Speedo re-calibration after re-prop?

2007 vlx. I recently upgraded to a acme 1235 prop (was 537) and now it seems that my speed is way off. When I used to run 23mph or so, I now need to run at what is reading 27-28mph. Using a gps app on my phone, I can see that I'm really only doing the 23 like I was accustomed to. Has anyone had this happen? Is it because of the new prop with a lower pitch? Do I have to recalibrate my speedo? How do you go about doing that?

no that doesn't make any sense.

if you're talking about PP speed, then yes you can calibrate

Yes I'm talking perfect pass (or the Malibu version of it)

Malibu and PerfectPass have owners manuals on line that tell you how to do it

Upgrade to GPS perfect pass and delete the paddle wheel...

Totally unrelated to the prop change. Speedometers are either pitot, paddlewheel, or GPS. Not sure how you'd calibrate on aVLX. On my pitot speedometer (Airguide) there is a knob you turn to calibrate it. It can also read off if plugged, but changing to a tournament flow through style pitot fixed any plugging issues I had. My other speedo is on the Perfect Pass and is paddlewheel, there is a calibration for that buried in the PP menus, I check calibration of both to my phone GPS once a year when I'm on a lake, or if it ever seems off I verify at slack tide on the river. Charlie, GPS is not an upgrade over a paddlewheel for anyone on a river, tidal water, or anywhere with a current. I've been anchored and seen my paddlewheel reading 10 MPH when turning the key on.

Prop change does not require speedo-recal. Not like changing tire size on a truck.