[Rhinoman]

Has anyone tried one of these?

http://global.rakuten.com/en/store/k-pr ... kSmCS.dpuf

I have the JB 2" lift and I'm looking to try and reduce the bump steer which is getting quite tiresome.

[zukenutter]

I've not seen those before. As usual with our laws it's probably not legal. I think that based on the previous chat about dropped pitman arms the suggestion that following close to the same angle of the panhard is the best approach for reducing bump steer. People with skills, feel free to correct me.

[Rhinoman]

That would be legal here because it is specifically designed to do the job, modifying stock steering parts is not legal. I read through that thread but there didn't seem to be a definite conclusion. I did see another thread that stated that the Vitara Pitman drop arm is longer and fits the Jimny box, is that a possibility?

[Gwagensteve]

drag link and panhard need to be in phase. (Parallel and as close as possible in length) raising one end of one won't do anything meaningful to address bumpsteer. I suspect the problem is less bumpsteer and more the effect of excessive suspension lift putting the bar on an angle that small suspension movements move the body left and right a noticeable amount. (This isn't bumpsteer) lifting the axle end of the panhard will assist in reducing this but increase bumpsteer.

Steve.

[Rhinoman]

My trip to work is 10 miles along a 60mph B road, its a bit uneven in places and when it hits a bump the steering wheel moves around 30 degrees which makes for a very lively ride, sometimes I think I could drive the windscreen wipers from the steering column!

[Gwagensteve]

So you're running 2" of lift, any other mods? Caster correct? Toe checked?

I was looking at this photo:



And a small lift to the panhard looks like it could help, but only 15mm or so. I'd be surprised if such a small adjustment made all that much difference.

You can readily isolate the effect of bump steer by bouncing the front of the car on level ground (stationary) and observing how much the wheel swings. Leaf sierras have terrible bumpsteer checked this way but drive OK. My own car has a similar relationship to a Jimmy (drag link/panhard) but barely bump steers at all.

Another test, drive over a speed hump square on with enough pace to get the suspension to cycle a bit. if its bumpsteer as bad as you say it is, the steering wheel should swing wildly. alternatively, if you "lock" the wheel with your arms, the car should dart left or right. (right, I think)

30˚ of steering wheel movement really sounds like a lot from driving on a tarmac road. This is why I'm suspicious it's not all/primarily bumpsteer, and might be due to another factor. What rims/tyres are you running? the leverage of heavier wheels/tyres/offset rims might be pulling the steering in the direction of the bump as the wheels encounter it. this will make it feel like bumpsteer. How is your kingpin preload/wiper seals - if these are loose you could be getting excessive tyre deflection (self steering) on bumps.

If you have aftermarket wheels/tyres with non-stock offset, can you try a set of stock tyres/wheels and drive the same route to see if it's reduced? My guess is it will be. Likewise, it doesn't take long to swap springs, can you put the stock springs back in? bumpsteer isn't related to lift height, only axle path, so it shouldn't get better with the lower springs. if it does, my guess comes back to my original call - a steep panhard angle transferring lateral force into vertical force and pushing the body around. I think any other factors are combining to make the car squirrely.

[Rhinoman]

Stock wheels and tyres, caster correction bushes. I'll have to get it in the garage and have a good look at it. I went to tax it today and found out that the annual inspection lapsed two months ago, oops. I won't be able to get that sorted until after the new year. I followed the TSB for kingpin preload - no wobble, no shims.

[shep]

I get a little bit of bump steer in mine but certainly no where near 30deg of steering wheel movement.
Approx 4" front and 5" rear lift when not loaded for touring. No sway bar

[shep]