profile and ground speed

[BikerBoy]

Corpse the difference is quite small - aprox +5km/h (on paper).
On street it's irelevant - PSI, compounds, friction, temps etc...change the equation.

If you're talking speedo accuracy - mines a +2T rear sprocket with a 55 profile and my speedo is +3km/h out (stock was +9km/h)

the http://www.gearingcommander.com/ website is good for figuring out this sort of stuff.........when Tony is offline and out riding