jusy wondering what your prairies do for top speed, my 05 will do about 60 - 64, it depends on the the day as far as temp and that is on flat pavement. ive also have 6 ply itp 589 26" tires on it.

A normal Prairie 700 does between 65 to 69 mph stock, but seeing you have 589s they consume a lots of power from the engine. So, a 5 mph lost is normal in your case.

keep in mind that your speedometer is no longer correct, with the taller tire the speedo is registering a slower speed than you are actually traveling, a 1" difference probably means around a 2 mph difference, then you have the extra rotating mass of the tires whichs takes away some of the power.

Of course, the speedometer was likely incorrect to begin with. If you checked it with a GPS and it was accurate, figure out the percentage change in tire height and add the same percentage to your final speed. So if your tires are 2% taller and your accurate speedo reads 64, actual speed will be 65.28.

FWIW, my 03 with stock tires and black spring being the only mod runs 65-66 (gps) on flat dirt on a good day. Low 60's on any given day. Aren't limiters great?