Suspension shudder

[Robot]

Hi folks. I'm trying to identify if I have a problem with my gen3. At low speeds it's nice and soft over bumps in a normal tarmac road but hitting things like "slow-me-down -raised-paint-lines" and slightly sunken manhole covers at 30+ is a tooth rattling experience. It seems primarily front but rear does it too. It's got a 2" suss lift and I recently replaced the rear shocks with Monroe +2 heavy duty ones and that cleared up a lot of rear end misbehaviour. Speed bumps at reasonable pace are fine but shorter sharper bumps make the dash crash and stuff jump out of the cup holders.
It's almost like its over damped?

[Robot]

Wow this forum is like a ghost ship!

[charvell]

what tyre pressures are you running? what condition/age are the tryes?

[Robot]

BFG KOs which are old and have about 5mm left on them, they are a good 6 or so years old. They're up at 28-30 psi at the moment.

[charvell]

I had similar on mine and changed the tyres not had a problem since

[Robot]

Hmm OK. Seems too easy to be true but I have been through everything else I can think of!
Thanks!

[Robot]

Just for reference, this is what it looks like!
https://youtu.be/VlUKj-OkvP0
The bump was 25mm and I wouldn't notice it on a road bike with 100psi tyre pressure! Yet I can hit a speed bump with one wheel and not know I've done it.

Anyone else get this?

[tashtego]

I get the same and drive over some crappy roads that are full of that type of obstacles. That is one of the downsides of the 3rd Gen surf I think. The suspension components (shocks, tie rod ends, ball joints etc) are new or almost new on mine and yet when you hit those sharp obstacles you get just that. It's not a problem with the suspension components being worn, I don't think. I think its the whole surf front set up that is very hard and so bits of trim and 'non- supportive parts' shake and make a lot of noise, like bumper brackets, parts of the dash etc. I have driven work cars and rented pick ups that are much softer and smoother where the suspension takes the brunt of the impact with road obstacles and the vehicle is nicely 'cushioned'. The surf is not like that at all, it feels as if the suspension passes on the strain of the impact onto the non moving parts, if that makes sense. The steering column of the 3 Rd gen and other similar vehicles (Tacomas, old Prados etc) is also notoriously rattley and refers a lot of vibration onto the driver. On the US forums there's a fix for the column issue. Ironically my old 2.4 surf with its old original front shocks and springs was a lot better because the soft shocks took on a lot of the energy from road roughness and gave a soft,if unsteady and wavering ride. These uprated shocks that we all fit are much harder and we feel every tiny irregularity from the road.
Other 3rd Gen surfs I have driven feel pretty much the same . I had a 1998 Prado, which has the same chassis and suspension, and it was exactly as you describe.
Keeping tyre pressure on the low side helps but then there are contraindications to doing that too as you can imagine.
The good side of it is that thanks to that stiffness you can drive the 3 Rd gen surf almost as if it's a sport car, it's very stable for a vehicle of that size and height and very forgiving on cornering and generally gives you that feeling that it's going to be hard to roll it. When driving some popular brand pickups however you get the impression you' ll soon be on your side!
Hope this puts your mind at rest.
Cheers

[Robot]

Perfect, thanks! That's exactly what I was looking for. I'll stop worrying and enjoy driving it