What's the course like? A flat, windy course is good for a rear disk, a hilly course is good for a lightweight wheel. There's a point at which they don't matter much, maybe low 20's average speed, especially if you aren't a flyweight where every ounce makes a big difference in the hills.<br><br>
For that kind of money, you might want to consider fresh tires and a tighter rear cluster to use for the flat courses, those two things can make a nice difference for about 140 bucks and you never have to return them.
I rented Zipps from racedaywheels.com for my A-races last year. It is spendy for multiple races, but a nice option if you don't want to spend the $ to purchase your own wheels and they do give you the opportunity to try out a particular type of wheel before you buy.<br><br>
They ship the wheels to you in a FedEx shipping box. You need to supply your own cogset, so you either need to have your LBS pull the cogset off your existing training wheel and put it on the race wheels (and reverse the process when shipping them back) or you need to do it yourself (it requires some tools like a chain whip and cog wrench). You also have to pay shipping costs to send the wheels back to them.<br><br>
thanks for the advice...my 1/2 course is fairly flat...but my avg. speed will be around 22mph...sounds like I could skip the wheels...and spend my money on something I can keep...any opions on wearing an aero helmet? Not sure I need to go that far...but I'm considering it.