Originally Posted by
dawgcord
Im looking to cycle for fitness. Ive been a roadrunner/weightlifter/rugby player for many years, but I can tell, at age 38, that its starting to take a toll on my knees and shins. Dont really have an interest in racing, but I guess its possible I could develop one once I get out there. I appreciate all of your answers. Its really hard to resist the online temptation. I see alot of bikes on ebay for hundreds less than in the the LBS. Im located in an upper middle class sort of wealthy CT suburb of NYC(I am not however!), so Im sure they have no problem selling the bikes
Two things to avoid when shopping used, Aluminium frames and Carbon Fibre reinforced plastics. Let me explain the logic here.
Aluminium bicycle frames can suffer from what is known as fatigue failure, if you take a steel coat hanger and bent the metal rapidly back and forth it will break, if you bend it once per day for 5 years it will not break. If you do the same thing with a piece of aluminum and bend it once per day, it will still break. It takes many, many miles before this occurs, with a new bicycle it takes many, many miles before it breaks, with a used bicycle, it can be very hard to tell how many miles are on the frame, especially if some of the components like saddle, pedals, chainrings and levers, rims are not original to that bike, and there can be many reasons why those components are not original to the bike, other then wear. So a frame could have very little fatigue life left to it.
Carbon fibre can suffer from cascade failure, what happens in this case is that a person lets call him Joe Sleaze, has a bike and crashes it, takes the bike to the shop and they recommend replacing the frame due to the crash. The manufacturer will pay for a new frame, but not the labour to switch over the components, Joe figures for a little more, he can get a whole new bicycle, so he does, and then fixes the cosmetics on the crashed one, and sells it on CL or fleabay. You buy it and end up with the frame disintegrating under you.
Steel can rust, don't buy a steel frame bicycle that has been recently repainted, sometimes the reason it was repainted was to cover up rust. Ones that have older paint are safer.