Every bolt on a bike is vital to creating a whole, safe machine. Yet there are some that are more vital than others. We are talking about bolts that hold on your levers, pedals, footpegs, subframe, etc. If any of those break, fall out, or otherwise become nonfunctional, you’d be in for some hard going. But there are some other bolts on a bike that, if absent, wouldn’t result in a catastrophic failure or major safety hazard.