Steering wobble

[buffet]

I have yet another problem that has been bugging me for some time. When I turn front wheels all way to either side and apply medium or full throttle, the front axle becomes really wobbly. Here is a video:

Steering wobble - YouTube

I wonder if it's normal to behave like that. I tried to figure out what is causing this, but I don't think that steering links (even though they are stock crap) are hitting the wheels, at least from what I saw. Any ideas?

 

[o0wiz0o]

Mine is the same. All wheels wobble. I wondered if my axels we're bent as different wheels do the same so ain't the rims.

 

[jvella]

This a copy paste :mrgreen: One of the other things that happens that is more noticeable in the front axle is there is play for the outer axle shafts. In other words you can slide them in and out of the knuckle. If you hold a front wheel and pull it out and away from the axles you will see there is about 1/16 inch of play or sometimes more. This alows the outer axle shaft to float around and not keep the wheel true. All three of my SCX10's do this. If you look at many pictures on here of rigs you can see where the wheel/tire is off camber on one or both sides, this is due to the play that I mentioned. It has never caused a problem other then it looks a little weird at times.


Or It´s caused by the tire and the foam inside.

 

[buffet]

So basic suggestion is to turn down EPA(or dual rates in case of stock axial tx) on the steering?

 

[Jus]

Besides the end play that the axles have, they also tend to be slightly loose in the bearings in the knuckles.. Also made especially worse by not being under a load, the dog bones or universals whichever you have, tend to bind a bit and the slop in the drivetrain (axles in locker and driveshafts) and make the whole deal look jittery.. It's not so pronounced when on the ground and actually driving it.

 

[Lukefalls]

Actually, its a combination of gyroscopic precession and either dog bone or universal axle shafts.

Precession - Wikipedia, the free encyclopedia

The precession is a factor of the spinning wheel. The dog-bone or universal shaft and case the wheel end of the axle to "whip" slightly. This whipping amplifies the precession.

U-joints and dog-bones only provide smooth operation when the shaft is straight. However, when turned, the cause a slight "whipping" motion at the wheel. The wheel actually speeds up slightly during the whipping phase of rotation. That is why some shafts have a "constant velocity joint". A CV shaft usually has a cup and ball bearings, though there are different types. Dog-bones and universals are not CV.

New bearings, shims or foam will only slightly help the wobble.

 

[ZippoMan]

Mine does that but my wheels have weights in them so I am guessing mine are not 100% balanced and the memory foam could be contributing to it too. As long as it is fine on the ground I don't care so much. I am not into high speeds anyway. I have universal joints on the front axles so it does matter if it was dog bone or not. Wheel balance is my issue I am guessing.

 

[tomvaillencourt]

I know this is an old thread, but I noticed the same on my wraith... Just dial back the dual rate, so the servo doesn't throw as far. You won't be able to turn quite as tight, but the stock axels won't bind. That's what is going on. Or you can swap the axels for ones made to accommodate high throw steering.

 

[nigelpheron]

Actually, its a combination of gyroscopic precession and either dog bone or universal axle shafts.

Precession - Wikipedia, the free encyclopedia

The precession is a factor of the spinning wheel. The dog-bone or universal shaft and case the wheel end of the axle to "whip" slightly. This whipping amplifies the precession.

U-joints and dog-bones only provide smooth operation when the shaft is straight. However, when turned, the cause a slight "whipping" motion at the wheel. The wheel actually speeds up slightly during the whipping phase of rotation. That is why some shafts have a "constant velocity joint". A CV shaft usually has a cup and ball bearings, though there are different types. Dog-bones and universals are not CV.

New bearings, shims or foam will only slightly help the wobble.

Interesting. Thanx for the info and link. Weird thing is, I've only had this wobbling crap on my SCX10. Every other dog-boned / cv'd / universl 4x4 R/C vehickle I've had (been R/C-ing from the late 70's till now), has never don this.

I have yet another problem that has been bugging me for some time. When I turn front wheels all way to either side and apply medium or full throttle, the front axle becomes really wobbly. Here is a video:

Steering wobble - YouTube

I wonder if it's normal to behave like that. I tried to figure out what is causing this, but I don't think that steering links (even though they are stock crap) are hitting the wheels, at least from what I saw. Any ideas?

Did you ever figure your's out? Mine drive'n my nuts.