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reinventing the wheel mumber 65037.....
mogman1969 - 1/11/10 at 08:07 AM

lust wondered if any one knows why when using 4 link suspention , the arms are not used in triangular form , pivoting at the normal locost mounts then fixed at a near 45 degree angle to finish on a mount near the diff ........one wouldnt need a panhard rod then , bearing in mind that no more that 100bhp is likely to be available


snapper - 1/11/10 at 08:20 AM

Early Lotus 7 and Lotus Cortina had an A frame link to the diff and 2 trailing arms.
It does concentrate a lot of force at 1 single point


SPYDER - 1/11/10 at 08:34 AM

Many cars have used such diagonal location arms, although usually just the top pair in conjunction with a parallel lower pair.
The TR7 being just one.
The geometry is compromised in ways that I do not begin to understand. It can be OK for a road car with it's usually soft set-up but is seldom seen on more performance focussed cars. AFAIK.
Now replacing one pair of trailing arms with a triangular frame that mounts directly to the diff centreline, ie. an " A-frame" is a different matter and can be the heart of a very precise setup as previously posted.
Both of these arrangements would be difficult to incorporate into the Locost I fear. The angled arms would encroach into the cockpit space.
One solution might be to keep the upper pair of arms as per usual then have a rearward A-frame apexing under the diff and pivoting from two mounts on the rear chassis rail under the fuel tank area.
It would compromise ground clearance but could be OK on a track oriented car.
This arrangement would be essentially the same as featured on our 3 times championship winning TR7V8, albeit turned back to front.

Geoff.


mogman1969 - 1/11/10 at 08:35 AM

not an A frame just a suitably robust bracket either side of the diff to take upper and lower trailing arms


daviep - 1/11/10 at 08:50 AM

Where does the 100hp limit come from?


mogman1969 - 1/11/10 at 08:57 AM

1275 a series engine ....if i get it tuned ya not looking at that much ......


mogman1969 - 1/11/10 at 08:57 AM

1275 a series engine ....if i get it tuned ya not looking at that much ......


daviep - 1/11/10 at 09:03 AM

Sorry thought we were discussing design in general.

Cheers
Davie


mogman1969 - 1/11/10 at 09:08 AM

my only thought was the more bhp going thru the assembly the more chance of trouble
so thought it had a bearing


ken555 - 1/11/10 at 09:10 AM

quote:
Originally posted by mogman1969
1275 a series engine ....if i get it tuned ya not looking at that much ......


The original Cox GTM had this arrangement.


mogman1969 - 1/11/10 at 09:20 AM

cox gtm ....mini based fwd with irs wasnt it ? looking at a solid axle here .....


MikeRJ - 1/11/10 at 10:04 AM

quote:
Originally posted by mogman1969
lust wondered if any one knows why when using 4 link suspention , the arms are not used in triangular form , pivoting at the normal locost mounts then fixed at a near 45 degree angle to finish on a mount near the diff ........one wouldnt need a panhard rod then , bearing in mind that no more that 100bhp is likely to be available


You would only be able to triangulate one of the four arms; any more than this and the system would bind up. It's something I thought about when I was making the rear end on my chassis, but then again a panhard rod isn't exactly a complex thing to make.


mogman1969 - 1/11/10 at 04:50 PM

ahhhhh so it would bind ..... ok ...option two , A frame time now wheres that drawin gone


Minicooper - 1/11/10 at 04:56 PM

I looked at the satchel link setup which appears well thought of in America, but since I didn't have a clue what would work, I stuck with a watts linkage in my case.
The linkage has two diagonals and doesn't seem to bind otherwise it wouldn't work would it?

Cheers
David


mark chandler - 1/11/10 at 05:54 PM

Classic range rover, cortina etc, lots of cars out there with linkage like that.

Range rover has ball joint on chassis with A legs on top of axle so opposite to most designs that are wider on the frame, close on the axle.


mogman1969 - 2/11/10 at 01:57 AM

satchel link ....thats a new one on me ....wiki time .....