Aren't jounce bumpers kind of useless?

[Franco]

It seems to me that the OEM “jounce bumpers” are soft enough that they wouldn’t actually do anything, no? The way it’s designed I suppose the function is to soften the hit of the cup against the spring perch. I just don’t see that happening with the hundreds of lbs of force applied to those things. What am I missing?

 

[jjvw]

... What am I missing?

You are missing that the jounces exist to augment the role shocks play in controlling movement.

 

[Rubiconned]

I'm putting new ones in the rear today when I install my spring perch correction plates.