I thought I was going to die! (Death Wobble)

I thought I was going to die yesterday...

We were greenlaning up in the Lake District yesterday (blog to be published later tonight), and when I got there I...



...disconnected my ARB quick release (well impressed with that, from JimnyBits ) and...



... then aired down to 15psi for the days 'laning... planning to reconnect the ARB and reinflate the tyres with the onboard (ARB) compressor at the end of the day...

Between 'lanes I developed frightening death wobble of a magnitude I've never seen before (only had a little wobble at 40mph when I had a 2" lift with no castor correction, and a little bit of a wobble towards the end of our last 'laning outing in Shropshire)... it was like driving a dodgy shopping trolley... I thought the whole car was going to shake itself apart! (Frightening for an ex-Vitara owner who's never witnessed this before!)

Anyway, we lived with it most of the day, as most of the time we were offroad... but doing a few road miles to the last few 'lanes of the day was nigh on impossible, unless I could keep under 30mph or over 40mph... and that was impossible in traffic...

So, discussing it with my passenger - Christian - for the day, we'd shot up the M6 doing 65mph for two hours, and we'd not felt a thing accelerating on the journey to or from the motorway, so the only thing that had changed in the course of the day? was?... tyre pressures! So we stopped in a layby, whipped the airline out and reinflated the front tyres back to 25psi... what a difference! The death wobble was all but gone?!

We shot back down the M6 - gingerly at first - but then doing 65mph behind our Brett all the way home...

With only a slight wobble around the 40mph mark...

Couldn't believe the difference that tyre pressure made anyway, that was the point of this post...

Now investigating more to fully eradicate the death wobble problem!

Frightening! :sick:

Jimny-Dave wrote: Couldn't believe the difference that tyre pressure made

Totally agree, pressures are crucial on tarmac, but maybe slightly dfferent depending on each trucks paticular set up.

I've noticed how as little as 1 lb pressure can make a big difference.

After rotating my tyres (because of outer edge wear on fronts) the wobble I'd had for over a year went away.

However, I noticed the rear felt a bit slippy and broke away a few times (no ... I am a careful driver, having started 30 years ago on bikes - old bikers will know what I mean) I hadn't realised I was running 24.5 front and 27 rear, dropping the fronts down to 23 cured the problem .... how this affects the rears I still don't know but the back has stopped kicking out.

Thanks Halford, I'll check the recommended pressure for my tyres and inflate to that, and won't bother airing down ever again! (never done it before in twenty years offroading, but thought I'd give it a go now I've got onboard air)

The other thing that struck me... I'm running the ORAs girder-like front radius arms, that are castor corrected for a 4" lift... but I'm only currently running 3" (JimnyBits) springs and have a heavish ORA front winch bumper and associated winch... I have got 4" (ORA) springs and 4" AVO adjstable shocks coming (from JimnyBits clearence in the for sale section) though...

Do you (all) thinking running "too much" castor correction could affect the 'death wobble' ?

I've got Ora +4 arms and 3" jimnybits springs as I removed my b4v spacers (sorry Dave) as I wanted my Jimny lower, and it drives miles better lower. Also as many know my Jimny is no lightweight. I have no death wobble at all.

Hmmm... not that then :laugh:

I just thought that as we lift the axle rotates forward, so castor correction sets it back slightly, but then - I was thinking - if we did "too much" castor correction we'd sit the axle slightly "up at the front"... but then it's only an inch...

So, in my quest to stop the wobbles... the next thing is...?

Tyre pressures up a bit
Thought it might be brake related last trip, but this trip as discounted that, but have got new disks and pads to fit thanks to Martin / BigJimny
Stiffer bushes in the radius-arm-to-chassis joints?
Kingpins/bearings felt alright during rebuild for the LSD
Tyres are tracked and balanced professionally...



... go and buy another Vitara?!?! :woohoo: :whistle:

I'm using superpro bushes and have been on a few years now and I feel they are as good as new still and also do not reduce flex either, I think it helps keep the jimny drive straight over standard type bushes.