Need help deciding on spec of electric bike

[JOB100]

Hello everyone

Am excitedly looking forward to getting an electric bike.

I've poured over a tonne of info online, just trying to hone in on a few basics so I can start looking at specific models / kits

I may buy a conversion kit for my full size folding (Tern Joe 26in bike, mechanical discs, 21 speed shimano derailleur) or I may buy a specific bike. I would prefer the former.

So here are my requirements:

I want to cycle without assist almost everywhere when on my own, but occasionally I am taking a child and / other heavy loads now. I usually do a combination of cycling + public transport in London, but it is virtually impossible as soon as it gets busy so I want to cycle to places directly now. Definitely going to be occasional use.

1) Remove battery and be able to cycle with a freewheel to keep myself fit like a normal bike

2) Do a round trip of 30-35miles without having to recharge with a child / load

3) Will use pedal assist with when I ride with the child/load. This is to stop myself getting too lazy, and keep the battery as small as possible.

4) But want the option of occasionally blasting along at say 25-30mph for say 2 x 5mins out of a 1hr journey on my own (not with a child!).

5) Almost all my journeys will be no more than 35miles round trip, on pretty flat terrain. Any hills I will tackle with pedal assist and human grunt. Acceleration isn't important to me. Pedal assist, efficiency and occasional top speed are


I lean towards mid drive because of the efficiency. However, I don't relish the additional maintenance and replacement of components. I am also keen to do this as cheap as possible.

Been looking at 750W 48V Mid drives with 13Ah battery or 1000W 48V hub.
I could happily drop to 36V and 500W, provided I could reach 25mph when on my own (without child / load).

Top end budget would be £500 all in, because I am capable of fitting the kit myself. Happy to buy direct from China or say buy a used motor kit + new battery to keep cost down. If I buy a full bike, it will be secondhand.


Would appreciate your suggestions guys


Thanks

 

[sjpt]

No need for anything other than a legal 250w motor for all your points except (4).

Also, as its flat mainly you will hardly benefit at all from a mid drive; they mainly help for steep hills and serious off-road.

Make sure that the controller is either torque sensing or cadence sensing current control. A speed control will give you too much power when you don't want it (and use extra battery to do so).

You say 'option of occasionally blasting along at say 25-30mph '. Maximum legal assist speed is 15.5mph. You can pedal yourself up to whatever speed you can manage (probably not 25mph)

 

[Nealh]

Tbh riding a bike without assist for long spells means imho either a tsdz2 mid drive which has high internal gearing or a similar high internal geared hub but with both one may find inclines need some good input due to excess weight carried.
Most hubs are lowered geared at 4:1 , though they are rideable unpowered one will soon likely feel like they are fighting a losing battle.
Any unpowerd riding will feel like one is riding through treacle due to the excess weight.

A high internal geared hub usually means buying a bare unit and having it built into a rim or doing it your self. Aikema hubs are higher internally geared or a small lightweight motor like the Bafang G370.

My Cotic Roadrat I built with a front G370 hub , recently I loaded it with 30kg of cat litter on the 5/6 mile return journey . I started the journey knowing battery volatge was low but thought I had enough to get home, halfway back home the battery hit lvc and I was able to ride the journey remainder easily withut power due to the higher hub gearing.

 

[Nealh]

Imv I would say tsdz2, though I think anyone who wants to ride at 25mph unassisted with a hub or midrive fitted is best to stick to lighter unpowered bike.

 

[matthewslack]

It sounds like you want powered assistance to 25mph. That's not the best starting point!

I'd suggest a lightweight 250W legal conversion on your existing bike as a starter, ride that for a few hundred miles and build version 2 when you work out what you really need.

 

[Raboa]

I ride both a rear hub motor and a BBS02, both of these bikes are used to carry shopping and scrap metal.
The BBS02 ,is a great kit but I find it needs some tweaking to work to my needs. It's the marmite of the kit world, you either love it or hate it
I find the rear hub kit is a nicer cycling experience and does not need any tweaking. I have used it loaded on hills with no problem
If I was to buy another kit it would be a tear hub motor, I also have replaced the thumb throttle with a half twist throttle.
You will receive many options on this, if possible try both systems. Whatever you buy enjoy it and stay safe.

 

[JOB100]

Thank you guys for your comments. Much appreciated. As far as going 25mph, I am well aware of the legal restrictions, but I still want that option. Either through derestricting or buying a kit that is actually capable straight off the bat. So I don't think a 250W motor is going to cut it? I'm pretty sure I'm going to be very disappointed with a bog standard e-bike.

 

[zoros]

Presumably if you build the bike to exceed 15.5mph, then you are going to tax. insure and MOT it too?

 

[Bikes4two]

Just a general point on your desire to ride unassisted often - motors give drag when unpowered and some more than others. I've read the drag on BBSxx motors is very noticeable whilst the TSDZ2 doesn't so much.

Irrespective of what motor and battery combination you settle on, the combined weight is unlikely to be under 6.5kg, which in itself is a -'drag' to pedal. Batteries really are weighty things and if you are looking to the non legal speeds you mention, then a hefty battery will be needed.

 

[Zlatan]

Thank you guys for your comments. Much appreciated. As far as going 25mph, I am well aware of the legal restrictions, but I still want that option. Either through derestricting or buying a kit that is actually capable straight off the bat. So I don't think a 250W motor is going to cut it? I'm pretty sure I'm going to be very disappointed with a bog standard e-bike.

At that point your requirements become virtually incompatible. Being able to do 25 mph plus will require lots of power, both motor and battery wise, making bike almost useless without power. And would require registration, tax, test etc etc.
Think you should try a few. Even my Haibike (my lightest ebike) is bordering on useless with no power,but on its super eco setting feels very similar to a lightweight carbon mtb, the little bit of power used compensates for the weight, and as such will return 75 miles or so.
There isn't a bike made capable of all your requirements. You need to prioritise, which do you value.
Also there is a common misconception you can't get fit on an ebike. You can. Your fitness improvements correlate to the level of effort made and not the equipment you do it on.
My output hovers around 150w (irrespective of bike). I can use that 150w to crawl about slowly on on ordinary mtb or can use it to go faster, further, higher on emtb.
My recommendation. Try any decent mid drive bike, kit or otherwise.. I have had Tonghshen and Bafang mid drive kits and Haibike and Giant emtb. (all legal). All offer slightly different qualities but all brilliant and I, d be happy on any of them. (not a fan of hub drives or folk riding illegaly)

 

[Raboa]

One thing you have to also consider is wear and year on your equipment, bike stuff is not getting any cheaper.

 

[StuartsProjects]

I think if I was going to carry a child on a eBike, I would want it to be road legal.

 

[Bikes4two]

+1 for what @Zlatan says especially about riding illegally of which such behaviour only brings the law abiding e-biker into disrepute.

 

[marina.vlasenko]

Thank you for sharing your requirements and budget for an electric bike. I recommend checking out the GIN X e-bike. It has a range of 75+ miles, is powered by a 250W Bafang motor, and has a 48V teslagrade battery. The price is £999. It has a good range and power which will fit your needs. Keep in mind that buying secondhand or directly from China can help keep costs down.
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[Bikes4two]

Thank you for sharing your requirements and budget for an electric bike. I recommend checking out the GIN X e-bike. It has a range of 75+ miles, is powered by a 250W Bafang motor, and has a 48V teslagrade battery. The price is £999. It has a good range and power which will fit your needs. Keep in mind that buying secondhand or directly from China can help keep costs down.

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That's an interesting option for a budget bike - pity that these style of bikes always seem to have front suspension which makes the bike heavier and really isn't necessary with the proper tyres inflated appropriately. Good luck with your sales.

 

[Sarge1892]

avoid 13ah if you want 30+ miles of range idk what mix of pedaling and motor assist your planning to use but id say start at around 20ah if your planning to do all pedal assist and 30ah if your doing all throttle

the way batteries are priced you will spend the biggest chunk just getting ANY battery but the amount to go from say 13-20 wont be much extra and you'd be better served having too much battery than not enough and having to spend a chunk on a new one

when you say pedal assist with the kids? do you mean with them in a child carrier or a trailer?

I'm not sure what you mean by that it sounds like you plan to be manpowered most the time but hybrid man power and motor when with kids but I'm wondering if you infact mean throttle mode but pedal assist when with kids

which if you do mean throttle mode then yes 20+ah battery is going to be a must