First, how do you know its choppy? Vegas preview? Playing rendered file with Windows Media Player? Dedicated media player hooked up to a TV? Playing back a high frame rate video can be very taxing on your computer system. If may actually be fine, but your system may not be playing it very well. System specs would be useful.
Second, what are your project and render settings? Again, screenshots would be the most useful way of providing this info.
Third, you may want to upload a small section of the rendered video. Just select a loop inside Vegas and render just that loop and upload.
Fourth, putting it on Youtube will be problematic. Because its skateboarding, you need a high frame rate to capture the action. Although Youtube now supports high frame rates, the playback may be choppy just because of slow internet connections. For YT, you could reduce the frame rate to 25fps, and see how that looks. If you try that, just remember to Disable Resample for your video events in Vegas.
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