Middrive e bike v. car drag race

[markz]

Excellent one Mr. Chalo

That's why serious bikers are running tubeless.

Haha. He said "serious" and "tubeless" in the same sentence.

[Grantmac]

This coming from your massive bicycle racing experience?
I'm not talking about pedi-cabs or fat old guys. Even the DH racers are running without tubes now.

[Chalo]

This coming from your massive bicycle racing experience?

Haha, he said "bicycle racing" and "experience" in the same sentence.

Thirty years ago, I was very fast on the bike. Used to overtake pacelines of wankers "training" on aero-bar bikes while riding my MTB in the hill country, and tow them for miles at a time. I stayed away from racing because racers seemed like the opposite of people I enjoyed being around. I already used my bike for transportation and touring, so I didn't need to contrive a way to fool around on it pointlessly.

Lots of bikes that come into the shop these days have tubeless setups. It's a giveaway for riders who don't need the bike or use it for anything important. So yes, you made the correct connection between tubeless tires and "serious bikers" (if by that you mean car drivers who have a bike instead of a video game console/RC helicopter/AR-15/stand-up paddleboard).

[speedyebikenoob]

Okay here's the thing. I have my doubts that a hub motor on my bike running the same kind of power levels as my middrive would have been able to keep up with the car for that long. Sure, if you dump more power in the hub it'll be faster, but I feel like a middrive makes the most of the 4000 watts the controller supplies. Am I right about that?

I have ridden several motorcycles (albeit lower powered 250cc bikes in foreign countries), and none of them feel nearly as responsive or quick as my e bike in it's lower gears despite having more power. If I start my bike off in 7th gear which is geared for just under 40 mph, it feels slow and pathetic, and I'd imagine that's how a similarly powered hub would feel.

[E-HP]

Lots of bikes that come into the shop these days have tubeless setups. It's a giveaway for riders who don't need the bike or use it for anything important. So yes, you made the correct connection between tubeless tires and "serious bikers" (if by that you mean car drivers who have a bike instead of a video game console/RC helicopter/AR-15/stand-up paddleboard).

After my brief foray into trying tubeless, I decided that I'm too lazy to do the occasional maintenance (checking/topping off sealant, or replacing it). I think if I were to build a mid drive, then I might try it again, since I'd be going in with the understanding that there will be maintenance involved.

[donn]

I feel like a middrive makes the most of the 4000 watts the controller supplies. Am I right about that?

I have done it only once, on a motorcycle ca. 40 years ago. The other guy probably had better initial acceleration - in principle, because if I remember right he had a single cylinder, possibly 2-sroke dirt bike, and I had a Moto Guzzi police bike. In practice, the Guzzi really had pretty good pull at a range of motor speeds, but more importantly, he didn't pull the gear shifts off, and I left him way behind. With a Guzzi, 1st gear is at its best well over 20mph if I remember right.

Are you thinking of practical results, or expectations of what might be achieved in principle? I think the principle under which crank drive is superior to hub motor is well understood.

[E-HP]

Okay here's the thing. I have my doubts that a hub motor on my bike running the same kind of power levels as my middrive would have been able to keep up with the car for that long. Sure, if you dump more power in the hub it'll be faster, but I feel like a middrive makes the most of the 4000 watts the controller supplies. Am I right about that?

I have ridden several motorcycles (albeit lower powered 250cc bikes in foreign countries), and none of them feel nearly as responsive or quick as my e bike in it's lower gears despite having more power. If I start my bike off in 7th gear which is geared for just under 40 mph, it feels slow and pathetic, and I'd imagine that's how a similarly powered hub would feel.

I drove a stick shift ever since I was a kid, literally. I liked having access to more performance that a comparable automatic. Probably around 40, I decided that I was lazy, and I could replace any performance shortcomings by just getting a bigger motor; so all the performance I'd ever want, and no shifting.
A powerful hub is not sluggish off the line. You have to tame the throttle in order to not do back flips, or launch like a motorcycle with most of your body over the front and with your legs trailing during the launch. It won't be pathetic like your mid drive in high gears. I don't know much about little motorcycles, since mine are all more than a liter and fast.
It's silly to compare based on "similarly powered" motors. Nobody is under that type of restriction, unless you're worried about the law. Otherwise, as the old adage goes, there's no replacement for displacement, or in ebike world, watts and copper.

[Chalo]

After my brief foray into trying tubeless, I decided that I'm too lazy to do the occasional maintenance (checking/topping off sealant, or replacing it). I think if I were to build a mid drive, then I might try it again, since I'd be going in with the understanding that there will be maintenance involved.

What cured me from (literally) messing with tubeless was watching my coworkers deal with theirs. No thanks; I already have an incontinent old cat to occupy that part of my life.

[Grantmac]

So no relevant experience, gotcha.

Maybe let people who know what they are talking about do the speaking?

[MadRhino]

So no relevant experience, gotcha.

Maybe let people who know what they are talking about do the speaking?

Trying to shut off others does not make your speaking any better.

[Chalo]

So no relevant experience, gotcha.

Maybe let people who know what they are talking about do the speaking?

I've been at the workbench doing real repairs during dozens if not hundreds of tubeless "setups". All of them left nasty puddles; many of them had to be revisited because they didn't seal up on the first pass. One memorable episode spilled a liter of Orange Seal across the bench top. I refuse to do these jobs.

This is more relevant experience than anybody needs. Tubeless is dumb, but it's your own business unless you get a professional to do it for you. In that case it's like defecating your pants on purpose and then paying a mechanic to clean up the mess.

[Grantmac]

So no relevant experience, gotcha.

Maybe let people who know what they are talking about do the speaking?

Trying to shut off others does not make your speaking any better.

I don't even read here that often but I know anything about mid-drives will eventually have Chalo talking about how useless their are, despite people really not caring what a pedi-cab mechanic thinks on the topic.
Likewise you will come on with some unverifiable anecdotes about beating mid-drive bicycles with your 20kw motorcycle.
It's predictable and unhelpful to the topic of building better ebikes.

[donn]

I have to say, I think I may care more about what a pedi-cab mechanic thinks, than about anything based on electric bicycle racing. I can think of nothing more nonsensical than a race between electric bicycles.

[MadRhino]

@grantmac
Discussion does mean letting everyone express their opinions and experiences, and making each his own conclusions regarding his preferences.

It is not a game that has a winner, even less a lecture from someone who want to speak alone his own truth.

Now, the power that we feed ebikes is irrelevant. We are not discussing law. Ebikes are electric motor powered bicycles and have a functional crank. That is what makes them ebikes, like it or not.

[Grantmac]

When the human is producing less than 1% of the available power then the cranks are simply foot pegs with bad ergonomics.
Where that line exists between a bicycle and a motorcycle is debatable. Maybe once the electric power is greater than even the best sprinters can produce?

Bottom line is that with 20kw you're playing against proper electric motorcycles and ALL of those builds will walk all over your hub motor "bicycle".

[MadRhino]

I am not playing against anyone. I am commuting in the city against everyone, and I build to do it best in all circumstances, reliably. My bike can be used as both, a motorcycle or a bicycle, and I ride it anywhere anyhow it is advantageous in the city traffic. What is important to me, is that it is silent power, looking like a bicycle and can be used as one. Frame and all components are bicycle. Many on ES can’t say so, and we still call their bikes ebikes.

I have nothing against gears, only the performance that I like to ride would make a mid drive either a motorcycle, or a frankenbike that would not give me the same freedom and reliability.

[Chalo]

I don't even read here that often but I know anything about mid-drives will eventually have Chalo talking about how useless their are,

That's not true at all. The only one I think is useless junk is the TSDZ2. I have bought and used the Bafang units, and I have recommended them to others. Maybe you're thinking about my criticisms of front freewheels that disassemble themselves?

I do sometimes remind people that using a mid drive will wear out and break their stuff, if I think they're not taking that into consideration.

[Michael B]

The only one I think is useless junk is the TSDZ2.

I expect there are 10s of 1000s of these in circulation, particularly in China where the adult population weigh less (per person). Certainly the TSDZ2 hasn't been engineered for weighty westerners who then choose to fit them to full suspension mountain bikes and go do jumps.

I'm 6'1" and 13 stone and for the commute on a paved road to work it's great. Best features are the torque sensing and changing gears. I use a 54T chainwheel. Throw the throttle in the garbage. Ride it like you drive the stick shift sports car.

[MadRhino]

While BB drives are now the most common ebikes in the western world, the 200 M ebikes that are riding the streets in China are almost exclusively hub motors.

[Chalo]

The only one I think is useless junk is the TSDZ2.

I expect there are 10s of 1000s of these in circulation, particularly in China where the adult population weigh less (per person). Certainly the TSDZ2 hasn't been engineered for weighty westerners who then choose to fit them to full suspension mountain bikes and go do jumps.

The default minimum bottom bracket spindle diameter was arrived at a long time ago, when westerners were not as weighty, and jumping bicycles wasn't a thing.

Tongsheng made their bottom bracket spindle the smallest diameter in the industry, smaller than any other design I've seen even on children's bikes, and then put a snap ring groove at the point of highest stress.

That kind of profound stupidity carries through to other elements of the design, no doubt. The unending problems that crop up in the bottomless troubleshooting thread about this system testify to that.

[HrKlev]

I would never go back to tubes on my trailbike or fatbike, so not feeling the hate. The amount of flats out in the woods has dropped to pretty much zero. Its sometimes a mess to set up, but its much better than fixing flats on the trail. Would never used it if I had to pay someone to set up or fix it, though. Have no idea how it would work on a commuter, but I do think the tubeless setups have large benefits in some cases.

And the spindle on the tsdz2 is a disaster. Im done with Tonsheng.

[MadRhino]

One of my bikes is tubeless. 39mm rims, DH tires with foam inserts and slime are very reliable. But, tubeless had proved extreme PITA with my street bike that has wide rims and 3’’ slicks, so it is back to tubes.

I can’t say tubeless is good for everyone and every ride. For MTB they are becoming the norm, thus the tires and inserts are readily available to make it reliable. Our ebikes though, are consuming lots of tires, and tubeless does make a tire replacement a dirty job. It is getting less annoying with experience.

[Grantmac]

I don't even read here that often but I know anything about mid-drives will eventually have Chalo talking about how useless their are,

That's not true at all. The only one I think is useless junk is the TSDZ2. I have bought and used the Bafang units, and I have recommended them to others. Maybe you're thinking about my criticisms of front freewheels that disassemble themselves?

I do sometimes remind people that using a mid drive will wear out and break their stuff, if I think they're not taking that into consideration.

No argument here, that's a piece of junk and the BBS aren't much better offroad.

Wear is such a minor concern compared to a system that just doesn't work in the application (hub motors).

There is a whole lot of improvement that could be done to ebike powertrains if the industry made some revolutionary changes.
Combining the motor with a central gearbox is the most obvious. Gearing an electric motor waaaaay down just to match human cadence which is then geared up (via small, fragile sprockets) is an asinine and lazy approach.

I have no faith that the big industry players will create anything really good so long as just okay sells. But individual innovation will find good solutions. Not always all the good ones in one place, but elements of the puzzle that can be put together.

[fatty]

...It can cost lots of time and money to successfully mod and tune a suspension with a heavy rear wheel. Yet proper weight distribution and geometry had never been so hard to achieve for me in over a decade building with hubs. The fact is, in a place where powerful ebikes builders are many, I never met a mid drive ebike who could compete, city or mountain.

...Unsprung weight is a problem, but can be solved with proper geometry/suspension mods and tuning, that can make a good handling up to 70-80 mph. After all, a lot of motorcycles have a rear wheel just as heavy as an ebike motor wheel...On the city streets though, a powerful hub motor ebike can compete with motorcycles advantageously.

Unsprung weight approaching sprung weight is a fundamental physics problem -- it cannot be "modded and tuned" to "make good handling".
A motorcycle wheels as heavy as ebike motor wheel is not an apt comparison, as such a motorcycle has much greater sprung weight, and even there, every effort is made to reduce that wheel weight, to the point of exotic magnesium and carbon fiber wheels.

There are compelling -- even overwhelming -- reasons to use hub drive. But we should distinguish between fundamental physics problems and mere engineering challenges (to wit: a mid-drive competing with a high-power hub).

[fatty]

Excellent one Mr. Chalo

That's why serious bikers are running tubeless.

Haha. He said "serious" and "tubeless" in the same sentence.

There are plenty of locations -- mine included -- in which commuting with tubes has simply become untenable. I would have to double my allowed travel time to account for likely punctures.

I don't understand this dismissive and derogatory attitude. We spend hundreds of hours across years researching, designing, building, and maintaining this hobby. Yet spending 10 minutes setting up tubless is to be laughed off a thread? Something kids in my local club now do unattended? Sounds like you are hopelessly stuck in the '90s.