Hi everyone. I am currently running a nice chunky 400x19 mitas on the front of my WM20. As the original spec calls for a 325 i'm wondering how much this is throwing my speedo out by,ie when it's reading 30 am i in fact doing 35.Has anyone done any speed checks whilst running these larger profile tyres?.

email (option): michaelggilbert@btinternet.com

I ran 400x19s for a while..but I didn't check the speedo readings. Anything that makes you think you are going faster must be good though ...Ian

Dunlop quoted Radius-under-Load figures of 12.65 inches for a 3.25x19 tyre on WM3 rim, and 12.9 inches for a 4.00x19 tyre. The difference is only 2%, so make sure the speedo reads a genuine 102mph before claiming to do have done the ton

Chris J