speedometer calibration is off

I've got a '96 S model with standard 13" steel wheels. I took my gps for a ride and discovered that the speedometer indicates about 5 mph faster than actual at 60 mph. So I got to thinking about this and a larger tire would theoretically fix this problem, perhaps like a 14" tire on the Si and VTEC models. So, my questions are: Did all models come with the same speedo, gearing, transmission or were they made differently to account for the tire size difference? and, is there anything I can do to recalibrate the speedo?
Thanks.

All speedometers are off +/- 3mph. Your GPS might be reading inaccurately too. Try clocking your car with another car and see what the difference is there. As far as I know, all the D series sol's had the same speed sensor so there may be some variation depending on tire size.

I did a little research on stock tire size:
'S' model 175/70-13 22.64" dia
'Si' model 185/60-14 22.74" dia
'VTec" model 195/60-14 23.21" dia

Therefore, the tire size can amount to only a 2.5% error while I'm experiencing an 8% error!

Has anyone else experienced this much of a difference? Is there anything that can be done about it?

You could try getting a new speed sensor - or getting one from a junkyard. If that doesn't help I guess you'll just have to mentally compensate all the time.

My speedometer on my 95 Del sol S model is off by exactly 5mph too. I found it out by timing myself on the highway numerous times. I attributed it to my possible engine replacement (d15b2), but I guess its more common. I do know Honda issued a recall on the late 90's and early 2000 Accords because of the same issue. It was suggested (but not proven) that they intentionally set them faster so the warranty would be up sooner, and save themselves money. I do not know if this is related or not. II dont worry about it because a del sol holds it resale value so well anyway, but may be something to look into. I dont mind it cause it keeps me out of tickets.