Affordable and fast possible ?

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bikermice

1 mW
Joined
Jan 8, 2014
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Hi everyone, i'm new here and would like to know if affordable and fast can be put into the same sentence with regards to building an E-bike ?

Just to mention i have a cycling background and am used to going fast, however for an e-bike i would only occasionally want to go to 80 km/h

Can anyone tell me what i will be looking at cost wise to get that speed on a mountain bike the most affordable way, i was thinking perhaps to convert a merida or gt.

I only need around 15km range, i will be ok with 10km if 15 0r 20km range will cost too much.

I was thinking about using hk turnigy batteries.

What motor, batteries (brushless ?) and controller would be a good choice ? And what do you guys think the final cost would be ?
 
The cheapest fast, is generally 20s lipo. 5 ah of it will be cheap up front, but a 40 amps controller combined with deep discharges can result in a quick battery wear out. So 20s 10 ah is better. Any more, with the cheapest motors, will melt them. So 10 ah max.

Then put that on the cheapest dd motor kit you can find like the Yes.com 1000w kit, but replace the controller with a 72v 40 amps model. Again, the cheapest one on ebay, rather than something nice from Lyens or Grin.

Definitely can be done well under a thou USD. That's the recipe for the cheapest 40 mph club membership, unless you got the connection for free batteries at the recycle place.

Yes, other motors can take 24s better, and that is faster. But not the very cheapest.

Surviving riding such a cheap hot rod ebike is another story. Hopefully you got some disk brakes at least. But at 40 mph, brakes won't matter near as much as not being stupid enough to ride it in much traffic. Dawn patrol, less cops, less cars. Still just as fun but a lot less stupid.
 
80kph is approx 50mph

80kph brief burst speed, or 80kph for 10/15/20km? Huge difference in motor and battery requirement.

Also, what is "affordable"? I would assume that someone who has ridden at 80kph unassisted would be buying premium quality bicycles.
 
Yeah, 80kph is going to take 24-26s. And then the cheap motor melts in about 7 miles.

So 80kph fast is going to cost more. You'll melt even more expensive motors, unless you go with the 145 mm wide stuff....

Which means it won't fit the cheap bike anymore,

What do you think, at least double the cost to go 80 kph vs 65 kph? Reliably that is.

40mph club, 65 kph is pretty cheap though. Not counting the ambulance ride.
 
dogman said:
Yeah, 80kph is going to take 24-26s. And then the cheap motor melts in about 7 miles.

So 80kph fast is going to cost more. You'll melt even more expensive motors, unless you go with the 145 mm wide stuff....

Which means it won't fit the cheap bike anymore,

What do you think, at least double the cost to go 80 kph vs 65 kph? Reliably that is.

40mph club, 65 kph is pretty cheap though. Not counting the ambulance ride.
Click to expand...


lol.... :D you cracking me up here.... (...i can't even pay for the ambulance ride...doh..)

Well from your reply i guess 65 km/h would probably look like the better choice.
Agreed doing these kind of speeds in traffic is stoopid. I just like to have the extra power/speed.

I'm thinking converting something like a merida matts or perhaps a dual suspension frame, under 1000 $ sounds very good. don't like melting motors however i'm sure i wont's be riding at full beans all the time, so 80 km/h would be nice so i can keep a cruise at 55 to 65 kph knowing i have not maxed out the setup.

You see i have a choice, get a 2k 250cc or 400cc motorbike, or try an e-bike conversion to commute to work and back which is roughly 6km away from where i live.

Punxor thanks i was wondering about the difference in price wrt 10km and 20km radius, i was thinking if i would settle for say 12km radius i could perhaps build a faster machine from the cost savings compared to 20 km radius.
wrt to quality equipment, i went at over 80km/h with a gt avalanche which cost me around 600 us back then, probably double the cost now, the bike was very good quality i must say, back then shimano deore lx hardware was included at that price, everything was lx, and it's as if lx back then was even better made than lx components from today, i have not tested the new stuff, that's just from a visual observation wrt my own perspective, anyway, the bike never gave me any problems, it's as if they had put more "passion" into building the bikes back then as compared to today's stuff which is so much more mass produced, or perhaps there's a company selling pirate components labeled as the real deal...lol.. i won't take this further it might not be the case, however that bike never failed me, except for the stem after 8 years, which i replaced with easton.

So what would you guys prefer, the motorbike or the e-bike conversion ?
 
I've had an 80cc scooter that I used for a 12 mile one way commute, I've ridden it on a bicycle and wasn't my cup tea. The bicycle allowed me to use bike lanes to stay out of traffic, the scooter could keep up with 45mph traffic, but noone saw me, I was invisible. I still don't have an Ebike, but want to build one, I did buy a $2k 250cc motorcycle and couldn't be happier. The real motorcycle gets the same gas mileage as the scooter unless I goose it or ride it on the Interstate, and it's big enough that I am more visible and can jump out in front of traffic.

Bottom line, both an ebike and a motorcycle have their place. I want both, you might too.
 
Depends on what you call affordable and fast. This is where I'd start with 24s lipo. I think these are the same motor. Note axle size. I'm pretty sure it's 12x16mm.
http://www.ebay.com/itm/3000W-100KM-Hour-Electric-Motorcycle-Motor-Extreme-power-and-Extreme-speed-/390735270517
http://www.ebay.com/itm/Electric-Motorcycle-Conversion-Kit-3000W-Brushless-Motor-w-gear-disc-brake-/261361874093
 
I assumed that affordable meant under a thou. So I was thinking 40 mph top speed was a lot more affordable.

But 6k distance? Hell, the cheapest dd motors will go that far without melting easy. Get a cheap DD motor, and let er rip with 20s, 24s, whatever. 5 ah of higher than 20 c rate battery might be enough too! Hell go for it. If you undercharge a bit, you can even still use the cheap 72v controller with 24s.

That's a really interesting motor Wes pointed to, if you can weld. Then it won't be expensive to make your new 145mm wide swing arm, and the dropouts to hold a monster motor. That is the motor, or one like it, if you really want 50 mph for longer distances. The nice thing about that motor, is you can get it in a motorcycle rim, and use tires that will last longer.

But hauling ass like that in the street, whether you get the bike or the motorcycle, they will turn in front of you. Dress for it.
 
Thanks Dogman and Wes.
The look on people's faces when i pass by at speed.. lol... Especially in south africa, no one knows about these things here... it will be like holy...shhhzz check this bloke... !

lol... man this is tempting... i should've never asked this question look now at the options i have been given... :D

Thank you both, i like the second link with the black hub/rim.

So is all inclusive there ? esc/motor rim/brakes/disc ?

Will two of these provide the necessary beans to carry me 12 km ? Or do i need 4 of them: ( making 2 separate parallel packs and connecting them in series? )

http://www.hobbyking.com/hobbyking/store/__26789__turnigy_nano_tech_a_spec_5000mah_12s_65_130c_lipo_pack.html

Dogman so are you saying this wheel won't fit in a normal MTB frame like a merida matts ? See the thing is, i'm not going to pump the throttle, acceleration will be slow and controlled and i won't be doing any off road, i'll be carefull not to stress the frame (if esc works smoothly ?) all going to be straight flat tar mostly. I'm thinking if i need to buy a different frame, cost might be adding up and a 250cc motorbike perhaps might be a better choice... (motomia) 18-19000 zar here (about 2.5k us $)

I'm thinking perhaps spend 600 $ on frame and 1.5k on everything to get it going.

I just love the concept of having something electrically powered if within cost frame above will make me a superEbike :D :D
 
4 of these is the same as the 2 12s packs and will only cost a fraction of the 12s packs. You could buy 8 of these for a lot less than just 2 of the 12s packs and get twice the distance.
http://www.hobbyking.com/hobbyking/store/__9176__Turnigy_5000mAh_6S_20C_Lipo_Pack.html
 
Awesome, thanks Wes :D Should i go ahead, i will definitely use the cheaper packs ! :D

If anyone can comment wrt to my other questions regarding the frame ?

I take it the esc is included, is this a brushed or brushless motor ? (2nd link)

i would think brushless would be the way to go... ?
 
Normal MTB bike rear frames are 135 mm wide at the axle. The "bike" motors are 135 mm. That monster motor is wider, and fits motorcycles or the downhill bikes that have 145 mm dropouts.

I think the cheapest way is all you need. 20s, and a cheap motor. 5 of those cheaper packs to begin with, and a 72v 40 amps controller.

But, your battery will last longer if you get 10 ah. 10 of the inexpensive 4s packs. You will run out of battery just a few miles before the motor melts, so your 6 k ride will go fine with the smaller cheaper motor.

It will still make people look at you like this, :shock: You will cruise at 35 mph at least, and will just hit 40 mph at the start of the ride, when voltage is highest.

40 mph club will still wear out your tires fast enough. Above 40mph, I definitely start to recommend a lot more money be spent on the bike, brakes, moped tires. All stuff you can get into later.

The following is more aimed at others reading, not you. You have gone fast on bikes, but do bear in mind, once you strap a motor and batteries to a bendy bike frame, the handling will suck compared to a normal bike.

Getting into the 40 mph club (65 kph) with your first ebike is hazardous enough. We get a lot of folks here that build a 30 mph bike, then a month later we get to read about the trip to the hospital. This is not usually from guys who rode motorcycles much, but from people with little experience even on bicycles.

It's like this, now you are on a motorcycle, if you built for 40 mph. But it's got weak bike tires and brakes. Real easy to lay down a 40 mph bike with those tires. Are you expert at laydowns? If so, put on your armor and let er rip. If not, think hard about faster than 30 mph. And stopping, if you ride motorcycles you already know. You never stop in time, it's all about just threading the needle to miss that car.
 
If you are serious about going 80 you need to first think about a frame.

This thread below will give you good ideas. It's important to make sure when building a bike for speed that the dropout are well fabricated. torque arms will be required on both sides. The bike will be producing close to 4 kilowatt of power to get speeds of 80kms an hour.

Downhill frame with removable dropouts. I had a norco for a while, actually still have the frame and they're tough and made for speed. I run a 2.5 times schumph drive as well.




http://endless-sphere.com/forums/viewtopic.php?f=2&t=34000&p=793461&hilit=Removable+dropouts#p793461
 
Yep, and in general it's leaving that affordable description behind, if affordable is considered to be less than $1000 usd.

Lots of great flyweight motorcycles with pedals to be seen here, but often the starting point is a bike that might retail at $2000 or more. $1000 forks are not remarkable in that class of bike.

If I had the cash, I'd start with the greyborg frame.

When I build my affordable 47mph bike for the track, I started with a 20 dollar frame. It had once been a top of the line quality hard tail steel mtb. A very stiff frame, so minimal high speed wobbles and felt good in 30 mph corners. The motor was hoped to last 12 laps. But I got a flat tire, and used more watts leaving the corners and flamed out of the race on lap 10. I had about $1500 in the bike, $1000 of it in two sets of batteries so I could run a heat and then immediately run the main event. It was competitive, but not a winner, till I flatted the front tire and had to run half of the main with a flat.
 
Thank you both for the info, i think i'm going to take some time and think thoroughly about whether i should do this or go with a motorbike, the link to the dropouts thanks, that might be a good option, i was wondering if the bike will handle much different with a powersystem than without, so now i know it will handle differently.

So now it's a tough call: a motorbike of 2k can handle all the power and conditions.
can go around 300 km on a full tank which will cost about 200 R to fill (about 28 us)
But it's a petrol maintenance prone machine.

Electric will be super reliable, super smooth, quiet, basically maintenance free and easy to store.
But i will have to charge the pack each day. And handling won't be as good as a proper motorbike, (but then again i'm not planning on racing at 80 km/h, just touch that speeds on a straight quite flat road once in 3 months or so)

mmmmm.... lots to think about...

Thanks guys if or when i go ahead, i will definitely post my idea and would welcome any opinions.
 
Thanks deffx, at the moment i'm thinking the same, however won't be able to afford both, so might go the motorbike route thx. But still would like an e-bike, so perhaps do one as a long term goal as you say. Just going to take much longer... :(
 
bikermice said:
Thanks deffx, at the moment i'm thinking the same, however won't be able to afford both, so might go the motorbike route thx. But still would like an e-bike, so perhaps do one as a long term goal as you say. Just going to take much longer... :(
Click to expand...

Bikermice as far as I'm concerned you're not really serious.
 
If you want to go fast (>50 km/h) on two wheels and you don't want to pedal, AND you don't want it to fail within hours or days, expect to pay well over $1000.

The electric motorbike/scooter option could be what you're really after, but that's well north of $4000.

We're not doing this for the cost savings :lol:
 
An option is to build a commuter say 48 volt. Good frame, I have 2 Phasor frames, I'm not saying that they're the best but they're an option. I'm now running one at 48 volt for commuting. It will still do 40 Kms an hour, and the second Phasor is 88 volt 70kms an. Hour with 17 inch motor cycle rims. One with a Cromotor and one with the 4080'. I've run them on different controllers both with different results.

As I have found out due to building 2 high powered bikes it's helped with previous knowledge from previous experience and that's come at a cost.
 
Bicycles aren't reliable or maintenance free - absolutely no where near automotive levels. Low powered ebikes are no better. Keeping a high-powered, DIY ebike going will likely be a hobby in itself.

As above, most people have ebikes for niche needs or purely for the fun of them. They aren't a cheap substitute for a car or motorcycle for the average person.

Sounds like you want a motorcycle ;)
 
One thing to definitely consider, is the additional cost of a motorcycle, in tags and insurance. Insurance could be very costly depending on who you are. At my age, with 40 years of having a motorcycle license its cheap to insure a motorcycle. Interestingly, the cost per mile of the 50 mph scooter and the 25 mph ebike were nearly identical, at about 15 cents per mile. But more expensive insurance can double that.

You may really want and need insurance, if you really plan on playing with traffic at above 30 mph. Even if you don't hurt somebody, hit somebody and now you are talking to cops about your illegal homemade motorcycle. It will be mentioned, if you were going 40 mph. IMO, riding a really fast ebike in traffic illegally is asking for trouble. Much different from track riding, or sneaking one out sunday at dawn.

Cheapest of all, is a legit, legal in your state, ebike. But likely you will be going 20 mph ish. No big deal really, your ride is very short.
 
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