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View Full Version : Any comments on initial 2D plot of IFS front suspension?


dav8427
09-02-2006, 09:07 AM
I've been working out the layout of a scratch built front suspension and was curious if any of you suspension gurus could offer any insight.
These dimensions are layed out in Solidworks and as of right now are in 2D.
Also since I am not sure what size rims I will be using, these dimensions are using the wheel mounting surface on the spindle.

FVSA lengths.
+4.0"--42.338
+3.0"--51.650
+2.0"--65.107
+1.0"--86.838
0.0'(ride height)--130.00
-1.0"--270.00

Roll Center Heights
+4.0"--4.629
+3.0"--3.914
+2.0"--3.341
+1.0"--2.878
0.0(ride height)--2.487
-1.0"--2.126
-2.0"--1.737
-3.0"--1.219
-4.0"--.359

Camber gain/loss
+4.0"--3.54*
+3.0"--2.31*
+2.0"--1.32*
+1.0"--.55*
0.0"--0.0*
-1.0"-- -.33*
-2.0"-- -.41*
-3.0"-- -.22*
-4.0"-- -.35*

I also would like to know if the comparison or ratio of SVSA length of a rear suspension vs. top view length (angle lower arms) should be kept within a certain range for best results or smoothest operation?

Being a novice,I am still learning and would appreciate any input anyone could offer.

Thank you

TLWiltman
09-03-2006, 12:44 AM
Not really a suspension guru, but...The first thing that strikes me right offhand is...
Your camber gain seems like it needs to be a little more aggressive in the first inch of travel, and a bit less so in subsequent inches of travel. Something like
-1" -1-1.25*
-2" -1.5*
-3" -1.75*

Roll center height. I hope all those negative numbers don't mean below ground. If so, you'll want to bring that up to a range between ground level and 4" above at ride height. If those negative heights are above ground, your roll center height should follow suspension movement (1"drop in suspension travel should result in about a 1" drop in roll center height). This is so that the suspension behaves consistently in travel (the suspension is seldom at nominal ride height)

FVSA to me looks a touch long. I'm not 100%, but it looks like you could get a bit more aggressive with that.

dav8427
09-03-2006, 07:00 AM
The way I have this info written up may be deceiving.
The positive numbers are actually suspension compression from ride height, and the negative are rebound from ride height.

All the RC heights are positive(above ground)