Wheel spacers.

[shawnmartin]

I put on 33x12.5x20 tires on a 2016 Ram 1500 Express and it required 1/4" spacers. Motorsport-tech said they preferred the 3/8" spacers with the lip instead of the flat 1/4" because ...("the 1/4" spacer is flat and covers up a lot of the hub so depending on the wheel bevel, it doesn't leave a great deal of hub exposed for the wheel. 3/8" cover less of the hub because it's thicker than a 1/4"). I'm confused on why 3/8" would cover less than the 1/4". Can someone explain this to me? I think I'm talking about a different part than he is when we say "hub". Here is the pic. The 1/4" vs the .375.

 

[Daw14]

The important piece is what goes into the rim, it keeps it aligned.

 

[crazykid1994]

The 3/8 or 1/2” ones have a hubcentric lip on them to help center the wheel. The 1/4 does not have a hubcentric lip and will cover up most of the hub lip that the wheel sits on and not let the wheel ride on the hub lip. A lot of wheels are lug centric and hub centric but putting in wheel spacers it’s best to keep the hubcentric as well to take some of the load off the lugs.