Modern Vespa

could someone please tell me what revs are at 30 mph on a GTS 250, thanks

The rpm at 30mph would, of course, vary greatly depending on whether or not it's a steady state on level ground with no wind, or more likely some other condition, like incline, wind, different total weight, acceleration, etc. I'm going to guess that in a steady state, 30 mph is a light enough burden for a 250, that the ContinouslyVariableTransmission would quickly "shift" up to its top "gear" ratio which would lower the rpm to around 3,000 (assuming the top gearing roughly puts peak power at 7,500 rpm near the top speed of between 75 and 80).

May I ask why you're asking this question? (It doesn't have a definitive answer...)

You may actually want to know something else.