Knuckle Shim and Preload

[kjkruer]

I'm in the process of putting my front knuckle back together. I put a shim in the top of the knuckle that felt to be about the same thickness as the factory one. When I got everything torqued back down I measured the preload with a scale I got from Cruiser Teq. I was right at 6lb. Is that good or should it be a little tighter? I think the speck is between 5.5 and 9 so it's on the light side. One other question... Does adding a shim make it "looser" or "tighter"?

Thanks!

 

[Kernal]

What model are you working on?

Assuming it's an 80 series:
What was the thickness of the original shim and did you replace it with
an identical shim? The shims are marked with their thickness so you shouldn't have to go by feel or guess. If the original shims were damaged better to replace them with OEM new IMO.

When putting the same parts back together you generally use the same thickness trunnion cap shim as what came from the factory (80 series). A thicker shim than the original would mean less preload on the trunnion bearings ie: it would be moving the trunnion cap slightly up and away from the bearings resulting in less "squeeze" or preload on them.

 

[kjkruer]

Yep, 80 series. I can't find any markings on the shim that I removed. It appears to have been a while since the knuckles have been done and the shim is pretty nasty. I'm using the knuckle rebuild kit from cruiser teq and it came with what appears to be 4 different sizes of shiims. Can't find any markings on those either... I think I'm just gonna swap them out and check again. It's not too hard and I don't want to have it incorrect. When I do the other side I can make sure to use the same one.

 

[Kernal]

Maybe try taking a few photos with and without flash at different angles of the old shims, the markings might become more visible?? Either way, seems like .20 is what's most commonly found for the trunnion cap shim thickness on an 80 series. IIRC someone posted up years ago that a change in .10 above or below .20 there's a change of 1lb in preload??