Here goes. First post, flame suit on. But I would appreciate any input.

In the UK, building a buggy. Have lurked, watched, read, searched and searched again. Read everything I could find and would just appreciate any comments on the following numbers (thanks for the 4 link calc, great start). This thing needs to drive on the road and handle at road speed. I appreciate there is no definitive answer and we need to build it and try but before that just wondered if anything in these numbers looked crazy.

Wheelbase 104.0 in
Tire Diameter 36.00 in
Tire Rolling Radius 17.00 in
Vehicle CG Height 42.00 in
Vehicle Mass 4,000 lb
Front Unsprung Mass 800 lb
Rear Unsprung Mass 700 lb

The rear

Upper Links x y z
Frame End 28.00 13.00 32.00 in
Axle End 3.00 0.00 27.00 in
Lower Links x y z
Frame End 45.00 9.00 24.00 in
Axle End 3.00 17.00 13.00 in


Anti-Squat 69 %
Roll Center Height 27 in
Roll Axis Angle 6 degrees (Roll Oversteer)
Instant Center X-Axis 229 in
Instant Center Z-Axis 72 in

Had real trouble finding anything about 4 link fronts but here we go

Upper Links x y z
Frame End 28.00 13.00 28.00 in
Axle End 3.00 3.00 25.00 in
Lower Links x y z
Frame End 45.00 9.00 24.00 in
Axle End 3.00 17.00 15.00 in

Anti-Squat 76 %
Roll Center Height 25 in
Roll Axis Angle 6 degrees (Roll Oversteer)
Instant Center X-Axis 109 in
Instant Center Z-Axis 38 in


And yes I know, small tires!

Especially interested if anybody has useful comments about front 4 links and calculating anti-dive.

Thanks, Tim

bump. Nobody can help this guy? He posted a well thought out question with specific data. At least he posted in newbie, if he was in hardcore he'd be molten lava by now... I'd help if I could but I'm researching 4 link stuff myself.

Try hardcore if nothing posts up...
Just post pics when you start fabbing :D

Calculating AS and AD are the same....As for your caculations looks pretty good, although you might want to recalculate to try and get you Roll axis angle as close to 0*or -1 to -2* as you can get..You might also wnat to get AD alittle lower 70% is a bit high for AD...Also i dont think 800 and 700# for your unsprung weight is no where near acurate....

The AD calc I posted is not the one we are using sorry. We have worked this separately (different equation from AS) to be 30% which is about road car standard.

The unsprung weight may be a bit low but this is the UK, land of small tires and skinny axles! I will redo these soon when we have the scales and the other unsprung bits.

Thanks for the input.

Tim

PS should have the frame in the garage in a few weeks!