Case of the wobbles

[Frustrated Dad]

Need a little help. Or a lot.

Building scout car for a race this weekend and can't get rid of the wobbles. We have to use standard axle slots. COM is .6 from rear axle. 2.5 degree rears. 1.5 degree DFW. Steers about 5 inches in 8' on a tuning board. However on the track is steers into the rail but bounces off and wobbles down the track. About the only thing I haven't done is trim down the DFW body a 1/16".

Any advice?

 

[TRE]

are the rears drilled or bent axles...try more steer and less wheel gap

 

[Frustrated Dad]

Bent. Should the gaps be the same for all 3?

 

[TRE]

bent rear axles could be your problem..rear gaps should be real tight front little more gap

 

[TRE]

If it were me i would run straight rears if you cant drill them with cant..put more bend in your steer axle 1.5 is not enough

 

[Frustrated Dad]

I will try to tighten up the gaps a little. Since we have to use the pre-cut axle slots I didn't have much choice other than to bend. I have not tried messing with the rears much. Only the DFW. How much steer would you recommend? Our pack uses a plastic Best track.

 

[TRE]

4 to 6 inches over 4 feet

 

[Frustrated Dad]

Correction. Derby Magic track.

 

[~JBD RACING~]

If you have to run that much steer there's a alignment issue whether Scout car / league car. You can run rear gaps at 8-10 thousand and front around 15. Send us a picture of weight placement... If your weight placement is too aggressive this will cause sway/wiggle also.. What wheels and axles you running ? There's very many variable that could cause this issue.. What's the wheel base ? Or is it stock 7/8 from rear and 4 3/8 forward from rears ?

 

[TRE]

well if he bent his rears they probably arent right and he will need more steer

 

[Quicktimederby]

You would be better off using straight axles and inserting them on a slight cant. Move one of the rears that is bent to 2.5 to the dominate front wheel. This will probably help out a lot. The other problem is the track, unless they have made a under section that the track sits flat on you have no idea it the lanes are level, this can cause al sorts of issues.

Since we have to use the pre-cut axle slots I didn't have much choice other than to bend.

 

[Frustrated Dad]

We have to use stock wheels and axles. Axles are polished. We can only use standard wheel base. Rear axle is one inch from back and front is 4 3/8 up from there. If someone can send me directions I will upload a photo of the weight placement. I will try a 2.5 in the front to see what that does.

 

[Choo Choo]

Have you tried swapping the rear axles yet?

 

[~JBD RACING~]

When running bent axles in rear you will have to rear tune your car TRE .. That's what I'm getting at. Whether this racer is doing that I don't know.. If the rear axles are not tuned right the wheels will not migrate out... This will cause wobbles... If wheels are staying against the body... BUT WHAT DO I KNOW... QT is right running more bend will also help. Is will tighten the front end up.

 

[Frustrated Dad]

Ok..I put a 2.5 in the DFW and tightened up the wheel gaps. This seems to have helped. I am still getting a little side to side at the bottom of the track. I would still like to get more steer from the front wheel. But it's getting down to the wire. Race is Saturday. I really appreciate all of the great feedback. You guys make it sound so easy. I guess that's why you're the pro's!

 

[TRE]

When running bent axles in rear you will have to rear tune your car TRE ..

Thats why i say you need more steer cuz they are probably not getting the rears perfect by trying to tune them thats a bad way to go..thats why i say run the rears straight..running rears straight is way better than bending rears or having a bad drill job

 

[BulldogRacing]

what is the current weight distribution on each of the wheels?

 

[Frustrated Dad]

Well he finished 1st in his den and took 2nd overall. His car finished consistently within one hundredth of a second. And no wobbles! Thanks everyone for your help. This is a great forum. Already thinking about next year's car.