by TheDarkInstall on Tue Dec 13, 2016 3:13 am
This is indicative of a larger problem with carbon frame manufacturing. I imagine there are thousands of frames out there that are really out of alignment like this Trek, but because people trust the companies without question (and often actually go into defensive mode at the mere mention that something is not perfect!) the manufacturers continue to put out really bad quality stuff. This is great for the companies as they can put out junk and not have to bin half as much as they should be, so profits remain decent, but for the end user it is often a disaster.
I would urge all people buying a carbon frame to see it in person before you hand over your money, as once the deal is done, it is often very hard to sort it out and you are at the mercy of the dealer / manufacturer.
Stuff that can and does go wrong;
-Off center rear triangle like this Trek; check this in the shop by putting a Shimano Dura Ace wheel in it (Shimano Dura Ace wheels are constistenty the most accurately dished on the market). Measure the left and right distance from the stays and check to see if the brake bridge is centered.
-Non-parallel drop outs. Again, put a wheel in, the slowly close the QR lever and watch to see if both dropout faces meet the axle ends perfectly flat. If one or both meet at an angle, reject the frame. Do this on frame and forks.
-Run your hands over it and see if there are any dips, bumps, depressions etc in the surface.
-Check the paintwork for signs of reworking etc
-Headset; tighten it down slightly too hard then spin the forks round slowly in the head tube and check for tight spots. Any tight spot will mean the bearing seats are not parallel. Unlike metal, you can't machine out the carbon to be perfectly straight so reject of not spot on.
-Examine the steerer very carefully for depressions, and squeeze it hard all over to check for excessive voids. Also check for dodgy resin areas.
-Shine a torch inside all parts and check for stuck inflation bags and dodgy molding.