Here I was thinking I'd have to build hydraulics for height adjust...

"Ramblin Rover - The Vivisector of Solihull" (RamblinRover)
02/24/2015 at 21:04 • Filed to: None

When it turns out linear actuators will do !!!error: Indecipherable SUB-paragraph formatting!!! , for less weight, and less overall cost. Thanks, China! (This is to turn bell-cranks attached to the top pin of my suspension on the Ranchero.)

DISCUSSION (11)

For Sweden > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 21:05

neat

Ramblin Rover - The Vivisector of Solihull > For Sweden
02/24/2015 at 21:06

science, bro

TheHondaBro > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 21:13

neat

Ramblin Rover - The Vivisector of Solihull > TheHondaBro
02/24/2015 at 21:17

Unlike single-action hydraulics, no ability for bouncing. I'm not sure if that's actually a minus. Adjustable height, OTOH, definitely good, and it'll stay where I put it like air, not just low/high (a plus). Also, unlike a typical low-ride, no pumps and surge tank. Basically, this is to be a better option than air, because cornering going to shit when low is Not Good.

415s30 W123TSXWaggoIIIIIIo ( •_•))°) > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 21:54

I like it!

HammerheadFistpunch > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 22:44

I;ve thought alot about doing this to the cruiser, how are you mounting the spring seat?

Ramblin Rover - The Vivisector of Solihull > HammerheadFistpunch
02/24/2015 at 22:56

Coilovers. It's already coilover in the back because Jag, so I need to weld up a cross-shaft with lever tabs to which the chock units mount with through-bolts, then have a second lever hooked to this bad mofo set (probably) longitudinally. In front, I'll have a distribution plate on the underside of the shock tower with two hinge points stuck through the shock hole, and I'll have the bell crank for this thing on one side and the other side of a Watt's link on the other. It'll be like this in ascii:

V\,

Where the V is the bell crank, the slash is the center piece to which the coilover attaches, and the comma is the other side of the link. The V pivots at its base, the comma pivots on the round part, and the slash goes up and down. Three metal sections per side, four weight-bearing pins (five and six if you count the actuator's attachments to body and to the V). The reason to use the Watt's link is that it'll be closer to straight up and down. In the back, no Watt's link - I'm oversprung anyway, so a little spring rate altering as it lowers doesn't hurt - and I have the room to go in and out some. I don't up front, not for that kind of height variance.

The existing shock stands at ~12" compressed when you count where it attaches, so that's the height of coilover I'll use. Crowmolly recommended QA1, and I can pick my spring rate fairly precisely - the original springs are soft and sloppy anyway, and the whole original setup is worn.

HammerheadFistpunch > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 22:59

This is way better thought out that my plan, which was to use worm gears to simply wind down a sliding top spring perch. You buy the tall shocks and you just crank up the perch to lower, and crank down the prech for lift.

Ramblin Rover - The Vivisector of Solihull > HammerheadFistpunch
02/24/2015 at 23:10

Well, in a sense, this is doing something similar, but with items that aren't compromised by being acted on in more than one force direction. There's also the problem with the worm gears not having any reason to stay put outside friction - believe me on this, worms *do* try to move if they possibly can. With an actuator like this, the worm has to turn the electric motor back through two stages (hard), and most have a brake on the motor that locks when it's not under power. Less rattling down to bottom limit. There's also one other issue with tall shock + adjustable spring, and that's that when you're low, the shock can't bottom out on the rise, so body roll starts and just doesn't stop...

Now, one thing that I did see someone do cleverly at Pirate 4X4 was using a hydraulic cylinder as a spring substitute, with a partial fill of hydraulic fluid pressurized by air. The damping was the same regardless how high the suspension was set, and the fact that the suspension had to move the cylinder and push fluid before getting to the real "spring" effect of the compressed air meant that it was never super-soft like an airbag. Now, all that's a horrible idea for everyday driving, but for some kinds of rock crawler it's pretty good.

HammerheadFistpunch > Ramblin Rover - The Vivisector of Solihull
02/24/2015 at 23:31

What you described in the 2nd part is a Toyota system used on the 100 series, except it uses the cylinder as the damper, and not the spring.

Ramblin Rover - The Vivisector of Solihull > HammerheadFistpunch
02/24/2015 at 23:36

In the second part, what I was describing was basically using ordinary industrial hydraulic cylinders as spring and damper so that the guys could get well over a foot of height adjust in a snap. It required them building brackets and doubtless would have rattled teeth on the road, but for the crawler it was on, it was perfect. Adjustable air shock for cheap, forget the spring, let the good times roll.