Bump steer issue? Space the tie rods ? How much travel does the front have? Maybe limit it if it does??

I had two motorhomes that did this. One was a straight axle and the other independent suspension.

Any issues backing up fast in a safe area? Had a typical funny car chassis with torsion front of the times. Added steering dampner and it worked. But one time took the front axle apart and got the torsion bar tweaked then the front would shimmy. Put some chassis scales and see if there is a major weight shift, then move the arms to lessen or move to opposite front.

I may have accidentally found the source of my problem. I have been reading articles written by Street Rod guys who have experienced the same issue and it has to do with geometry issues with the drag link, the angle it has when attached to the drivers side steering arm and the travel plane of the tie rod since the steering arms do travel on an angle (they don't travel on a level plane due to the 9 degree caster setting). Everything works fine until you hit a bump, OR when the front wheels drop after a wheel stand, everything gets a little goofy.....aka front wheel wobble.

If you set the toe with the wheels (loaded) while it's on the ground, check it again with the tires lifted as they would during a wheel stand to find if the toe setting changes.

Bob Meyer recommended that I increase the toe from 1/16 in to 3/16 in. I'm willing to give it a try but only after jacking the front end up (to reduce the load) and re-check the original 1/16th toe in. Bob's logic (as explained to me) makes sense and the guy is a very experienced Alky Dragster chassis builder. What I have now (1/16th in) doesn't work, might as well give it a try.

A /16th IN is still within the standard range. I'll give it a try and video the results.

Bob

ps: ALKYFOOL : No issues backing up

Very interesting thread.

Jim:

Removed the tires from the rims and checked the run-out. They (tires and rims) are round, zero run-out on both before and after they were mounted. I don't detect any vibration just the wheel wobble.

See the post I made at 7:58 today.

Thanks for the suggestions guys!

Bob

Go back to my first two posts here and I mentioned raising the front end up and checking toe in as you do to see for changes there.

Now if it is changing you may be able to shim your steering box to get it closer in same plane as the tie rod ends. There will always be some as the suspension moves. But if you get it centered better it reduces the amount of change. Sometimes you can use spacers on tie rod ends to lower them closer to level to steering box.

Still the steering stabilizer may be easiest way to cure it.

Bob, hopefully the advice from Meyer will cure the issue.
If not, and you want to share the video you mentioned, just create an account on YouTube, then post your video on there. Then you can just copy the link from that video and paste it into a post on here.

so it does have bump steer

I checked the front end for bump steer a second time. Once loaded and again un-loaded, it didn't change. I am beginning to believe that the problem is in the angle of the drag link and the angles of the two steering arms. This became an issue when I increased the caster from 7 degrees to 9.5 degrees. It appears that I need to compensate for the increased caster, haven't figured out how, but that may correct the wobble. Adding toe might have an effect, wiling to give it a try.

Bob

You need to check for bump steer through full travel, not just ride height and fully extended. it could be toeing out at mid travel, or with the front end compressed ****her than ride height.