Yet Another "What Conversion Kit" Question

General Discussion about electric bicycles.
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Scuttling-Claws   1 µW

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Yet Another "What Conversion Kit" Question

Post by Scuttling-Claws » Nov 10 2019 3:33pm

I’m sorry for posting yet another “What ebike kit should I buy” thread, but I’m new to this world and I’m having trouble wading through all the information.

I’m an experienced cyclist, and used to bike just about everywhere, until a new job and subsequent move put me on top of a pretty decent hill. I still made it work for a while, but getting off work late, and then pedaling uphill for an hour was taking a toll on me, so I starting driving more. I’d like to bike more, so a bit of a boost up the hill seems perfect.

So, here’s all the information I’ve been told to provide.

Terrain: my commute home is a sustained climb, averaging 5% but maxing out close to 10% for short periods.

Desired max speed on level ground-I don’t have to go above fifteen, however, I’d like to get at least 10 mph on the climb home.

Max Range-It would be great if I didn’t have to charge it every night.

Budget is whatever is appropriate.

I have a couple of bikes in mind that I could convert, both 700c (my preference) and 26 inch wheels. Both are rim brakes, and bonus points if I can get wheels built for Presta valves.

The real kicker for me is that I’d still like it to feel like a bike. I don’t want a motorcycle, I just want this hill to kick my ass a little less each night. I’d prefer a front hub motor (if that’s possible) just for ease of installation. While I’m reasonably experienced with bikes, I don’t know how much power it would take to meet my goals. Weight is also a consideration, but I think that's part of maintaining the "bike" feel.

Balmorhea   100 W

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Re: Yet Another "What Conversion Kit" Question

Post by Balmorhea » Nov 10 2019 4:16pm

Scuttling-Claws wrote:
Nov 10 2019 3:33pm

Max Range-It would be great if I didn’t have to charge it every night.
[...]
I have a couple of bikes in mind that I could convert, both 700c (my preference) and 26 inch wheels. Both are rim brakes, and bonus points if I can get wheels built for Presta valves.
You didn't say how far your commute is. You also didn't say what your weight is, which matters a lot for climbing.

Motor kit wheels usually come with thick spokes and rims drilled for Schrader valves. You can use Presta valves if you like, because they fit through Schrader valve holes. There are grommets available to take up the extra space, if that matters to you. It seem like an odd request because Presta valves have a number of shortcomings versus Schrader.

If you want a well built wheel with a nice quality rim and appropriate spokes, you should buy a bare hub motor and save some shipping cost in the process.

For the purpose you describe, I think a 201rpm Q128 or AKM-128 geared motor at 48V would be a good choice. It packs a respectable amount of torque for its modest weight, and it doesn't drag on you when you're not using it. If you're very lightweight, a Q100/AKM-100 would work, and if very heavy you could consider a Bafang, Ezee, or Mac geared motor accordingly.

How much power it takes to feel like a motorcycle instead of a bike has a little to do with your expectations and a lot to do with how much power you usually apply with your pedals. Stay within that general power range, and it will feel bicycle-like. Exceed it, and you're a passenger. It's easy to get used to, though. Lately it's my pedal bikes that feel like something's wrong with them. :D

If you want a low powered motor to climb at 10mph minimum, you'll need about 20mph unloaded wheel speed.

Scuttling-Claws   1 µW

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Re: Yet Another "What Conversion Kit" Question

Post by Scuttling-Claws » Nov 10 2019 4:54pm

I'm on the larger side (about 200 pounds)

The presta request is simply that all my other bikes have presta valves, and while I know the grommets exist, it's one more thing to have to fiddle with.

markz   100 GW

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Re: Yet Another "What Conversion Kit" Question

Post by markz » Nov 10 2019 5:04pm

That is light weight to some, shall we say medium weight!
Distance and speed of ride, along with terrain gradients will determine the size of your battery in terms of Ah (distance), and Voltage (speed)

Scuttling-Claws wrote:
Nov 10 2019 4:54pm
I'm on the larger side (about 200 pounds)

goatman   10 kW

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Re: Yet Another "What Conversion Kit" Question

Post by goatman » Nov 11 2019 8:27pm

im not a mid drive guy but it sounds to me like that's what id be doing in that situation if I wanted to pedal. Andy Kilby on youtube just did a build with one and he also sells the entire bike kits. he did 72v 50amp into a bafang with a phaserunner and hes atleast 200lbs

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dogman dan   100 GW

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Re: Yet Another "What Conversion Kit" Question

Post by dogman dan » Nov 12 2019 6:50am

Hmm.. One thing I often tell new folks, don't ruin your favorite bike with a conversion. It makes the bike completely lose its bike feel, when you add 20 pounds or more of battery weight and motor weight to it, using hub motors. Can't get around that one, "bikes" are under 35 pounds. Take a 25-30 pound bike, and make it weigh 50, and now its feeling like a lead sled.

If your commute is long enough, like 10 miles or more, you are saving huge money bike commuting vs the car. Adding up all costs, cars can cost two or three times per mile what e bikes do. ( about 25 cents a mile for most of my commuters) So there is a lot of savings there to budget towards the most bike like feeling ebikes out there. Good quality factory bikes, with mid drives and modest size batteries carried on the downtube of the frame. https://www.trekbikes.com/us/en_US/bike ... rCode=grey


Anything else, starts to go towards that moped feel.. But hey,,, mopeds are great! Nothing wrong with a moped feel.. If the budget is tight,, buy a 7 speed beach cruiser, and put an affordable rear wheel kit on it. carry the battery on the rear rack, ideally one that is a welded on part of the frame. It don't feel like a bike all that much, but under power, it pedals like you got a pro racer behind you on a tandem. Its a heavy bike, but with the power, its not pedaling heavy.

This type of conversion is an ideal commuter, its got fenders, a chain guard, and you sit on it comfortable, head up to look at the traffic hazards.

On the weekend, keep pedaling your road bike, and enjoy that bike feel then.

Lastly, you will charge your battery daily, so it lasts longest.. If your ride is very long, quite possibly even a top up at work, so you make it up that hill in all weather.

MikeSSS   100 W

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Re: Yet Another "What Conversion Kit" Question

Post by MikeSSS » Nov 12 2019 10:37pm

With a conversion you can climb the climb you mention, but with normal flat land effort and flat land speed. The feeling is really good doing this. On flat terrain you can ride at your normal speed or at a higher speed. With a throttle you can ride without pedaling, even coast uphill. But, it is hard not to pedal, because that's what we cyclists do.

Geared hub motors are better than direct drive for your use. A throttle works a lot better for me than pedal assist, at least the pedal assist that is based on crank rotational speed and not pedal torque. That is a common type of pedal assist, the cheaper and simpler kind. The second type pedal assist senses how hard you push on the pedals and increases your effort using the motor. Typically there are settings from 0 to 5, 0 being no assist and 5 making it feel like you have racer legs.

The Trek I rode used torque sensing pedal assist, the amount of assist was variable. It was very much like riding pedal powered but with stronger legs when desired, even much stronger. This Trek was very natural feeling, the assist was transparent to me unless I turned it off, then its absence was very apparent.

For comparison, crank speed type pedal assist is not natural feeling to me, but a throttle is very natural feeling. I like a twist throttle a lot better than a thumb throttle, the thumb throttle I'm using caused a lot of muscle pain for the first year I used it, that doesn't happen with twist throttles. Besides the scooter and motorcycle use twist throttles, so twist is more natural.

Motors are designed to be efficient at one speed or another, depending on the number of wire turns in the motor. Fewer turns are used for high speed and high power motors but sacrifice efficiency and controlability at low speeds and high power loading, like climbing. More turns gives finer control and higher efficiency at lower speeds, but sacrifices high speed and limits total power output. A high turn, lower rpm motor would be my choice for your type of use.

A battery will last longer if never charged fully to 100% and never discharged below, say, 40%. Also, a battery is sort of a consumable. Lithium ion and Lipo batteries are damaged if charged to 100% and not used for a long time.

Like Dogman Dan pointed out, a good road bike and a good ebike host can be quite different.

Keep us in the loop as you proceed on this adventure, there's a lot to consider but the reward is very big.

docw009   100 kW

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Re: Yet Another "What Conversion Kit" Question

Post by docw009 » Nov 14 2019 2:12pm

It's hard for a DIY guy to beat the price of a low cost import, especially now that better ebikes are available around $1000. Even less. Can't come close to these Walmart specials. It costs me about $200 for the motor, and $300+ for a battery, and I've converted six or more bikes. Being a DIY guy, I'd have no concerns with these, whereas there are buyers that cannot handle a flat tire or bent derailleur out of the box, and ship a bike for that.

https://www.walmart.com/ip/Hyper-E-ride ... /568743494

https://www.walmart.com/ip/Schwinn-EC1- ... /598102543

I did buy one last Soring. It was $779 but I got it shipped for $700 on amazon. A well made bike, but I didn't really need a 20" fatbike. The Bafang motor would have cost me $250. And it's a $250 ebay battery.
https://www.ecotric.com/collections/e-b ... e-and-blue

My bike converting days aren't over though. I've got two motors sitting around. My experience is that a 8 pound motor in the rear, and a smaller 6 pound battery still makes for a bike-like ride. If you aren't looking to throttle up a hill, a 500W geared will do for a short climb.

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