I have to say that the 8.5 with 60a was quite surprising on sunday when cranked up but im not sure if they do an Ezrun 10.5. I didnt know Xerun existed in the range until joining this forum thinking that there was only Ezrun and then Speed Passion. Xerun do a 120a and 10.5 set which i would imagine would be pretty special for about £120/130 delivered off of Ebay.
I would agree that the gearing is a lot to do with it. I think that we will have to take the pinion down a couple as at the braking point for the end of our 25 meter straight its still gaining speed and therefore not reving out.