My first attempt to design the front wishbone.

The uprights are sierra and copied from locost7.info. The front chassis section is close to a +4. Wishbone lengths are my own. Right height is 5". Compression travel is 2.5" and rebound is 2.5”. Measurements are in mm

Did i pass the test ?

Normal height


Full compression


Full rebound

I would say so, CofG looks good there IMO, but what engine are you planning on using? as 127mm ride height at the front is pretty high...

Steve

quote:

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Originally posted by 9000rpm

Did i pass the test ?

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I am planning to use a F20C which has a longish oil pan. I was originally designing for a 4inch drop but having roads worse then the moon, i opted to design with 5 inch.

I pointed my lower wishbone a little bit down-wards about 19mm.

My RC is at 75 which is a little bit high.
But it is one big compromise.

My ride height is 125mm front.

I think you could raise the upper inner a little bit, which is better for your RC.

grtz

To be realistic work with 3.5" total suspension travel -- a transit drag link has limited articulation.


Front Rc looks a bit low
What size tyres are you planning ? if you used a smaller outer dia tyre & wheel combination it might help get the wishbones at better angles

As a rule steeply angled wishbones should be avoided

quote:

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Originally posted by britishtrident
To be realistic work with 3.5" total suspension travel -- a transit drag link has limited articulation.


Front Rc looks a bit low
What size tyres are you planning ? if you used a smaller outer dia tyre & wheel combination it might help get the wishbones at better angles

As a rule steeply angled wishbones should be avoided

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Roll centre around 45 mm is a good start,
I personally would not go lower than that

Plenty stuff on wheel-geometry around here.

Rear roll-centre if IRS around 90 mm
Mine are 75 front and rear 100 mm.

I use 195/65 R 14 to gain bottom space

Front RC should be slightly lower than the rear, I would start by trying to get the Rc about half-way between the ground and the bottom of the chassis, say 52 -65 mm

The lower wishbone should be roughly parallel to the ground (for a road car usually inner end very slightly higher than outer)

[Edited on 10/7/07 by britishtrident]

If you take a good look at the front suspension of 1960s Formula 1 or 2 racer (for example Lotus 33) you should get an idea of basic practice.

I did search for the lotus 33 as mentioned and found a good reference of the wishbone angles. After some home work i determined the upper is around 15deg and lower is 5deg (approx).
http://www.vsrnonline.com/Mags/MC/Vol1/V1N6/MC_V1N6_p283.jpg