It should not take much more than 5 minutes to change a flat, clincher or tubular. Why did you even buy a spare, if you don't know how to change it? With all the money and time people spend on races, it just doesn't make sense to let a flat ruin your race. Unless you are going for the overall in a sprint race, a flat should not have that big an impact on your race.

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"When I first had the opportunity to compete in triathlon, it was the chicks and their skimpy race clothing that drew me in. Everyone was so welcoming and the lifestyle so obviously narcissistic. I fed off of that vain energy. To me it is what the sport is all about."