Standing vs. high rpm for acceleration I've been working on my cadence for several months now, and I feel like I've gotten to the point where I'm more comfortable using high cadence instead of standing up when I want to accelerate hard.

At stoplights if I'm really gonna accelerate hard, I'll start in first gear and shift up when I get to 140-150 rpm.

I stay seated the whole time. I feel like I'm faster this way than I am standing up, but I'm not sure. Until recently, I've always assumed that standing up in a higher gear was the best way to put on speed fast.

Can someone provide data or logic that points one way or the other?
The only way to be sure is to measure. 

You can use an app such as Strava during the ride, then look at it's analysis later. It will show you how fast you were going at each point, and also gives an approximation of your power output.

We don't know what algorithm or assumptions it uses to calculate the power, but since it uses just one algorithm you can compare results for seated and standing sprints. Strava doesn't know what the wind speed is, nor does it know what your frontal area is (which changes when you stand), so the power values are not correct in an absolute sense. The speed measurements are more useful.

I would expect that you'll be producing most power at the higher end of your cadence range, 120-140 rpm.

In my experience a standing sprint is good for a short burst, rather than the extended acceleration you describe.

Using the higher cadence will be better for your knees over time.