Three eee (or however you spell/saythat) Urban bike has three or four broken spokes from heavy weight son bumping up and down kerbs (I suspect). Can anyone please tell me where I can get new spokes? Local bike shop is at a loss.
Where do I get spokes please?
- Thread starter Tracey Hinton
- Start date
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Deleted member 4366
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You need to know what thickness they are and the length from half-way through the elbow to the end of the thread before you can buy replacements, otherwise get them from 3E.
Spokes fail on hub motored bikes because of the extra tension on them from the greater power... Of course bunny hops and pavement jumping don't help.
There are plenty suppliers on eBay, including a few excellent UK based manufacturers. I got mine at a reasonable price on line from a UK source.
You need to extract a good spoke and measure it's overall length in mm , it's diameter and the length of the knee the little bended bit.
When you get them, it would be wiser to bring them to your local shop to fit and true the wheel.
The better eBay vendors have a look up tool for selecting them. They should also be supplied with the screwed ferrules. These are the bit which in mounted on the rim of wheel and tightens the spoke. The old ones, even if available may have a different thread.
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Deleted member 4366
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Jeez! Where did you get that from? How come I've never had a broken spoke in 10,000 miles using hub-motors that produce serious torque, despite using the cheapest spokes and rims I can find? Most of the guys on this forum have hub-motors. How come we don't get posts every day about broken spokes?
More likely, the spokes broke because some Chinese guy on piecework didn’t tighten them up properly and the owner never checked his/her spoke tension regularly like you're supposed to.
.. error on my part, should have used the word torsion not tension. There have been postings on this topic before, some to which you have contributed.The fault will occur in the swaged button the hub.
Remember, that earlier model hub motors will have larger diameter hubs, meaning that the spokes are shorter, and less able to flex. Whether human error , cheaper materials or additional strain are factors well God only knows.
I had almost a third of the spokes fail on my UrbanMover, over its lifetime, all on the hub. The wheel did still work, but was getting out of true, small wheels are stronger.
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Deleted member 4366
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So, your wheel fell apart on your cheapo Urban Mover and it had a hub-motor. Ergo, all wheels on hub-motors will fall apart. I bought a trekking bike from Halfords in 1988. It's wheel fell apart too. Ergo, don't buy a bike without a motor in the wheel, else the wheel will fall apart. That's the same logic.
Most electric bikes have hub motors. Wheels that fall apart are normally the back one. Most bikes with hub-motors have the motor in the back wheel. Most electric bikes with wheels that fall apart have rear hub-motors. They're the facts as I see it. You cannot conclude that a wheel fails because it has a rear hub-motor.
It's the same logic as saying that most cars are silver. Most car accidents involve silver cars. Therefore, don't buy a silver car because you're more likely to have an accident.
Most electric bikes have hub motors. Wheels that fall apart are normally the back one. Most bikes with hub-motors have the motor in the back wheel. Most electric bikes with wheels that fall apart have rear hub-motors. They're the facts as I see it. You cannot conclude that a wheel fails because it has a rear hub-motor.
It's the same logic as saying that most cars are silver. Most car accidents involve silver cars. Therefore, don't buy a silver car because you're more likely to have an accident.
Impeccable logic, however the UrbanMover was not a cheap bike it cost 1200 in 2007, and the wheel did not fail even with up to 10 failed spokes , it was usabl
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Deleted member 4366
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Here's some more of my impeccable logic: cheapo bike + expensive price = rip-off.
Oh well, live and learn!
Oh well, live and learn!
.. my logic goes along the lines of.
Why are the back wheel spokes more likely to fail... We agree on that.... Reason more weight, more strain , more torsional forces. Agreed?
Why do we use electric motors .. to increase the power beyond that which the average human can produce.
Where does that force be applied ... Oh the back wheel again., Except in the front hub motor variety.
How much is this force well typically 3 times what the human delivers.
.. I won't labour the obvious.
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Deleted member 4366
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Nice logic, but sometimes layman's logic doesn't get you to the answer.
Think about steering a bicycle. Logic says that you should steer the handlebars to the right to turn right. That's true on a trike, but on a bicycle you turn them to the left to go right, which seems to defy logic, though it's totally true.
You have to understand all the science and consider all the relevant interactions before you can draw conclusions. The logic in your hypothesis above conveniently omits some factors. If it were true, my Xiongda motor that gives massive torque and the BPM that I ran at 64v and 30 amps would have spat out their spokes, but both performed faultlessly, yet guys with 24v motors running 12 amps suffer loose and broken spokes. In my logic, that means that spoke failure can't be directly related to torque.
Think about steering a bicycle. Logic says that you should steer the handlebars to the right to turn right. That's true on a trike, but on a bicycle you turn them to the left to go right, which seems to defy logic, though it's totally true.
You have to understand all the science and consider all the relevant interactions before you can draw conclusions. The logic in your hypothesis above conveniently omits some factors. If it were true, my Xiongda motor that gives massive torque and the BPM that I ran at 64v and 30 amps would have spat out their spokes, but both performed faultlessly, yet guys with 24v motors running 12 amps suffer loose and broken spokes. In my logic, that means that spoke failure can't be directly related to torque.
.. Throwing the science card again, maybe I trump you there, but let's stick with known facts. Were the torque from your motor sufficiently high it would have ripped the spokes from the hub, or have sheared the spoke itself, so it wasn't. But it will create more wear at the swaged bit of the spoke on the hub than on the ferrule on the rim. What gives eventually and when depends on a variety of factors including the softness of the hub material, the flexibility and tensile strength of the spoke , and the quality of the construction. But all other things being equal, torque would be the variable.
Spokes work in traction, when it is compressed, it breaks. That is likely caused by loosened nipples.The shorter the spoke, the easier it breaks when compressed. That's why spokes attached to a hub motor break more than on the other wheel.
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Deleted member 4366
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That's it. Spoke tension is the key characteristic. If it's not enough, the spokes in compression go loose and the nipples will unwind a bit each cycle until the whole spoke is loose. That then makes the adjacent spokes bend too much under load so that they suffer metal fatigue at the weakest point and eventually break. That's why thin spokes give less problems than thick ones.
It's like the old engineer's problem with the bolt hole in the flywheel that makes it break. Layman's logic says that a smaller bolt will have less weakening effect than a bigger one, but that's wrong. A bigger bolt hole causes less stress concentration, so the flywheel becomes stronger.
Some people figured, using layman's logic, that the stresses were too high for the spokes, so they tried thicker ones, which ended up breaking more easily. There's more elasticity to keep tension in the spokes when you use thinner ones. That spreads the load more evenly and stops them from going loose in compression.
If you'd built a wheel with 12g, 13g and 14g spokes, you'd see what I mean. The 12g go from loose to fully tensioned in about half a turn. 14g ones can be turned about 2 or 3 turns after you take up the tension from slack.
Somebody probably applied layman's logic to the hub-motors. They figured that a motor would turn the wheel harder than a person, so they'd better use thicker spokes. Consequently, most motors are designed to work with 13g spokes, though 12g or 14g ones can be used without washers.
apparently, that law applies to marketing too.
You rubbish your own product to get people talked about it.
You rubbish your own product to get people talked about it.
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Deleted member 4366
Guest
Try it and see what happens. Just ride straight and push the bars to the right. Report back your surprise findings.
the result would depend on speed and body position which determine the centre of gravity. It is fair to say that it is easier to turn if the centre of gravity is inside the turning circle.
I'd been cycling for years before I tried this, you have to try it to believe it.
Dave.
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Deleted member 4366
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It doesn't depend on anything other than pushing the handlebar. It's simply physics.
While I'm at it, contrary to popular belief, you don't steer a motorbike by weight-shifting or leaning. It's all done by turning the handlebars in the opposite direction to your turn.
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