City E-bike

Hi!

I've been nosing around the forum and have tried to use the search function, unfortunately without much success. I'm fairly confident that the questions I'll be asking are already answered multiple times. Just point me in the right direction and I'll soon be a happy e-biker, or blow me away with your wonderful suggestions and advice!

My initial goal is to have an e-bike that will enable me to go about 50km/h (around 30mph?) with a range of about 40-50 km (70-80km ideal but I suspect that the battery costs/weight would get to high). And although I have a nice Cube MTB frame ready to convert, I first want an e-bike on a city bike frame so the bike can be used by my girlfriend and co-housers. The bike will mainly be used for my work commute but also to do our weekly shopping with a bike trailer. The terrain here is almost completely flat. Throttle isn't necessary and I would prefer peddle-assist only. Regen-braking would be a nice plus. LCD with simple battery level and speed indication is a must.

If my guess work is correct I should be looking for a 750-1000w motor (hub for easy install and low price). What common dropout dimensions should I be looking for when searching for a suitable bike frame?

What kind of e-conversion kit or combo of controller/motor/lcd and battery would you guys recommend? My Budget is around the €1000.
I do have some DIY electrical experience so I don't mind putting together my own battery and soldering it to a BMS (if necessary).

Thanks a bunch

See need advice link in sig.

Which kit you choose won't really matter much regarding the needs you describe. Trailer loads up hills would require a direct drive type hub motor, or a mid drive. But you don't have mountains to climb. Because of the speed you want, and the trailer, you will need what is typically called a 1000w kit of some kind. This in general, just means its a 48v kit, and not a tiny motor with 250w.

Some kits will hit true 30 mph, others more like 27, with both going a bit slower as the battery empties. A more realistic expectation for 48v is a 25 mph cruise most of the ride. That's 40 kph.

You are quite correct that to cruise full speed for 50k will get expensive, and bulky. It may take as much as 30 ah of 48v battery. But here is my advice, buy a 48v 15 ah, or if you can afford it 20 ah. The 48v 15 ah pack WILL go 50k, just not at full speed. Most of the time, you won't want to haul ass with the trailer anyway, and you will still have a pretty good range hauling ass. Its always possible to ride fast 25 k to a destination, then charge for 4 hours or so, and ride back. IMO, 15 ah is plenty for nearly every body, 90% of the time.

Later on, like next season, you might be able to budget another similar size battery, and then you will have huge range. It is that nice to have the huge range, but you don't need to pay for it this year.

Budget should be ok for a decent 48v 15 ah, and a motor kit.

Most rear hub motor kits in 1000w or less take a 135 mm wide dropout. Steel bikes that are 120 mm can easily be bent out to 135, but just pick a typical bike with 7 rear gears and it will be 135mm. Despite the heavy weight, a 7 speed steel beach cruiser can be a great choice for a city bike. Fenders are nice, 7 gears is plenty, and for the weight, you plan to tow a trailer anyway, so its not going to be light. Light still good if you have to go up stairs with it of course, but if not, it don't matter.

@ Wensnewell; Thanks, I already read that post, but apparently seem to have forgotten that I did. Because my basic questions seem to be answered quite well with it.

@ Dogman Dan; Thanks, now that I know that a 7-speed usually has a 135mm dropout, it'll be easier to hunt for a good second-hand bike.
So according to you a generic kit would be okay. I know that cheap DD hubs are quite durable, but I don't know if that also goes for the controllers. Should I worry about the controllers in the cheaper kits? I've read somewhere that the KT controllers have good PAS and regen, so maybe I'll look for kits with KT controllers.

About all the import duties and taxes, I'd rather avoid these things by buying inside the EU, however this limits my choices quite a bit. More so because I don't know many EU based sellers. Anyone got some good recommendations? I know some sellers on AliExpress state they ship without EU Tax etc and there are some UK or Germany based sellers on Ebay, but I don't know any other sources?

Thank you for your input!

Hi again

Unfortunately my search for a used city-bike frame with decent enough components wasn't successful. So I opted to convert my existing Cube MTB frame, this already has SLX brakes which are easily strong enough to stop all the extra added weight and has front suspension which will ease out the ride at high speeds.

So, now that I'm using a MTB frame I'm also going to up the power/speed game a bit (and if need be, budget).
I was thinking of buying this 1500w kit:
https://www.aliexpress.com/item/48V...-Gearless-MXUS-brand-LED-LCD/32814726839.html
I'm just a bit concerned about the controller, they said they use this one:
https://www.aliexpress.com/store/pr...l?spm=2114.10010108.1000023.22.77184406FMfEfs
But on their spec sheet it says it is rated for 22A, which seems a bit on the low end for 1500w?


I'll also going to buy a 52V triangle battery from UnitPackPower on Aliexpress. I've already asked and they said they can fit a 52V pack with a 40A BMS so it'll be suitable for a 1500w system. I'll also be asking to use 4 connections for each series-connection so it can handle the current, is this also important for the parallel-connections?
What cells would you guys use if longevity was the main concern? I was thinking of either LG MJ1 or Panasonic PF. The Sanyo GA are a bit overpriced imho.

What's your opinion on my choices?
Thanks.

That's a MXUS 3000W motor with a 48V 45A max (22A rated) controller. I've got a 4t v1 model and it's width is about 145mm, so make sure it will fit your bike. The speed you'll get will depend on which winding you get. It's made in 3t, 4t, 5t, and 6t, with the 3t being the fastest wind. I run a 96V controller on mine.If you can find out which wind it is, you can go to the simulator for approx. max speed. And you can always replace the controller or shunt mod it for more power and speed if need be. It's probably overkill if you just want to do 30mph, I get 50mph out of mine with a 24S lipo battery and a shunt modded for 60A controller using 26x3.0" rear tire.