[slicer]

Spacers will not cause vibration on their own absent another issue. I can honestly say that I have never experienced an issue with a spacer Accross multiple cars, platforms, wheels, etc.

Possible reasons include:

Rust, dirt, grease or something else on the spacer, hub or mounting surface of rim or rotor hat (causing it to not sit even / flat onto mounting surfaces)

Torquing the wheel nuts with weight on the wheel (load could cause wheel and spacer to be misaligned and not sit flat and square). It's best to be at least near torque spec while wheel in the air - unloaded. Impact driver is best way to do this since the front wheel will spin freely.

Faulty spacer that isn't perfectly flat. I only use Turner Motorsports or the new Future Classic spacers.

10mm spacer used with a hub or wheel that doesn't allow it to fully seat

Use of a spacer in a size that eliminates the wheels contact with the hub - resulting in a lug-centric fit instead of hub-centric. For example a 7mm spacer can not be hub centric unless you install hub extenders.

Wheel has a bend or some run-out (could be very slight and only detectable with road force balancer). Not all balancers are created equally.

Tire could have some run-out; AKA not perfectly round. May be correctable via road force balancer.

Tires could have uneven wear causing a vibration

Tires could have damage such as a sidewall bubble from an impact.