I've been snooping on the boards for awhile now, and on Easter weekend, picked up a 2005 Trek 520 on Craigslist for $600. It's practically new and still had on factory grease on the chain. I took it to my LBS for a quick tune up and I've been riding around for the past few days with mixed results.
First off, it's definitely taking a while to get used to riding. I wasn't prepared for riding so low and tight. My last bike was a fat-tired, heavy mountain bike/cruiser type beast and it was a pleasure to ride. I guess I didn't realize what an adjustment riding this new bike would be! From the bar end shifters to the drops, it's made me a bit shakey and I've taken a bit of a psychological beating! I definitely plan on riding lots and I'm sure I'll get adjusted and find this bike a pleasure to ride after a while as well.
My main problem is with the gears. I've already had the chain pop off 3 times already because of the severe angle of the chain between my front and rear gears. It seems for stability's sake, I can only leave my front gear on the middle chain ring and the chain starts skipping if I go on the highest rear gear! I can't seem to get a nice momentum building experience on this bike! Should the crankset be replaced for something not quite so drastic? I really want a nice granny gear on my bike but I also like using higher gears for building momentum coming off a hill.
I'm not the most technical person, but I do plan on taking a intro bike mechanic course next month and I'd like to build a good relationship between me and my 520! Help this girl out.
Congratulations, that is a nice bike. Check out www.parktool.com/repair/. They have a great how to section on repairs and adjustment.
First, it is not a good idea to run the chain at large angles. Chains like to be straight. This is called cross-chaining. In the big ring up front, you generally shouldn't be on the big cogs in back. On the small chain ring, you should avoid the smallest cog on the back.
The chain falling off could be a result of cross-chaining, but it could be that the deraileurs also need adjustment. Your bike has a triple crank set, so it should have all the granny gear you will ever need. It is highly unlikely you need a new crank, just some minor tweaks.
You shouldn't loose the chain even when cross-chaining. I agree that you should always try to keep the chain straight as possible. Be advised that there is a big difference between bike mechanics. Ask around for those that have had great luck with a mechanic and take your bike there.
Thanks for responding, Barba! I definitely have to get used to the gears and using them properly, because I definitely want to stay away from cross-chaining, but I think it's a bit strange that the chain has popped off so regularly already. I don't plan on changing anything for quite awhile, but maybe some minor adjustments are necessary. thanks!
Your chain shouldn't be falling off when you're in the middle ring up front and on the smallest cog on the rear. You might get a bit of chain noise but that should be all. It could be other things (component wear, chain stretch, etc) but that doesn't sound likely so I would guess that you probably have a derailleur adjustment problem there. Easy to fix by yourself with some time, a couple tools, a guide of some kind (website/book/friend) and some patience.
If you go to MEC (there's one in Vancouver), you can check out a book called "Zinn and the Art of (Mountain or Road) Bike Maintainence." Two years ago I was exactly where you are now but that book, a bunch of tools and a dozen skinned-knuckles later... I can build a new bike up from parts. I'm not a pro mechanic by any means but when I'm on a long ride, I like feeling more secure just knowing that I can fix something if it goes wrong. That being said, I still swing by my LBS every now and then to get them to do some things I don't want to mess up or don't have the tools to do (cutting headtube, pressing cups, etc).
Collect some tools, gather some resources (books/websites/etc) and dive in. You'll be a lot more secure knowing how to fix your ride and you'l be a lot more confident knowing that you can handle most problems if they should come up. Don't worry too much because if you mess something up or can't get it back together, you could always 'walk' your bike down to the shop to get them to fix it. It might cost you a bit of money and pride if it doesn't go right but the possible benefits and experience far outweighs the downsides.
My guess is that you have some cables that have streched and now the deraileurs are out of adjustment. It is really not that hard a fix. If you go to a shop to have it done, make sure you ask them to let you watch and give you some pointers on how to do the adjustment yourself.
Great deal on your 520! I always liked that "beaujolais" color. With the 9-speed you have in the back, the chain alignment becomes more sensitive than older bikes with 7 or 8 speed, but you still have the benefit of being able to "trim" the front derailleur slightly to eliminate the dragging sound if nec. Nonetheless it is good practice to use the small front chainring (granny gear) only for the 4-5 biggest rear cogs, the middle chainring for all but the largest and smallest cogs, and the large ring only for the 4-5 smallest cogs in the back. Your chain deflection remains smaller that way - more efficient, less wear, and less rubbing/noise. I have lower gears in front than you but still end up in the middle ring for most of my riding.
First of all, great deal you got there. I have a 1994 520. Great bike.
You didn't say which way the chain is popping off the chainrings. In either case it is generally a simple limit stop adjustment on your front derailleur.
As for the rear skipping when you get to the higher gears, the cable tension is probably wrong. It is possible that the rear derailleur cable is binding a bit in the housing. In either case, very simple repairs.
I would take it to another bike shop and expect to pay about $15 to get these issues addressed. Maybe $20 if the shop replaces the rear derailleur cable and housing.