Anyone using the solid spacer on a DD 9"? Are they re-usable? Safe for street use? Anything special I need to do/know?

This will be a stock case 31 spline one open on spooled.

The stock crush sleeve is not reusable. If someone has put the solid spacer (crush sleeve elinimator) in it it can be reused but most likely will have to be reshimmed for the correct pinion preload. There are no issues wth using it on the street.

i've had a solid spacer on mine with a detroit and i reused it when i broke the 3rd member housing ans haven't had a problem. i drove it as add for 4 yrs. just as overkill48 said keep your shims for incase you need to regear or have bad bearing wear to preload the bearings.

i just made a little spacer on the lathe to re use my crush sleeve :D

I prefer the solid sleeve. I used the solid sleeve for many years in my old spooled 9". I never had a problem and never had to re-torque it (crush sleeves seem to loosen up over time). I re-used the shims and the solid sleeve many times in that same setup. I'd def do it again and probably will very soon.

a solid spacer is 1000000x better then a crush sleave, on and off road.
Get one.

Yes.