hannahmontana

My rear de railer is not accurate anymore. By that I mean it seems to be landing between the gears somehow. It skips and shifts up and down when I pedal. In the past, my dad has always fixed these things but I REALLY want to do this myself. Is it hard?

If you answer please don't use inaccessible language, I am new to bike mecahnics. thanks

Panthers007

I would suggest starting with taking the rear-derailleur - RD - off the bicycle. And this means unscrewing the pinch-bolt that clamps the cable (pay close attention to how the cable is attached) from your shifters to your RD. Once you have this off, the idea is to clean it thoroughly - use WD-40 and an old toothbrush to get all the accumulated grime off of it. Some photos of the RD would be most helpful - so we can see if there is any obvious damage that will end up needing you to replace the RD altogether. If it's nice and clean and shiny, apply oil to all the moving parts. There are many oils (at a bike-shop) that will work. My personal favorite for this task is a dry-lubricant such as TriFlow Teflon lubricant. One drop to every moving part.

Now bolt it back onto your bicycles. Re-attach the chain* and replace the cable with a new one from your shifters to the RD and replace any cable-housing as well. Use the old housing as a guide of how & where to cut it to fit. Drip a little oil into the housing and wet a paper-towel with oil and pull the cable through this to oil the cable. Pull the cable taut through the pinch-bolt and clamp it down firmly. Now for the fun part - How to adjust your RD. Here are better instructions than I can give you without sitting across the table from you right now:

https://bicycletutor.com/adjust-rear-derailleur/

and

https://www.parktool.com/repair/readhowto.asp?id=64

For working with your chain, read these:

https://www.parktool.com/repair/byreg...mageField2.y=5

And this should about do it.

JiveTurkey

The most likely problem is that the cable has stretched. Before doing anything else, I'd suggest following the instructions in Panthers007's second link: https://www.parktool.com/repair/readhowto.asp?id=64

DOS

+1 to what JiveTurkey said. Completely removing the derailleur -- while a good learning experience if you are able to get it reinstalled -- is likely more than you need top do to get the derailleur working correctly. Follow the Parktool directions; installing and adjusting cables is not hard.

IK_biker

Besides what others already told you, I highly recommend you go to this site
https://www.bbinstitute.com/manual.htm
and download Chapter 32 for your perusal.

You'll learn a lot from that one, as long as you are capable of learning.

hannahmontana

hannahmontana

I had the thing half off before I saw the other advice. Man those parts are dirty! I had to go to work and had a terrible time getting the black crap off my hands. Is there a knack for that too?

Metzinger

Lots of products out there for that.
In a pinch, use a bit of laundry detergent.
Though it can sting a bit if your fingers are already raw from guitar playing.

IK_biker

Hey, I don't know you.... Hope you are of the capable ones.

As to your hands getting dirty, what I do is use latex gloves and discard them after the particular repair.

rumrunn6

Sounds like a simple cleaning & adjusting is in order. Depending on how old the cable & housing (plastic tube) is - you might find replacing them makes shifting dreamlike.

Replacing cables and housings is fun but a little dirty. You just need a good pair of needle nose pliers that also cut wire. When cutting the housings, you want a clean cut.

Panthers007

And that is exactly why you should NOT use needle-nose pliers with those crude snips on their sides. They will mash the cable and cause it to fray on the spot. You could easily need to go get another cable. Beg/borrow/buy real cable-cutters meant for cutting bike-cables and housing. And a trick to making the cut less likely to mush the liner in your housing is to make the cut with an old piece of cable inside them. Just be sure to remove it before proceeding.

Al1943

What Jive Turkey said.

rumrunn6

Um, OK who knew they had such a tool. Technique has a lot to do with it though - my cuts were fine. I'll keep an eye out for a proper bike cables cutter - it sure would be easier.

I do have a proper cable cutter though and it does a nice job on the wire cables. I bought it for hanging artwork, and was so glad to have it when working on the bike. Thanks for the suggestion!

Panthers007

Good cable-cutters - and you don't want cheapies from Harbor Freight or such - will cost some good money. But, if you care for them and not use them for cutting spokes or such, they will last you a lifetime. I prefer and suggest the one's from Shimano. I bought mine in 1984 - and they work perfectly.

If you're going to be working on your own bike - and maybe friends' bikes - these should be on the first-list of tools to acquire.

rumrunn6

Panthers007 - can you suggest a good 'housing" cutter?

Panthers007

The Shimano cable-cutters are deemed the best by many informal polls around here. And I concur. Cable-cutters - by default - are housing-cutters, too. Most mechanics around here dislike the Park cutters, and a few like the Felco (Swiss) ones which are the most expensive - $75ish. But many others dislike the Felco as well.

Last Analysis: Shimano wins.

rumrunn6

Just tried my Midewest cable cutter. It seems to do a good job. The hole for the cable is free and clear but still leaves a small straight edge. With the right technique with good pliers with a cutting edge and small hammer I get the same results. But the cable cutter took a millisecond by comparison.

+1 for good cable cutters. I got mine at Home Depot, but they're not cheap. I think I paid about $35.

IK_biker

Nothing beats a Dremel with a cut-off wheel for cutting housing.
It would trump even the best cable cutters out there...

Cable cutters are great for cables.

Panthers007

How in the heck does one manage to cut housing with a Dremel w/cutoff-wheel? How does one keep the housing from shifting and flying off? Please explain. I've got one of these tools and am trying to figure this mystery out.

hannahmontana

Ok, I was able to take off the derailler and clean it and put it back on. It still isn't working right, so i started looking the the cables based on what I have been reading here. And ohoh, there is a place where the plastic is worn right through and I can see the cable inside. And worse, the cable is rusty looking. Now what?

jack002

From post #2
and replace the cable with a new one from your shifters to the RD and replace any cable-housing as well

Note, RD means REAR DERAILLER, I know he didn't mean to, but thats 'bike forums speak' and not plain english.

IK_biker

1. Measure your housing, decide where to cut.
2. Hold onto the side you want to use (the other side you will discard), about 3 to 4 mm from the cut line
3. Put the housing onto a bench/table/any sturdy support, making sure the cut line is overhanging past the support's edge with a few milimeters
4. Hold firmly in place
5. Cut with the Dremel, making sure the cut line is perpendicular to housing's axis (or slanted if you prefer so, which sometimes comes handy for RD cable). Go slow, with minimum pressure applied.
6. Let the cut cool down for 10 seconds since the plastic liner may have partially melted
7. Use awl to make a conical opening into the plastic liner inside the housing (I use the sharp tips of a set of 2 very thin files - a triangular and a conical one)
8. Use an intact piece of cable suitable for this housing to make sure it passes through the opening you just made in the liner.
Done. Piece of cake.

Unskilled folks would want to mark their cut line on the housing. For me, after many applications, it's easy to make a distinction of 1 mm by eyeballing before I cut.
Find what cutting speed works best with what housing (brake/shifter/4mm/5mm) in order to minimize the melting of the plastic liner. The diameter of the cut-off wheel (new vs. used) affects this as well due to lower/higher peripheral speed.

Panthers007

Thank you very much - now I have a new toy to play with!