Can get it way off the clocks being un restricted and with sumo wheels on standard DTR speedo pick up, would imagine it would read about 90 if you could see it. But for several reasons I doubt it's near the actual reading.
I doubt it'd under read. Usually speed-o's over read, so when you're at 30MPH, you'd really be doing 25-28 MPH. Least that's what happened on my ped. It said I was doing 50MPH, realistically I was doing about 40-45MPH.
If mines under reading, I'm going to get disqualified and I'm getting tickets in the post. O_O