Off Road IFS Design Vol 4 JEHC EP8
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- Опубліковано 11 чер 2022
- In this installment of the Off Road IFS design series I review Shock geometry and proper bump stop mounting along with some bits on the difference between vertical and horizontal bearing arm setups.
I am very greatful for your ability to provide this information to the public. You consolidated decades of trial and error into these videos. I'll be committing to applying these concepts over the summer on a build, so thanks to all you've done.
I think you need to make some shirts that say "quakculations" and "cattywampus" Jason lol
man, thank you sooo much for this series!
there are others talking about susspension geometry but... 30 minutes is not enough by any means.
Hi!
About the lower arm/shock mount configuration starting at 58:00
Consider a typical setup with a lower shock mount at ~60%, inline between inner & outer pivots, and angled such that at full bump, shock is 90 to lower arm.
Front view at ride height: draw a triangle between inner pivot, lower shock mount, and upper shock mount
Now, imagine if you rotate that triangle about the inner pivot.
Up, the lower shock mount is now above the centerline of the inner and outer pivots, and the top mount is closer to center of the chassis - the shock appears leaned in at the top.
Down, the lower shock mount is below the centerline, and the top mount is further away from the center of the chassis - the shock appears more vertical.
Both configurations are similar to the original. Motion ratio & piston speeds vary a bit.
I think this is why Robby gets away with such a "leaned-in" shock because it is not as progressive as it seems. Same with some of the pre-runners that feature swept arms with lower mounts well below the inner/outer pivot center and damn near vertical shocks - I bet they aren't as digressive as they seem.
Great content - Cheers!
Could you do an episode on I beam design
How much of the "it doesn't matter up to 15 degrees" is because everyone has bypass shocks and can make the shock progressive to cancel out the digressive geometry?
Also, if you calculated the raw dampening at the tire, (after all the effects of geometry and valving have interacted) how different are the top trucks? Are they just getting to the same conclusion with different designs?
If intrested I will tell you how Jim at Brandwood sand cars told me how to set up the top shock location. I appreciate the time you have sacrificed.