Mostly its economics. Look who are the mfgs?
1) Almost all 'brands' outsource their mfg to the cheapest possible factories. And in, fact, there really is no accountability directly to the frameset. Like Crappendale, Truck, etc - it's a holding company that has acquired a commodity and just wants to monetize it. Everything they are presenting to you is marketing and very little of it is actually functional technology. The goal is to get the bike off the assy line as cheaply as possible.
2) At the same time - the large factories must adhere to certain ECO standards which logistically prohibit them from actually using the 'good stuff'. Its far cheaper to cut out the steps that incur hazardous waste and use materials that have less impact - yet, far lower degree of performance.
3) Conversely , the smallest makers struggle because they don't have access to the high end mfg process and even if their prdt is technically more advanced, the actual mfg may be even lower quality! So - somewhere there are makers that are putting together top quality prdts at commensurate prices and you do, in fact, get what you pay for. I'd say right now this is limited to a very few NA and EU 'brands' that have a very long history in putting wheels in the peletons. And some very small mfg's doing extreme custom components on a one-by-one basis, because they simply cannot scale their skill (like most framebuilders).
4) If you want cheap , AND Good, then I'd be looking more at the generic , 'no brand' approach and pay more attention to the factory from whence it came and the desired geometry than the sticker that someone put on it. The price will be such that you can ride it, crash it, toss it and no worries about replacement as an heirloom.
5) Back to John's frame - this kind of overall corrosion on various parts is more typical of environmental exposure than anything. For sure sweat can accelerate the issue (due to the electrolyte content), and same as the galvanic issues (like Todor mentions) - so, to take care of these issues, you just need to make sure the frame is washed, dried and properly lubed after each ride or several rides. And use some alloy shielding spray.. So here's where I give you some real tips:
1) Alu-Guard: This is common in the boat yards. I think you can even buy it at WesMarine. After you've thoroughly cleaned and degreased the alloy tube - then spray this on it.
2) T-9: Developed by Boeing - also known as Boeshield. This stuff really works. Again, degrease and spray.
3) Linseed Oil: One of natures wonder oils. Applies wet, dries sticky. We used to use this with a combination of paraffin wax and then dip a frameset into it to boil. The result is nearly 100% coverage of a very highly protective rust and corrosion guard. We also used it in a pressure sprayer (like for insecticide) and then just periodically douched the whole frameset.
4) There are aerospace solvent washes that will clean and self-etch. Like AeroKlean, etc. Here's a pretty good article on EPA recommended techniques.
http://www.epa.gov/ozone/snap/icel/aircraf2.pdf Bear in mind the most important thing is that after you've washed the machine, go out and fly it! The wind and vibration will dry it off. Never WASH AND SIT! I got my pilot's license nearly for free because I'd wash anyone's machine for free (including a short 'drying session') Built up lots of hours that way just making a few turns around the pattern.
5) Use some wax preventative on your finish. This won't help the bubbling (internal corrosion), but it will seal the coat and prevent some surface damage and of course scratches should be always be polished, touched up, then wax covered or sealed.
6) Galvanic issues can be mitigated by making sure you a 'zero ground' potential on your wiring - and if you are using the frame as one of the current paths, then adding a small sacrificial 'zinc' may be a good idea. Otherwise - isolate all wiring within a coax carrier and use teflon washers between any metallic parts that maybe serving as a conductor.
By the way - most of these chemicals and stuff are very common in the aerospace or boating industry. You can find most of this online at industrial supply sites or yachting supply for alot less then as a bicycle branded prdt.
What do I personally do?
1) I build Ti framesets - alot less corrosion resistant and trouble free especially for an island environment. And I do the linseed oil spray internally.
2) Apply a liberal amount of teflon grease onto everything I assemble to provide some barrier against moisture. I do this on all the hubs internally as well as headset bearing, BB and seatpost.
3) Wash my bike alot. I use a mild detergent (100y store dish stuff), then rinse thoroughly, then go for a ride a few times around the block. After that I'll usually hit the ends with some WD-40 or CRC to further displace any residual moisture.
Incidentally - you can get CRC Super Rust Guard at Donki. This is not the best CRC product (as with most rebrand or licensing in Japan) but it's ok and cheap enough. The best CRC product for this purpose is the heavy duty corrosion protection they sell primarily for boating industry.
Good post, Tim.
Yeah, there are a number of things about expensive road bike frames that still dumbfounds me; the latest one is the fact that they still don't (on the whole) use hollow dropouts.... Madness.
