Also, when they wear out, I don’t want to be vendorlocked to any certain polyurethane supplier/manufacturer. And I want to choose my wheels too. And I want wheels that are designed to be the best wheels for a longboard, not wheels that have been shoehorned in with other engineering goals. If your wheels suck, then your entire board sucks. The wheels are what makes it work.
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lol, people like Chris come here, and talk about wheels, but the reality is, they are not doing rocket science. There’s no reason why others can’t make wheels just as good. It’s a process, but that’s how they made them in the first place. They didn’t wake up one day, and say, oh, I’m going to start making wheels with this magic formula and they will be great. Give hub motor manufactures time. There will be a wide array of options, and wheels will just get better.
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That is correct. It is simply iterative formulaic science. Making good wheels is an iterative process that has had much, much longer to mature. Hubs have a ways to go thane wise. Materials science just isn’t there yet. You can’t absorb the same kinds of impacts with less thane as you can with more thane. Ride quality is directly affected. Chris didn’t spend several years trying and failing urethane formulas because any fool can make wheels. IF any fool can make wheels now, its because companies benefitting from thane formula trial and error such as Chris’s are popping them out.
Can i call up Labeda and throw $10k at them and get wheels? yes! Can i call Chris up and throw $10k at him and get SuperFly’s in pink and with a bizarre durometer? Yes!
Can i ever possibly get as much thane on a hub as I can on a direct drive or belt drive or gear drive? No!
Heat is still a problem, even though its a lot less of a problem than it was in two of the hub designer’s motors out of a swath of garbage out there. Thane is still a problem, though the degree varies subtly between hubs.
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Actually, there is one reason. If you have to try to fit a motor inside it that’s as big as possible.
Sorry, I’m still not clear on why reductions are theoretically more efficient.
Is it because as torque in the motor increases, losses increase exponentially while when you use reduction the relationship is linear? And hub motors will always have to output more torque cause of no reduction?
Also if the only difference between the setups is ERPM then wouldn’t changing the amount of poles fix that?
Sorry if my confused ramblings are derailing things, I’ve just always been curious about this.
Me too. Torque takes amps. Without a reduction u need more torque from the motor for same motor torque output. U can trade speed for torque w a gear. If the motor is big enough though it’s not a problem. More poles gives greater control but not really almost any more torque. U either end up w a bunch of smaller weak magnets or large powerful. Surprisingly despite a magnet’s strength not being linear and they are stronger when closer…many experts have told me no free ride there. At best with more poles u can decrease the airgap diameter(not thickness) as the many magnets can be a hair less thick for same strength when in an array so now the aigap could be at maybe 47.5 instead of on the 47. It made sense thered be a lateral airgap and decreasing it would enable less current needed for same leverage. Makes sense but at this point I’ve heard it from many experts saying it doesn’t work that way. Why I don’t know.
Bigboytoys has two hub motor sets, one w double the poles\magnets but I think otherwise the same. I think he might be able to do a comparison.
Unfortunately I just dissassembled them and the newer version of the TB hubs has a longer stator than the earlier version in addition to having 24poles so anapples to apples comparision for 14 vs 28 pole counts motors isnt possible with these.
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You would need four motors while I would still only need one to outperform the four. Have you seen Jens Twin Leopard 80mm attached to one of our boards, twin VESC SIX at 120A per motor (5.3KW per motor). F…hell fire… Even one of them would have outperformed a quad hub drive with ease, assuming realistic 1.2KW per hub. Motor size is approx the same.
Apples to Apples again: single drive vs.single drive.
At this stage we have roughly the same output power if we compare a rather small 650gr single belt drive motor to two big fat hubs (approx 1.2 Kg each), while the single belt drive is way more efficient, stays cooler and is light weight. And if you have an issue its only one issue, one motor, one ESC, one sensor cable to fix.
You can stick four hubs or belt drives to a board, but who wants that? Keep things simple! The best part in a system is the part you don’t need, agreed. You could argue that hubs stripped away the belt drive - at the price of two heavy motors, two ESCs and less efficiency. That is not really “getting rid of parts” in my eyes. It is shifting around things at the price of triple the weight and no choice of Urtehane/Wheels. To some this is appealing, others have a different view. From a vendors point of view this is appealing, since you can sell a lot of spare tires to your customers. Each hub sells four tires over time and there will be no standard. But you will sell zero tires to customers of your competition…
Other industries: Why cars have no hub motors although the would have the space to fit them: Weight is the answer. Heavy hub motors cause problems to the suspension system - more mass swinging up and down + batteries are heavy already and you want the car to be light. So they use a single or twin, small, geared motor instead.
Modern E-Bikes use geared motors to keep the weight low and benefit from the efficiency gains. Less magnets, copper, centred weight, a lot more power etc.
Wind turbines usually use geared systems. Some still use direct drives but neodymium price stands against this technology >> 10x the neodymium per MW.
Other industries have been through the hub design matter and ended using geared system. Electric motors simply like higher RPM and low torque. Power density and efficiency is a lot higher when you gear down.
The golden rule: If your application is running at high RPM low torque you can go for direct drive (e.g. spinning a small propeller). If you need torque and low RPM you gear down.
And now I would like that heavy extra bacon thing @longhairedboy was talking about. Could you post an image please. I imagine it to come with enough grease to kill a donkey.
Frank
Ps.: I’m not sacred of hubs. What really scares me are those 80mm Leopards. They are lifting the boards front wheels when you pull the trigger. The only downside: The gears need extra grease…
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but there are hub motors on cars and bikes still and no sign of them disappearing. lots of people use them and are happy with them. Even if the hub is not 4x as big, and there were to be decrease in efficiency, there are many other benefits. the biggest reason I got into hub motors is lack of noise of pulleys and I like the simplification and with it there’s a lot less maintenance and possibility of parts to break. and they do break. I know I was getting awesome efficiency with even the last hub motors and will get a test done…a real test…soooon.
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Teslas don’t have multiple gears.
This apples to apples thing is stupid. What kind of apples are you talking about? weight? If so then belts clearly win. If your apples are power output then apples to apples each has their advantages. I want hummies hubs cause they look cooler, their simpler to make a DIY with and I don’t care about the extra weight or lower potential maximum power output as a dual drive will likely be enough for me.
The Model S has always had just 1 gear. The Nissan Leaf has 1 gear. The BMW i3 has 1 gear.
The Koenigsegg Regera has only 1 gear too !
@evoheyax Thanks for the precious infos specially about awg wires differences IRL tests. When my motors fail on my due to heat I’ll know what to upgrade first.
Neither do locomotives.
I mean if you add a transmission to the board then hubs become second tier. Seems like a very tough engineering challenge.
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Doesn’t it really come down to acceleration/top speed/efficiency? IDGAF about weight if I can get all the same metrics I care about in a hub.
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This debate is old and been going on in the bike world for a while with hubs vs mid-drive and results depends on the motor specifically and what type of riding. General use will see a mid-drive do better, with the motors out there now, but a hub can be better efficiency in some cases such as sustained high speeds. We will see. There’s also what happens to the energy when it’s not converted to torque…is it stuck on a stator or is there a good thermal pathway to a good heatsink that can dissipate it into the air or something. in that department a skate hub motor has an advantage over pulley motors or bike hub motors. Even if the motor is bottled up inside urethane, which is very much a thermal insulator, air is not much better of a thermal pathway when there isn’t much surface area to get it out there. The new design I have coming with a hollow center has a huge amount of surface area as well as ability to transfer heat with great contact surface area going to a huge aluminum hanger. I’m dying to do some testing and this week will. maybe @Jinra you could do loops with me somewhere and we can compare watthours spent?
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woah a lot of technical details in this thread ( will read them later)…
but @BigBoyToys does it mean that the motor with more teeth on the left has lower KV rating?
Im also still getting into this motor technology thing 
I don’t think either are worse or better than the other mate.
I think a lot of people here lost what the initial debate was once someone made a comment along the lines of the “belt drive guys” or whatever it was. A lot of the debate was not belt drive motors are better blah blah etc, it was that you can’t make the claim hub motors are more efficient than a geared system, it’s fundamentally wrong.
The key part of efficiency is the amount of input versus the amount of output. A 1:1 system will always generate more heat.
As for “apples to apples”. I’m not sure why we started comparing weight… as far as I’m concerned you can’t compare anything other than the same kv or W based motors otherwise your comparison is pointless.
The reason you see this claim of “hub motors are more efficient” comes from the following analogy.
Geared systems have had a guy that’s been able to lift 50kg/110pounds in a 1:1 ratio. He’s been using a seasaw to do it though allowing him to lift 500kg/1100pounds with the same effort. Then came hub motors, to make it so that they can lift 500kg/1100pounds, they pumped the iron at the gym until the guy could lift 500kg/1100 pounds. The thing you have to note here is that both guys have to bust their asses to lift their 1:1 ratio. However you get that buffed guy a seasaw and all of a sudden 500kg/1100 pounds is something he can do with a single finger, thus requiring less effort, creating less heat, wasting less energy, creating a more efficient system. That is why you can’t argue that gearing a motor will not make it more efficient. That is also why comparing a 100kv to 300kv @ 1:1 ratios efficiency is completely pointless.
Lastly, don’t think I’m banging on hubs. They are my next focus on my next build. I love my dual leopard trampa and I’d challenge anyone to make a hub setup that can compare to the acceleration, speed and distance that thing can do. However it also attracts a lot of attention and I’d like a more stealthy setup 
but I’m under no delusions that it would do much more than get me around town
Sure maybe this weekend. We have a group ride on saturday, but maybe we can meet up sunday
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