Ride London 100

Blimey, when I said I was slow.... I didn't mean quite that slow, for reference to JazzyT, my average on the two Box Hill rides is a relatively sedate 15 & 16mph (over 66m & 44m respectively).

So the "advanced/Sky Ride", will not even make it in front of the 9hr sweeper on that pace!!!

My basic maths brane was thinking the same - if you are starting out cycling then that's a fair pace - if you're hoping to ride a fairly challenging 100 mile route in a few months then you're need to pick up the pace a bit!

this is worrying at me :/
distance I can do. speed... not so much.

To get round the route within the 9hrs you need to be doing a minimum 11mph (and no lenghty stops)

11/12 mph is sorta average london commuting in traffic pace. On clear roads I can do 14mph with very little effort when riding fixed, with gears I can maintain 16/17mph without too much effort.

The point I'm labouring Hoefla is that I'm slow but I'm pretty confident it wouldn't take me 9hrs to do 100miles - and I'm sure you aren't as slow as you think you are...do you have any bike computer/smart phone action. If you actually monitored/noted your speed I bet you'd be reassured.