Hello. About a fortnight ago I started building my own single-speed. I've never built a bike before but I'm loving every second of it and I'm very excited for the finished product! I just have a couple of questions.

I picked up an old Raleigh Sirocco from ebay for £20, and I managed to pick up some drop handlebars and a seat post from Freecycle. Problem is the seat post is too small, and I need to buy a stem, but I don't know what sizes I need.

Do any of you know any tricks for measuring, or even the exact size seat post/stem I need to get hold of? From what I can find online it seems to be a 27.2mm seat post and a 22.2mm stem, but not everyone agrees.

Any other advice you might have would be welcomed!

Thanks in advance!