Wheel Wobble 2015 Jimny

I have a 2015 Jimny, Bought it secondhand fitted with a 2" lift kit, side bars, and a few smaller upgrades from standard.  It wasn't long after I bought my Jimny that I found I had a wheel wobble around 80km/hr. For 2 years I researched and tried most things I found on-line. I reduced it a bit but gave up trying to get rif of it.
To protect the front of the Jimny from people who want to back into me, I took the front panels off and buit a substantual bump bar which is securely fitted to the chassis.  I replaced the body panels and it looked small and neat but very strong.  It wasn't long until I notice the wheel wobble had disappeared completely.  I asked myself why and thought it might be the additional weaight of the metal I added. After little more research I found the Jimny's in the front end are under engineered. (got that information on-line from an engineer). They aren't heavy enough in the front end.  When you add additional weight to the front of the vehicle, it fixes the wheel wobble problem.  When I talked to my local mechanic he confirmed what I had found out saying they are too light in the front end.  He seemed surprsed I had to ask.  It aslo handles better in the corners. Yeah!  So if you have a front wheel wobble and have tried all the expensive things, add weight to the front of the vehicle. I put standard tyres on the vehicle and that improved the car again.  Don't know what the NEW vehicles are like.  Hope this answers any questions you may have around wheel wobbles.

Just my opinion - Jimnys are just fine, when they leave the factory, but when you lift them you change the caster angle, and this reduces the front suspension's ability to "self center", when you add weight to the front, it causes the front to droop, this reverses the caster change that occurred when it was lifted, especially, if the front droops and the back doesn't.

The issue is not that the front is too light, or the front end is "under engineered", it's designed to do what it is designed to do - but, live axle, radius arm, three link suspension has it's limitations, and if you're going to lift the vehicle, you need to address the caster change - the "normal" way to deal with it is offset caster bushes.

When you choose to modify a vehicle, you need to do so "holistically", many of the "lower cost" suspension lift kits are developed by enthusiasts, not engineers, and that is where the problems originate - keep it stock and you won't have the problem, use a properly engineered lift, and you won't have the problem.

I believe that the jimny is around 52/48% front to rear weight distribution from factory. I would certainly challenge the assertion that you make that additional weight on the front is going to in any way improve the dynamics of the car it's only going to upset the natural tendency to understeer. The usual culprit for a steering wobble is going to be worrn or incorrectly preloaded kingpin bearings. Altering the geometry with a lift is going to exacerbate the issue as will fitting bigger heavier tyres though fitting a steering damper will hide the effect of the tyres to a certain extent. But certainly just making it heavier is really not the answer. I contend that the people who have advised you are probably not as familiar with the character of the jimny as they may be with toyota or land rover or Nissan in their assessment that a jimny is under engineered, compared to a similar size city hatchback a jimny is hugely strong and robust.

The workshop manual for the Gen.4 does not mention a figure for the kingpin bearing pre-load but it does suggest that "shimmy" may be caused by wear on the steering knuckle rubber seal.

Roger

And on the gen3 the figure is a tolerance either side of 35 Newton after overcoming inertia, measured by spring balance in the track rod hole.