Suspension Mods for Faster Off Road?

[WesBrooks]

I'm off to find some tech articles on shock absorbers as my thoughts are going well beyond my knowledge of dampers at the moment!

[Ed Poore]

On 5/22/2020 at 3:09 PM, Gazzar said:

At the risk of being called a luddite, what's wrong with good old fashioned air suspension, coupled with ground radar and lidar scanning coordinated by a machine learning AI to anticipate the territory and speed requirements, so the wheel is actively assisted to be in the best position at the right time?

Or am I oversimplifying things?

It's probably on the way - after all Rolls Royce do it for gear changes on the road.

[Gazzar]

And jaguar for suspension, don't they? I always thought that active suspension, based on a reading of the road ahead, makes most sense. Have the damper already pumping out/ in as the pothole/ ramp is approaching.

[Bowie69]

https://www.extremetech.com/extreme/259042-bose-sells-off-revolutionary-electromagnetic-suspension

 

Already been done, with just visual sensors

[discomikey]

4 hours ago, WesBrooks said:

The bypass shocks look - at least from the exterior - a mechanically complex device.

Potentially contentious question but have they become overly mechanically complex?

I get the external reservoir but isn't all the extra valves just controlling two parameters? Resistance of the shock offers when the axle is falling relative to the chassis and resistance when the axle is rising relative to the chassis?

Edit: control of parameters with respect to position.

They are in fact, cleverly simple inside. 

each bypass tube consists of a needle/ball valve with a spring, the spring only acts as a one way valve. Its position/orientation on the body alters what effect it has and at what point on the travel of the damper.

Inside, the piston /shim stacks are laid out conventionally. There really isn't much to go wrong. and they prove to be reliable in use.

Internal bypass is another feature. it is effectively a bumpstop, consisting of another pair of shim stacks, (one acting as the bump stop and the other acting as a one way valve to replenish the void with oil when rebounding, There is a needle in the top of the damper that goes into the hollow shaft in the last portion of travel, this needle acts as a piston forcing the oil inside the hollow shaft through the secondary shim stack. 

[WesBrooks]

I phrased badly. By mechanically complex I was referring to the whole geometry of the damper rather than just the pure mechanical system of non return valve and shim stacks. Plenty of assembly and fabrication time in them by their looks at least.

Cost wise I would imagine it cheaper to manufacture two large bore bypasses and site a variable restriction valve in that bypass.

Am I understanding things right as follows?

Ignoring the gas charge for the time being the monotube dampers comprise of compression and rebound control on the piston, and bypass shockers add one or more bypass zones that reduce the damping from that set by the pison head.

Edit: + the 'bump' zones at the extremes of travel.

 

Edited May 24, 2020 by WesBrooks

[discomikey]

2 hours ago, WesBrooks said:

bypass shockers add one or more bypass zones that reduce the damping from that set by the pison head.

yeah that's spot on. 
 

2 hours ago, WesBrooks said:

Cost wise I would imagine it cheaper to manufacture two large bore bypasses and site a variable restriction valve in that bypass.

I'm struggling to picture what you mean. 

[WesBrooks]

Having rested the topic on mind for a bit I think I understand a little better. Longer travel suspension is generally required to soak up bigger bangs or drops without having to compromising the compliance needed to soak up smaller bumps without upsetting the main sprung weight too much. Suspension position related damping that firms up as ther car dives allows a more controlled catch for heavier impacts without harming the small bump damping.

Moving off the dampers a little is it possible to fit front radius arms on the rear (with required bracket mods) with panhard rod on a standard, rather than two front ends (ie tomcat) style chassis?

 

[Ed Poore]

Rear tank or not? Or willing to move the fuel tank to locate the panhard rod?

Anything's possible - just how much work are  you willing to go to?

[WesBrooks]

 I'd been toying with the idea of shortening the chassis (only about 200mm to remove the bit that sticks out) which would have meant moving the tank.

Doing this would mean it was a little more than just aesthetic reasons!

[RedLineMike]

13 hours ago, WesBrooks said:

Moving off the dampers a little is it possible to fit front radius arms on the rear (with required bracket mods) with panhard rod on a standard, rather than two front ends (ie tomcat) style chassis?

 

my understanding for using 2 front halfs Vs modifying a standard rear to take radius arms is that the front chassis has more rake in it giving more axle > chassis clearance than the standard rear, @discomikey may be able to confirm this as its been a few years since ive played with standard chassis stuff

[discomikey]

I couldn't say on that one to be honest. 

If you're going down the route of changing arms for handling I'd recommend considering D2 arms and watts linkage rear. I find the D2 geometry handles favourably.