Can polyurethane spring isolators ride against the spring?

[Rubicon John]

Is it a bad idea to have a polyurethane front spring isolator as the only isolator up there?

I’m not sure if having the spring ride against polyurethane rather than rubber is a bad idea. Anybody with experience doing this?

Only asking because I’m figuring out my options to try and attain a completely level ride height.

 

[Steel City 06]

It probably wouldn't hurt anything. Maybe a little more vibration and it might dig into the polyurethane a bit, but it shouldn't break anything.

 

[jjvw]

I ran aluminum spacers with no soft isolater for about a year. I couldn't tell a difference.