| To read over your actual speed, you'd have to have the tire size too large, which on an adult size bike, you've only got so much room to do without exceeding the capability of the computer. Most will only go up to a tire size of 700c x ~55mm, if that large. If you're on a hybrid bike with 26" wheels, the smallest possible tire you could have is about 1.4 inches (smaller ones exist, but they're rare), the most you could possibly be off is about 15%, so you'd still be going about 26 (see here)
If your hybrid has 700c wheels (some do), you'd have to be off by less than that.
From a physically possible side of the argument, the answer is totally possible. If you worked it up to top gear on a downhill, even a slight one, you could do it. On my way too and from the office, I can average about 13.5 mph getting there, and 18 getting back, with no effort at all and the slope is barely noticable. With a little work, hitting 30 would be pretty easy.
Given a long enough slope, with good pavement and favorable winds, you can go a hell of a lot faster than even 30. I hit 45 once without even realizing it, and I wasn't pedalling. |
