Bump Steer

[tom4bren]

Several members in the past have mentioned severe bump steer (vehicle jumps to the side when encountering a significant bump at speed).

Several members in the past have indicated that their rear axle is shifted to the right (due to lift or for any other reason).

Question: If you experience bump steer with your VX, is your rear axle shifted?

Mine is not shifted and I don't experience bump steer. I'm just trying to figure out if a panhard rod drop shakle will help with this problem.

Tom

PS - how do you set up voting in this here poll???

[mdwyer]

The entrance to my datacenter has a severe crest where the gutter meets the pavement. My not-lowered Subaru sedan scrapes underparts when I try to go over it.

I went over it in the VX a little too fast and I swear I almost tipped it over!! The front was fine, but the back leapt up and I probably ended up turned 30 degrees when I landed.

So, yeah. There's a problem there.

Now, just eyeballing the VX Butt, I don't see anything off-center -- not at all like some of the pictures I've seen of lifted ones, at least. Any idea what I could measure from?

[JHarris1385]

Lifted and exp the bump jump.

[Thmstec]

My VX is still stock, not sure if the axel is shifted

I wouldn't say I experience bump steer... but when I catch some air flying over a certain set of railroad tracks, the rear end might jump up to 5 degrees on the rebound.

PS: To post a poll, check the box you see in this picture

[nfpgasmask]

You know, I have never experienced any of this on road, but off road, when hauling tail over a dirt road that has lots of "ribs" from being washed out, my rear end will shift back and forth all over the place.

I was talking to a friend about this, and he thinks it is because we have such stiff coils in the rear. Basically, we are bouncing off the ground. If we had mushyier (is that a word?) springs, or leafs back there, out rear tires would essentially cling to the ground better, instead of catching air all the time. I don't know if he was right, but it sounds good.

I do not think the lift makes a difference, I had this problem lifted and not lifted, and in fact, I think it was worse when I was still stock. I can recall a specific moment on a dirt road was before I lifted where I almost went into the ditch because of this...

Bart

[Solitude]

It has a little to do with the short wheel base too.. I drove over a steel bridge in oakland once that caused it to kinda porpoise sideways over the bridge

[tom4bren]

Bart,

Yes, short wheelbase vehicles HATE washboard. Mushier springs will help some but will not solve the problem.

The bump steer I'm talking about is a single bump at speed that some have mentioned is bad enough to cause an inadvertent lane change.

Thmstec,

Thanks for the tip. Judging by the responses, it doesn't look like I need to start a poll on this thread but I'll try to 'member for the next time.

I'll have 'Welder Guy' fab up a prototype to try out on CSTYLES' VX since he has both symptoms. I'll let you know how it goes.

Tom

[Chopper]

Look at Baja trucks. They're so soft, they are difficult to drive on anything other than straight pavement. Isuzu realized these things would spend %90 of their life on pavement and built accordingly. I'd hate to soften this thing up.

[nfpgasmask]

Bart,

Yes, short wheelbase vehicles HATE washboard. Mushier springs will help some but will not solve the problem.

The bump steer I'm talking about is a single bump at speed that some have mentioned is bad enough to cause an inadvertent lane change.
Tom

Well, then I can safely say I have never experienced what you are talking about. It sounds scary.

Bart

[Knigh7s]

I experience this on a daily basis. But I have to say It scared the snot outa my nose the first time it happened.

There is a crease between the off ramp and the bridge where I exit the freeway everyday and if I get the green light, I’m coming in at least 45mph and hit the bump mid way in the turn; my back end always pops up and shifts to the right throwing off my "line" of driving. But I’m so used to it now that I already know how to compensate for the bump. I’ve got the Rancho 9000xl installed and set to number 9 and sitting in the stock stance btw. Setting it any lower I float around like a semi truck cab sitting on springs or something…

[vxcp]

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[evillecutter]

when i hit a bump on certain roads my vx pulls to the right and sometimes i have to hold the steering wheel at about a 15 degree angle for the yellow gremlin to go straight - it did not do this before i bent the inner passenger tie rod end - going to try to replace it this weekend and have it aligned and see if that fixes it

how do i know if my rear axle shifted?.

and wtf is a panhard rod drop shakle? (other than a kick *** name for a rock band)