I know that 650c wheels are for the front, but thats it
Copper pipes do get build up from minerals in them over time also sweated joints break down and seep and leak. Copper gets brittle and sagging causes breakage and then there is hot and cold expansion and contraction, it takes it's toll on copper as well. So fifty years with a few repairs along the way is a pretty good estimate.
I have seen copper lines in older homes that get thin in the heat affected areas next to the joints. It looks like the copper was dissolved inside the pipe. I believe it is a water quality issue and does not happen everywhere. In some locations, 50 year old pipes look like new inside.
actually copper pipes fail most commonly from freezing. Freezing makes pipes expand to accommodate formed ice in the pipe. This expansion never shrinks, but the expansion causes weaknesses in the pipe walls. Eventually pipes that have frozen will split or burst, it's just a matter of time. 50 years is a conservative estimate. Copper pipes do corrode, and they can become victims of a process called electrolysis. Electricity can cause chemical bonds and molecular makeup to become unstable, thus causing weakness in pipe walls, or soldered surfaces. It is a safe practice to inspect under house piping at least once a year. Twice if you have experienced a hard winter freeze.
650c wheels are smaller diameter. There are many smaller framed bicycles that use 650c wheels both front and rear. 700c wheels are certainly more popular. Safety note: make sure that you have the correct size wheel for your frame if you want to use rim brakes, otherwise your brakes might not contact the rim and help you stop. Many states require a front brake on single/fixed gear bikes, and besides it's just plain smart. Power and speed are nothing without control;) For more than you probably ever wanted to know about wheel sizing, check the link below. Have fun!
