Hot answers tagged derailleur
20
The first rule is make sure the rear derailleur is adjusted correctly before adjusting the front derailleur.
There are three adjustments that you can do on the front derailleur:
Clamp Position
Low limit stop
High limit stop
Clamp Position
Here you can adjust the height of the derailleur, normally this is recommended as a 2mm clearance between the ...
12
A lot depends on the rider and what you mean by efficiency.
It is easy to keep a hub gear running well for years, but an unmaintained derailleur will become inefficient very quickly. A hub gear allows the chain to be fully enclosed, for all but the most dedicated cyclist; an enclosed chain will be more efficient as it will be cleaner and better oiled.
An ...
11
If you can, with the chain in one of the middle cogs in the back, shift to each of the front chain rings then your front derailleur is likely in proper alignment and adjustment. This question and answer cover how to adjust the derailleur if you want to learn how to do it yourself.
What you are describing, shifting to small ring in front and small cog in ...
11
Jan Heine performed some wind tunnel tests of "Real World Aerodynamics" a few years ago. A link to a blog post (and the results published in Bicycle Quarterly) can be found here. Those tests cover only one component (the aero drag component) of commuter-type bicycles vs. "racing" bikes.
If you want to make your own apples-to-apples comparisons of ...
10
I don't have an internal hub, but I want one for the following reasons: They are sealed and protected from the elements. They are nice for commuting because you can shift them while stopped... If you've ever stopped at a red light on a normal bike and struggled to get going again because of your gear, you can appreciate this. With an Internal hub, you can ...
10
There is no 'conspiracy' to keep friction shifters off the market just so that you have to buy the index shifters. It is simply a matter of supply and demand. Nobody in the OEM market wants friction shift gears because bikes with friction-shift simply do not sell. That leaves the after-market and you have a similar position there - the demand does not exist ...
10
A front derailer is a bit more complicated than it looks, and can be quite complex to adjust if you're starting from zero -- just having installed the unit.
There are five (and a half) adjustments --
Height, sliding up and down the seat tube.
Rotation around the seat tube.
Low limit
High limit
Cable tightness
Generally height is such that the derailer, ...
10
Yes, there is a difference between front chainrings for derailleur equipped bikes compared to bikes without a derailleur.
Basically a derailleur suitable chainring "wants" to fall off. It's designed so that the chain is happy to climb onto the gear and also fall off the gear. There are various ramps for the chain to engage into.
Non-derailleur chainrings ...
9
Worn derailleur pulleys (also known as "jockey wheels") will not cause excessive wear on a chain because they aren't made of metal.
Eventually, though, the bushings inside will become worn and the outer teeth will wear down. Park illustrates the latter progression in their article on rear derailleur overhaul.
As with many things in bicycle maintenance the ...
9
There are a number of reasons that the shifting on your rear derailleur is not working well:
The derailleur hanger (the bit of the frame that the derailleur bolts onto) could be bent. To check this look at the angle that the derailleur cage is at. When viewed from behind, it should be vertical, when viewed from above, it should be parallel to the ...
9
It depends on the model you get, but the efficiency is generally comparable. Derailleurs that are in really good condition and properly lubed will be more efficient, but marginally, and will often be less efficient due to real world conditions.
At least that's what the wiki says:
http://en.wikipedia.org/wiki/Hub_gear
I have one road bike with a 3x9 ...
9
Well I thought we needed an answer to this, so I just phoned the shop. He's a nice fellow (as you can tell from the vid) and said that his mechanic is convinced that this method works to free-up seized and corroded mechs. Apparently dousing it in something like GT85 and lighting it for a very short time boils in the lube, and works.
I assume that the ...
8
This type of problem has 5 likely causes, listed in order of elimination.
Bent dérailleur hanger, or Bent derailleur cage. (Your derailleur hanger looks straight, but the cage appears slightly twisted in the upper photo. Could be the angle of the shot, though.) Edit: This turned out to be the correct answer, after all.
Bent, twisted, or sticky chain link. ...
8
The spacing between 9 speed and 10 speed is controlled at the shift lever.
A 10 speed rear dérailleur will work with a 9 or 10 speed cassette and shifter. A 9 speed rear dérailleur is not compatible with 10 speed.
The width of the chain and the cogs is the biggest issue. The pulleys on a 10 speed dérailleur are narrower, and a 10 speed chain will not rest ...
8
No, you will need to get a whole new cassette, the largest 3 rings are connected to each other, you cannot just purchase individual cogs. You may want to get a new chain as you will probably need to make a chain length change with jumping from a 25T to 27T or 28T largest cog.
Do you know if you have the SS or the GS?
With the SS (short cage) you can go as ...
7
Typically you quote gear sizes in gear inches, very basically this is the drive wheel diameter multiplied by the ratio between the two gear cogs, traditionally quoted in inches.
Also sometimes mentioned is development which is the amount of distance travelled by one revolution of the cranks (the astute will notice that is going to be proportional to gear ...
7
From your photo, the left pulley (beefier, with metal bushing) is the top one, which goes closer to the cassette.
I know that because that's how things were in every shimano derailer I had over the years, and I think that makes pretty much sense, since the beefier pulley (the upper one) actually shifts the gears, while the bottom, thinner one is only an ...
6
The difference probably arises because there is more tension being exerted on the chain when you are cycling as compared to the bike being up on a stand.
The screws on the dérailleur (as you probably know) are for setting it to stop at the right place (ie not to come off either towards the wheel or off the small gear). Do you have shifters which move the ...
6
To add on to Mike's answer, slipping is probably due to your chain being old. As a result of your chain being old, it has probably worn down the teeth on the rear cassete (you should be able to examine it and see grooves and uneven wear on the gears you use the most). Replace both the chain and cassete, then get yourself a chain wear indicator and check it ...
6
Adjusting the rear derailleur is a matter of tightening or slackening the shifter cable so that the chain runs smoothly for all rear cogs. The easiest way to do this is using a barrel adjuster -- there's normally one where the cable runs into the derailleur and you may have another where the cable runs into the shifter or on the downtube for a road bike.
...
6
Some possible culprits:
cog and the chainring are not in line.
rear hub is not tight enough and twists under load (see 1.)
chain is stretched or cogs worn out - so the chain doesn't 'seat' well in teeth
what the shop says - chain not tight enough
6
Did you change the chain after the first derailleur broke? If the same chain was on and you're positive the derailleur didn't connect with the spokes, then the chain is a likely culprit. Another thing to watch out for is loose pannier straps (or anything else that could get caught in the chain and take out the derailleur).
6
Campagnolo derailleurs come in three lengths, short, medium and large.
To determine the size measure it. The centre to centre distance between the sprockets is 55, 72.5 and 89 mm and my guess is that you have a medium flavour rear derailleur...
How much are you selling it for, b.t.w.?
6
Trek had a bicycle a few years ago named "Lime" which had 3 speed automatic gearing. I don't think it sold well. It used a gearing system called "Coasting" that was created by Shimano and actually controlled by a computer chip from signals from the front hub.
"A dynamo is fitted on the front hub that gauges the revolutions of the wheel. It sends this ...
6
As you ride and shift your shifting cables stretch. You can take up some of the slack by turning your barrel adjusters counter clockwise. Eventually, you will reach the limit of what your barrel adjusters can handle. At this point you will need to loosen the bolt that holds your shifter cable to the the derailleur and pull in the slack, then tighten the ...
6
You will need a 10-speed cassette, 10-speed rear derailleur, and 10-speed right side shifter and a 10-speed chain to work with the narrower spacing on the rear cassette. There tend to be some compatibility issues with 9-speed derailleurs run on a 10-speed drivetrain (some people seem to have luck using 9-speed shimano mountain derailleurs with 10-speed ...
5
Jerry Coffin has correctly displayed it.
You can also see it in the context of a bare frame. In the pictured Salsa Fargo, with a black removable derailleur hanger at the rear dropouts, you can see the projection that hangs down with a hole in it. That's what the hanger bolt screws into.
5
Step 1
Clean the derailleur pulleys by holding the blade of your screwdriver against the sides of the pulleys and turning the crank. You can do this with the wheel in the dropouts, or with the wheel removed.
Step 2
Brush the dirt off of your derailleur using a combination of brushes with bristles of varying length and stiffness, like the ones in the ...
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