Bicycle Mechanics - Front DR issues
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07-10-03, 07:17 PM
Is it normal for a front DR to be a big pain in the butt? :mad:
Took the roadie out for a little spin this evening to test out the wheels (got them tensioned and stress-relieved) and the front DR was acting up. Shifted the chain right off the small chainring, it did.
Also, the shifter is kind of hard to shift. You really have to push hard to get it to shift to larger chanrings. The other direction, no problem.
BTW - I'm speaking of a Tiagra DR and shifter.
The LBS said that this is sort of normal with this type of shifter, and that it takes some break-in and getting used to.
Shfting off the small chainring means the limit screw is not adjusted properly. If it's really hard to push the lever to get the chain on to the big chainring, that limit screw might also not be adjusted properly. If the chain scrapes the derailleur and won't change into a higher gear, you may have too much slack in the cable.
The LBS should do an immediate tune-up job on the FD. Shimano are not fools, and this equipment is designed to operate right off the bat without any "break-in" that displays these sorts of symptoms, providing the adjustment is properly done (by the LBS) in the first place.
FWIW, a lady friend recently took delivery of a Giant OCR3. Her gearshifting was less than smooth. The FD cable was really slack. A roadside adjustment with the FD clamp to take out the slack had her changing smoothly and quickly in no time at all.
07-11-03, 05:53 AM
I'm annoyed at myself for not yet learning how to make these adjustments myself. It's getting to be an inconvenience hopping to the bike shop every time I need a tweak.
I think I'll do some reading and adjusting on my own today. :)
Barnett's Manual is a good place to start. Lots of reading, but you don't have to read every word. Just do it on an "as-need" basis. It's not quite the bible. Sheldon Brown's site at harriscyclery is good, along with the Park Tools site for referencing some of the more common problems. Barnett's tends to overdo the line drawings rather than show perspectives in photographic form, which the other sites do. It still can be confusing.
Don't worry, even the pros started somewhere, and that usually meant working on their own bikes, making a few mistakes and learning by them. Probably a couple of things to remember:
1. When disassembling something, use either a twist-tie to retain the parts (eg, cogs) in the order and direction they come apart, or make up a simple drawing as you dismantle. I'm am not well-disciplined in this area.
2. You *will* end up with a bit left over if there are more than five pieces to assemble. Don't worry. Just dismantle and start again. It's good practice and will take you half the time to do again!
3. Lubricate most threads with grease (to avoid corroding together). Exceptions are bottom bracket threads if you believe most advice (use Loctite in the blue variety).
4. Don't overtighten. Snug it down. Barnett's has good detail on torque settings. If you do enough of your own work, you can "feel" the torque automatically on your hands.
5. Don't force anything. If it isn't working as it should, there is a reason. Investigate why.
6. Undo anything with ball bearings in it over a bowl, plate, table with battens around it... anything to stop those pesky little things disappearing forever into carpet pile or some distant corner of the room.
7. Enjoy the challenges. The more you learn, the more self-reliant (and creative) you become!
07-13-03, 09:08 PM
Once in a while I work on my co-worker's Trek OCLV road bike, and her shifting is usually literally sticky from energy drink sloshing out of her waterbottle, down the underside of the down tube, and onto the cable guide under the bottom bracket, where it dries. Nice carmelization effect there :) and an attack with a hot, sudsy sponge is just the ticket, dissolving the sugary buildup.
I doubt your brand-new bike is sufferering from sugar buildup, but thought I'd throw it in for fun :) Do put a drop of lube where the cable rides in the guide, and confirm that it's in the guide and not riding off the side of it.
Great advice! I reckon sweat can do the same thing, too. I recently replaced a very rusty brake cable that ran under the top tube. I've also heard an ex-racer say he's seen bikes break a quarter of the way along the top tube after rusting through because of sweat dropping on to it.
So, piece of advice No 8: Clean you bike before working on it. Usually a once-over with soapy warm water (I use a dish mop with handle to reach all the crannies), and hose down with *slowly* running fresh water (I prefer a bucket). Clean the wheels/tyres well, too. You can check out things like BB guides and so on as you wash. Then when you've finished your work, a spray over of Pledge (or Mr Sheen here in Australia) will give quite a durable shiny finish.
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