Actually you can do it either way. I'd just try both ways and see what works best for you!
A third option is to just manually update the wheel position/rotation every loop.
EXAMPLE:
function position_wheels(LFwheel,RFwheel,LBwheel,RBwheel,len,wid,chasis)
position object LFwheel, object position x(chasis),object position y(chasis),object position z(chasis)
set object to object orientation LFwheel, chasis
move object LFwheel, len/2
move object left LFwheel, wid/2
.... etc.
...then all you need to do is keep track of the wheels rotation so you can set it each loop!
Hope that helps!
