Re: Not really that fast
If your speedo is made for a smaller wheel, it will actually read faster than what you're going. I had a mechanical speedo that I bought from a bike shop and was told it could be used on a 24" or 26" wheel, but that was wrong. It really should have only been used for a 24" wheel. I had a 26" wheel, and when I checked it against gps, the mechanical speedo was at least 3mph faster than I was actually going. I've since bought a handlebar mount for my smartphone, and now use that for a speedo. If gps ain't accurate, nothing else will be.