derf
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| posted on 13/10/05 at 02:44 PM |
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Very interesting suspension design
Small disscussion on locostusa.com:
http://www.locostusa.com/forums/viewtopic.php?t=144
I happened apon this a few minutes ago, and was very interested in it. very low shock design, pushrod, mumford linkage.
The first and second pics are digital renderings, but the third one is shown on an older mustang II
[Edited on 13/10/05 by derf]
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smart51
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| posted on 13/10/05 at 02:51 PM |
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Horizontal dampers are usually a problem. Citroen managed to make it work in the eighties. Rover engineers tried but failed to copy it. It's
a good idea for space saving, lowering C of G and increasing luggage space. If you can make it work.
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britishtrident
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| posted on 13/10/05 at 03:16 PM |
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The Watts linkage is good but the rest I suspect is trying to be much too clever without any real gain.
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britishtrident
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| posted on 13/10/05 at 03:17 PM |
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[Edited on 13/10/05 by britishtrident]
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derf
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| posted on 13/10/05 at 03:38 PM |
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Yes it's an excellent design, and would definatly fit in with the design of the locost frame. Since I saw it, and I am going to re-do my front
suspension. I have been contemplating re-doing my rear suspension along the lines of what is shown here. The way that it sits would definatly fit in
the chassis, and would also give a hight adjustability into my rear.
The only modification to the design is to get rid of the 3rd center link, and add a second set of trailing arms above the ones that are there.
Can anyone take a guess if the watts link will fit below the chassis?
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gustavo_brum
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| posted on 13/10/05 at 03:41 PM |
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That Mustang owner really went through a lot of cutting and welding to make a chevette rear suspension... Three-link suspension like this one (and the
chevette) are pretty good for turning, although not much better than the locost´s 4 link. I agree the watts linkage is the only original thing there,
the rest is just useful to impress your friends, but no better in the performance department, and heavier too.
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Bluemoon
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| posted on 13/10/05 at 04:34 PM |
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Spot the two bolts in shear, and there holding all the weight of the car? I would'nt wan't is like that, it's not going to last
long.
Dan
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MikeR
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| posted on 13/10/05 at 04:51 PM |
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Dan, look at the suspension mounts on most vans - all the ones i've seen in the traffic light queue have them mounted in single sheer. Its not
the best practice but is ok if engineered correctly.
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Syd Bridge
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| posted on 13/10/05 at 05:01 PM |
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What's wrong with the standard damper arrangement?
And a sensible Watts Link has the crank attached to the chassis. Unsprung weight and all that. Only a seppo could dream up that nightmare.
The most interesting thing is those mufflers/silencers. By the look of the weld print through, they are Flowmasters, and date back to the mid eighties
in design. But, are very effective and create little back pressure.
They'd have to be the most sensible part of the whole car, and would do more for the total performance than that abomination of a rear
suspension setup.
[Edited on 13/10/05 by Syd Bridge]
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gazza285
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| posted on 13/10/05 at 05:38 PM |
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Different angle.
It doesn't work correctly. The fixed arm means the axle will just pivot around the front mount and put unnecessary loads on the pinion and
propshaft. Nice use of different coloured paints, but other than that it's bullshit baffles brains thinking.
Edit.
The more I look at it the more it upsets me. Just looking at the crank arms and it doesn't take much to figure that the rate will fall fairly
dramatically. Daft thing is that with the pushrod mount being so low on the axle that there is room to put a vertical shocker unit anyway.
[Edited on 13/10/05 by gazza285]
DO NOT PUT ON KNOB OR BOLLOCKS!
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millenniumtree
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| posted on 13/10/05 at 05:57 PM |
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Why the hell didn't they just do dual trailing arms AND the horizontal dampers?
That inane center arm would cause the whole rear axle to twist in relation to the propshaft.
It's fine if you don't actually expect the axle to move. 
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Peteff
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| posted on 13/10/05 at 06:15 PM |
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I can't see what locates the top of the axle at the wheel ends. It looks like it will pivot forwards. I don't think changing things for
the sake of it does anyone any good. The Watts linkage is a proven method of locating axles as is panhard and mumford links but all that is doing is
complicating something for no gain.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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quattromike
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| posted on 14/10/05 at 12:35 PM |
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quote:
Originally posted by Syd Bridge
The most interesting thing is those mufflers/silencers. By the look of the weld print through, they are Flowmasters, and date back to the mid eighties
in design. But, are very effective and create little back pressure.
They'd have to be the most sensible part of the whole car, and would do more for the total performance than that abomination of a rear
suspension setup.
[Edited on 13/10/05 by Syd Bridge]
Is it just me or does the exhaust just exit right underneath the car? That'll be a bit fumie at the traffic lights 
Mike
[Edited on 14/10/05 by quattromike]
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chrisf
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| posted on 14/10/05 at 01:08 PM |
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quote:
I don't think changing things for the sake of it does anyone any good.
I agree. It seems a better solution for using inboard dampers is to use the traditional locost-style rear suspension with a pan hard bar. If you want
the inboard suspension, just weld on the drop links and connect them to the rockers.
But consider this: how strong is your chassis after the rear bulkhead? Can it take the lateral loads of the dampers? On a live axle chassis, there
isn't much structure after the rear bulkhead. It's main purpose is to provide a fuel tank location and provide the frame for the rear ali
panel. I suspect that when damper loads are placed through the rearmost part of the chassis (assuming no additional bracing is done), a pretzel will
result.
FWIW, the pictured design uses a falling rate suspension. I question the person that goes throught the trouble of modeling it all up--then designing
in a falling rate suspension. Seems worthless.
--Just an opinion, Chris
PS. A lot of American muscle cars dump their exhaust under the car. I don't really know why, but it doesn't seem to cause that much
trouble. It is illegal in most states, though.
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Dale
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| posted on 14/10/05 at 02:44 PM |
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Running a watts link horizontal like that would put the rear roll center at the center pivot point?
I would like to find some info on mumford link design but it seems to like the black box in programing that says "miracle happens here"
Dale
Thanks
Dale
my 14 and11 year old boys 22
and 19 now want to drive but have to be 25 before insurance will allow. Finally on the road
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MikeRJ
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| posted on 14/10/05 at 09:19 PM |
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Hmm, all this work...and it's still a live axle. Effort better expended on a good IRS design IMO.
Didn't Lotus have a series of axle housing failures with their original three link design? Forces from accelerating and braking put torsional
forces through the axle tubes which aren't there with a 4 link setup.
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Bob C
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| posted on 14/10/05 at 09:56 PM |
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I think some posters have missed the point - the pictured suspension is grafted onto the underside of an existing car that looks like it had cart
springs. With some ingenuity they've improved the axle location a million percent within the space constraints and made a nice looking job of
it.
You'd be insane to put it on a locost though . . . . .
cheers
Bob
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Bob C
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| posted on 14/10/05 at 10:29 PM |
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oh yeah...
"I don't think changing things for the sake of it does anyone any good."
I change things for the sake of it whenever I get a chance..... I happen to think it's how progress happens!!
So who wants a go in my car when it's done ? ? ? ?
ttfn
Bob
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gazza285
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| posted on 14/10/05 at 10:55 PM |
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quote:
Originally posted by Bob C
I think some posters have missed the point - the pictured suspension is grafted onto the underside of an existing car that looks like it had cart
springs. With some ingenuity they've improved the axle location a million percent within the space constraints and made a nice looking job of
it.
You'd be insane to put it on a locost though . . . . .
cheers
Bob
I'm afraid not. What they have done is added loads of weight, made the axle rotate around the forward pivot, reduce the efficiency of the
springs/shock absorbers, and made a nice job of it.
Just about every live axle racing/rally car had four trailing arm and either a Watts linkage or Panhard rod coupled with vertical coil overs.
This was not by chance.
One simple question, how is this better than the standard Locost rear end and why.
DO NOT PUT ON KNOB OR BOLLOCKS!
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Peteff
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| posted on 14/10/05 at 11:06 PM |
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I change things for the sake of it whenever I get a chance..... I happen to think it's how progress happens!
Then it's called improving it, not changing it, and is a completely different matter. If that is replacing a cart spring rear then it's
probably an improvement. I agree that he would have been better off with another set of trailing arms instead of the contraption bolted to the diff
though. edit:- I've just looked again and he could have mounted the shocks upright from the bolts that the bellcranks pivot on and saved even
more time, weight and effort and probably be more efficient.
[Edited on 14/10/05 by Peteff]
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Peteff
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| posted on 14/10/05 at 11:33 PM |
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Here's a picture of a mumford link setup Dale.
There's a bit about it on the site as well here
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Bob C
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| posted on 14/10/05 at 11:53 PM |
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hi gazza,
I think you missed my point - it's not in a locost is it? The installation photo shows you can't put the upper trailing arms in so the
chevette/ascona/manta style system has been used. Quite right, it's not better than a std. locost system but it's not in a std. locost
etc. etc.
FWIW I agree it would be simpler lighter & probably better with vertical dampers & it looks like there's room. There's plenty not
to like, rod ends holding whole weight of car stuck out 3" on a bolt & spacer, questionable triangulation of the back face of the
'box' - at least the bellcranks on the photo look sturdier than the rendered ones (gorgeous rendered images though!).
night night
Bob
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Rorty
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| posted on 15/10/05 at 01:50 AM |
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I've looked at the pictures (agreed, nice renderings) over and over again and the only answer I can come up with is "because he
could"!
It's not progress, it's overkill, it's 'king ugly, it doesn't appear sturdy or safe and it doesn't look like it
would actually work very well, if at all.
But, if I had his brain in my head and the same amount of spare time and cash, I would probably have done the same thing.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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cymtriks
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| posted on 15/10/05 at 11:04 AM |
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quote:
Originally posted by gazza285
Different angle.
It doesn't work correctly. The fixed arm means the axle will just pivot around the front mount and put unnecessary loads on the pinion and
propshaft.
Not quite!
The central arm has a floating link at the front so it cannot locate the axle fore-aft.
What it does do is to stop the axle from rotating. The two trailing links provide fore-aft location, a third, or fourth trailing link to prevent the
axle from rotating isn't needed as this movement is prevented by the third central link.
The complete set up goes like this:
Translation:
fore-aft by the two side links
sideways by the Watts linkage
vertical by the springs
Rotation:
About car centre line by the springs
About Axle centre line by the trailing link and the central floating link
About the vertical by the trailing links
That's all six taken care of and not conflicting so it does work!
Having said that how many links are there?
2 pushrods
2 bell cranks
2 trailing links
2 lateral links
1 Watts link centre
1 trailing arm
1 trailing arm vertical support at the front
That's 11 links!
What on Earth's wrong with a Satchell link? Just four links, two upper trailing and two lower angled from the ends of the axles to the back of
the transmission tunnel. All for links being rubber bushed or spherical jointed. Simple. Cheap. Works well.
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britishtrident
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| posted on 15/10/05 at 02:19 PM |
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quote:
Originally posted by Syd Bridge
What's wrong with the standard damper arrangement?
And a sensible Watts Link has the crank attached to the chassis. Unsprung weight and all that. Only a seppo could dream up that nightmare.
snip
snip
[Edited on 13/10/05 by Syd Bridge]
Actually in the real world nearly all Watts linkages have the crank mounted on the axle, most follow the Ford "zero steer" axle location
first seen on works Mk1 Escorts circa 1972, the same arangement was used by Spen Wilks (seppo ?) on the rear of the Rover Sd1 --- main reason for
mounting the bell crank on the axle is it is difficult to mount a pivot on fresh air --- the increase in unsprung weight is tiny in comparision to
the live axle weight.
Of course it dosen't alter the fact the suspension design under consideration is flawed and way over complex for no reason.
[Edited on 15/10/05 by britishtrident]
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