Rear rim and spokes for MAC hub motor?

[-dg]

It's not the size of the spokes causing them to break, it's the quality of the spoke and the wheel build.

The original statement I was replying to asserted that the 12 ga spokes were fine because the Chinese e-bikes use them and no-one complains. As far as I can tell, you are agreeing that the Chinese wheel builds are not very good and that people do complain.

You are additionally asserting the hypothetical that if they used better 12 ga spokes and built them more carefully then they would be good wheels. If so, why is this not more common? As far as I know, the only common bicycles with thick spokes tend to have bad wheels. Better bicycles with good reliable wheels tend to have thin spokes. If you are aware of a decent bicycle or wheelset that has 12 ga spokes as original equipment, please let me know, I've never seen one.

Finally you are asserting that it is possible to do a good wheel build with 12 ga spokes and a normal bicycle rim. It is possible to do a less bad wheel build, but a good build would require starting with suitably matched components.

 

[johnrobholmes]

We relace just as many wheels as we build new. They don't always have a broken spoke, but they are always loose with 12g because of the inability to tension high enough.


By in large the most heard complaint is the crappy wheel build from china.

 

[Monsoon]

@Chalo, the proof is in the pudding. there are thousands, probably tens of thousands of hub motor bikes in commission, with a damned good chunk of them coming pre-spoked with large gauge spokes.
and if it was that bad of a problem, people would be coming out of the woodwork on forums like this, causing a ruckus about broken rims, hubs, spokes, etc.

Dude! The common complaint about Chinese e-bike kits after wiring that does not match the almost non-existent documentation is crappy wheel builds, wheels that won't stay true, spokes loosening, and broken spokes. People are coming out of the woodwork on forums like this to complain about these things, but you've only been here for two days so you might not have seen that yet. Seriously, if you wish to make your case by appealing to popularity, the most common bicycle wheel for the past 50 years or longer has straight 14 gauge spokes. That's billions of wheels, not tens of thousands. A major reason for straight 14 instead of thinner or butted which are known to be better is that it is easier to initially build a wheel with thicker spokes and 14 ga hits the sweet compromise between warranty repairs and production cost. I'd even speculate that the reason the the Chinese build with thicker spokes is that they are less concerned with warranty repairs. .

Anyway, If you don't want to believe Chalo, fine, but read "The Bicycle Wheel" by Jobst Brandt first. Wheels don't work the way you think they do.

you were right about it until the detail about breaking spokes.
i've spent a lot of time reading up on this here and at other forums. and it's the looseness of the spokes that everyone has been mentioning, not broken spokes.

as far as thicker vs. thinner spokes, unless you were using bench top equipment, there would be absolutely no reason for a thinner spoke to cost more than a thicker one. ever.
even the double and triple butted spokes are no big deal from a production point of view. it wouldn't even necessarily add a second or third process depending on how well designed the machine would be.
i've been in manufacturing for over 30 years, i've got 15 years in machining, and i'm currently in forging. so I know this stuff in an out.
keep an eye on those chinese spokes you speak of. because if one of those places gets serious about building spokes, it's going to drop the price of quality spokes down to a nickel.

 

[Monsoon]

It's not the size of the spokes causing them to break, it's the quality of the spoke and the wheel build.

The original statement I was replying to asserted that the 12 ga spokes were fine because the Chinese e-bikes use them and no-one complains. As far as I can tell, you are agreeing that the Chinese wheel builds are not very good and that people do complain.

You are additionally asserting the hypothetical that if they used better 12 ga spokes and built them more carefully then they would be good wheels. If so, why is this not more common? As far as I know, the only common bicycles with thick spokes tend to have bad wheels. Better bicycles with good reliable wheels tend to have thin spokes. If you are aware of a decent bicycle or wheelset that has 12 ga spokes as original equipment, please let me know, I've never seen one.

Finally you are asserting that it is possible to do a good wheel build with 12 ga spokes and a normal bicycle rim. It is possible to do a less bad wheel build, but a good build would require starting with suitably matched components.

"better bicycles" in your instance = lighter bicycles every single time. think about that.

would a motorcycle be better with thinner spokes? no, of course not! the only reason we're having this conversation is because of the point that's already been brought up in this thread. the bike industry's obsession with lighter=better.

you want to see the best perspective you're likely to ever see for lighter=better being wrong?

you don't get better credentials than this guy.

http://www.youtube.com/watch?v=NF4MIEkIBZs

 

[wesnewell]

It's not the size of the spokes causing them to break, it's the quality of the spoke and the wheel build.

The original statement I was replying to asserted that the 12 ga spokes were fine because the Chinese e-bikes use them and no-one complains. As far as I can tell, you are agreeing that the Chinese wheel builds are not very good and that people do complain.

You are additionally asserting the hypothetical that if they used better 12 ga spokes and built them more carefully then they would be good wheels. If so, why is this not more common? As far as I know, the only common bicycles with thick spokes tend to have bad wheels. Better bicycles with good reliable wheels tend to have thin spokes. If you are aware of a decent bicycle or wheelset that has 12 ga spokes as original equipment, please let me know, I've never seen one.

Finally you are asserting that it is possible to do a good wheel build with 12 ga spokes and a normal bicycle rim. It is possible to do a less bad wheel build, but a good build would require starting with suitably matched components.

Totally agree that some wheel builds are really bad and use crappy spokes, but I wouldn't limit it to Chinese even though most come from there. And yes, if they used better spokes and built the wheels more carefully, they'd certainly be better wheels. They'd be better wheels with the same crappy spokes if they just tensioned them properly to start with too. What I disagree with is that smaller spokes make better wheels. It's a fact that smaller spokes are weaker, just like smaller bolts are weaker than larger ones, assuming made from same material. There's two reasons I can think of why smaller spokes are used on more expensive bicycles and it has nothing to do with their strength. The main reason is weight. The heavier the bike, the harder to pedal. That simple. The other reason is cost. Less material equals less cost. Same goes for narrow rims. Now if I were racing without a motor those extra pounds would matter. I'm not. I want a strong bike. I'm 270 lbs. Another 5 pounds means nothing to me. I want something strong, so I use 12g spokes on a rim designed for them that is 39mm wide and weighs more than twice as much as most rims with 2.4" tires at 65psi. Now I'm sure that good quality 14G spokes are better than bad quality 12G spokes, but made from the same material, the 12G spoke is a lot stronger. And all this crap about them stretching being better is just that. You don't want your spokes to stretch. When and if they do they lose their tension, come loose and put more pressure on adjacent spokes until something breaks. Not good.
And that all I have to say about this.

 

[cal3thousand]

Sounds like we need a wheel build off competition :wink:

 

[Chalo]

I want something strong, so I use 12g spokes on a rim designed for them that is 39mm wide and weighs more than twice as much as most rims

Right, if you are comparing against race/sport rims that are narrow. But guess what? Your rim is twice as big physically, so if it were twice as thick, it would weigh four times as much as a race rim. But it doesn't. The implication is that the walls are about the same thickness those of a race rim, which means you face puckering, cracking, and pull-out at the same tensions.

You don't want your spokes to stretch. When and if they do they lose their tension, come loose and put more pressure on adjacent spokes until something breaks. Not good.

This is the most correct thing you have said so far. Can you not see that thin spokes are better at this than thick ones? When I talk about spokes stretching, it's not stretching like bubble gum, but like a rubber band. But you have to keep in mind that in this analogy, the rim is made of softer rubber than the spokes.

If the spokes are too thin for the rim, then the rim moves around enough for spokes to go slack-- and a slack spoke is the same as a missing spoke, in terms of supporting the structure. Thus thick spokes constantly create the not-good situation you describe, where loads are transferred to other spokes or borne by unsupported spans of rim.

 

[Chalo]

as far as thicker vs. thinner spokes, unless you were using bench top equipment, there would be absolutely no reason for a thinner spoke to cost more than a thicker one. ever.

Thin spokes have to be made of stronger, more perfect materials than thick spokes. That's why they are more expensive. Butted spokes undergo further processing to thin them in the middle. That makes them more expensive yet.

DT and Sapim use intensively cold-drawn, vacuum degassed stainless steels for their spokes. Sapim publish the material strengths for their different spokes in the descriptions on their website, so you can go see for yourself that even their own spokes are not all the same in terms of material strength.

Cheap Chinese stainless 12ga spokes are made of the same stuff as Ikea doorknobs and Home Depot refrigerator veneers. That's why it helps them to be so thick. And it's why they still break more often than the good kind even though they are much thicker.

I am quite baffled why you think minimum-cost no-name Chinese manufacturers could possibly be doing better spoke design and engineering than DT Swiss, who have a long production history and reputation to uphold. DT Swiss does make a 13ga spoke-- but you know what? It's 15ga in the middle, because spokes for bicycles have to be thin to work worth a darn.

 

[-dg]

"better bicycles" in your instance = lighter bicycles every single time. think about that.

would a motorcycle be better with thinner spokes? no, of course not! the only reason we're having this conversation is because of the point that's already been brought up in this thread. the bike industry's obsession with lighter=better.
...
http://www.youtube.com/watch?v=NF4MIEkIBZs

"better = lighter every time"? Really? Where did I ever say that? Why would I say that? I weigh over 270 these days. I can assure you that a lighter bike is not going to be better every time. Plus also too, I'm a retrogrouch. Since you are new here, you may not have noticed that, but the signs are there. My ideal bikes are road and touring bikes from the Golden Age of Japanese Steel, aka the 80s.

My main bike is still a 1984 Specialized Sequoia (lugged steel sport-touring bike) that I bought new and rode across the USA and then did some more touring and a few years training with a racing club on it. Since then I use it for commuting, grocery shopping, errands, etc. It has fenders, a rack, panniers and typically 10 to 40 lbs of books or groceries or beer or something. I suppose it has on the order of 50,000 miles on it. It came with a set of Wheelsmith built 14ga wheels. I still ride the front wheel. The rear I had to replace last year when the flange pulled out of the hub. I did break a spoke touring the mountains in Idaho in the late eighties, but since then the wheels have been stable and have not needed more than trivial truing a couple times. The replacement wheel I built with 14/15 butted spokes. It has not yet needed any truing.

My other current bikes are -

- 91 Trek 950 (steel lugged rigid Mtn bike) thatI I found on Craigslist for $100 needing only a new chain and a bath. This will be getting a BPM and wide rims to run wide tires so I can pound along the pot-holed streets we have here. The BPM is currently loaned to spinningmagnets for his teardown and MAC comparison thread. Wheels will be Alex DM-24 with 14/5 butted spokes, the most bombproof I can make. I'm going electric because I've had some health issues that have slowed me down a bit and since I don't own a car, I need to keep my speed up or errands take too much time.

- Xootr Swift (aluminum 20" folder) which I just put a Bafang SWXU in. Wheels are Sun Rhynolite with 14/15 butted spokes except the front motor has straight 14 ga because butted ones are not available that short.

I raced an aluminum Trek for a couple years in the late 80's. It was ok, but I did not keep it. I shattered a deep aero rim on that bike by hitting a hole in the road on a descent. No broken spokes. I've broken a couple of frames on other bikes, but still no other spokes.

I do not believe that carbon fiber is a good material for bicycles or any safety critical items that are not regularly inspected. Fine for aircraft Inspected) or tennis rackets (non-critical), but bicycles lead hard lives and get little care. Carbons failure modes don't really mesh with that.

I've built several sets of wheels over the years, all are still in service, almost all are i4/15 butted. The only wheel that ever needs attention is the first one I built. I should probably retension it correctly as it has a couple of spokes that tend to loosen.

 

[-dg]

I want something strong, so I use 12g spokes on a rim designed for them that is 39mm wide and weighs more than twice as much as most rims

Right, if you are comparing against race/sport rims that are narrow. But guess what? Your rim is twice as big physically, so if it were twice as thick, it would weigh four times as much as a race rim. But it doesn't. The implication is that the walls are about the same thickness those of a race rim, which means you face puckering, cracking, and pull-out at the same tensions.

Exactly. For example, Sun RIngle specify the same spoke tension for all of their rims, from the narrowest lightest road rims to the heaviest widest downhill rims:

SUNRINGLÉ FAQ:

What is the max spoke tension for my Sun Rims?
110kgf


There is no point to using a spoke that can handle more tension than 110 kgf on a Sun rim. And plenty of downside to over-tensioning it.

 

[-dg]

They'd be better wheels with the same crappy spokes if they just tensioned them properly to start with too. What I disagree with is that smaller spokes make better wheels. It's a fact that smaller spokes are weaker, just like smaller bolts are weaker than larger ones, assuming made from same material.

The point that you seem determined to miss is that you cannot tension them properly because they are too thick and need too much tension for the rim.

This also happens to be true for bolts. Bolts stay tight because the tension tends to lock the threads. That is why torque wrenches exist, they help to make sure the bolt is tight enough. If the bolt is too large for the application it will crush the part before it stretches enough to hold tension. So it will have to be under-tightened and then it won't stay tight.

 

[-dg]

Sounds like we need a wheel build off competition :wink:

Figure out how to test and judge it and keep the cost reasonable and I'm in.

 

[Joseph C.]

Bigger doesn't always mean better.

Two of the resident bicycle experts, one a wheelbuilder, have patiently explained why a higher gauge is better. Sources to well-known experts in their field have also been provided and yet some keep insisting they are right. :?

This place. :lol:

 

[wesnewell]

I want something strong, so I use 12g spokes on a rim designed for them that is 39mm wide and weighs more than twice as much as most rims

Right, if you are comparing against race/sport rims that are narrow. But guess what? Your rim is twice as big physically, so if it were twice as thick, it would weigh four times as much as a race rim. But it doesn't. The implication is that the walls are about the same thickness those of a race rim, which means you face puckering, cracking, and pull-out at the same tensions.

You just don't get it. My rim isn't twice a big, it's just twice as strong. It's just wider. And just by <50% at that. To be twice as big all aspects would have to double.

 

[Monsoon]

They'd be better wheels with the same crappy spokes if they just tensioned them properly to start with too. What I disagree with is that smaller spokes make better wheels. It's a fact that smaller spokes are weaker, just like smaller bolts are weaker than larger ones, assuming made from same material.

The point that you seem determined to miss is that you cannot tension them properly because they are too thick and need too much tension for the rim.

This also happens to be true for bolts. Bolts stay tight because the tension tends to lock the threads. That is why torque wrenches exist, they help to make sure the bolt is tight enough. If the bolt is too large for the application it will crush the part before it stretches enough to hold tension. So it will have to be under-tightened and then it won't stay tight.

This would only be true if the big bolt has a course thread, which of course it will, since there's no point in putting a fine thread on a larger bolt, due to the fact that it's the deep thread that will give it it's strength. put a fine thread on it though, and it would hold a much lighter torque spec with no trouble whatsoever.

what all of you are missing though, is that a 12 gauge spoke has the same 56 thread pitch that a 14 gauge spoke has. so pinning it at a given torque spec will be no harder than on a 14 or 15 gauge.
in fact, since the thinner spoke stretches (you guys all say so!), then it's only logical that the torque is actually changing MORE on the thinner spoke than it would on the thicker spoke.

 

[wesnewell]

They'd be better wheels with the same crappy spokes if they just tensioned them properly to start with too. What I disagree with is that smaller spokes make better wheels. It's a fact that smaller spokes are weaker, just like smaller bolts are weaker than larger ones, assuming made from same material.

The point that you seem determined to miss is that you cannot tension them properly because they are too thick and need too much tension for the rim.

This also happens to be true for bolts. Bolts stay tight because the tension tends to lock the threads. That is why torque wrenches exist, they help to make sure the bolt is tight enough. If the bolt is too large for the application it will crush the part before it stretches enough to hold tension. So it will have to be under-tightened and then it won't stay tight.

And the point you seem to miss is that they can be tensioned properly. The rim is designed for them.

 

[wesnewell]

Bigger doesn't always mean better.

Correct, but stronger is always better than weaker when it comes to an ebike. And in this case the 12G spoke is stronger than a smaller size.

Two of the resident bicycle experts, one a wheel builder, have patiently explained why a higher gauge is better. Sources to well-known experts in their field have also been provided and yet some keep insisting they are right. :?

I consider myself an expert on many subjects, and I'm also a wheel builder. Only built one, but it's not rocket science. It was actually very simple.

 

[Monsoon]

@chalo

You might not want to believe it, but making spokes is about as simplistic of a production process as you're going to find.
And if anyone thinks otherwise, then they clearly have NEVER worked at any sort of modern manufacturing level.
It's ridiculously simple. Even the metal is ridiculously simple to make.
Do you seriously think the Chinese are not capable of making refined stainless? Seriously??
I've got news for you, some of the absolute finest materials and tools are coming out of China right now, and it's growing by the DAY.
You know what the most badass cordless impact wrench on the planet is? It's the Ingersol Rand W7150. Put's out 780 ft-lbs of reverse torque, and 1100 ft-lbs of straight on torque. From a CORDLESS.
And you damn sure guessed it, it's made in China.

Make no mistake about it, there would be absolutely nothing stopping a large Chinese manufacturing plant from focusing on spokes, and making a world leading product. And they would do it cheaper than anyone else, because their costs are absurdly low.

Oh, and the rolls of wire that these companies use? Yeah, DT is not making that.
Trust me when I tell you, DT does not own their own foundry.
Neither does Sapim.
They order from the big guns with their own foundries, to their spec.
Not only that, but from my experience, I can tell you that there is a significant chance that this stuff is an alloy that had already been engineered, and companies like DT and Sapim select out of a catalog.
Modern manufacturing has gone way past the days when you would do every single bit of the R&D for your product.
The fact is that unless the name on your company brochure is Alcoa or something similar, you're buying a significant chunk of your product from someone else.

I've mentioned my machining background. Well I started out in aerospace.
The company I worked for made the actuator for the Patriot missiles that did so well in the first gulf war.
You want to talk about tight tolerances. It took most of a shift just for the setup on the valve body.
And the stainless we used was insane. I guarantee you that there is no spoke made on earth that has a higher grade stainless than those had, and that was 25 years ago!
When we talk spokes, we're talking about VERY basic metallurgy here.
This is not rocket science by a long shot.
In fact this all reminds me of similar arguments back in the day about speaker wire. I recall a period of a few years or more when teflon covered silver plated wire was coveted as nearly the finest speaker wire made.
All the audiophile magazines praised the clarity that it brought to the music, and the stuff sold for several dollars per foot for the cheap stuff.... right up until Audio magazine pointed out the very real and very unfortunate fact that the big wire producers like Belkin sold the stuff for 20 cents a foot.
You see, to the big wire producers, it was no big deal.
What you found out over the years, was that the audiophile companies were simply going to the wire companies and digging through catalogs until they found a gauge of wire that was useable for either interconnects, or speaker cable, and had some sort of fancy production process to it, such as teflon coating. Then they would market it as the newest and bestest holy grail, and the money would just pour in.
Sound familiar?

 

[-dg]

Make no mistake about it, there would be absolutely nothing stopping a large Chinese manufacturing plant from focusing on spokes, and making a world leading product. And they would do it cheaper than anyone else, because their costs are absurdly low.

This looks like a lot of squid ink, a great opaque cloud to obscure the creature scuttling away from the original topic. To clarify: No one has said that the Chinese could not make good spokes, or build good wheels, just that the wheels commonly supplied with cheap Chinese e-bike kits are not well built and have poor spokes. No doubt when they decide to upgrade, they will be able to.

However, 12 ga spokes are still not suitable for normal bicycle rims.

 

[Chalo]

I worked for almost six years as one of the first employees of a private space program. I have had to machine Inconel 718 into rocket engine tooling myself, along with a lot of other exotic materials for other purposes. You don't have to lecture me about materials. I was the go-to guy about exotic metals processes for a group of elite aerospace engineers.

What I can tell you is that the good stuff costs, and the Chinese manufacturers of 12ga spokes that wholesale in the USA for $0.20 aren't paying for the good stuff.

Dig. This Sapim 15/18ga spoke uses material rated at 2900N/mm^2. That's 421,000 psi. Not your granddad's 12ga Chinese spokes, to say the least.

 

[-dg]

And the point you seem to miss is that they can be tensioned properly. The rim is designed for them.

It is true that rims designed for 12 ga or thicker spokes exist, especially on motorcycles and scooters. Also, tank tracks, and road grader wheels exist, and they are even stronger. However, none of these are commonly needed on bicycles.

Again, please point out a decentish normalish bicycle or wheelset that is supplied with 12 ga or thicker spokes. Either current production or from anytime since Nixon resigned. I'm not certain there isn't one, but I've never seen one.

 

[-dg]

you were right about it until the detail about breaking spokes.
i've spent a lot of time reading up on this here and at other forums. and it's the looseness of the spokes that everyone has been mentioning, not broken spokes.

You are correct, it is loosening and loss of true that are complained about more commonly. I am guilty of being imprecise and possibly even of over-egging the pudding. I'll try to avoid this in the future. Thank you for your comment.

 

[wesnewell]

Again, please point out a decentish normalish bicycle or wheelset that is supplied with 12 ga or thicker spokes. Either current production or from anytime since Nixon resigned. I'm not certain there isn't one, but I've never seen one.

Then open your eyes.
http://www.google.com/search?q=wheelset+12g

 

[Chalo]

Again, please point out a decentish normalish bicycle or wheelset that is supplied with 12 ga or thicker spokes. Either current production or from anytime since Nixon resigned. I'm not certain there isn't one, but I've never seen one.

Then open your eyes.
http://www.google.com/search?q=wheelset+12g

Um, you just proved his point. You turned up an easy few wheelsets that are neither decent nor normalish.

 

[wesnewell]

Again, please point out a decentish normalish bicycle or wheelset that is supplied with 12 ga or thicker spokes. Either current production or from anytime since Nixon resigned. I'm not certain there isn't one, but I've never seen one.

Then open your eyes.
http://www.google.com/search?q=wheelset+12g

Um, you just proved his point. You turned up an easy few wheelsets that are neither decent nor normalish.

Right, none of the American made wheelsets are either decent nor normalish. BTW, a few to me is 3. There's more than that on just one site. And that took me all of 20 seconds. You've just proven to the whole forum you're whole agenda.
Just one site of more than a few selling 12G wheelsets.
http://custommotoredbicycles.com/sta-tru_heavy_duty_bicycle_wheels_26_inch_x_2125_assembled_in_usa_better_chrome