"Could swap for a bit if you want to see the difference as it has the option of shiing in daytime, if you prefer that"
It actually has a switch for that as well, so can have daytime running lights if I want (still don't know if the sensor works, was dull enough this morning that they were on, but I want to get out in brightness to see how good it is at sensing - in truth I guess you want them coming on before it's truly dark...
@wingpig - popping out at lunchtime, I'll swing by the bike and measure. The 42T is good for flat sprinting and downhill, but I think the 39T is more sensible, especially when the weather goes properly inclement and windy again. Oh, and I liked the look of the thermometer StemCaptain.
@Insto - cheers! Probably have the bits end of July, start of August (to give me a month's running in time).
@stickman - Nice to know I'm not the only one who ogles some of the bikes down there!