Please help me critique my dream ebike.

s1dewinder

1 mW
Joined
Aug 11, 2020
Messages
15
I plan on building another ebike. I have some design goals, a rough components list, and a dream.

In short: I want a fat mountain bike e-moto conversion with dual electric drive and no shifting (single speed).

Design goals:

It must be possible to assemble the bike from existing components in the market. Required handywork must not exceed wrenching, filing, and soldering. I don't have access to custom parts or a machine shop.

170mm rear drop out fat bike conversion build (from components, not from an existing bike)

Dual electric rear wheel drive: mid drive+direct drive rear hub (don't try to stop me, this element is non-negotiable)

Must be able to handle the heat generation of full throttle on a 10% grade from a full charge to nearly dead and then roll back down the hill with regen braking. Again, without risk of overheating. Assuming a 220 pound rider.

60 MPH top speed.

Single speed

No tubeless wheels

Frame: 18” Framed Minnesota 2.0/3.0

I built my current ebike on the 20 inch version of this frame. I love it. Huge triangle space. Rides great with the seat slammed. Very much like a mountain bike but fat. Sportier geometry, like a more acute rear angle, would be cool, but I do love this frame. Going smaller, 20" to 18", should yield a small gain in agility.

Rear direct drive hub and wheel: ENC3000

I've used this motor in the past on my current bike and I love it. It's 11.94 Kv, so it is a relatively fast winding. The primary reason for using this motor specifically is because Ncyclebike told me they could send me one with a 170mm compatible axle laced into a 19" motorcycle wheel. (I'm considering going 17" for less weight, more stiffness, more agility, and more torque). They also told me they could send me an 11 tooth single speed rear freewheel for it.

Mid Drive: CYC X1 Pro Gen 2

With a BAC 855, 12/72 gearing, and an 11 tooth rear freewheel. Disable/bypass PAS and spoke speed sensor.

Rear hub controller: Phaserunner 

This controller will drive my rear hub. It is expensive, but ideal for now. The guys at Grin tech are hub motor guys and their controller comes with a suite of support for when it comes time to program it for my ENC3000. I considered a BAC 2000, but I feel there is a risk I will struggle to pair it with my ENC 3000. Also, the phaserunner's lower power will be safer on my dropouts as well as generating less heat to satisfy the 4th design goal. (Though, I will use dual grin tech torque arms, so the BAC 2000 may be an easy option for an upgrade later). This controller will handle speedometer, as well.

Battery: 72V 32AH (litespeed)

Big voltage and capacity to make maximum use of my big triangle. 300 amp BMS means my 105 amps of draw (65A BAC 855+40A phaserunner) will never challenge the battery. It also leaves plenty of room to eventually upgrade the phaserunner to a BAC 2000.

Brakes: Shimano Hydraulic Disc Brakes with 200mm or larger rotors.

Fork? (Idk yet)

I want a stiff/high speed/high performance front suspension fork. Any recommendations?

Front wheel?

Once I figure out my fork I can figure out my front wheel. 17" or 19" motorcycle wheel would be great, but I don't know how to mount that to quick release drop outs so that may violate the first design goal. 24" or 26" plus size or fat size wheel may be what I end up going with. Then, I'd need to find fast tires for the wheels.

Throttle: right thumb throttle

No twist throttle means I can grip and rip the handle bars without accidentally pumping my throttle.

According to the system calculator at ebikes.ca this sort of setup should yield somewhere between 5kw and 6.5kw of power and 85-95 ft/lb of torque. The calculator tells me a top speed of roughly 50mph, but I think that is an under-estimation due to assuming too much drag and rolling resistance. My current ebike's top speed outperforms the ebikes.ca estimation by between 5 and 13 mph depending on riding conditions, so the 50mph estimation does not discourage me from my 60mph goal.

Please let me know your thoughts about my dream bike and help me make it a reality by enlightening my amateur ebike assembling mind.
 
Okay, since you want critique.

You'll experience instant regret going beyond 35mph on a bike without full suspension. The second you have a wheel lift into the air from a bump and land in a place you don't expect, causing an emergency counter-correction, you'll regret your frame choice, because you know this will happen again and again.. and learn how suspension is not just a comfort feature, but a safety feature too, at speeds like those.

A rear DD hub capable of those speeds that isn't heavy is still a rare bird. I would recommend overvolting the 3000W mid drive instead to achieve your target top speed.

Beware that an upright bike that can hit 60mph will chug energy like wild. You'll need the biggest battery possible in the space you have on the bike. The technology to ge a decent range at high speed doesn't exist yet, unless you're okay with your bike being an ugly looking battery on wheels.

hiryuu_spring.jpg


I went to build the ultimate high speed ( 60mph peak capable ) sleeper bike and ran very hard into the battery storage issue. This and the flimsy 26" tire problem is how i got into semi recumbent bikes, which use way less energy at high speeds.

I would urge you to consider a recumbent, since you are just as demanding of me of your machine. You want a kind of excellence that is almost technologically infeasible without building a frame around a massive battery, basically.
 
neptronix said:
Okay, since you want critique.

You'll experience instant regret going beyond 35mph on a bike without full suspension. The second you have a wheel lift into the air from a bump and land in a place you don't expect, causing an emergency counter-correction, you'll regret your frame choice, because you know this will happen again and again.. and learn how suspension is not just a comfort feature, but a safety feature too, at speeds like those.

A rear DD hub capable of those speeds that isn't heavy is still a rare bird. I would recommend overvolting the 3000W mid drive instead to achieve your target top speed.

Beware that an upright bike that can hit 60mph will chug energy like wild. You'll need the biggest battery possible in the space you have on the bike. The technology to ge a decent range at high speed doesn't exist yet, unless you're okay with your bike being an ugly looking battery on wheels.

hiryuu_spring.jpg


I went to build the ultimate high speed ( 60mph peak capable ) sleeper bike and ran very hard into the battery storage issue. This and the flimsy 26" tire problem is how i got into semi recumbent bikes, which use way less energy at high speeds.

I would urge you to consider a recumbent, since you are just as demanding of me of your machine. You want a kind of excellence that is almost technologically infeasible without building a frame around a massive battery, basically.

I appreciate your input. It has made me more closely consider my design, though I am skeptical of some of your assertions.

1. I am skeptical that full suspension is really so necessary. My current ebike has zero suspension and will get up to 45mph and I've had it as fast as 49mph with no issues. I'm riding fat tires at 19 or 20 PSI, which provides a limited (albeit bouncy) dampening effect. I admit I have to slow down for bumps like railroad crossings, but when I'm standing on my pedals and hovering over my seat I am able to create a very effective suspension with my legs. I weigh a lot more than the bike, especially with my gear and backpack on, and I do not feel limited by lack of suspension. Furthermore, hard tail motorcycles don't have a problem with 60 mph. Why should my hard tail front suspension ebike?

2. The dual electric drive design is non-negotiable because of the torque and heat elimination it will provide while remaining single speed. I'm not worried about the weight of the ENC 3000. it isn't small, but it also is not too big.

3. I am not worried about exceptional range. Roughly 20 miles at 35mph is my minimum, but I think the 72v 32AH from litespeed will do better than that.
 
1) Oh i see. You're using low tire pressure to get suspension at the expense of added rolling friction. You will still hit a limit with that approach at some speed. I hit my limit at 30mph on 2.0" tires when hitting odd-shaped irregularities in the road that sent my wheels into the air and sideways. I've seen it happen to others at high speeds. Those wheels need to stay planted at all times... that's how suspension is a safety feature.

If you have to slow down for bumps, you have inadequate suspension though. A good suspension floats over those bumps and you barely notice them. I never once bothered slowing down for a bump on the bike i showed you. Even at ~55. No drama, no fear... absolute riding confidence on the street.

2) I know this is non negotiable, but negotiating is smart here.

I skipped over the fact that you were going single speed, yet had hills to take. You're defeating the point of a mid drive by doing that, and all those reductions meant to slow the RPM of a mid drive are adding friction for nothing - you should be driving the back wheel directly. You might as well get a REALLY BIG hub. You will get better efficiency and range with a big hub actually, since you take zero additional mechanical friction penalty that way.

In your case i'd be running a 4-6kw lowish rpm motor direct a rear disc brake sprocket using a thick chain that can take the power. This would be the ultimate motor setup for you.

All the most technically impressive builds on this forum have went with that gold standard: rear chain drive.

3) Ok, but how are you going to fit a 72v 32ah battery on your bike? have you worked out that, dimensions speaking? a battery like that is monstrous.
 
neptronix said:
1) Oh i see. You're using low tire pressure to get suspension at the expense of added rolling friction. You will still hit a limit with that approach at some speed. I hit my limit at 30mph on 2.0" tires when hitting odd-shaped irregularities in the road that sent my wheels into the air and sideways. I've seen it happen to others at high speeds. Those wheels need to stay planted at all times... that's how suspension is a safety feature.

If you have to slow down for bumps, you have inadequate suspension though. A good suspension floats over those bumps and you barely notice them. I never once bothered slowing down for a bump on the bike i showed you. Even at ~55. No drama, no fear... absolute riding confidence on the street.

2) I know this is non negotiable, but negotiating is smart here.

I skipped over the fact that you were going single speed, yet had hills to take. You're defeating the point of a mid drive by doing that, and all those reductions meant to slow the RPM of a mid drive are adding friction for nothing - you should be driving the back wheel directly. You might as well get a REALLY BIG hub. You will get better efficiency and range with a big hub actually, since you take zero additional mechanical friction penalty that way.

In your case i'd be running a 4-6kw lowish rpm motor direct a rear disc brake sprocket using a thick chain that can take the power. This would be the ultimate motor setup for you.

All the most technically impressive builds on this forum have went with that gold standard: rear chain drive.

3) Ok, but how are you going to fit a 72v 32ah battery on your bike? have you worked out that, dimensions speaking? a battery like that is monstrous.

1. I see. You have a good point about having to slow down for bumps and keeping my wheels planted.

2. You are probably right about the very large rear hub and more powerful controller being a better solution for my goals. However, I am in love with the idea of dual electric drive. Even if I put a larger rear hub on I would still feel compelled to add the mid drive as well.

3. The minnesota 2.0 has enough space in the triangle, I think. A triangle shaped battery of the same size would definitely fit. Maybe I should look for a similar battery that is triangle shaped. If I were to pursue full suspension then I'd need a different frame and I have no idea.


Thanks again for your input.
 
s1dewinder said:
2. You are probably right about the very large rear hub and more powerful controller being a better solution for my goals. However, I am in love with the idea of dual electric drive. Even if I put a larger rear hub on I would still feel compelled to add the mid drive as well.

That would be more expensive, less efficient, and more heavy than going with the big hub though.
If you had multiple gears and lower top speed requirements, a CYC Pro on lots of volts would be so ideal.
60mph is overrated anyway.. it is fun but you are going to be a huge cop magnet.. if you could lower your expectations and use gears, the cyc pro would be fantastic alone before even bothering to modify it.

Your setup would require a 26lbs total in motor though.. a single reduction motor to the rear disc sprocket would be in the 10-15lbs range and have higher efficiency too.. a disc brake mounted motor would be my first and only choice at the power levels and requirements you have.

s1dewinder said:
3. The minnesota 2.0 has enough space in the triangle, I think. A triangle shaped battery of the same size would definitely fit. Maybe I should look for a similar battery that is triangle shaped. If I were to pursue full suspension then I'd need a different frame and I have no idea.

Yes, it's awfully hard to fit a large battery into a FS bike. Compatible designs are rare.
You may like one of those stealth/enduro type frames.

A 20 mile range at 35mph would require a much smaller battery than you're thinking though. Check out the ebikes.ca simulator with the largest DD hub.. but.. 75v 15ah might work for you.
 
neptronix said:
s1dewinder said:
2. You are probably right about the very large rear hub and more powerful controller being a better solution for my goals. However, I am in love with the idea of dual electric drive. Even if I put a larger rear hub on I would still feel compelled to add the mid drive as well.

That would be more expensive, less efficient, and more heavy than going with the big hub though.
If you had multiple gears and lower top speed requirements, a CYC Pro on lots of volts would be so ideal.
60mph is overrated anyway.. it is fun but you are going to be a huge cop magnet.. if you could lower your expectations and use gears, the cyc pro would be fantastic alone before even bothering to modify it.

Your setup would require a 26lbs total in motor though.. a single reduction motor to the rear disc sprocket would be in the 10-15lbs range and have higher efficiency too.. a disc brake mounted motor would be my first and only choice at the power levels and requirements you have.

s1dewinder said:
3. The minnesota 2.0 has enough space in the triangle, I think. A triangle shaped battery of the same size would definitely fit. Maybe I should look for a similar battery that is triangle shaped. If I were to pursue full suspension then I'd need a different frame and I have no idea.

Yes, it's awfully hard to fit a large battery into a FS bike. Compatible designs are rare.
You may like one of those stealth/enduro type frames.

A 20 mile range at 35mph would require a much smaller battery than you're thinking though. Check out the ebikes.ca simulator with the largest DD hub.. but.. 75v 15ah might work for you.

Thanks again. I am learning from you with each reply. Do you have any idea about the possibility of mounting a motorcycle wheel to quick release drop outs? Or recommendations for high speed bicycle wheels and tires?
 
Motorcycle wheels are going to be too wide and have much larger diameter axles, so you can forget that.

A 22" bike rim ( some are sold for BMX purposes ) is said to take 18" motorcycle tires.. you could have about a 23 inch diameter at best.. so there is some geometry that will need to be adjusted for by shortening the front suspension/running a smaller wheel up front, and maybe even going with slightly smaller cranks. Alternately if you have the ability to lengthen the rear shock on a FS bike, none of these compromises are needed.

Once we start talking about these smaller wheels.. a hub starts to make more sense at higher voltages because the wheel RPM per MPH will be faster and the hub will make more power.. in the same way that if you spin a gasoline engine to a higher RPM, you get more power out of it.

If i were building the bike i showed you again today, i'd go with a 22" rim + 18" tire in the rear and a 26" bike tire up front, so that i had flat protection and excellent traction on the rear wheel.. plus that little 10% boost to a motor's power density you get from a smaller wheel... at the expense of added tire friction.

In the slightly smaller wheel, a 45mm wide DD would produce enough power to get you up those 10% grades as long as they aren't prolonged. Expect to push 5000W at a bare minimum.

With a 45mm wide DD in a 23" outer diameter wheel, it's real likely that you could cruise at 45mph all day long without worrying about heat, and bursting up to 60mph for decent periods of time. Hill climbing power would be nutty enough for you to make it up practically everything and ferrofluid would help soak up a lot of heat produced from doing that.

Honestly if you're willing to keep to 40mph continuous on average, a leafbike 1500W 4T would work for you and even allow you to keep your 7 gears. It's the most powerful 35mm wide motor on the market still and only weighs 16lbs. On air cooling, i was able to sustain 40mph indefinitely ( 2000w load ) and spend lots of time in the 45-55mph range without it getting too hot. With the cooling fins and ferrofluid available these days, it could probably sustain 45mph or even more, and take the occasional burst to 60mph as well.
 
The mid drive is an excellent route too, 3000w of power isn't a joke, it is likely just as powerful as the 45mm DD, but bike chain and derailleurs etc are rated at 500w, so they are sort of disposable maintenance items at those power levels.

A downhill bike with very strong torque plates running a DD won't give you any mechanical problems other than the pain in the ass of taking a 16-24lbs wheel out of the bike to patch a flat :lol:
 
neptronix said:
Motorcycle wheels are going to be too wide and have much larger diameter axles, so you can forget that.

A 22" bike rim ( some are sold for BMX purposes ) is said to take 18" motorcycle tires.. you could have about a 23 inch diameter at best.. so there is some geometry that will need to be adjusted for by shortening the front suspension/running a smaller wheel up front, and maybe even going with slightly smaller cranks. Alternately if you have the ability to lengthen the rear shock on a FS bike, none of these compromises are needed.

Once we start talking about these smaller wheels.. a hub starts to make more sense at higher voltages because the wheel RPM per MPH will be faster and the hub will make more power.. in the same way that if you spin a gasoline engine to a higher RPM, you get more power out of it.

If i were building the bike i showed you again today, i'd go with a 22" rim + 18" tire in the rear and a 26" bike tire up front, so that i had flat protection and excellent traction on the rear wheel.. plus that little 10% boost to a motor's power density you get from a smaller wheel... at the expense of added tire friction.

In the slightly smaller wheel, a 45mm wide DD would produce enough power to get you up those 10% grades as long as they aren't prolonged. Expect to push 5000W at a bare minimum.

With a 45mm wide DD in a 23" outer diameter wheel, it's real likely that you could cruise at 45mph all day long without worrying about heat, and bursting up to 60mph for decent periods of time. Hill climbing power would be nutty enough for you to make it up practically everything and ferrofluid would help soak up a lot of heat produced from doing that.

Honestly if you're willing to keep to 40mph continuous on average, a leafbike 1500W 4T would work for you and even allow you to keep your 7 gears. It's the most powerful 35mm wide motor on the market still and only weighs 16lbs. On air cooling, i was able to sustain 40mph indefinitely ( 2000w load ) and spend lots of time in the 45-55mph range without it getting too hot. With the cooling fins and ferrofluid available these days, it could probably sustain 45mph or even more, and take the occasional burst to 60mph as well.

I appreciate this insight. Thank you very much.
 
I agree with Neptronix first post here. The bike I ride the most has fat tires and a suspension seat-post. It's awesome at my usual street cruising speeds near 15-mph, but high speeds would be a disaster at the first big pothole or hitting a curb to escape a 4,000-lb car.

It really smooths out the ride on the road, but it is definitely not a real suspension.
 
Put all the motor mass into either a big hub or big mid-drive. Running both gives the worst of both without any advantages.
 
You want a light motorcycle -- you're going to have to build it like one. This is sort of an easy design exercise, since there simply aren't many ways to achieve your goals. A common set of solutions coalesce for a project like this:

I have a thread on fat bike tires vs FS at 45mph. Part of the problem is that street ebike tires are not available in fat sizes -- they max out around 27.5 X 2.60, severely limiting the attainable suspension effect. Motorcycle tires are too stiff to provide any suspension effect on a bicycle. The clear consensus is FS at 45+mph, as seen in all commercial roadgoing vehicles.

60mph on an upright mountainbike is going to take 5500-7500W depending entirely on tuck and aero. While any hub motor will compromise rear suspension, a hub motor that can push 5500-7500W will be heavy enough to render rear suspension ineffective, so as expected (based on commercially-available examples), you're looking at a FS mid-drive, and with that much power, single-speed (as desired).

At 72V, you need 80-100+A battery to hit 5500-7500W, which locks you in to LiPo pouch cells.

Talk to Mike at Lightning Rods for a Big Block Mid-Drive Kit -- highly recommended:
http://lightning-rods10.mybigcommerce.com/mid-drives/
https://www.facebook.com/Lightning-Rods-613804531978401/

Check out the RockShox ZEB Charger R E-MTB fork:
https://www.sram.com/en/rockshox/models/fs-zeb-r-a1
 
..i'd say in practice with a leaf (16lb hub ) and very light tires, i retained maybe 33% of my rear suspension's action. It wasn't as luxury smooth, but still better than not having suspension at all for sure. I didn't feel uncertain at high speeds, but yea.
For offroad, a mid drive does shine. On the street, less of a big deal.
 
Your dreams kind of require a motorcycle. Perfect description of a honda 250. At least, get the rolling chassis of one to electrify. 60mph requires 60 mph motorcycle tires, unless you are doing a one set of tires per race kind of thing.

NOT knocking the idea of a 40 mph or so e bike. I have had them, rode em for years, loved it. But in my state, above 30 mph gets you into legal issues on the street, and you are cruising for a bruising uninsured. So I rode with a 30 mph cruising speed on the street for the most part.

After a decade or so of all kinds of e bikes, I go fast on motorcycles. They feel solid to me at speed. 70 mph on a yamaha 250, 110 mph on a bmw. They are fully insured, even for theft.
 
s1dewinder said:
Dual electric rear wheel drive: mid drive+direct drive rear hub (don't try to stop me, this element is non-negotiable)

Cool-- great way to drive away knowledgeable help.

Let us know when you break your hub motor's right sidecover.
 
Chalo said:
s1dewinder said:
Dual electric rear wheel drive: mid drive+direct drive rear hub (don't try to stop me, this element is non-negotiable)

Cool-- great way to drive away knowledgeable help.

Let us know when you break your hub motor's right sidecover.

I did not mean to ward against criticism. Perhaps my language was too absolute. I have heard of this being a point of failure before. Could you explain to me how this failure occurs? Is it simply from the torque of the mid drive turning over the freewheel during normal operation? or is it from the chain becoming out of alignment and ripping/pulling on the freewheel?

If you have insight for me I do want it.
 
s1dewinder said:
Dual electric rear wheel drive: mid drive+direct drive rear hub (don't try to stop me, this element is non-negotiable)

What about a direct drive motor as a mid drive?
https://endless-sphere.com/forums/viewtopic.php?f=6&t=38553&sid=239c9362e9c37a58c7768412124885a1#p562377
1.jpg
 
s1dewinder said:
Chalo said:
Let us know when you break your hub motor's right sidecover.

Could you explain to me how this failure occurs? Is it simply from the torque of the mid drive turning over the freewheel during normal operation? or is it from the chain becoming out of alignment and ripping/pulling on the freewheel?

Hub motor sidecovers are usually crude aluminum castings, mostly flat with a few radial reinforcing ribs inside. They're well-suited to carrying loads imposed by the wheel, but not so great at withstanding cyclical bending loads from the chain pulling on the freewheel or cassette. If you pedal hard and often, and/or use a small front chainring, it's easy to crack the aluminum cover at the base of the freewheel threads, and detach that part of the sidecover which also contains the axle support bearing.

For most e-bikers, this is not a problem because they pedal weakly, intermittently, or not at all. But when you add a crank drive to a hub motor, suddenly you have the equivalent of a very strong (or superhuman) rider pedaling a lot of the time. It greatly increases the likelihood of this characteristic hub motor failure.

If you use a hub that has mass similar to both the motors you intend to use combined, you'll likely have more power available and equal or better heat capacity. You'll certainly have lower maintenance and fewer failure modes.
 
I would not say breaking the cover is certain, but it sure is likely you have problems with a 5000w or more mid drive running bike chain. The solution would be bigger chain, or belt, on the left side. Likely with the sprocket or belt pulley attached directly to the rim. Not sure where you get a whizzzer rim, but wheelchair rims often have points where you attach a hand pushing wheel. Make something similar from a motorcycle rim. Ooops,, now I have you welding.

Off topic,

Yes, I've crashed motorcycles in the last few years. Dirt riding, I crash at least as regularly as I did riding dirt with 40 mph e bikes. But if I crash the dirt bike just as much, its because of how I ride. You know me by now, you find the limit of your tires, then ride just inside of that limit. But both types of ride, its always the same crash, deep soft sand is harder to ride in, but the fatter tires and power of the 250 just ends up having me in that kind of riding more. So I end up having the same crash, sub 25 mph, eventually a rut in the sand grabs your front wheel and twists it. Bike goes down and I go over the bars into a big soft sand pillow. And I'm always wearing full head to toe armor. But riding on hard, rough roads, I don't crash. The suspension and tires of a 250 dirt bike just don't let me down like the bike stuff did. Bear in mind, I never paid for the really good bike stuff. I never had $1000 forks on my dirt electric bikes. I never felt comfortable riding a dirt road over 30 mph on those bikes. 50 is fine on the yamaha.

Street is different of course, and I don't spend a lot of time at 110 mph. Its briefly, passing a row of semi trucks kind of thing. Speed limit is 75 here, and I tend to cruise at about 80, where local cops won't pull you over. But even at 80 you simply don't crash, as if your life depends on it. Where I'm more likely to crash is riding in the mountains. But those roads slow you down, apexing corners as slow as 20 mph.

I laid down a scooter at 60 mph four years ago on one of those mountain roads, entirely my fault. Big wide corner you can take at 70, followed by one more like 45 mph. I smoked into that corner at 60, and then made a critical mistake, I grabbed brakes. When I left the road at 60 mph with brakes on, soon as I hit the gravel I laid it down. Broke a rib. 58 years old at that time. I keep my speed down on those roads now, but on other roads built for faster, I have no fear of a 75 mph corner.

Two years ago on a scooter at 60 years old, I got run completely off the road by a car on my side of the road. I was doing about 25, and dumped into a ditch then laid it down. That time I hurt my ankle. Armor protected me pretty good. I was quite glad I was on a motorcycle that time, since in a car it would have been a head on collision. I'll take a motorcycle lay down any time vs a head on wreck in a car.

I have not laid down the BMW yet, and I must say its not likely. Its tires are so incredibly superior to the smaller scooter tires. Its just a truly capable motorcycle. Why did I choose this one? Its the one I see chasing the tour de france. Very stable at low speeds, yet when they start running down the mountain, it easily keeps up with the bike racers, who corner like maniacs. My bmw is the r 1100 rt. R means the boxer engine with the low CG which helps at low speeds. RT means it has the full touring fairing and saddlebags, vs the sport version. Its low CG is a problem in higher speed corners, so you must counter steer it with authority, just like the scooters, or it won't lean over for you. Once you get it leaning though, OMG do those tires stick!

Anyway, if you want to ride like its a motorcycle, it at the very least begins with motorcycle tires. On the race track, I overheated a bike tire enough that when I took it off the rim, all the cords were loose inside the tire. It took 45 min. You want a DOT high speed tire on any e bike that goes 60 mph for prolonged periods of time. You don't want to risk what the tour de france riders do.
 
Hub motor side covers are notoriously flimsy indeed.

markz said:
What about a direct drive motor as a mid drive?
https://endless-sphere.com/forums/viewtopic.php?f=6&t=38553&sid=239c9362e9c37a58c7768412124885a1#p562377

The days which that made sense to do have long passed.
We have fairly decent 1000-3000w mid drives available to us now.

You can go and buy a hyper efficient ( 0.25mm or lower lams in the stator! ) 1000w 1.7kg ( lightest mid drive ) or 3000w 5.6kg ( CYC Pro ) now. The only unsolved issue with mid drives is drivetrain and chainstay durability... the motor part of the question is solved.
 
Big direct drive makes a ton of sense, especially if on a motorcycle frame. For 60 mph. 40 mph a much more practical, and less expensive goal for bikes.

Never said gets from 0-40 mph slow, never said limit that. :twisted:
 
s1dewinder said:
I plan on building another ebike. I have some design goals, a rough components list, and a dream.

In short: I want a fat mountain bike e-moto conversion with dual electric drive and no shifting (single speed).

Design goals:

It must be possible to assemble the bike from existing components in the market. Required handywork must not exceed wrenching, filing, and soldering. I don't have access to custom parts or a machine shop.

170mm rear drop out fat bike conversion build (from components, not from an existing bike)

Dual electric rear wheel drive: mid drive+direct drive rear hub (don't try to stop me, this element is non-negotiable)

Must be able to handle the heat generation of full throttle on a 10% grade from a full charge to nearly dead and then roll back down the hill with regen braking. Again, without risk of overheating. Assuming a 220 pound rider.

60 MPH top speed.

Single speed

No tubeless wheels

Frame: 18” Framed Minnesota 2.0/3.0

I built my current ebike on the 20 inch version of this frame. I love it. Huge triangle space. Rides great with the seat slammed. Very much like a mountain bike but fat. Sportier geometry, like a more acute rear angle, would be cool, but I do love this frame. Going smaller, 20" to 18", should yield a small gain in agility.

Rear direct drive hub and wheel: ENC3000

I've used this motor in the past on my current bike and I love it. It's 11.94 Kv, so it is a relatively fast winding. The primary reason for using this motor specifically is because Ncyclebike told me they could send me one with a 170mm compatible axle laced into a 19" motorcycle wheel. (I'm considering going 17" for less weight, more stiffness, more agility, and more torque). They also told me they could send me an 11 tooth single speed rear freewheel for it.

Mid Drive: CYC X1 Pro Gen 2

With a BAC 855, 12/72 gearing, and an 11 tooth rear freewheel. Disable/bypass PAS and spoke speed sensor.

Rear hub controller: Phaserunner 

This controller will drive my rear hub. It is expensive, but ideal for now. The guys at Grin tech are hub motor guys and their controller comes with a suite of support for when it comes time to program it for my ENC3000. I considered a BAC 2000, but I feel there is a risk I will struggle to pair it with my ENC 3000. Also, the phaserunner's lower power will be safer on my dropouts as well as generating less heat to satisfy the 4th design goal. (Though, I will use dual grin tech torque arms, so the BAC 2000 may be an easy option for an upgrade later). This controller will handle speedometer, as well.

Battery: 72V 32AH (litespeed)

Big voltage and capacity to make maximum use of my big triangle. 300 amp BMS means my 105 amps of draw (65A BAC 855+40A phaserunner) will never challenge the battery. It also leaves plenty of room to eventually upgrade the phaserunner to a BAC 2000.

Brakes: Shimano Hydraulic Disc Brakes with 200mm or larger rotors.

Fork? (Idk yet)

I want a stiff/high speed/high performance front suspension fork. Any recommendations?

Front wheel?

Once I figure out my fork I can figure out my front wheel. 17" or 19" motorcycle wheel would be great, but I don't know how to mount that to quick release drop outs so that may violate the first design goal. 24" or 26" plus size or fat size wheel may be what I end up going with. Then, I'd need to find fast tires for the wheels.

Throttle: right thumb throttle

No twist throttle means I can grip and rip the handle bars without accidentally pumping my throttle.

According to the system calculator at ebikes.ca this sort of setup should yield somewhere between 5kw and 6.5kw of power and 85-95 ft/lb of torque. The calculator tells me a top speed of roughly 50mph, but I think that is an under-estimation due to assuming too much drag and rolling resistance. My current ebike's top speed outperforms the ebikes.ca estimation by between 5 and 13 mph depending on riding conditions, so the 50mph estimation does not discourage me from my 60mph goal.

Please let me know your thoughts about my dream bike and help me make it a reality by enlightening my amateur ebike assembling mind.

looks like you are looking for a QS205 V3 5T hub motor with an unlocked SVMC72150 controller
 
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