At my tri this weekend, I noticed quite a few people making a big rookie mistake.
As soon as I got out of transition and started the bike ride, there were about 3 fallen bikers with flat tires. This was about a tenth of a mile at most from the transition station. When it happens immediately out of transition, I can tell you what went wrong…
Guys, do NOT pump your tires to capacity the night before a race. Especially a race at the end of September. The air temperature at night is significantly cooler than in the day time. If you pump your tires at night, the air inside the tubes warms up and expands during the daytime and if the air expands enough (and it will), then your tubes will pop. You’ll learn this lesson the hard way if you ever try to leave your bike in the trunk of your car on a warm day.
Wait until the morning of the race to pump your tires, and if it’s still pretty cool outside when you’re pumping, leave a little room for the air to expand. Look on the side walls of your tire for the appropriate pressure range, and stick to the low end. Remember that all tires are different, so don’t ask your friends for the appropriate pressure. Look on your tires and use the manufacturer’s instructions.