Bicycle rear derailleur, gear changer fix

The biggest challenge for us commuter is living in a hilly neighbourhood. Some of us have learnt to get the most from the gearing range instead of getting up off the seat for every grade. These days although no budget bike, Electric Power Assisted ( EPA ) bikes are now becoming common.

Personal transport every day becomes a lot of ware and tear. Building up a lot of kilometres commuting hilly religions gear changers get a lot of use. There comes a time the mechanism starts the habit of poor shifting response. It can be a sign of cable sticking problem developing. Before you read on cable sticking should be first ruled out.

Other than that, commonly budget types, become well worn. Large sprockets tend to stretch the derailleur to maximum twisting particularly the rear derailleur jockey wheel cage and hangers parts.

Bicycle manufactures stress their case in point as far as standard budget gear changers are concerned anyway, not recommending the use of the maximum large front and rear sprocket combination. The derailleur parts and chain are set at maximum stress twist, stretch and chain angle.

Minor chain link distortions start caused by a gradually twisting derailleur parts. Twisting jockey wheel cages  chains rub on the misaligned angle. Another source of chain link distortion is clunking gears specially moving upward from moving upwards from the smallest sprockets. It should not be ignored for to long. A sign is scared teeth marks on the tip of the teethes. Time to inspect the chain for signs of distorted chain inks before they get so bad will come apart. A slight twist will get worse in time.

A simple experiment with a brand new bike is a reasonable facsimile of what a any system should be.

The chain engaged with the largest front chain wheel and the largest rear sprocket. When the peddles are spun rapidly backwards in the freewheeling direction there will be no resistance. You should be able to spin freely quite a rapid spin with out jamming. Operating on the principle of a new bike action it's a reasonable guide of what we'd expect any system should be.

Gear change mechanism designs are influenced by the rear wheel drop outs, from competition racing and  mountain bikes to standard budget commuter to the non standard long stretched frame designs of tandem and cargo carrying capability bikes.

Competition race bikes tend to have small rear sprockets and very large front chain wheel designs. Standard budget commuter mountain bike tend to have a fairly large rear sprocket and front chain wheels. Competition models quite small front chain wheels.

Off the shelf stock budget defaulters are not really interchangeable. They certainly won't work on tandem and cargo carrying capacity bikes. Long tail cargo carrying capacity bikes need tandem derailleurs. Fitting standard budget types just won't work properly if not at all. Any brand will do so long as it compensate for the extra long frame. Searching the web or visiting shops for rear gear changers for the extra long tail cargo carrying capacity bikes be sure to use the search word term Tandem.

There is two types referred to the way they are mounted each one with their unique way of doing this. Common on budget bikes, hangers are built on the derailleur itself. They are typical budget changers mounted on the open C shape of the rear wheel drop out of budget bikes hanger and all. Standard budget bikes are standard enough the gear changers easy to get.

Alternatively hangers are often found built in as part of the rear drop out in the frame itself. Fasteners are built in the derailleur. Budget bikes tend to be fixed and irremovable interchangeable with off the shelf budget derailleur  while expensive bikes tend to readily removed for any need of replacement. Both are fairly common.

Standard budget derailleurs fitted to quietly bikes tend to be the wrong types specially tandem and long tail cargo fames causing gear changing inefficiency. Even only just working puts stress on the derailleur reverts in budget types holding the body together can be a significant cause of gear change inefficiency. The first signs of a twisting out of alignment is the habit of constantly adjusting the stop screws to stop chains from derailing at the extreme ends of the gear cluster. It also happens when the gear changing is constant copy with hill tertian cities and neighbourhoods

For the the screw on derailleur threaded hangers weakening threads will twist the derailleurs out of alignment. This is common with long tailed cargo bikes designs. Standard budget derailleurs won't work properly. Aluminum hangers are used in the event of a crash acting as a safety feature breaking away. Aluminum is always dodgy disadvantage. Just looking at aluminum threads side ways they cross thread.

The constant use of the gearing range keeps an on going weakening already weekend threads and twisting the hanger. Theoretically high tensile Iron and steel threads specially carbon fibber frames should cure the problem. But for preferred safety reasons aluminium is preferred.

Even occasional crashing of the rear gearing shouldn't be overlooked in the first place. Guided by the efficiency of back peddling freewheel new bike behaviour. The gear jockey wheel chain route condition is a reasonable derailleur and hanger guide condition. We should aim our repairs to close as possible to new bikes do.

Inspecting the tread of screw on changers don't over look dodgy looking threads when reassembling it because you will only make things worse in cross threading trying not to cross thread it when attempting to reassemble it. If you do with out new parts to get yourself up and running quickly again on hand you'll only regret it making things worse. Off the shelf standard budget spare derailleurs are not interchangeable to most bike certainly not the extra long length of cargo bike fames.

Trying to careful reassemble back on into a dodgy thread you will only have everything falling apart faster than you can put it back to getter again. If it doesn't matter to get going quickly again with new parts on hand you can't get yourself going again when ever you want. On gear cluster side of the drop there will be some form of unscrewing element provided where the hanger can be replaced with the new one.

All bikes except for some macho sprint and mountain  bikes have a spoke guard behind the rear gear cluster. Riding all the time in the largest rear sprocket large front chain wheel combination is the biggest contributor to the twisting gear derailleur twisting the hanger and damaging thread problem. Well warn changers  tend to catch the chain derailing off between the spokes and the largest gear sprocket.

Budget bikes tend to be clip on spokes plastic clip on's. In cold whether conditions they tend to get a bit fatigued brittleness. A twisted and well worn changer jockey wheel cages tend to clip the ridge of the guard chipping at it. In bad case ripping great chunks out of it. Any sign should be headed as a sign of worn derailleur and dodgy threads that soon going to let you down. If you won't to get up and running don't touch a thing treating it as inevitable you will be ending up having to by a new derailleur and hanger parts anyway.

When plastic bike guards get fatigued it's possible to break to peace's getting it out from behind the gear cluster. This is a sign of cold wet whether fatigue. Eventually the derailleur cadge dragging on the guard chips pieces off. The derailleur cadge is starting the habit of chipping off and eventual the risk of getting entangled in the spokes. If there is a persistent problem it should not be ignored when attempting to fix though adjustment. Time to replace the gear changer or hanger or both before they become a state everything made worse faster than you can fix it.

The following is assuming a brand new bike. It also an ideal case the deadlier should be the correct derailur for the bike. Don't ignore the signs of a sign of a warped warn out changer or and an on going cross threading in the gear changer threaded and the signs of the wrong type for the design of the frame

For both the front and rear changers adjust the smallest sprocket stop screw moving the derailleur inwards the chain just rubbing the derailleur cadge. Undo the inner cable fastener enough you can pull on the inner wire tail and retighten. As you readjust the stop screw back the slack will pull the cadge away from the chain.

The stop screws are like door stops preventing the chain from riding off the cogs into the spokes and the or jamming in the drop out stay. Changing different speed derailleur have a certain amount of  tolerance but most of the time not enough to prevent the derailleur to operate properly specially if modifying a10 speed frame to a 21 speed bike. The stop screw lengths can be effected where you may need longer or shorter screws. If you ride your bike in winter as much as you do summer odds are the wet weather has clogged stiff the changer

Not only in the changer mechanism but the inner wire cable sliding both ends of the outer cable. Neglected specially weather related a complete overhaul of the inner wire cable inside the outer to free the corrosion can often be necessary. Before you remove a derailleur set the handlebar changer engaging the largest sprocket, turn your bike upside down resting on the seat and handle bars and observe the "S" route though the jockey wheel cadge.

That is how you reassemble the chain route though the derailleur when you reassemble it. The most important observation the chain route should wrap well forward on the sprocket. It should not be straight. If it is the teeth of the sprocket can't engage the chain and you have extreme gear changing difficulties. When reassembling the derailleur you must make sure the stop screws are adjusted allowing the derailleur to run the chain well forward on the sprocket. Exchanging derailleur can off set this resulting in not pulling the chain forward on the sprocket resulting in a straight chain. A good dose of CRC spray concentrating on each end of the outer cable will free up the corrosion.

CRC won't immediately fix your problem but will in time free the inner cable. Spraying the derailleur with CRC often cures stiff nut and bolt anchoring the inner cable problems. A too oily derailleur attracts to much road dirt clogging the spring mechanism gumming up the efficiency of the spring function.

In the wet the oil is washed off leaving the grit behind. The changer needs to be taken off and the excess cleaned off ideally with petrol like motor mechanics clean excess oil from parts.  The springs need to be free to pull the derailleur pulling the chain off the largest sprocket to the smaller ones smoothly. There is also a back lateral movement. If it is the derailleur doesn't come forward the jockey wheel To avid grit clogging up the derailleur again lubricate with CRC spray instead keeping dirt from sticking to it. The same applies to the inner wire cables at both ends of the outer cable.