Kyb Shocks in rear--which side does bushing offset go on?

[Euphanasia]

I'm installing KYB shocks on a '97 Roadster. The metal spacer going through the rubber bushing is offset, with twice as much on one side as on the other. Do I:

Put the long side on the outside, to get a better angle, or

Put the long side on the inside, to decrease leverage on the bolt?


Or is it a matter of clearance?

Thanks

[zellamay]

https://zroadster.org/threads/locati...t-spacer.4072/

[Euphanasia]

https://zroadster.org/threads/locati...t-spacer.4072/

Shoulda told me to bring the popcorn. I've never seen so many people fighting over all of them having the same answer!!!!

So--long-side to the trailing arm. I guess that makes sense. With the KYB shocks, if you bolt in the tops of the shocks, you can't even get the bolt threads started if you've got the short side of the bushing against the trailing arm.

[Vintage42]

... With the KYB shocks, if you bolt in the tops of the shocks, you can't even get the bolt threads started if you've got the sort side of the bushing against the trailing arm.

If that was so, there would be no question, no discussion, no need for the popcorn.
I removed OE Sachs, installed Sensens, then removed them and installed KYB, all the time concerned about which way the bushing should be turned. The brand is not a factor.
With any shock, the rubber in the upper mount allows so much wiggle at the bottom that the bushing can face either way.
As for starting the bolt threads, that depends on how straight the bolt has been aligned with the hole in the trailing arm, using a supplementary jack.

[Euphanasia]

If that was so, there would be no question, no discussion, no need for the popcorn.
I removed OE Sachs, installed Sensens, then removed them and installed KYB, all the time concerned about which way the bushing should be turned. The brand is not a factor.
With any shock, the rubber in the upper mount allows so much wiggle at the bottom that the bushing can face either way.
As for starting the bolt threads, that depends on how straight the bolt has been aligned with the hole in the trailing arm, using a supplementary jack.

Hang on---gotta go pop the corn.




If the shock is mounted into a pivoting upper point on a fixed axis, moving the lower bushing in or out will change the angle of the hole in the bushing. The bolts fit to a very tight tolerance, so if the angle is off, they won't thread in unless you change the angle of the bushing--something I think would be near impossible by just using hand leverage against the mounting bolt. And why would you want to? Why not mount it in the position that puts the least stress on the rubber?

Munch....Munch....Munch...

Moving it outward 1/2" still changes the angle by at around 4 degrees at full compression, and around 2.5 degrees at full extension. Not a lot, but enough that KYB chose to mount the metal bushing off-center to accommodate a perfect alignment with the long end against the trailing arm. I replaced one shock with the suspension fully extended and the other with it fully compressed. In both cases, the bolt would not thread in with the short end against the trailing arm.

I don't understand your point about needing a supplementary jack. These aren't struts. You can move them up and down by hand to meet up with the hole in the trailing arm.

[Vintage42]

... I don't understand your point about needing a supplementary jack. These aren't struts. You can move them up and down by hand to meet up with the hole in the trailing arm.

Mine were hard to move and hold in position against the trailing arm, maybe gas pressure. I found it easier to put a little jack under the trailing arm to position it for the bolt.

[Vintage42]

... I replaced one shock with the suspension fully extended and the other with it fully compressed. In both cases, the bolt would not thread in with the short end against the trailing arm...

I replaced my shocks with the short end of the bushing against the trailing arm, in the photo, no problem with threading.
Later I turned them the other way.

[Euphanasia]

I replaced my shocks with the short end of the bushing against the trailing arm, in the photo, no problem with threading.
Later I turned them the other way.

And it looks very much like the rubber bushing is under stress because the bolt is not perpendicular to the shock. Perhaps the hole is larger, but once the metal bushing is sandwiched between the trailing arm and the bolt head, the bushing changes angle.


My KYBs came with washers that go under the bolt head. It looks like yours didn't. I would think you'd still need the washer. The original Boge shocks have a squared-off flange on the bolt-head side.

[Vintage42]

And it looks very much like the rubber bushing is under stress because the bolt is not perpendicular to the shock...

Based on the forum advice, I did turn the shocks 180 degrees soon after that photo, and they have been fine for the past 7 years and 18,000 miles.
The point of the original 2013 thread, which sequelled into this thread, is that when I removed and discarded the original shocks, I did not remember which way the unequal-length bushing tube faced. And it seemed counter-intuitive to cantilever the shock on the long end of the bushing.