Help! Lightweight e-kit for coaster brake bike - alternate e-bike and 'normal' bike experience.

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
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West Wales
Any electrically assisted bike gives you the feeling of having borrowed a professional cyclist's legs. It does not, however, do all the work for you. It is an assistance only. You still get a work out as myself and many here will attest, especially when hill climbing is invovled.
Adding a kit to a bike will inevitably increase the weight. My own avatar bike weighs in at atound 27/8Kg. Yet I cycle the hills of West Wales in my 70's. I do cycle without power - downhill or with the wind on my back on the flat. But I know that when I turn the power off It feels like cycling through treacle, it's not an enjoyable experience.
I feel you need to adjust your expectations before you spend hard earned money to do something that doesn't work for you.
I would not worry about the extra weight of a kit, it's assistance will overcome that extra. Having an assisted bike is not 'cheating', you will still be working and arrive at your destination with less emissions than the car driver who accuses you of such, but less sweaty!.
In order to get you and your kids up a steep hill without bursting your lungs or legs, you need a high torque motor backed by a quality battery.
Just one other thing. Check the Spanish regulations. We know, from a previous forum member, that Spanish police are strict. I know that means:
No throttle
No assitance above 27kph
When pedals stop turning assist must stop.
There may be other subleties I'm not aware of.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
The tsdz2 coaster brake version would be my choice if planning on converting the original bike , as a mid drive you wouldn't notoice any weight difference because the Cof G is central and very low and in general will be easy to lift or manouvre.

Small light hubs are ok if you don't live in a hlly area but you are also talking about carrying more weight.
 
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matthewslack

Esteemed Pedelecer
Nov 26, 2021
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For rear wheels, but then there's often an additional front wheel brake (a v-brake in my case).
Often? I would hope always! Two independent brakes are a fundamental safety requirement.
 
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LauraEG

Finding my (electric) wheels
Apr 5, 2024
11
1
I'd like to see photos of your other bike with the V-brakes. Let the hub motor kit experts get properly stuck in.
It's in storage in a different location from where I live, but I'll share pics when I have it with me!
 

LauraEG

Finding my (electric) wheels
Apr 5, 2024
11
1
when I turn the power off It feels like cycling through treacle
That was a very useful description ; )

Indeed, I don't really know how riding an e-bike feels (I've tried some but just for short test rides, not for my day-to-day). It's good to hear your experience with exercising with an e-bike. In fact, my motivation for searching for punctual electric assistance (instead of fully embracing having an e-bike as @Az. was pointing out) has in part to do with wanting to have my daily workout dose (I don't have much time for anything else 'healthy' for me). But I also want to keep my biking setup as minimalist and 'independent' as possible. Meaning, if I know that I can still ride my bike even if the battery runs out, or if I forget to charge it one night, or if I just want to do an errand without the kids... that's part of my mental peace :)

Anyway, I have learned a lot from all of your valuable insights, suggestions, and comments which are certainly food for thought! I hope to be able to share soon what my solution has turned out to be in the end :)


@
 

guerney

Esteemed Pedelecer
Sep 7, 2021
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It's in storage in a different location from where I live, but I'll share pics when I have it with me!
You could visit your second bike at it's location, take photos and leave it wherever it is... but only if you have court mandated visitation rights.
 
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LauraEG

Finding my (electric) wheels
Apr 5, 2024
11
1
Hi! I haven't yet found my ideal solution, but I wanted to share something I learned, that might be useful for others looking to electrify a coaster-brake bike. Apparently, in Spain, any e-bike must have brake handles. So regardless of the existing technology that could make it possible to electrify my coaster-brake bike, it wouldn't be legal to use it on public roads in Spain. I wonder if other European countries have similar regulations.
 

Az.

Esteemed Pedelecer
Apr 27, 2022
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Plymouth
Apparently, in Spain, any e-bike must have brake handles. So regardless of the existing technology that could make it possible to electrify my coaster-brake bike, it wouldn't be legal to use it on public roads in Spain. I wonder if other European countries have similar regulations.
Your bike has front rim brake.
 

harrys

Esteemed Pedelecer
Dec 1, 2016
363
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Chicago, USA
Here's the PSWpower coaster brake option for 36V. There might be a 48V version.


I've installed two 48V TSDZ2/TSDZ2B kits. Here's the main reason why I like them over hub motors. With some installs, you get this issue, when the 12x10mm axle of a hub motor doesn't sit deep enough into the 10mm dropout of your bike. Everyone has different views on it. Cutting the dropout is required, but whether there's enough safety margin afterwards .... I just prefer to avoid it by using a TSDZ2 kit, and they aren't much more expensive than a hubmotor and allow normal tire changes, etc.

20240421_174120.jpg
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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Is there anything that stops a coaster braked bike also having a rear disc or V brake?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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saneagle

Esteemed Pedelecer
Oct 10, 2010
7,007
3,241
Telford
How about removing lock on rear wheel and fitting brake instead?
Probably easier to loosely bolt one end of a spanner to the frame and a piece of string to the other. Tie the other end of the string to the brake lever so that when you pull the brake lever, the string pulls the lever into the spokes. That would stop the bike pretty quickly.