Won't changing to a 70 profile front tyre affect the speedo reading?

One would presume the speedo will be a little down, but the same can be said if your tyre is worn, under inflated ect. But then again the speedo is only accurate when going in a perfect straight line. Ever noticed how the engine revs pick up when you lean into a corner? This has the same effect on the speedo drive so it will almost never give a true reading.

Reason i ask about the speedo reading is because my 3TJ has a 70 profile front and the bike can hit 190kmh max speed on the speedo in 4th gear, so obviously 2 gears to go, don't think its very accurate at all

Dont think it would make that big a change!