Not really talking about double wish bone, but something similar to what an all out race car would have. Instead of two giant arms flailing up and down, have a bunch of bars going all over.
Just a curious thought. Reading up on it because it's in the back of my NC, wiki mentioned it being used in the front... of course, no examples were quoted.
Nissan 350z/ Infiniti G35?
P10 Infinity G20
The early 2000s for Audi A4 and A6.
Chrysler LX body. Or whatever the MB similar chassis.
Pontiac GTO/G8's same deal.
RossD said:The early 2000s for Audi A4 and A6.
This! As seen here:
Yeah so basically a bunch of cars you could have or have already driven and not noticed. It's well down the road of diminishing returns, especially once you're throwing ride quality out the window (doing racecar things) since being able to tune ride quality is probably its main benefit.
I think the last bmw 5 series did too
In reply to Vigo :
Allows the manufacturer to tune geometry that meets BOTH comfort and handling. Instead of a give and take.
There are many links, yes. My favorite being the integral sway bar mounted to the firewall behind the engine.
The VAG B4 and B5 chassis definitely did, the B5 being the easier one to work on, especially if you had the triple-square tool kit.
I'm pretty sure that GM Alpha chassis is front multi-link as well
The 'multi link' systems shown are just SLA's with virtual ball joints. That is they still work like an SLA, the the location of the ball joint is a virtual point in space and can/does move around.
I'd like to see what race cars use multi link front suspensions. I'm sure that there's one somewhere but I can't think of any purpose built racers that aren't double wishbone. The main advantage to multi-link is having control over the toe curve...which is kinda irelevant once you bring steering into the equation. There are lots of cars that are DW or strut and the lower control arm is two separate links instead of one to create a variable steering axis. That's probably about the happy medium between functionality and not being needlessly complicated and heavy.
buzzboy said:There are many links, yes. My favorite being the integral sway bar mounted to the firewall behind the engine.
Stabilizer bar should never be integral with anything, IMO. It makes the arm move in a weird arc and it requires the stabilizer bar to flex.
It's good if you are trying to minimize weight, and need a fairly stiff front bar anyway because your rear suspension geometry sucks and you need to keep the front from being able to move. That is a band-aid solution to a problem easily avoided.
Adrian_Thompson said:The 'multi link' systems shown are just SLA's with virtual ball joints. That is they still work like an SLA, the the location of the ball joint is a virtual point in space and can/does move around.
When I dissassembled the W8 Passat, I was purplexed by those dual a-arms, why they do that? I researched it, but forgot why at this point..lol Yeah, they move the pivot point to the center of the tire instead of the inside of the tire, which improves the 'scrub radius'. Now not sure I understand why that matters, a quick review of it doesn't help much.
I believe the current E-series and S-series have multi-link front suspension.
NickD said:I'm pretty sure that GM Alpha chassis is front multi-link as well
Do you mean rear multi-link? It uses MacPhereson struts in the front.
Might be a little too oversimplified but one of the main things about multilink is being able to isolate different bushings to control different things with less overlap, such as a lateral link having a stiff bushing and a fore/aft link having a softer bushing. If anyone's familiar with the compliance bushings found on one end of your typical lower control arm that always fail because they're designed to be soft in fore/aft and end up flexing themselves to failure relatively quickly, a multilink is a more elegant and expensive way of trying to get compliance in one direction without compliance in the other directions. As far as the multiple ball joints thing, that's a little more complicated but Adrian already gave the simplest explanation.
In reply to Vigo :
You can still have compliance bushings with a single arm.
I'm definitely not an engineer, but at first glance this seems like SLA with more failure/service points.
nimblemotorsports said:Now not sure I understand why that matters, a quick review of it doesn't help much.
Scrub radius:
If you extend an imaginary line of your steering axis to the ground, you get a point. If you compare the location of that point to the center of your contact patch, you get caster/trail and scrub radius. The distance the contact center is behind the steering axis point is caster/trail. Left or right is scrub radius.
What does it do? Imagine you are putting wheels from a dually on a regular truck front axle. Install so they stick way out and you end up with a big, positive, scrub radius. Install the wheels so they tuck in and you have a bug, negative scrub radius.
The truck is on the shoulder, left tires on the road, right in the mud, and you are running only front drive. It's either a nightmare or a LeMons race, but that's not important right now.
You hit the gas and the left tire grips more than the right, which is going to make the truck pull to the right and further towards the ditch. With positive scrub radius, that grip is going to torque steer and the steering wheel is going to turn to the right and send you faster into the ditch. With negative scrub radius, the torque steer is going to turn your steering wheel to the left and try to help steer you off the shoulder. If you get it balanced just right, in situations of rapidly changing grip, the steering wheel dances back and forth in your hands and the vehicle still goes mostly where you were pointing it.
The virtual pivot makes it easier to get a negative scrub radius with wider wheels while still not letting the wheels hit the control arms at steering lock.
Now back to your regularly scheduled post topic.
Matthew
You can still have compliance bushings with a single arm.
I was just using compliance bushings as an example of the desire to have different stiffnesses in different directions and that multilink is another (more expensive) way to address that.
I just texted a customer of mine with a Mazda 6 (multilink). I told her "you have six control arms in the front end and 5 of them have bad bushings" and then asked her how many she could afford to fix. If anyone's wondering i did the other one already a few months back. I'm with Will that it's just more failure points unless it's attached to a car that justifies it somehow.
In reply to Vigo :
I kinda see your point though, im retrospect... with multiple links, you can have compliance bushings putting tension perpendicular to the bushing axis, AND be able to actualy assemble it without complicated sub-brackets.
You guys are smart.
That's all.
ebonyandivory said:You guys are smart.
That's all.
Came here to say this. Left because I can't contribute without looking like a 4yr old.
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