Roll Center Explained - Suspension Design

[HQA]

Yes that'll do it. The other thing you need to calculate is natural frequency. Which is simply springrate/mass at each axle. Rear needs to be equal or higher than the front when loaded or it'll be a pig with a steering wheel.

Panhards get pretty sucky at longer travel as the angle causes them to jack in one direction and squat in the other. That's why triangulated 4 links and ball joints are better.

All great information guys thank you. You have given me a-lot to think about

I am over sprung in the front. The guys at Accutune set me up with the latest valving and mentioned I have more than enough spring.

Rear: 16” shock
Lower spring 1600.300.0500
Upper spring 1400.300.0350
Front: 12” shock
Upper spring 1200.300.500
Lower spring 1200.300.500

 

[bdkw1]

Those apring rates don't look to far out of line. 250 8nitial rate in the front is a little high, how much preload?

 

[HQA]

Those apring rates don't look to far out of line. 250 8nitial rate in the front is a little high, how much preload?

not much preload the collars are at the top of the threads with no more adjustment when I have it sitting the lowest with 4" up travel.

 

[HQA]

I like the idea of wrist arms at the rear axle. I will try this first.

I think these are the best numbers that fit in the space I have and ditched the rear panhard.

Am I wrong or do the short upper links work? The con is the pinion angle going flat at full droop however with the high pinion the driveline angle works

I tried to get the roll axis angle nearest 0 and near squat near 100%

*this includes lowering the front axle roll center 5 inches from where it was.

 

[bdkw1]

I like the idea of wrist arms at the rear axle. I will try this first.

I think these are the best numbers that fit in the space I have and ditched the rear panhard.

Am I wrong or do the short upper links work? The con is the pinion angle going flat at full droop however with the high pinion the driveline angle works

I tried to get the roll axis angle nearest 0 and near squat near 100%

*this includes lowering the front axle roll center 5 inches from where it was.

That looks way better than what you have. Now if you could just get the shocks mounted out further.

Edit, I was looking at the first poc which I assume is the front. Second pic, not so much.

 

[Bebop]

I like the idea of wrist arms at the rear axle. I will try this first.

I think these are the best numbers that fit in the space I have and ditched the rear panhard.

Am I wrong or do the short upper links work? The con is the pinion angle going flat at full droop however with the high pinion the driveline angle works

I tried to get the roll axis angle nearest 0 and near squat near 100%

*this includes lowering the front axle roll center 5 inches from where it was.

Rear still suck.
Less than the previous ones, but not really...

Also worth mentioning the CG location is probably way off so it will throw all of this out of whack.

Moving the shocks outboard would make a huge difference.

 

[Weasel]

Rear still suck.
Less than the previous ones, but not really...

Also worth mentioning the CG location is probably way off so it will throw all of this out of whack.

Moving the shocks outboard would make a huge difference.

He's keeping the same CG numbers so it's still useful in getting an idea of the incremental change and the direction it's gonna go. But yes you can't rely on the numbers as absolute.

I'd agree that 2 diff between the 2 setups isn't enough to warrant the work. I'd shove the IC a far out as you can and I wouldn't worry as much about the AS.

Moving the springs out would help but that looks to be a whole lot of work.