Alex_alex

Hello everyone,

This is my very first post on this (or any other bicycle) forum , so forgive me if my questions seem very basic. I would like to setup my first e-bike and would like it to be 48v 1500 watts. I currently own the Scwhinn Women's Trailway 700c/28" Hybrid bike from Target.. The challenge for me is the tire size offered on the current e-bike conversion kits. I read the markings on my bike tire, and it lists the following: 40x622 (700x38c 28 x 1 5/8 x 1 1/2). The e-bike kits from ebikeling say the included wheels they provide are only good for 28c or 32c. If I get the ebikeling kit, and just buy the rubber tire for it, can I use that on the bike I currently have? Or will that be a problem since I'll be running two different size tires on the front and back?
Honestly, I am open to any bike kit, it doesn't have to be the ebikling one. I just need the easiest installation possible, as long as it provides 48v 1500 watts. Any help would be appreciated. So if you know a kit that would work for me, or any suggestions, please feel free to let me know. Many thanks!

late

My ebike has 250 watts. I'd prefer 500, but 1500 seems like overkill. With that much power you would drain a battery real fast.

There's also the question as to whether a cheap bike will be able to handle that much power.

You need to find out how big a tire you can get on your bike. You want a big, rugged tire on an ebike.

Alex_alex

I'd definitely not want to go any bigger on the tires than what's been provided. The added drag is not fun to be honest.

gsa103

Call them and ask what the internal rim width is? Anything in the 17-23mm internal width would be fine for a 700c x40mm tire. If it's less than 17mm internal width, you don't want to put a 40mm tire on it.

2old

The rim width is 19 mm, so you should be able to use your current tire. Just be aware of the massive power with your 48V, 35amp (controller) system (2+ horsepower), and the extra weight you'll incur (15+ pounds for the rear wheel). Also, the frame is some series of aluminum alloy and probably needs two torque arms for safety with that much power. Unless you know this is what you want, I think you would be better served with a less powerful kit and/or a steel MTB frame..

Alex_alex

Thank you for your input. Okay, just to make sure I've understood... When you say internal width of the rim, you are referring to the width of the rim (side to side) looking at it top down, and without the tire on, correct?

Alex_alex

Actually, to be honest, I'm not sure this is what I want. The only reason being several people have told me 1500 watts is too much power for this frame. I respect the laws of physics, and don't want to push my luck. Honestly, this has all kind of overwhelmed me. All I'm looking to do is be able to setup an ebike on a budget (therefore no off the shelf bikes) , and I want it to be able to go a decent speed (like > 25mph). I would love to be able to do this on my current bike, the Schwinn Women's Trailway bike (700c / 28") sold at Target. What type of setup would you recommend for me to achieve this goal? Links to Amazon, eBay, Aliexpress, etc.. would definitely be helpful if you have a specific setup in mind.
On a side note you mentioned the rim width is 19mm... Can you please tell me how you were able to find that information? Again, this is all new to me so my apologies for what may sound like silly questions.
Thank you so much once again!!

Doc_Wui

If you're going to average 22-34 mph, you might want a bike with disk brakes.

The issues I have found with larger tires is getting rim brakes to fit around them, and keeping a fender over them. They don't have to drag, I outweigh my wife by 50 pounds, and her bike has 2.1" Schwalbe tires compared to my 1.75" Kenda tires, and when we coast down hills, she passes me. Not supposed to happen. I'm not that wide. Must be better rolling tires,

A 1500W direct drive motor probably is a iron pig to pedal with power off, and there is 10 pounds of inertia in those big magnets. That's why I never dabbled with the big motors with the 6+ ebike kits I've put together. I like coasting down hills. Direct drives make for good regen braking though, if your controller supports it.

Tradeoff is speed kills range. Probably use 3X the battery AH at 25 mph, opposed to 15 mph. Just a guess.

Alex_alex

Okay, so 1500 watts is too much power for that frame - Agreed. What about if I buy a 26" mountain bike and then pair that to a 1000w 48v kit off ebay?

Leisesturm

The added drag is irrelevant, because you have the equivalent of six (more actually) other riders on the bike with you. You said you wanted >25mph. 28mph puts a bike into Class III. Take a look at some Class III bikes on the market: Giant Quick E+; Raleigh Redux IE; Trek Allant 8s ... all of them have 2.4" tires. All of them have hydraulic disc brakes with 180mm rotors. All of them have fenders.

We are all completely desensitized to what potential "only" 25mph has to hurt you, because that is a trivial speed for a motorist. For a bicycle it's not so trivial. Your bike cannot handle 1500W. Period. End of story. It might handle 500W if the motor is put in the rear of the bike. A 500 watt motor kit will do most of what you want. You will not 'cruise' at 25mph, nor do you want to. But just about any 500W system made can handle 1000 (or more) watts for a few to several seconds so you can sprint to 30mph if you really need to but you will be cruising around 20mph most of the time.

Regarding tires, 20mph 'can' be done on 1.5" tires, but 2" is better. I had a look at your bike and the front end has lots of clearance for plus size rubber, but the back end is more limited. I think you could get 47mm at the back, maybe. Usually if you run mismatched tires you have the bigger tire at the rear. You will also NEED a torque arm when setting up your kit.

2old

My 1000w, 48V (with 52V battery), 33+ mph bike has been fine with "V" brakes for five years, so I don't think that's a problem. I recommend you look at the e-bikeling 36V, 500w rear hub system. You should get close to 25 mph with the 22 amp controller unless they have a "cut off" set at 20 mph. Call them in Chicago; they are very responsive. The specifications for the system (7.4 pound motor and 19mm rim width) are on their website. IMO, you would be better off with a steel MTB from the late 80's to early 90's; these were $100 - $200 pre-COVID, but more expensive now. Also, read the tutorials at ebikesca from the smartest guy (IMO) n the business. Also, ignore the individuals who say you need to go to an OEM and spend $$$$ for something reliable. I put a picture of my setup with a 90's or so steel bike and "V" brakes. Make sure the brakes on whatever you build work correctly. You'll have more weight and more speed to contend with.

Pop N Wood

Well, no. I put a 1500 watt Bafang mid drive kit on an 80's vintage aluminum bike and have had zero issues with it. Rim brakes. I weigh 240 pounds so the bike sees a lot of abuse. I take it off road.

Battery only gets eaten up if you ride at max power. Turn the power down to 250 watts, every kit made lets you do that, and the battery will last as long as the underpowered bikes everyone is trying to talk you into. The only difference the bigger motor makes is it gives you the option for more power if you feel you need it and when running at a lower assist the motor won't be working as hard.

Unlike the overpriced factory bikes the Bafang lets you program the settings anyway you want. ​​​​​The bike is pleasant to ride unpowered. I usually start off with the assist at zero and only boost it for hills or to get somewhere quick.

Luna Cycle sells BBSHD and BBS02 kits. Get a 52V battery because the new Bafangs are set up to handle it. A higher voltage battery will last longer and need less frequent recharges, all of which means a longer battery life. Lots of Bafang information available on line, plenty of aftermarket parts, all of which means you can fix it yourself.

Man, lot of bad advice in this thread.

A mid drive should not need a torque arm. 25 mph is not that fast or uncontrollable. I like to cruise at over 30 mph with my bike. It will easily do close to 40 mph on level ground.

gsa103

Mid-drives are a completely different beast than hub motors, because they can take advantage of drive train gearing. Mid-drives also have zero drag when un-powered.
I converted one of my bikes with a Luna kit, it's great. The catch is that mid-drives are really in an entirely different price category. My 750W BBS02 kit and 600Wh battery was about $1100.
With about 200W of assist I can comfortably cruise at 23-25mph, which is what I was after. I use it to commute 12mi each way. I can start at 80% battery, and end at 40-50%, so it's easy on the battery. I specifically tuned my Bafang motor to reduce peak power, so that it feels more like a normal bike and conserves battery.

1500W is an eMotorcycle. At above 500W, pedaling isn't adding anything.

2old

T
The OP was talking about a hub drive (notice the reference to rim width). My point was that the weight and power of a 48V, 1500w motor requires two torque arms on an aluminum frame. As above, a mid-drive is the more expensive option and not a better choice depending on application.

Pop N Wood

Yes, I read the first post.

If you really want 1500 watts on a department store bike a mid drive will do it. The bike will handle it. You can still pedal when putting out more than 500 watts, should pedal actually if you want the battery to last. But at 500 watts output, depending on the weight you are carrying, winds and grade, you have the option of not pedaling if you don't want to. A lower powered bike, hub or otherwise, won't give you that option.

Even at 1500 watts we aren't talking a lot of power here. Only 2 horsepower, a hair dryer. Go uphill on a bike loaded with groceries or towing a trailer full of kids and you may need every watt, especially if your battery is getting low and output has dropped.

A BBS02 kit will install in a day and from the numbers I have seen weighs about the same as a Bosch/Brose/Yamaha factory mid drive. Batteries are what adds the weight (and expense) and that is true regardless of the motor type or size. But since hub drive motors are commonly permanent magnet types and mid drives are not, mid drives should be more efficient and like you say disengage when not powered giving further efficiency.

Sounds like the OP may way to get some help installing a kit, whether mid drive or hub.

Yes, cost is a trade, but one needs to know the options before they can make the trades.

sloppy12

You will be fine with the 1500 watt kit. the ebikeling and voilamart most of the kits use the same motors for 750, 1000, and 1500 watt kits. they just add a bigger controller.

I have built a few now and you can easily reach the speeds you desire on a 750 watt direct drive with some pedal assist. Personally I usually go with the 1500 watt systems just for the extra overhead on the controller. and Then just use the aux settings to lower the output for PAS. in other words put it on 2 0r 3 on the little screen and use the 2-300 watts and your legs. save the throttle for hill starts or Whatever(I honestly never use the throttle unless I forget to shift).

Like others have said dont worry about drag from a bigger tire, it wont matter.

2old

As usual, if you define your requirements, it's much easier to assist you (Weight of rider, amount to spend, speed desired, terrain - hilly or flat -, wind, distance traveled, can you charge at work if used for commuting, do you need to carry the bike upstairs, is it stored inside or not, are you handy with tools, etc) are considerations for the type of system which will provide the best result.