Tourist in MSN

One more final piece of advice. Do not work on your bike before you start that long event. Make sure you have some miles on the bike before the event, then you will know if it is ready. Exception, lubing the chain while the chain is on the bike is likely needed and that is not really working on it.

Example:
I did a century over a decade ago, a few miles after the start, there were about a dozen riders stopped on the side of the road. I stopped to see if someone needed help. The bike owner of the dysfunctional bike said that it was really strange, both front and rear derailleurs broke at the same time. This peaked my curiosity, so I looked at the bike. Found that the rider had shifted onto the biggest ring in front and the biggest sprocket in back, and his chain was too tight, his rear derailleur cage was at an odd angle. I asked him when was the last time he changed the chain, he said he had a bike shop change it for that ride a few days earlier. I told him to remove the rear wheel, put it in a different gear, re-assemble and DO NOT go into that gear again. And told him the next day to go to the bike shop and chew out the mechanic for cutting the chain too short.

Another example:
It is common to replace a chain, but find out after several miles that the cassette needs changing too when the chain skips on a sprocket or two. But once you start an event and you find one commonly used sprocket skips, that is really bad timing.

It can be tempting to make changes shortly before an event, but you really need to make sure the bike is in good shape with some miles after any changes. After any changes I make, I like to get 20 to 30 miles on a bike before I do any special events, some of those miles include pedaling hard, like up a hill to make sure the drive train can take the stress if I change any drive train components.