Purchase new or DIY

IanNoob

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Jun 28, 2022
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I'm new to ebikes.
My issue -- before purchasing , contemplating getting a Biktrix ultra fs pro.
Comes with a bafang m620 mid drive and 11 speed rear cog.
What would be the upper speed limit of such a drive combo without the governed speed restrictions programmed in
I'd like to be able to go faster than the 28mph advertised in throttle only mode.
My communication with someone from that company said not doable. Is it ir isn't it? Or maybe I need to build my own?

I'd like to have an upper limit 45-50 mph
Cruise at 30-35 mph
Range 75-100 miles
Weight 185 lbs
Budgets no issue

Skill level -- worked on aircraft 15 years, currently electronic tech on light rail vehicle mass transit
So I think assembling my own wouldn't be much of an issue.

Are new bikes easy to reprogram or if I have to DIY my own il would like to purchase a dedicated frame that accepts a bafang mid drive m620 . I DO NO WANT TO DO A CONVERSION.
If there's substantial savings on a DIY I'd like to do that

Advice pls
Thanks
 
You might be better off looking at e-motorcycles. Bicycle components are not designed for those speeds. The cruising speed you want should be doable, but not with that range. Most of your power will be needed to overcome air resistance at those speeds. So you will need a large battery and the more aero your position on the bike, the better. Depending on the size of the battery, you can probably expect 20-30 miles of range? The top speed you want might be possible with an aero position on the bike, the right gearing, and perhaps the Archon X1 controller upgrade to 2300 watts. You can play with the motor simulator at Grin. They don't have the m620, but you can use the BBSHD motor.

https://ebikes.ca/tools/simulator.h...2&tr=11&batt=B5220_GA&axis=mph&frame=mtn_tuck
 
You should plan on a DIY as there are no off-the-shelf ebikes that can hit those speeds with that range. You'll need 2,500 watts of power just to hit 50 mph with no hills and no wind.
 
IanNoob said:
I'd like to have an upper limit 45-50 mph
Cruise at 30-35 mph
Range 75-100 miles
Weight 185 lbs
Budgets no issue

You mean bike weight 185lbs, right? Is that max?

Checking the Grin simulator using my bike as an example, I would need a 72V 75Ah battery to maintain 35mph for 100 miles.
https://ebikes.ca/tools/simulator.html?motor=Leaf%205T&batt=cust_72_0.05_75&cont=cust_70_200_0.03_V&hp=0&axis=mph&frame=mountain&autothrot=true&throt=78.5&grade=0&wheel=25i&mass=110
That's a lot of weight, so I'm in agreement that an electric motorcycle is likely a better choice, and way safer. The lower end electric Harley might be a good option, since budget isn't an issue. It has decent performance. The fastest model e-Harley does 160 and 0-60 in 2.5 seconds, so pretty much the same specs as my gas bike. I've seen a couple of other e-motorcycles around, and they seem pretty decent too.

BTW, those Bitrix bikes are pretty popular; I see a lot of them, but mostly the step thru models. They seem to have a decent build quality. I see a couple of elderly ladies riding them around, tearing up the streets and bike paths, LOL, long braided gray haired ponytailed bikers. My bike may be faster, but they never slow down, so I don't even try to keep up.
 
IanNoob said:
I'm new to ebikes.

I'd like to have an upper limit 45-50 mph

I'm going to second what RunForTheHills said and also suggest considering an electric motorcycle. While it might sound fun (or safe) to go 50mph on a bicycle, I kind of doubt you'll feel that way after you do it. I can hit 30mph on my ebike, and every time I do I tell myself "that's too fast for a bicycle, you shouldn't do that." I have ridden motorcycles all my life, and I can honestly say that there are only a few bicycles out there that are going to feel safe above 35mph.
 
Diggs said:
You should plan on a DIY as there are no off-the-shelf ebikes that can hit those speeds with that range. You'll need 2,500 watts of power just to hit 50 mph with no hills and no wind.

My calculation says that I personally (very tall, very heavy, assuming 150 lbs of bike) would need more than 6500W at the wheel to maintain 50 mph on the flat. That means 8000 to 10000+ watts from the battery, depending on system efficiency and how well the top speed approaches the maximum efficiency speed.

I think pretty much anybody would need aero aids to hold 50 mph with only 2500W.

So, the OP should be advised: you will not go that fast with a Bafang whateverdoodle and you will burn it down if you try. And forget fat goofy tires if you want to go fast. You might as well drag a footlocker on a rope.
 
You are not going to be pedaling at 50 MPH anyway.
Koppla Gator Fat Tire Electric Motorcycle
https://kopplamoto.com/products/koppla-gator-electric-motorcycle?variant=41779380289730
 
Chalo said:
My calculation says

This is what I tend to use for those calcs. How accurate it is I don't know - https://www.gribble.org/cycling/power_v_speed.html
 
IanNoob said:
Are new bikes easy to reprogram or if I have to DIY my own il would like to purchase a dedicated frame that accepts a bafang mid drive m620 . I DO NO WANT TO DO A CONVERSION.
If there's substantial savings on a DIY I'd like to do that

Be aware that limiting yourself to a CAN bus motor (as I did in also selecting the M620) severely limits your machine's malleability and exposes you to very poor motor programming. I consider myself fortunate that my M2S bike allows me to change the top speed on-bike, and deeply unfortunate because the programming is trash that I can't change.

I would agree with the other assessments here - if you're wanting to cruise at >30mph and surge to 50mph, you should probably look more at the e-motos or at the very least the Sur Ron "pedaling is optional" type.
 
Yep, like everybody has said, bicycles are not robust enough to meet your specs. Just to consider doing what you want to do means you will have to start converting your tires to moped tires, building a custom frame to hold enough batteries to equal the weight of two 50lbs sacks of cement, suspension that doesn't bottom out simply by you sitting on your bike if not before. Not to mention a breaking system to handle the inertia of stopping while the trailer you are towing that houses your humongous battery is pulling you in a circle.

Opitions? Convert a downhill bike that has less range. 50mph is doable, but not for long and very dangerous for components build to take lesser stresses. Think cruising at 15mph for 20 miles.

Or, build a custom hybrid downhill bike/moped frame that might get you closer to what you want. 100 miles at 35mph is doable, but you are going to have to basically build a motorcycle with a pedal system from the ground up.

Step 1: Play around with the grin simulators to get an idea of efficiencies. (start here: https://ebikes.ca/tools/simulator.html?batt=cust_72_0.2_100&cont=C40&mid=true

Around here we think in terms of 25 watt hours per mile. The faster you go or the more you stop and go the more watt hours you burn.

I tend to use 27 watts per mile averaging 12mph due to the stop and go city I live in.

Basically, (and I do mean basically) volts ='s speed and amps ='s torque you will need a high voltage bike to do what you want. Think something like 72v at 40 amp hour battery as a place to start. Use that as a starting point to explore component size and weight of what you may want.

Also, study Luke's "death bike" to get an idea of what a high powered bike is about. [youtube]lnGvSEcldzQ[/youtube]

:D :bolt:
 
rick_p said:
I have ridden motorcycles all my life, and I can honestly say that there are only a few bicycles out there that are going to feel safe above 35mph.

Crashing at over 35mph even on a motorcycle brings a high probability of serious injury or death. Bicycle or motorcycle, neither feels safe or is actually safe. :lol:
 
There are plenty of builds in the "40 mph club" so you don't need to study and calculate a lot of theory. Its known, and it's expensive.

Anything over 30 mph will benefit greatly from aero mods. Without a front and rear partial body, 50 mph will take twice the horsepower, and the battery range will be cut in half.

I'm not saying to don't do it, in fact whatever you do, I'd like you to take pics of the whole process.

Any stock 28-mph ebike is going to be fairly pricey, and modding it to do 50-mph will just fry the motor. Famous ebike hot-rodder LFP started out this way. Start with a steel frame, it makes welding easier and cheaper.

The LightningRods big block motor can do 50-mph, and it will just get barely warm after a while. It would last for decades.

One of the problems you will face is finding a controller you like. High amps means a fat controller, but a slim high voltage controller means a more complex battery and BMS. You get to choose your poison.

Are you willing to reveal what you'll be doing that requires 50-mph?
 
Diggs said:
Chalo said:
My calculation says

This is what I tend to use for those calcs. How accurate it is I don't know - https://www.gribble.org/cycling/power_v_speed.html

Here's the one I use:
http://kreuzotter.de/english/espeed.htm
 
Chalo said:
Here's the one I use:
http://kreuzotter.de/english/espeed.htm

This is a great one to illustrate the power requirements. An "average" user of 5'10" @ 165lb on a 120lb bike (roughly how much a Sur Ron weighs, IIRC) on medium-width slicks requires 900W to sustain 31mph. To travel 75 miles at that speed would require about 2.5 hours, so 900*2.5 == 2250 watt-hours. For comparison's sake, most commercial removable batteries (regardless of voltage) tend to top out somewhere around 1400W-h and weigh 10-15lb. A 72V Sur Ron or similar would probably satisfy your requirements, but those are arguably not bicycles, nor using a Bafang mid-drive.
 
Heh - I just stumbled across this 8,000 watt hub motor and controller on Amazon. I'm not saying it'll live up to those specs but I guess the speeds and distance requested by the OP is more feasible than I first thought if you can find a bike frame to carry that much battery.

https://www.amazon.com/NBPower-Bluetooth-Electric-Conversion-Controller/dp/B07KNP86QB?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=AJ92L3D6HFN3B
 
boudin said:
Chalo said:
Here's the one I use:
http://kreuzotter.de/english/espeed.htm

This is a great one to illustrate the power requirements. An "average" user of 5'10" @ 165lb on a 120lb bike (roughly how much a Sur Ron weighs, IIRC) on medium-width slicks requires 900W to sustain 31mph. To travel 75 miles at that speed would require about 2.5 hours, so 900*2.5 == 2250 watt-hours.

Keep in mind that it calculates watts required at the wheel. Motors average 80ish percent efficiency if kept in their happy speed range, and controllers take another little bite of 5-10% depending on several factors. So our electrical watts and watt-hours available have to account for these losses.

I always select "robust touring tire with thread" (sic), because that's what heavily puncture protected bike tires are like. And I always set the pedal RPM to 1, so I can separate the aero drag of pedaling from the motor's performance.
 
e-beach said:
Also, study Luke's "death bike" to get an idea of what a high powered bike is about.

:D :bolt:

That is SICK (in a good way).

So, if I'm understanding all this correctly, if I wanted build "The Bat Out of Hell" eBike, as in a bicycle not a motorcycle, and I don't really care how far it can go, all I really care about is that the front wheel comes off the ground or the rear wheel leaves rubber on the pavement when I crank on the throttle... What I would need to accomplish a build like that is, a battery with a lot of voltage, but not necessarily a lot of amp hours to keep the weight down, and matching hardware (controller and motor that can handle it) so as not to have a melt down. Is that correct? Bear in mind I'm only asking about theory, I understand that off-the-shelf materials to build something like that may not even exist.
 
It isnt too hard and very satisfying to build a cheap DIY ebike on a full suspension frame with a 1000w + rearhub DD motor and thick phase wires that can scare you with a 72v battery.. Torque arms , Slime tires and well fastened components are a must.
 
MxusMick said:
It isnt too hard and very satisfying to build a cheap DIY ebike on a full suspension frame with a 1000w + rearhub DD motor and thick phase wires that can scare you with a 72v battery.. Torque arms , Slime tires and well fastened components are a must.

I have a sturdy old Pedego rigid frame bike with a more recent 1000w rear DD hub motor on it. The battery is 48 volt and the controller is labeled as only rated for 48 volt. It is a back up bike for me now because I have purchased another bike since then that is better suited for my commute, so now you have me thinking 🤔 about upgrading it to 72 volt. I actually have a slightly older Phase Runner II controller rated for 72 volts, but will I need a 72 volt throttle? And will I need to change the existing phase wires that go to the inside of the hub motor, which look to be about 12 or 14 gauge to me? Beefing up the phase wires sounds difficult at best because the hole in the axle doesn’t look big enough to fit three 10 gauge wires.
 
rick_p said:
...... Beefing up the phase wires sounds difficult at best because the hole in the axle doesn’t look big enough to fit three 10 gauge wires.

Beefing up phase wires in a through axle hub motor is a real pain. I did it with 10 awg motor wire with a couple of layers of shrink tubing. It was real work to get them into the axle and they are rigid coming out of the axle so I am careful not to catch them on anything that might cut the insulation and short them.

However it works.

:D :bolt:
 
rick_p said:
MxusMick said:
It isnt too hard and very satisfying to build a cheap DIY ebike on a full suspension frame with a 1000w + rearhub DD motor and thick phase wires that can scare you with a 72v battery.. Torque arms , Slime tires and well fastened components are a must.

I have a sturdy old Pedego rigid frame bike with a more recent 1000w rear DD hub motor on it. The battery is 48 volt and the controller is labeled as only rated for 48 volt. It is a back up bike for me now because I have purchased another bike since then that is better suited for my commute, so now you have me thinking 🤔 about upgrading it to 72 volt. I actually have a slightly older Phase Runner II controller rated for 72 volts, but will I need a 72 volt throttle? And will I need to change the existing phase wires that go to the inside of the hub motor, which look to be about 12 or 14 gauge to me? Beefing up the phase wires sounds difficult at best because the hole in the axle doesn’t look big enough to fit three 10 gauge wires.

I ran my cheap ebay 1000W hub on 20S for about a year before upgrading to my Leaf motor. If you're only going to be doing burnouts and wheelies, you probably won't need to upgrade phase wires. If you plan on running full throttle all the time, then you may want to consider it. It was pretty fun running at around 50A. If you get bored with that, the wider stator on the Leaf and 70A-80A commands some respect. It also has skinny phase wires, but 7kW bursts aren't an issue.

https://endless-sphere.com/forums/viewtopic.php?f=6&t=97945&start=75#p1590048
 
Ive read that beefing phase wires from the controller to outside of axel is ok, and the throttle should be fine, but I am no expert like Amberwolf. 72v batteries are pricey and thats alot of speed for a hardtail. I feel safer with a bigger front tire 26" and smaller rear 20", I put on BMX bars also to bring the front up and put me in the backseat. I have 36v batteries which is about 20mph, I have tried a 60v battery once and went closer to 30mph, it was a little creepy with no helmet on a regular bike. You dont want to have a surprise failure any faster, I ride motorcycles too, 05 Honda CRF450, so I know what fast is.
 
MxusMick said:
Ive read that beefing phase wires from the controller to outside of axel is ok, and the throttle should be fine, but I am no expert like Amberwolf. 72v batteries are pricey and thats alot of speed for a hardtail. I feel safer with a bigger front tire 26" and smaller rear 20", I put on BMX bars also to bring the front up and put me in the backseat. I have 36v batteries which is about 20mph, I have tried a 60v battery once and went closer to 30mph, it was a little creepy with no helmet on a regular bike. You dont want to have a surprise failure any faster, I ride motorcycles too, 05 Honda CRF450, so I know what fast is.

My normal riding speed is 18 mph; maybe up to 24 mph if I'm in a hurry. But I can ride along with traffic if I'm forced to, and I have the option of throttle to get me out of a hairy situation; which can be necessary if braking or maneuvering aren't options in the situation. I'm on an ebike to avoid riding a motorcycle, since I don't have the reaction time that I had when I was younger, and on a motorcycle, I like going fast. I have 300k miles on motorcycles, and I'm still alive. There were so many situations where the only available escape route was to apply a lot of power and get ahead of the problem; so for me, it's safer to have the power on tap, even if you don't use it. My wife knew that too, and would never ride passenger on a smaller bike. If it wasn't over a liter, she wouldn't get on it.
 
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