Pro Tip: If your car is relatively common, score a full set of hubs and load them up with good bearings. It's probably $50 a corner to pre-load them*, but if you've got a couple hundred bucks and the time do it before the race weekend, the math checks out on the time/money it'll save.
I say this like I was smart enough to do it when I raced. I wasn't, but we did carry spare half-shafts and could swap them out in ~10 minutes. A hub swap should be probably about the same? Front-wheel-drive cars (I assume that's what you have if you're asking about presses) straight-up murder wheel bearings and half-shafts in Lemons.
*That's a first-time cost. You'll have the hubs already for a second race, so it's just the cost of fresh bearings after that.
Eric Rood
Everything Bagel, 24 Hours of Lemons
eric@24hoursoflemons.com