New tires before event?
 

Kind of a dumb question, but I'm wondering whether to change out my road tires 2 days before a century. My current rear tire is a little squared-off, and my front tire has numerous small cracks - not major, but not new. Would the decreased rolling resistance of new tires make much difference? I'd be going from Continental 4-seasons (old) to Continental Ultra Gatorskins. I guess it's only superstition that would prevent me changing them...

Change your crap.

Your tires don't sound too bad. Squared off is not a problem unless the rubber is so thin that you can see the cords about to pop through.

I would try to get at least one training ride in (even if just an hour) on new tires before a big race. That will give you time to notice any defects or installation errors.

Squared off IS a problem when you go around a corner.

What are you saving by NOT changing your tires? Why push your luck?

The reason only the rear tire squares off is that the rear tire does not affect cornering much. A squared off front tire would be a problem, but that never happens.

You save money not trashing your tires when they still have 1000 miles of life left. If you too much money, then you can ignore this.

Century? This doesn't sound like a race....

Change them and break them in proper-like.