ACE, what you actually have on your T now are GL1800 Gold Wing-sized tires. (The front tire is the same size as a Valkyrie.) It's impossible to tell you exactly what you're speedo error is because the speedos on the T have a fairly wide ranged variance on them to begin with (something like 0-12%). To get the exactness of your speedo, I suggest that you do what I did; have a car that you know has the OEM tires on it to ride in front of you and have them drive at the most frequently used speeds (30, 45, 65, etc.) and see what your speedo says. Then you can calculate the mileage difference. I can tell you that your engine is now turning more rpm's than it used to, but the T can handle it.

Gary

"Life is not a journey to the grave with the intention of arriving safely in a well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow!!! What A Ride!!!"