[Del]

So I got my new bike today - awesome! I didn't have too much time to test ride it in the parking lot and when I got home I realized the outer wall of the front derailleur cage is rubbing against the chain when it's in both the small ring and large ring.

No big deal, I thought. I'll just adjust the two "L" and "H" screws on the derailleur and observe how it moves while I turn the screws. When the derailleur is moving away from the frame, I am doing it right.

Well I started messing with the screws but I didn't see the derailleur moving at all. In past experience the movement was clear. And now whatever I have done has caused it not to shift from the small chain to the large one. The cable leading to the derailleur is super slack too now, but I didn't touch the screw that clamps onto the cable.

Can someone help me with the tuning of my derailleur? I checked out some sites but nowhere addresses the problem that the derailleur simply will not shift. I'd take it back to the shop but they are far away and honestly I don't think I really want to do any more business with them.

I really wanted to go ride, too

Edit - I hope this advice comes fast as I am beginning to drink some beer.

 

[binary visions]

You cranked down the "H" screw way too tight. Back it all the way out.

 

[Del]

Okay I will try that - what about the L screw? I messed with both of them because I wasn't seeing any movement with the derailleur while adjusting them.

 

[binary visions]

Here's a much better description than what I can give you:

http://www.sheldonbrown.com/derailer-adjustment.html

That will walk you through setup. I was just trying to get you started on why the derailleur wasn't moving.

 

[Del]

Thanks binary visions, you are mighty!

 

[Del]

I was looking at this page and from Sheldon Brown's example it looks like the derailleur they put on my bike is for a triple chainring setup and I've got two rings. Does this matter?

My problem is that the H and L screws don't seem to be noticeably moving the derailleur. In past experience there was always noticeable movement when turning the screws. I've taken the H far out and it is still rubbing.

I just love paying to have my bike built up "professionally" so when I get home I have to work on it more before I can even ride it.

I'm contemplating bringing it to the bike shop closer to my house and having them look at it. I spend over a half-tank of gas getting to the shop that put this thing together so I'll have to spend money either way.

This wouldn't be a big deal if I was even .001% mechanically inclined but I am not.

 

[Wumpus]

Shimano service instructions for LX:

edit -- http://bike.shimano.com/media/cycling/techdocs/en/bikecomponents/FrontDriveSystem/SI-F650F_v1_m56577569830556709.pdf


More tech manuals

 

[binary visions]

There will only be noticable movement from the H and L screws if you're either at the top or the bottom of the shifting range.

Try using your barrel adjuster on your front shifter that adjusts cable tension. If you unscrew it, it will move the derailleur in the direction of the big chainring. Screwing it in will move the derailleur in the direction of the small chainring. Only use it for tiny adjustments, though, if you adjust too much you'll throw your cable tension out of whack and it won't shift right.

 

[sanjuro]

Another possiblity is the front derailleur position, which is one of the trickiest adjustments. The outer cage should be 1-2 mm above your biggest ring (the middle I believe on your bike), and the tricky part, the inside of the outer cage has to be parallel to the big ring.

The way front derailleurs are now, with slight ridges to improve shifting, will make this adjustment extremely difficult to get it just right. Now the instructions from Shimano will be critical because they will have diagrams which sometimes I have to refer to...

EDIT: And many shops will not touch the FD on a new bike install. It comes preinstalled on most bikes, and a bad mechanic will just do a cursory check. And if this mechanic did not test ride your bike, then he might not realize that there was rub.

 

[johnbryanpeters]

Another common mistake is to set the derailleur height based on the bash guard rather than the biggest chain ring...

 

[Del]

It comes preinstalled on most bikes, and a bad mechanic will just do a cursory check. And if this mechanic did not test ride your bike, then he might not realize that there was rub.

Or in my case the shop calls on Friday afternoon to say the bike is pretty much ready. All that is left to do is cut the steerer tube and bleed the brakes. I tell them I will be in Saturday morning shortly after they open shop. When I get there Saturday (3 hours after they opened), the steerer tube still had not been cut, the brakes probably were never bled, and the seat and seatpost weren't even put together.

So their mechanic definitely didn't test ride it. And because I didn't expect to have to wait 45 minutes before I could test ride it, I ended up short on time and didn't get to do a thorough ride. So yeah, I should have made sure of this at the shop but due to unexpected factors I couldn't.

In the end I wound up taking it to a shop which is much closer, cooler, and apparently much more competent than the shop where I bought the bike. If I was more mechanically adept it wouldn't have been an issue at all but because I am not I must rely on others.

Thanks all for the advice