You can see the hole that the cotter pin goes through on the side in shadow. Use the Park Tool Ruler to determine what size cotter pin you need. This is a cheap cotterless road crank. Notice that the hole in the middle of the chainring is square instead of circular. Cottered cranks attach differently to the bottom bracket. This is a closeup of the above crank. Notice how the crank is bolted together using ordinary hex nuts. If the crank were good, it would be bolted together using allen bolts.
This is a cheap mountain crank. The chainrings are steel and they are riveted together. They look sort of like they might be bolted using allen bolts, but an inspection of the back of the crank lets you know that they are not. Most of the bicycles I ride are fitted with cottered cranks, and have given me plenty of kilometres of problem-free service.
If you do want to change to cotterless I don't necessarily consider it an upgrade , I would think that a cartridge type bottom bracket would be ideal. I believe that they are sealed, and basically require zero maintenance for the life of the cartridge. Post by rkelsen » Tue Aug 11, am hartleymartin wrote: I find that the biggest problem when disassembling cottered cranksets is that who-ever did the assembly or maintenance didn't put any grease on the cotter pin. However, that only solves part of the problem.
If you put in some hard pedalling, the cotters being the softest component can deform into the little cavities that they don't normally fill, making them as difficult to remove as if they were rusted in.
In the past, I've had to use excessive force to remove cotters. I don't particularly like taking a hammer to my bikes. Post by Resg » Tue Aug 11, am With this particular bike I have been considering the 'restoration' vs 'strip and single speed' option, and I'm leaning more towards the SS option at present, because then things don't have to stay too original.
Since it wasn't top shelf in the first place i don't think i need to worry too much about preserving it. So that's influencing the choice of parts - if can make maintenance etc easier by replacing a couple of parts then I don't mind spending a little. Do i need to determine what size spindle i need? Post by rkelsen » Tue Aug 11, pm Resg wrote: Do i need to determine what size spindle i need?
Information from other souces, including this comprehensive and detailed PDF found in the Mountain-bikers workshop pages say that the pins should be free from grease or oil and should be cleaned with acetone or alcohol prior to installation, only after the pin is installed should some grease be applied to the stud threads before attaching and tightening the cotter pin nut.. Post by rkelsen » Thu Dec 09, am ch!
Post by master6 » Thu Dec 09, am This is a bike, not brain surgery. Forget the acetone, or you might cause something requiring surgery. If the cotter pins are dirty, wipe them with a rag. Just an average clean rag! No need to sterilise, deodorise, or pasteurise. Now wack em in, tighten nut, give em another hit, retighten nut, and get out and ride the thing.
Those who are a bit fussy will have checked to see that the cranks are at degrees to each other after finishing the nut tightening; a far more important matter than what type of perfume to put or not put on the parts. If the cranks are not at degrees, think. Think again. Do you have a bench grinder, or a good flat file.? You now have an interesting task ahead, which I will not descibe here as I would expect that the pedantic author who suggested acetone will have already covered this matter.
If not, he must wank acetone! K serar serar. Shimano introduced the first such crankset with its One-Key-Release system. Other manufacturers offer similar units. All work the same way. Instead of the customary 14, mm or 16 bolt, these cranksets use a bolt with a 6, 7 or 8-mm Allen head. This has two advantages: the necessary tool is small and practically weightless, and the Allen head can be exposed through a small hole in the dustcap.
Crank which removes without a puller. Unscrewing the fixing bolt presses it against the dustcap. The steel dustcap functions as the "nut" in a standard crank puller, and when you're removing the crank, the fixing bolt functions as the crank puller's "bolt. This system is particularly well-suited for touring and for air travel when you need to remove either the pedals or the cranks to put your bicycle into a box.
You can adapt other brands of cranks to this system by replacing the dustcaps and fixing bolts. Retrofit kits will work with all Type I spindles that use a bolt to hold the crank to the spindle and cranks with 22 mm dustcap threads.
Crank bolts which have an Allen head but are not one-key release generally have a plastic dustcap which is attached to the bolt instead of the crank. Any self-extracting system has a dustcap with slots as shown above or holes for a pin spanner so the dustcap can be threaded into the crank. Extractor threads can get stripped out -- see warnings about compatibility earlier in this article.
Or, you may have to remove an older Stronglight, TA, Campagnolo or Lambert crank and not have the necessary crank puller. A small automotive gear puller can remove a crank. This tool works like a crank puller, except that instead of threading into the crank's extractor hole, it has three hinged arms that hook around the back of the crank.
On a right crank, the arms should attach near the spindle so the pull doesn't tend to bend the spider. Getting a gear puller started, especially on a right crank with four or five arms, may require three or four hands to hold all the parts in place.
You may need to remove the chainwheels first. Expect that the crank puller will blemish the rear of the crank. You might also heat the crank. Aluminum has a higher expansion rate than steel, and you may be able to tap on the back side of the crank and loosen it using a hammer and wooden block.
A crank with stripped threads can be reinstalled as easily as any other. If you are working on your own bicycle, you may decide to reinstall it, but removing it later is not a job you would want to pass off on someone else!
Before replacing a crank, check it for cracks starting to form. They could be at the corners of the square hole, at the pedal hole or in mid-crank. They lead to in sudden failure, and very likely, a crash. The size of the square-tapered spindle ends varies among brands and models, and so, not all spindles are compatible with all cranks. If you are using a new crank or spindle, install the crank loosely and make sure that they mate well. The crank will pull in by about 2 mm when you tighten it, and so the end of the spindle should be recessed by at least 3 mm inside the square tapered hole in the crank.
The back of the crank should easily clear the end of the spindle's tapers and the bottom-bracket. At this time, you may also check the chainline, remembering that it will be a couple of mm closer to the frame once the crank is tightened. See the article on bottom-bracket tapers for more detailed information and advice. Also see the articles on chainline. Grease the threads of the fixing bolt or nut.
Also grease the splines of a splined spindle. Much ink has been spilled about whether to grease square-tapered spindles. Jan Heine of Bicycle Quarterly magazine performed an experiment , voted for grease but indicated that some cranks will have problems, greased or not. The tide of opinion seems to be with light greasing. A square-taper spindle will go on any of four ways, but if you have marked it as suggested earlier, then you can put it back on the same way, and it will not have to adapt iself to the spindle again.
You need to make sure a splined spindle and crank match, as there are different kinds. A splined spindle has one spline different from the others. Align this with the corresponding notch in the crank, or you will ruin the crank.
If you are replacing a bolt-type spindle with a nut-type spindle, then at your next rebuild, you will need a crank puller which doesn't interfere with the nut.
Also check that the boss on the end of the spindle doesn't prevent the dustcap from threading in all the way. It is best to avoid using a nut-type spindle entirely with an older Stronglight, TA Lambert or heresy! Campagnolo crank that can't take a standard crank puller. The shallow angle of the tapered square hole multiplies the force from the crank fixing bolt or nut by many times.
The bolt or nut will continue to turn for half a rotation or so after it first snugs up, before it reaches full engagement and starts getting much harder to turn. Don't use all of your strength. Preferred torque wrench readings are in the range of inch pounds, and a torque wrench is recommended if you don't have well-calibrated hands -- especially with splined cranks..
Cranks tend to loosen after first being installed. They should be retightened after the bicycle has been ridden a few miles. They may loosen again; an early warning of this is a loud "crack-crack" noise with each turn of the cranks. If the bicycle is ridden much at all with a loose crank, the spindle hole will become enlarged and misshapen, and the crank must be replaced. It is a good idea to carry a wrench to fit the crank fixing bolts. However, loss of crank bolt preload is normal; repeated, routine re-tightening is not recommended.
One role of dustcaps is to capture the fixing bolts so they don't fall out and get lost. This can happen without the crank's coming loose.
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