I'm doing a report on the mars rovers and am wondering what material did NASA use to construct spirit and opportunity's wheels. Was it aluminium? Rubber? Titanium? Magnesium? I don't know. Can't find any information on the topic so hoping you guys have some good idea of what they're made of.
Aluminum and foam according to this page that describes the wheels as manufactured from a single Aluminum block with foam inserts into the spiral suspension system spokes. The black surface of the wheel itself is just an anodized coating.
Interestingly the wheels are described as being by design less effective in sand than they could have been by having curved rather than square cleats, to avoid getting snagging while crossing the airbags.
Given both rovers ended up getting bogged in sand possibly another data point in the decision to land later rovers under power rather than by airbag, since it avoids needing to compromise the wheel design this way.