I know. It's a terrible cliche. Large bloke gets bike. Large bloke covers himself in Lycra. Large bloke gives it all up as a bad idea within six weeks. Large bloke puts bike on eBay.
But the fact of the matter is that I don't want to weigh 18 stone any longer. I tried going for walks, but the scenery didn't change quickly enough. I didn't want to join a gym, because, well, that just seemed ridiculous. So cycling it was.
I was quite sensible about the whole endeavour. I didn't get one of those racing bikes that weigh the same as a crisp packet. I got a sensible bike, with flat handlebars, so I didn't have to crouch down like a racer. The saddle is still like sitting on a razor blade, but I'm told you get used to that over time.
I am surrounded by people who cycle at a vastly different level. They come into work on a Monday morning and talk about the 80km they did at the weekend. They have bikes that seem to be made of approximately 12 carbon atoms that cost something equivalent to a Central American country's nation debt. They chatter about things like cadence and chainsets.
Meanwhile, I talk meekly about the pitiful miles I have done, sweating up the hills and extravagantly crapping myself on the way down again. I don't mention the times I have to get off and push, my heart pounding like Santana's rhythm section while stars float in front of my eyes.
But I've gone and done it now, haven't I? Tomorrow morning I'm actually doing an organised cycle. The plan is that I'll do 30 kilometres (about 18.5 miles to you and me) which is a few miles more than I've ever done before. Real cyclists will be sniggering up their Lycra-clad sleeves already, but it's a bit of a big deal to me.
I'm doing this for the British Heart Foundation. I lost my dad to heart disease nearly six years ago, so it's a sacrifice I don't mind making. It's a worthwhile cause so any discomfort on my part (and distress caused to spectators as they watch this blubbery mess cycling around Solihull) is just a means to an end.
If you have a few spare quid, the link is http://www.justgiving.com/philsawyer2
I must be out of my mind.
