My first +50mph e-bike

g4free

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Jun 19, 2017
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Hey all

I am thinking of building my first e-bike. Any suggestions on what parts to be use would be greatly appreciated.

Max speed: +50mph
Range: +10 miles
Wheel size: 26"/27.5"
Brake type: disc
Rider weight: ¬80kg
Terrain: flat
Budget: £1000 - £2000
My location: Manchester, UK
 
First this:
I'm a Noob and I Wanna Go 50MPH


then these:
https://endless-sphere.com/forums/search.php?keywords=50mph&terms=all&author=&sc=1&sf=titleonly&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
 
Hmm, I don't know you. Have you mastered the trick of laying down a motorcycle at 50 mph? If not,,,,

If you have, then you likely have the clothing for such activites. With the skinny bike tires, its really amazing how much easier it is to crash a 50 mph bike, vs a 50 mph motorcycle.

Depending on your skill set, Id suggest you practice the 30 mph crash a bit before going to the 50 mph one.
 
20mph crashes hurt when you're fat..
I'm still recovering, 4 years later.

Might wanna build something more conservative if you are not experienced.
 
See sig.
 
Bike frames and components are not so many that are making a safe ride at +50 mph. Of course you could build any cheap bike to ride 70 mph, but nobody with some brain would ride it at that speed. Easy to be able to say that your bike can do 50, but it is another story to actually do it safely and reliably on a daily basis.

45 mph and up, you need a stiff FS frame with quality components, and good wheels/tires to make a bike that will handle fine. Brakes especially, need to stop you short and neat to save your bones.
 
Do you really need to do 50 mph on a bicycle ? Do you understand that once you start going above 17 mph, the issues of drag result in major efficiency losses .

Stick with top speed of 30-35 mph, and I bet you will find you wont even use that top speed all the time and will be happy to cruise along near 20 mph, and enjoy the ride and the scenery.
 
My current e-bike quickly accelerates to 30mph and then struggles to reach 35-40mph.

I want something that can quickly accelerate to 40mph. I quoted +50mph thinking that actual road speed would be 80% of that.
 
So you are saying you do know how to lay er down at 40 mph? And have the clothing.

40 mph club is easy, 72v 40 amps controller, and a strong 72v battery. Nearly any direct drive motor can handle the 3000w for a short ride at full 3000w. Tires, frame, etc will be pushed to the limits, but for a sturdy frame, hitting 40 mph at times will work. It will still be very easy to lay it down if you start cornering much over 30 mph though. Or, surprise a car and have to do the laydown for your life. OWWW, but it beats hitting that car at 40 mph head on. Because the tires are inadequate, you can just about forget brakes being much help at 40.

50 mph is a much bigger ante. I once wore out a tire in 45 min running 50 mph power. It cooked the tire from the inside. The crash was fairly comfy, since I was wearing full body armor. (this was on a race track) The motor and battery have to double in size, weight, and cost. Your tires and most likely the frame are pushed more beyond the limits.

Oh sure, you see those racers hit 50 mph daily.. and the mechanic gives em new tires and brakes, daily. And they know how to lay er down, but dressed the way they are, they go to hospital when they do.

The best way to do 50 mph +, is to get a machine made for it. My yamaha scooter did 90 mph easy, had tires I could count on, and cost less than most of my ebikes. I did screw up once, got into the gravel, and layed it down at about 45 mph. The body armor helped me ride away from that one with two broken ribs, nothing more.

" I won't crash" YEAH, RIGHT.
 
Laying her down and go for a slide is not so bad when you are not nervous. I have had some scratches and burns, but did it so many times that I can do it without any protection. The cell phone does take most of the rub. I slide on the Iphone 50 ft and it cost me 110$ everytime 8)
 
dogman dan said:
.... Have you mastered the trick of laying down a motorcycle at 50 mph? ...
I have done it a couple of times but I have yet to 'master' it. A bit more the other way round but I did walk away each time.
 
I have made many bicycles that go 50MPH
It is unwise... they are unstable and do not have the gyroscopic benefits of a motorcycle

35MPH is plenty fast.
It is acceleration that gives you a thrill... speed just peels off your skin.

If you are going to do it anyway, please wear gear equivalent to Motorcycle Gear.
If you fall... you will slide for many seconds on the concrete
Your skin will rub off in that case... or you may start tumbling

It is not a joke.

-methods
 
My scooter does just under 50mph and on the straights it's great fun but when a bend approaches then not so much, Wheels need to be better balanced and stronger to cope with giroscopic forces and the frame will be storing alot more kenetic energy over small bumps etc, but it's doable on your budget easy I got to 48mph for less than £500 with good buys but Im using 6.5 tyres that need good balancing or the wheel hops like mad and makes its as silly and dangourous as it's rider.

Go down the diy route I would myself and wait for a good bargain you will learn a ton and feel more attached to the end product just plan well and read lots of good meaty threads for tips and info and remember if the ride feels and looks dodgy then it most likely all ready killed someone.
 
methods said:
I have made many bicycles that go 50MPH
It is unwise... they are unstable and do not have the gyroscopic benefits of a motorcycle

35MPH is plenty fast.
It is acceleration that gives you a thrill... speed just ...

You are making it look like it is impossible to build a bike that is fine and safe to ride 50 mph. It is expansive and does require some experience but it can be done, even much faster. My daily commuter beats the 70 MPH and riding 50 does feel very safe and comfortable, better than most motorcycles that I've had. Acceleration is fun and sometimes part of safety, but top speed is also important to ride with cars around and still have acceleration as an option to evade a collision.

I just believe that building high speed and power without the investment to make it a safe ride is stupid. That is the warning I give to those who do have that ambition. Yet, after seeing many who did, I noticed that none of them are riding fast very long on bikes that are not built for it. When you commute at 50, you build accordingly or soon deserve a Darwin award. :wink:
 
How about a kit that can average 40mph and a good quality bike (preferably second hand)?
 
Dogman is right . A big dd hub and 72 volts will do it . But look at MadRhinos bikes in his sig. Quality bikes , motorcycle tires , hyd. brakes etc. A lot of money for sure but cutting corners at 50 mph. would be bad idea.
Check out pinkbike and post a couple bikes you like and the sphere will tell you the good/bad.
 
I saw a great video with Neil degrass tyson on kenetic energy vs objects and it's the basics of mosts destructive failures.
The strength holding the object together once over come makes the object explode, it sounds simple enough it's why astroids are vaporized on impact the kinetic energy is so great it breaks the bonds of the atoms themself's.
So what does this mean for us well basically at the higher speeds the more stored kinetic energy we have so ride fast enough and even a small stone will colapse the wheel in or push the forces on to the next weakest link in the chain.
So it's safe to say when pushing components we are on a knifes edge of invisible math constantly fluctuating over the rides preasure points and to me anything beyond 10% on top of stock stats of a part starts to get to the realm of serious upgrading and thought to safety.
 
Ok... if we are encouraging it...

My first ebike went 45MPH out of the gate because I did my research. I bought it as a kit and modified it.
Nothing but a cruiser bike with 4pcs 6S 4.5Ah in series (original plane white shrink Hobby City packs, no markings)
No BMS, No special charger - bulk charged with a supply.
Motor was an old Crystalyte 5405 (the lower KV)
Controller was standard Crystalyte 12 fet - but I swapped the fets and changed LVC
Brakes were PEDAL BRAKES

Know what? Went 45MPH... :shock:

Accelerated hard

Then I took a long journey
Added a drum brake to the front
Welded bosses and added a V-Brake to the front
Bought full face helmet, Jacket, gloves
Doubled the battery
Started bumping current limits further - got into Kelly controllers
Twisted the axle out of the shaft of the motor...

Discovered that I need suspension and lots of it
Big tires with a strong bead
Disk brakes - large - front and rear
Bright lights

In the end... what folks are talking about is building a light weight motorbike.

Industry capped ebikes at bicycle limits. This was stupid.
I would cap them at 35MPH and as much thrust as you can handle (no power limit).
Over 35MPH what you have is a Moped or Motorcycle or some other device which can destroy your body in surprisingly subtle ways.

As far as regulation goes... in the US there are 20,000 laws on the books... JUST FOR GUNS.
That's just guns... not everything else... so - what I propose is that its time for a clean sweep.... or a timer starts on every single law such that it takes a lot of work to keep it in place.

How did I get off on that rant?

-methods
 
I liked the explination of your rides sounds like most of us with a thirst for more power, as for laws with timers sounds a great idea i like it patents have them, damn in the uk I read we still have a law that u can go round the back left side of your horse and cart shout release 3 times and go for a pee, Is it taking the piss or not ? I dont know :lol:
 
g4free said:
Hey all

I am thinking of building my first e-bike. Any suggestions on what parts to be use would be greatly appreciated.

Max speed: +50mph
Range: +10 miles
Wheel size: 26"/27.5"
Brake type: disc
Rider weight: ¬80kg
Terrain: flat
Budget: £1000 - £2000
My location: Manchester, UK

Well, I guess you've gotta start somewhere. Remember there is a pretty steep trade off between high speeds and efficiency. 50 mph uses way, way, way more power than 35 mph. If range is any concern you will soon find yourself going easier on the throttle.

• You should be prepared to invest a lot more than you think

• Use heavier grade components that bicycle. 16 inch moped rims and tires (20 inch bike is the same rim diameter), disk breaks, full suspension etc. Check out some of the scooter motors made by QS Motor, they might interest you.

• Wear appropriate protective clothing. I've discovered this is hard to do if your vehicle is designed to be pedaled. A combination of motocross and DH gear works but you look pretty Road Warrior which attracts attention.

Good luck.
 
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