1) they have hard to service cottered cranks
2) headsets are difficult to adjust
3) frames are never aligned at the factory
4) bearing grease is dried up
5) they have chrome steel rims
6) aluminum components are not anodized
7) spokes are plated steel
8) frame tubes are heavy low carbon steel
9) bb & fork threading is non-standard
10) they are usually over-priced
I've owned and restored about a dozen GP's over the years. They are not highly regarded but are fun to work on simply because of the flaws mentioned above. I have taken liberties with them that I would not have done with nicer bikes. I once crushed a GP head tube by trying to reinstall the headset cups with a home-made press. As a result of my experimentation, I have become a fairly proficient amateur bike mechanic. I find a great deal of satisfaction taking a neglected GP which was never great to begin with and turning it into a lighter, better riding and easier to service bicycle.
