I turned my 24-gear bike into a fixie for a morning ...

My chain is slipping. Whenever I accelerate hard, it slips, rattles, crashes, crunches. It's driving me nuts. I've fiddled about with all the settings, and relucantly realised it's because the spikey bits are so worn. But I also realised that on the lower two sets, and especially the lowest one of all, the wearing is less pronounced. So I decided this morning to stick to one gear the whole way - the lowest of the three, and the highest of the 8. And it became a "fixie". Without fancy pink tyres or those strange narrow handle bars. And it seems to be holding up.