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MacPherson / cantilever hybrid suspension?
akumabito - 27/2/21 at 09:28 PM

---I hope it's ok to post something not locost related - I could use some input from some ingenious home engineers---

I am working on a restomod of a 1980s Fiat Panda. Although there is great cross-compatibility of engines, gearboxes and brakes between Fiat models, I have no such luck with suspension upgrades. There are no off-the-shelf coilovers available, and Cinquecento/Seicento or Lancia Y10 parts are incompatible.

So that got me thinking about DIY solutions that would offer full adjustment for minimal expense. Would it be possible to make a hybrid between a MacPherson strut and cantilever/pushrod suspension? The (motorcycle) shocks could be mounted as in the sketch below - integrated in a strut bar, or rotated 90 degrees and fitted in a longitudinal direction.



The concept seems relatively easy to fabricate, which has me a bit worried. I've never seen it done before, so I'm probably overlooking something really obvious!


Sam_68 - 27/2/21 at 10:23 PM

Your 'top mount' will effectively be following an arc, hence geometrically, it's a double wishbone with a really tall upright and a really short upper wishbone. But for that reason you'd also need to be careful about deflection of the components (particularly the 'strut'/upright, and upper rocking link under heavy braking).


MikeR - 27/2/21 at 10:59 PM

So i'm looking at an upright with a double bolt mounting - couldn't you make a bracket that used the double bolt to attach the bracket, the bracket then had a single bolt. Then make a mounting for the macpherson top mount to have a single bolt hole hanging down from it. You now have an upper and lower bolt hole to attach a shock absorber in. The only issue would be the amount of movement you'd have. If its a problem, then replace the lower shock absorber with a push rod going to your original idea.


blue2cv - 28/2/21 at 06:14 PM

Didnt the old Rover 2000 have something like that


jollygreengiant - 1/3/21 at 12:12 AM

quote:
Originally posted by blue2cv
Didnt the old Rover 2000 have something like that


Correct the Rover P6 (2000,2200, 3500) did, The road springs operated horizontally from a pivot point on the suspension to the rear against a spring seat on front bulkhead.


steve m - 1/3/21 at 08:48 AM

I used Honda Goldwing shoxs and springs on the rear of my Locost, they lasted about two weeks]


Mr Whippy - 1/3/21 at 12:19 PM

if that is to scale I can't see how that is going to fit in a panda, it's springs ontop of the bonnet or if shorter you're going to have to leave the engine out...


Toys2 - 1/3/21 at 02:56 PM

How will the steering work in this arrangement?
Doesn't the steering pivot at the top mount on a MacPherson strut?


Mr Whippy - 1/3/21 at 03:05 PM

quote:
Originally posted by Toys2
How will the steering work in this arrangement?
Doesn't the steering pivot at the top mount on a MacPherson strut?


Well spotted


MikeR - 1/3/21 at 03:10 PM

Cough cough.... Yeah I'd spotted that too. I was just waiting till 29th Feb to mention it 😃

Id guess you could go back to my point of fitting the shock between the lower mounting point and upper MacPherson chassis point, but the shock won't be designed to take the twisting force.


Crockpot - 20/3/21 at 03:40 PM

It might be worth trying Gaz for suspension upgrades.


coyoteboy - 20/3/21 at 05:55 PM

Could still work just fine with a ball joint up top and a rigid enough link. That's just an UCA really.