Roll understeer. How much is too much??

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This is for a dual triangulated rear setup. By playing around with the numbers in the 4-link calc I can go from 8 degrees understeer down to 4. I like all the other numbers with the 8 degree setup better than 4 but I worry if that will be too much roll understeer.

Looking around the web for roll understeer has told me that for car racing applications you want rolls test to be 0, but it's better to have understeer than oversteer if you have to. It makes sense on a track for this to me, but I wonder just how important this is for driving around town and trail riding/ rock crawling.

Thanks for any input y'all may have.

[ATL ZJ]

How do your anti squat and the location of your instant center change when you make the adjustments to reduce roll understeer?

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heres a screen shot of where I settled up, pretty happy with everything except for the 5 degree roll understeer. what do you think?

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as for adjustments to change roll understeer, easiest way is to outboard the lower link more, but then i would sacrifice my travel roll axis. I could change the upper link axle mount higher to change it, but that increases AS and would cause my uppers to hit the floor board and limit my up travel too much to answer your question atl zj, thanks for taking the time to answer btw

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So I went ahead and built the setup with 5 degrees roll understeer and cycled the suspension. Here are my observation: on droop, the tires stay pointed pretty straight, but on bump, they point in towards the center of the jeep.

Seems like one should aim for as close to 0 as possible for their understeer/oversteer numbers in the calc if they plan to run an even split up/down travel. And more understeer for the more their suspension has bias towards down travel.

Does this sound about right?

[Kraqa]

keep it as close to 0 as possible.

i woudl lengthen the upper arms.

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Why would you lengthen the uppers?

I agree with you on going go 0 degrees understeer at ride height for most vehicles. But I feel like in a full body vehicle that runs 80% of its travel down having a little understeer is a good thing.

I say this after noticing that as the axle droops, the understeer approaches 0 and then starts going into oversteer category.

Would you agree with that? I know you have way more experience with this, just trying to make sure I got a good grip on this principle. Thanks

[Kraqa]

the uppers being so short will pull your pinion down....a lot. as you stated you will be runnign lot of down travel. your pinion is goign to do soem funky things with uppers that much shorter than the lowers on full droop.

i run my set-ups at 0 degrees at ride height because it seams to work best for me. your logic makes sense to me. but i have always found that 0 at ride height works well.