Advice to other new owners looking at "HD Upper Spring Seats" Topic is solved

[oragex]

I am about to remove my Febi seats stamped Made in Germany, one year old, one side already cracked, and replace them

[mrbrian200]

Also some mechanical theory. Strut does not go down out of mount on rebound: compressed spring discharges way more energy than gravity can supply to a wheel in air + moving suspension parts to drop them down. Spring always pushes seat against mount. If it's not able to do so, suspension is broken and car is dangerous to drive.

Bad handling of XC70 over obstacles comes from capacity of it's suspension: when strut compresses (and it compresses a lot on a high ground clearance car) it changes toe angle drastically, because movement of control arm and tie rod in a horizontal projection is not equal. Did you notice that sports car have very limited vertical movement allowed in suspension?

When you replace 10 years old sagged suspension on XC70 and set camber bolts into same position, toe goes from 0.1 to like 0.5..0.7. And that's just a mere inch of height increase or so.

I'm not sure you understand: the strut/spring is not allowed to snap out freely: The rate of extension, if you will, is controlled at a specific rate by the internal strut valving. When you jack the car up the top washer contacts the strut bearing. This is both a combination of bushing flex and vertical travel of the spring seat within the mount. I can look at that for ten seconds and figure out pretty quick it is 'supposed to do that, obviously a design function centered around ride quality. There's a reason my friends are commenting on how impressive/smooth the ride is on bumpy South Bend IN city streets. These comments/observations started immediately when I put the OE spring seats back, not before with the aftermarket seats.