Shift cables and front derailer messed up.

[jmd03]

Can anyone tell me where to begin when resetting the position of the front derailer and shift cables on a cheep older Walmart bike? I was trying to fix the scrapping of the derailer and shifting problems but messed up and loosened the shift cable bolt and can't get anything back. I loose the large ring or the small during shifting so I need to start from scratch...but where?

[nfmisso]

Follow these instructions: http://bicycletutor.com/install-front-derailleur/

[jmd03]

Thanks for the reply Nigel. That was the first place I went to and got the height set but I couldn't get the derailer to go far enough over to shift to the large ring. So I moved the cable...big mistake. I can't get both rings now, either the small and the middle or the large and the middle. Unfortunately, I messed with it so long that now the cable bolt is stripped and won't tighten so I can't even work on it till I replace it. Is there a special way to set the cable so it will allow the derailer to go out farther? The stop screw is already out as far as it can go without falling out. I can move it over manually but can't get the cable to pull it.

[cny-man]

You need to make sure the shift lever is in the low gear position (1 or no tension on the cable). Next, make sure the cable moves freely in the housing by moving it back and forth by hand, without the lever (and lubricate or replace if not). Finally, pull on the cable by hand at the derailleur clamp and tighten. You might have to retighten after moving the derailleur a few times with the lever, but as long as you have not changed the lever you will be able to reach the large ring.

It may be difficult to locate a compatible bolt. You may want to check to see if there's a bike co-op or other source that has used derailleurs, as that one's pretty rusty.

[nfmisso]

I picked up a couple of these for lowend projects:
http://www.amazon.com/Shimano-Fd-Tz30-Tourney-Bottom-Pull/dp/B002K2MMVQ/
They worked extremely well with Shimano M131 28/38/48 cranksets and SRAM MRX grip shifters.

[DaveM]

It looks to me like you have the cable clamped slightly wrong which may be making this worse. Usually the cable should run straight and vertical and too the inboard side of the clamp bolt. There will often by a light groove for it to clamp in or sometimes a little cross hatching on the clamping area to give it better grip. It won't make a huge difference, but if the cable is clamped too far out, moving the shifter will make the derailleur move less than it is supposed to.

[cny-man]

I thought it looked odd, too - but it looks that way due to the derailleur being on the large chainwheel.

[nfmisso]

(09-08-2014, 04:12 PM)DaveM Wrote:  It looks to me like you have the cable clamped slightly wrong which may be making this worse. Usually the cable should run straight and vertical and too the inboard side of the clamp bolt. There will often by a light groove for it to clamp in or sometimes a little cross hatching on the clamping area to give it better grip. It won't make a huge difference, but if the cable is clamped too far out, moving the shifter will make the derailleur move less than it is supposed to.

Good catch - also based on the view, it looks like the cable would have to bend over the cylindrical feature a bit below that attachment point when on the smaller chain ring.

But as CNY says; could be the angle of the photo.