WHEEL PARTS SALVAGING
This basic tutorial will demonstrate the disassembly of a typical multi-speed rear wheel that includes a Shimano type threaded freewheel. This type of freewheel and steel hub are often used when creating a custom bike or trike because you can easily modify the hub and adapt the freewheel to an axle. Shimano type freewheels are easy to identify because they have an inner spline, which you will see through in this tutorial.
To completely disassemble a wheel into its individual components, you will need several basic tools and one custom tool. Two wrenches will be needed in order to release the cone nuts or the hub nuts from a slightly rusted axle: one to hold the axle from spinning and the other to loosen the nuts. You can also purchase a cone wrench that will allow you to grip the small collar on the cone nut and remove the locking nut on the same side of the axle.
The other tool is a custom made freehub spline tool that was made by filing down a bolt to fit snugly into the freehub spline in order to turn it. The bolt is welded to a steel arm or rod to gain leverage (I used an old steel bicycle crank). You can also purchase a freehub spline tool at a bicycle shop, but the homebuilt tool works just as well.
When you are known as the neighborhood bike building person, you will often receive all sorts of bike part donations from friends and neighbors, and many times, you will find a lot of surface rust on bolts and exposed steel parts. Fear not - surface rust can usually be cleaned up with minimal effort, and even the most badly twisted or rusted cycle will yield an abundance of reusable components for your own designs.
If you cannot unscrew the axle nuts by hand due to a damaged thread or surface rust, then you will need to use a pair of wrenches in order to hold the axle from turning as you loosen the hub nut. Place one wrench on either lock nut (the nut closest the hub) and then loosen the axle nut by turning it in the counter clockwise direction. If the threads are well worn or rusted, you may not be able to remove the axle nut on either side, which means that you will have to cut the axle in order to salvage the hub or freewheel. In the case of a really stuck nut, the cone nuts and locking nut bay start to unscrew instead. If this happens, try the axle nut on the other side instead.
Once the axle nut has been removed, most of the surface rust will have been removed as well since the nut will cut a new path through the rust and grime, leaving the bare threads. One way to clean up a rusted axle or one with slightly flattened threads is to run the axle nut up and down the threads a few times by screwing it on and off, making it act like a thread cutter. The remaining surface rust can be removed using a wire brush and some Varsol once the axle nuts have been removed.
The next nut on the axle is the locking nut, a flat nut that sits on the outer face of the cone nut to lock it in place. Since the cone nuts also include a bearing race, it is important that they are held in place on the axle to maintain the correct tension between the bearing face and the ball bearings. The entire weight on the axle rides on the two cone nuts, which sit on the ball bearings. There are two ways to remove the locking nuts: by using a cone wrench to grip one of the cone nuts or by using a second wrench to hold one locking nut as you loosen the other. Most of us do not own a set of bicycle cone wrenches, so just use a pair of wrenches to loosen one of the locking nuts by turning it in the counter clockwise rotation as you hold the opposite nut from moving with another wrench.
If you are using the two wrench method, then it will be random as to which of the locking nuts comes loose. If you loosen the non-freewheel locking nut then it is easier to pull the axle because as you will soon see, the freewheel cone nut is buried beneath the face of the freehub where a wrench cannot reach. Either way, you can certainly remove the locking nut once it has been loosened as the axle threads should now be fairly clean.
As luck would have it, I managed to get the freewheel side locknut free from the axle, so now I have the added challenge of removing the cone nut that is sitting in the freehub opening where a wench cannot fit. You can't even use a socket on the cone nut since it only has two flat sides, but not to worry, there is always a way. Also, note the spacer found between the locking nut and cone nut to allow the locking nut to clear the outer face of the freehub.
Since no wrench will fit in the freewheel hole to grip the cone nut, you will have to find other means to hold it in place as you turn the axle in the counterclockwise direction to unscrew the cone nut. If you have needle nose pliers that are small enough, you may be able to grip the flat sides of the cone nut, but a flat head screwdriver will also do the trick. Place the blade against one of the flat sides on the cone nut and then spin the axle to unscrew the cone nut. Since the axle will be clean from being under the spacer, the cone nut should easily unscrew with minimal friction as you hold it in place with the screwdriver and spin the axle in the counterclockwise direction.
The cone nut is shaped like a cone on the side with the bearing race, and you can see the area where the balls roll; it will be the well worn light colored track near the end of the cone. If this area is badly rusted or cracked, then your cone nut will need to be replaced. When the cone nut is coming free from the hub, the ball bearings will most likely fall out since they do not include a retaining ring. Work over a bucket so you can collect the balls as they drop out of the race.
The axle parts removed from a bicycle hub consist of one axle, several ball bearings, a spacer, two cone nuts, two locking nuts, two axle nuts, and usually a few axle washers. If you plan to reuse these parts again, make sure that there are no cracks in the cone nuts and that there is no rust on the surface of the ball bearings. If the ball bearings do not shine after a cleaning, then they are no good.
A thread on Shimano type freewheel has an inside spline that needs to be gripped in order to unscrew the part in the counter clockwise rotation. You can't just grab the sprocket teeth and try to unscrew the freewheel since it will just ratchet backwards as it is designed to do. The inside spline is like a bolt turned inside out, so you need a tool that is the opposite of a socket in order to grip the spline. Bicycle shops sell freewheel removal tools, but you can easily make your own removal tool for next to nothing using a bolt and an 8 to 12 inch long piece of steel rod or pipe.
This is my home brew freewheel removal tool, made by welding a bolt to the end of an old steel bicycle crank. This tool is now 15 years old and has removed more freewheels than I can even count. The bolt chosen was one that was slightly too large to fit into the freewheel spline so it could be ground down using a flap disc to fit tightly into the spline. Since you need a lot of leverage to remove a stuck freewheel, an 8 inch or longer arm will be necessary in order to crank out the freewheel.
The bolt is ground or hand filed on the flats until it fits tightly into the spline in the freewheel. With five sides, the bolt will be plenty strong to torque out the freewheel, even if you have to pound the end of the lever with a hammer, as often is the case. Weld the bolt around the threaded area using a good solid bead so that it can withstand the punishment of being cranked and hit with a hammer.
To use the home made freewheel removal tool, place the bolt over the spline (with the axle removed) and then tap the bolt into the spline. The bolt should fit tightly into the spline but not so tight that is has to be pounded in. A store bought freewheel spline tool will drop right into the spline and can be handled with a crescent wrench. I think it's actually easier to remove a freewheel using the home made tool than the store bought tool since you can't pound away on the store bought tool without damaging your wrench or cracking the tool itself.
Once the freewheel removal tool is inserted tightly into the spline, give it a good crank in the counter clockwise direction to see if the freewheel will budge. It probably won't! You need to hold the rim between your legs and then pound on the end of the handle with a hammer in order to get the freewheel to loosen from the hub. A few good whacks should get it to turn and then you can remove it the rest of the way with minimal effort. Remember that the freewheel has been torqued on from years of hard pedaling and may be rusted as well, so expect a small battle here.
Once you have a good grip on the rim, place the freewheel tool handle in the parallel position and whack on it with a hammer, making sure that you are pushing the freewheel in the counter clockwise rotation so that it unscrews. If you don't want to scratch the rim, place it on a board or on top of a cloth so it is not bent or damaged from the force of the hammering.
The threads on the freewheel and hub are very fine 1.375" x 24 teeth per inch, which is why the part was so tightly bound to the hub. As you are probably noticing, the freewheel is a fully integrated assembly and it will be easy to adapt it to an axle for trike or quadcycle use, and this is exactly how it has been done in many of our plans.
Freewheel and axle parts are mostly interchangeable between different wheels, so you can repair one wheel with a damaged hub using the freewheel parts from another, or swap freewheels with different sizes of chain rings to alter the overall gear range of a cycle. Even a single speed BMX freewheel will thread onto the hub in place of a multispeed freewheel, so always salvage these parts for later use, even if the rest of the rim is badly bent and of no use.
Hub threads are also common to all hubs that use the Shimano type threaded freewheel, and the steel hubs are of particular interest to this hobby since they can be cut and welded in order to create different drive systems for various home made vehicles. Our OverKill Chopper uses a hub like this that has been modified to fit into a wide car wheel, and our Viking Tandem Tadpole Trike uses these parts to create a unique independent crossover drive system so one rider can stop pedaling without interfering with the other rider.
To remove the hub from the wheel, you will need to remove all of the spokes. A flat head screwdriver is all you need in order to turn out the spoke nipples to remove the spokes from a wheel. You can actually customize your screwdriver to be a little more spoke friendly by filing out a small section from the center of the blade.
By filing a notch out of the screwdriver blade, any part of the spoke body that protrudes past the spoke nipple will not obstruct the screwdriver blade. Normally, you won't want any part of the spoke threads sticking out that far, but it can happen, and it is difficult to get a screwdriver blade into the nipple if the spoke is in the way. A hand file or zip disc can make a notch in the screwdriver blade as shown here.
If you intend to reuse the rim, then it is important to loosen the spokes a little bit at a time as you work around the entire rim so that the offset spoke tension does not warp the rim. Start at the valve hole and then turn each spoke nipple two turns in the counter clockwise direction until you have loosened every spoke the same amount. At this point, the spoke will all seem fairly loose.
With each spoke loosened by two or three turns, you can probably unscrew the nipples the rest of the way by hand, using two fingers to spin them from the inside of the rim. Once the spokes are loose, you don't have to worry about warping the rim, so go ahead and remove each nipple one after the other.
One hub and a matching set of spokes to go with it. There are many different lengths of spokes available, so screw the nipples back in the ends of the spokes and then keep them in a bundle so you have a complete set. Badly rusted spoke nipples or spokes should not be reused as they will not hold the tension properly once pulled tight.
The completely unassembled wheel reveals many reusable parts. Although this wheel was obviously left out in the elements for several years, most of the damage is only surface rust. This can be easily cleaned off using some light sandpaper, steel wool and cleaning solvents. I have yet to see a wheel that is so far gone that there wasn't something usable on it.
Start by degreasing the parts with a rag and some cleaning agent like Varsol. Sometimes the parts will come back to life as if new with just a little cleaning, but this is not always the case. Bearings and bearing races should always be cleaned thoroughly and checked for damage before re-using since these parts will fail if rusted or damaged. Steel parts will usually clean up nicely if the rust is not too deep, and light surface rust can be taken down using fine grit sandpaper or steel wool.
A wire brush is perfect for cleaning those sprocket teeth since the bristles will work deep in-between the teeth to remove old grit and dirt that has built up over the years. Place the freewheel on a flat surface and then run the brush along the teeth, holding the brush sideways so it works deep between each ring. Made of hardened steel, the surface rust will probably come off quite easily as you brush the part clean.
After a little work with the wire brush and a cleaning rag soaked in Varsol, the parts came out almost as good as new. All of the ball bearings retained their shine, so they were ready to be repacked and used again and the bearing races cleaned up with no signs of excessive wear or cracks. Even the hub shell looked almost new again after the dirt and light surface rust had been removed using the steel wool and a wire brush. Now, these parts could be reused in another human powered vehicle project.
Bicycle spokes are made of either steel or stainless steel. Stainless steel spokes may get dirty but will not rust, so they can be easily cleaned using steel wool or fine grit emery cloth. Non-stainless steel spokes will be rusted and are usually very low quality spokes, so they are not really reusable. If the nipples are rusted to the spokes, then they are probably no good and can just be cut from the rim using a zip disc and discarded. To clean stainless steel spokes, wrap a bit of steel wool or a scouring pad around them and pull them back and forth until the shine comes back to the surface.
Here are all of the wheel parts after disassembly and cleanup. There were certainly a good deal of re-usable parts salvaged from this otherwise junk wheel. In fact, the only part that will not go back into service is the rim as it was badly bent and of low quality. So, the next time someone offers you a bike, even a really badly beaten low budget bike, take it for parts as there is always something usable when you are doing your own human powered vehicle designs.
If you have a spare afternoon and a rim to play with, why not challenge yourself to pull it completely apart and then re-assemble it, spokes and all? Wheel building is a great skill to have, and it is not as difficult as you might think if you take your time and have a plan. So, recycle and reuse! There is no junk pile tall enough when bike building becomes your hobby!
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