Puch Prima Super 12

thehairs1970 Posts: 142
edited August 2009 in Workshop
I have a Puch Prima Super 12, year unknown but it is running 27x1.25" tyres so must be a fair vintage. I use the bike for a bit of road work when local conditions mean that mountain biking is not so good. I'd like to change the pedals, primarily, and perhaps the chainset, as the gearing is very high for Dartmoor. When I tried to fit an old pair of Shimano SPD pedals I had, they wouldn't go on. IS this due to a sizing change? If so, changing the chainset would help, but would I then encounter probs trying to get a chainset to fit. BB is currently square taper. Or should I sod it due to expense?