Chas> best to start in high gear then?
Start in your big-ring, and c.2/3rds down the block.
Thurman Merman's top-tips for a successful '10':
I know i have to warm up thoroughly
For a ten, mate, you should arrive on the start-line dripping in sweat.
Go hard for the first mile, but NOT balls-out. Build up to a steady 'plateau' of near-max effort (just below where it hurts) and keep it there for the middle 8 miles. THEN go balls-out for the last mile.
Keep your cadence high.
Get your back as low and flat as poss, and keep your elbows and knees in.
Concentrate. Don't let your mind wander (this is easier said than done…)
Repeat the following Tuesday evening.
And if you can't taste blood when you've finished, you haven't tried hard enough.
And if you beat 21:14 I'll buy you a pint 😉