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-   -   "trying" to replace a cable for front derailleur (https://www.bikeforums.net/bicycle-mechanics/627760-trying-replace-cable-front-derailleur.html)

velocifish 03-11-10 02:09 PM

"trying" to replace a cable for front derailleur
 
I bought a Se.kai with Sun.Tour derailleur, however, the front derailleur does not shift. I've been looking at it and it seems to be the cable. Today, I attempted to remove the cable hoping I can replace it. But the cable seems to be integrated. Am I correct? Or perhaps there's a way to remove it and I just don't know.

http://photos-e.ak.fbcdn.net/hphotos..._4729108_n.jpg

http://photos-g.ak.fbcdn.net/hphotos..._4215392_n.jpg

http://hphotos-snc3.fbcdn.net/hs493...._3105396_n.jpg

http://hphotos-snc3.fbcdn.net/hs493...._3810478_n.jpg

http://hphotos-snc3.fbcdn.net/hs513...._2429901_n.jpg

http://hphotos-snc3.fbcdn.net/hs493...._7381121_n.jpg

Now, am I correct in assuming the cable is suppose to move freely through the rubber hose? Because it is not and is, in fact, the reason I feel the cable must be replaced. The cable seems to be "locked" in to a bracket on the frame near the front derailleur, and to the shifter itself. I have no idea how to take it apart short of cutting.

Please help!

jco1385 03-11-10 02:14 PM

it may be rusted inside of the housing. since you are replacing it, i'd cut it in front of each stop so you won't need to 'feed' the cable back thru it. and at the shifter, it should have a head on it that will just push out. hope i didnt lose you.

Panthers007 03-11-10 02:41 PM

Take the housing to a bike-shop and tell them you need it replaced. Ask them to cut it at the same length and include new ferrules (end-caps). And buy a new gear-cable. The following cut & paste are instructions for fixing a front-derailleur that it causing problems. The links will explain cables and all as well:
____________________________________________________________________________________________________ _________________


Take the cable off the FD. Now install it from scratch as per Park Tool Repair:

http://www.parktool.com/repair/readhowto.asp?id=75

And BicycleTutor:

http://bicycletutor.com/adjust-front-derailer/

When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.

It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.

Adding an inline barrel-adjuster can solve many problems with the cable coming loose - or being too tight.

Barrel Adjusters:

http://www.biketoolsetc.com/index.cg...rrel-Adjusters

JanMM 03-11-10 05:31 PM

As suggested by jco1385, if you cut the cable just below the shift lever, you should be able to push the cable stub through the lever, although in this case a squirt of WD40 or similar might be needed first.

roberth33tiger 03-11-10 08:56 PM

your small chain ring looks like toast in your pictures.

bigbossman 03-11-10 09:18 PM


Originally Posted by roberth33tiger (Post 10514181)
your small chain ring looks like toast in your pictures.

Not to mention the rear tire. A new cable might cost more than that bike is worth.

wrk101 03-11-10 09:24 PM

+1 Bike needs a lot of attention. Start with a new cable and housing.

Yan 03-12-10 03:09 AM

I wouldn't worry too much about the dry rotted gumwall tire. Ride it till it fails, but keep it on the rear wheel.

Kimmo 03-12-10 03:21 AM

The tyre will prolly be fine, but that chainring is toast. Which means the chain and freewheel almost certainly need replacing too...

oldroads 03-12-10 06:29 AM

Just cut off the old cable and housing. Your local bike shop should be able to sell you a new cable and housing for about $7.
Keep the old housing so you can cut the new housing to the same length.

The tire looks like it has a season left in it, as does that sharktooth chainring.

So, spend $7, DO IT YOURSELF, and ride the thing.

oldroads 03-12-10 06:30 AM

Replace the rear tire...

operator 03-12-10 08:08 AM


Originally Posted by bigbossman (Post 10514301)
Not to mention the rear tire. A new cable might cost more than that bike is worth.

I wouldn't go that far, but yes that bike has seen better days. If the OP is willing to put labour in and can get parts at at discount (re: bike co-op/kitchen type deals) then it may be worth it if the OP is on a budget. I would do a serious inspection of that dry rotted tyre there and be prepared to do it until it fails, or pony up the $10-$20 for a new tyre.

OP: The cable head is seated in the hole - simply push the cable through - if some idiot use the wrong cable then you will have one hell of a tough time getting that cable head to come loose - worse case is you drill it out.

http://www.cyclesuperstore.ie/shop/p...m/SL7900FH.jpg

rumrunn6 03-12-10 08:18 AM

I rode on a nasty tire like that once and it was fun (not) listening to the threads pop. I was lucky to make it home and I was pissed it cut that particular test commute short.

velocifish 03-12-10 01:31 PM

Wow! Thanks a lot for all the advice guys and gals. This forum is quite more lively than I expected. :thumb:

I've been doing a lot of reading, thanks to the links. I was at first really worried the cable was set permanently to the shifter housing, but it looks like they do come apart. Hopefully they aren't fused together by rust!

With regards to the small chain ring, it is toast. If I use that chain ring with the chain and put any pressure, my crown jewels are likely to feel the pain (found that out the hard way). However, the big chain ring and rear sprockets seem to be fine. I am hoping to only use the big chain ring. The chain doesn't seem to sit on the big chain ring correctly. Would the chain need to be replaced?

Man, I am sooooo super excited about fixing it up. Despite the 5 days of rain DC is getting, it is finally getting warm enough to ride. :D I wonder why I didn't pick riding up sooner!

helicomatic 03-12-10 01:42 PM


Originally Posted by velocifish (Post 10517367)
The chain doesn't seem to sit on the big chain ring correctly. Would the chain need to be replaced?

From the wear on the small chainring, and how poorly the chain is sitting on the big chainring in your pictures, the chain is probably seriously worn out, and you'll find the freewheel cogs are worn out as well. If you replace the chain, it'll skip over the cogs in the rear under load. If you choose not to replace your chain, you'll wear out the big chainring too.

If money is Seriously tight, you could put off the drivetrain replacement until it starts skipping again or your chain snaps, but it won't be a good time when it does. That rear tire probably won't last long either.

jco1385 03-12-10 01:43 PM

if you have a steel ruler, measure the chain. it should be 12" over 12 full links: http://www.sheldonbrown.com/chains.html (scroll to the bottom)

you probably need to replace the freewheel/cassette also.

Kimmo 03-12-10 01:53 PM

Measure 24 links of the chain under tension; if it's much over 12&1/16", you need a new one. The new chain may skip over your freewheel if you don't replace that too, or at least wear out too quick.

Pff to replacing the tyre, just cause the tan rubber's perished... it does nothing but protect the side of the casing from abrasion; Conti GPs have virtually no rubber there... I lost more than one with plenty of life left thanks to sidewall damage. Replace it only if it has any bulges or expands alarmingly as you approach 100psi. My Conti Supersports are so old and perished I was able to scratch off all the moulded-in writing off the sidewalls, but the casing and tread are just fine.

As for getting the cable out of the lever, hit it with WD40 and grab the cable just where it comes out with vice grips and twist in the direction the strands go. If that doesn't work, the cable may break off where it meets the end; then you should be able to punch the end out. Trying to drill it out from the other side would prolly be a bastard.

Al1943 03-12-10 02:09 PM

With that much rust on the frame and components it makes me wonder what kind of shape the bearings are in. Most likely you will need to clean and grease or replace and grease the bearings in both hubs, headset, bottom bracket, and pedals.

Al


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