW side? Like make it upwards of 15 grams heavier than the DRW side?
Sorry, I may have used an unconventional abbreviation? Here's what I meant:
NDRW = Non-dominant rear wheel, the rear wheel on the opposite side of the dominant front wheel
DRW= Dominant rear wheel, the rear wheel behind the dominant front wheel
DFW= Dominant Front Wheel, the front wheel that steers
NDFW= Non-dominant front wheel, the lifted front wheel.
If I'm working with a car that won't run right, I'll try to overweight the NDRW side to see if it straightens out. If it does, to me it means that the drill is bad so I scrap it. I would have already tried swapping wheel/axle assemblies in the rear by that point so there's no saving it.
NDRW = Non-dominant rear wheel, the rear wheel on the opposite side of the dominant front wheel
DRW= Dominant rear wheel, the rear wheel behind the dominant front wheel
DFW= Dominant Front Wheel, the front wheel that steers
NDFW= Non-dominant front wheel, the lifted front wheel.
If I'm working with a car that won't run right, I'll try to overweight the NDRW side to see if it straightens out. If it does, to me it means that the drill is bad so I scrap it. I would have already tried swapping wheel/axle assemblies in the rear by that point so there's no saving it.
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