Lightweight kit from MTB (9 year old)

Hi,

I'm an enthusiast enduro rider, and I'm trying to get my son who is 9 years (and 145cm, approx 40kgs) more into mountain biking. He had a 24" mtb and I'm in the process of getting him a used 26" kids bike (approx size 13.5"). We live in a area with lots of smaller hills, which are small for me but too big for him.

I thought that one way to help him out (I have occasionally used my home made tow rope) to pull him up, but when were are out on a family ride with my 6 year old daughter and my wife I have difficulties getting them up the hill.

So i thought that I will convert his bike with a rear hub motor, so that he can join me more often when i go riding, and can also pull my daughter when I pull my wife up the hill. Looking to cover approximately 300-500 meters vertical over say 15-20km. So I would prefer the lightest 250W rear hub option with a small battery (should we go for a longer ride, I can happily take an additional battery in my pack, as I want to keep his bike as light as possible, and also a 13.5" bike does not have a lot of room in the front triangle ).

I wrench almost everything on my bike (apart form the suspension/dropper cartridge), so hopefully I can solve the conversion on my own, provided that I can get all the pieces of the puzzle.

 

I would appreciate any thoughts/help on choosing the right kit or components. I'm living in Hungary, so would prefer to source the components from the EU.

 

Many thanks for your help.

Hi,

I'm an enthusiast enduro rider, and I'm trying to get my son who is 9 years (and 145cm, approx 40kgs) more into mountain biking. He had a 24" mtb and I'm in the process of getting him a used 26" kids bike (approx size 13.5"). We live in a area with lots of smaller hills, which are small for me but too big for him.

I thought that one way to help him out (I have occasionally used my home made tow rope) to pull him up, but when were are out on a family ride with my 6 year old daughter and my wife I have difficulties getting them up the hill.

So i thought that I will convert his bike with a rear hub motor, so that he can join me more often when i go riding, and can also pull my daughter when I pull my wife up the hill. Looking to cover approximately 300-500 meters vertical over say 15-20km. So I would prefer the lightest 250W rear hub option with a small battery (should we go for a longer ride, I can happily take an additional battery in my pack, as I want to keep his bike as light as possible, and also a 13.5" bike does not have a lot of room in the front triangle ).

I wrench almost everything on my bike (apart form the suspension/dropper cartridge), so hopefully I can solve the conversion on my own, provided that I can get all the pieces of the puzzle.

 

I would appreciate any thoughts/help on choosing the right kit or components. I'm living in Hungary, so would prefer to source the components from the EU.

 

Many thanks for your help.

Forgot to say looking at PAS only, so no throttle, very miniamlistic display, and the mtb will most probaby have a 9 speed shimano hg freewheel

Hi, I bought a 36 volt / 350W kit last year from company Yose - they shipped from their EU (Germany?) warehouse. Not sure if they supply any kits with simple displays, mine came with a basic LCD display and has been very good for me.

Website https://yosepower.com/

Looking at their site now it looks like batteries are now sold seperate.

For info there is also a "UK-only" Yose website just so you don't buy from there by accident.

 

More experienced folk will have suggestions about which kit might suit you best, hope you find one to suit you.

For lightest kit or should I say lightest hub you will have to buy form China. Any EU sourced hub will be 3.3 kg - 4.4 kg approx. , a reputable brand from China like an Aikema 100 hub will come in at 2.1kg for freewheel model or 2.2kg for freehub model.

 

AKM-100H 36V350W EBike Rear Driving Hub Motor [AKM-100H rear motor] - $90.00 : Zen Cart!, The Art of E-commerce (topbikekit.com)

 

AKM-100CST Cassette 36V250W EBike Rear Driving Hub Motor 32/36 holes [AKM100CST EBike 36V250W motor] - $105.00 : Zen Cart!, The Art of E-commerce (topbikekit.com)

 

Use a KT controller 15a and use the tiny LCD4 minimalist display with BZ10c PAS sensor/disc.

Edited June 1, 20214 yr by Nealh

The main problem i can see will be the battery size fitting it into a small frame, yose power will supply all your needs make sure its from the German warehouse

Just in case you don't know, it's illegal for anyone under 14 years old to ride an electric bike anywhere except private land with the owner's permission, which makes all other points of legality moot.

Just in case you don't know, it's illegal for anyone under 14 years old to ride an electric bike anywhere except private land with the owner's permission, which makes all other points of legality moot.

True for the UK but OP is in Hungry...not sure what the rules are there.

Many thanks for all your help and recommendations, luckily in Hungary it is not forbidden for a kid to ride a pedal assist bike

 

So based on the recommendation I was thinking of ordering this motor:

 

http://www.topbikekit.com/akm100cst-cassette-36v250w-ebike-rear-driving-hub-motor-3236-holes-p-728.html

 

If my current bike has a Shimano HG cassette (using it with 9seed at the moment) which option would I need to choose as the HG freewheel is universal?

 

On the rest, I will also go with the recommendation for the LCD4 display and BZ10c PAS sensor.

 

When it comes to batteries, I think one of these might actually fit:

 

http://www.topbikekit.com/bottle-mini-battery-36v5ah-18650-10s2p-with-kt-inner-controller-p-961.html

 

or this one:

 

http://www.topbikekit.com/bottle-mini-battery-36v64ah-10s2p-panasonic-18650bd-kt-inner-controller-p-962.html

 

Questions here:

1. Would you recommend choosing the Panasonic one, it has slightly more ah on paper

2. I have chosen this as the base can house the controller which is this one:

http://www.topbikekit.com/mini-bottle-case-inner-controller-10s-36v12a-6mosfets-kt-sine-wave-controller-p-978.html

 

Would this be a good enough fit for the motor?

3. I guess I will need to add another cable for the PAS sensor, but would I need any other 9pin extension cables for the set

4. For charging the suggested charger is either the M120 (2.5Ah) or the T120P (2Ah)

 

Many thanks

Oh yes and the last question, I assume that this battery holder bolts onto the water bottle mounts of the bike right?

thx

Order all the parts from the drop down menu on the Panasonic battery page, so:

Controller-36v inner controller

9 pins-60cm this is an extension for the motor

Brakes-not needed for PAS only

Charger-2.5 amp it's prob. slightly better quality

Display-LCD4

Cable-2-1 for the display to connect. 4-1 for throttle and brake cut outs.

Throttle-no

PAS-BZ10C-plugs direct into the controller

 

Yes, battery will fit to bottle mounts

Order all the parts from the drop down menu on the Panasonic battery page, so:

Controller-36v inner controller

9 pins-60cm this is an extension for the motor

Brakes-not needed for PAS only

Charger-2.5 amp it's prob. slightly better quality

Display-LCD4

Cable-2-1 for the display to connect. 4-1 for throttle and brake cut outs.

Throttle-no

PAS-BZ10C-plugs direct into the controller

 

Yes, battery will fit to bottle mounts

Great many thanks for your help!

The BZ10C I mentioned as it is quite universal for fitting most bikes, more so those that use the Hollowtech BB or Sram equivalent.

The HG I believe is a cassette for freehubs so you will need the 100C model, but make sure 100% before ordering. Freewheels are screw on and the cassette slides on via splines and a key way with fine thread retainer.

The first two bottle batteries CAN have an integrated controller in the base of the support bracket /receiver so as Pete has mentioned select the options from the drop down bars on the same listing.

The LCD4 has the functions of the excellent LCD3 but in a miniscule unobtrusive display.

 

As the battery is only 2 cells in parallel opt for the 2a charger typical charge time will be 3h 20m max from empty, also the 6.4ah /230wh battery will last a little longer. It won't be mega range but in low assist about 40km.

Edited June 1, 20214 yr by Nealh

Great many thanks for your help!

I've just noticed the 2:1 cable I suggested to you is only 60cm long, which will prob. be too short, so get the 4:1. sorry for that, hope I've caught you before you place your order.

I've just noticed the 2:1 cable I suggested to you is only 60cm long, which will prob. be too short, so get the 4:1. sorry for that, hope I've caught you before you place your order.

no worries thanks , just in time as I have sent them a question about spare battery and the hg casette compatibility

no worries thanks , just in time as I have sent them a question about spare battery and the hg casette compatibility

Great, that's a relief, glad i checked, will teach me not to rush a post

Just in case you don't know, it's illegal for anyone under 14 years old to ride an electric bike anywhere except private land with the owner's permission, which makes all other points of legality moot.

Never have i come across anybody so obsessed with public obedience to the unlawful 'legal' system.

I think that the OP has his answer, just-joined Andy. Unless you can help?

Just in case you don't know, it's illegal for anyone under 14 years old to ride an electric bike anywhere except private land with the owner's permission, which makes all other points of legality moot.

 

Thanks for the information, I had assumed that (in the UK) the regulations on electric bikes applied to all ages.

Hi, so I have just got my hands on the bike (see picture attached) facing the following issues:

 

1. It has an ISIS BB. My original plan based on the recommendation was to use BZ10c PAS , would I be able to fit this on ISIS BB? If not any alternatives I could use?

2. It seems that this battery pack (incl contoller)

http://www.topbikekit.com/bottle-mini-battery-36v64ah-10s2p-panasonic-18650bd-kt-inner-controller-p-962.html

will be too big for the frame. Has anybody come across some decent priced say 36V 6aH water bottle shaped battery packs I could use, or will I need to go down the DIY route (which I wanted to avoid).

3. Also now that I need a different battery, which speed controller should I use with this setup?

 

many thanks

Gabor

The sensor bracket/ring will clamp behind the threaded retainer, the magnet ring will have to be secured to the inner chain ring.

cool thanks, any suggestions with the battery?

Possibly a frog type battery mounted, or one can use power tool base plates in the link to mount said power tool batteries.

 

Makita 18V Li-ion Drill Battery Cable Connector Output Adapter Tool For BL1850 | eBay

 

Mount a pair and wire in series and use 18v Power tool batteries, one will need an external controller. You should be able to get a base plate to suit any battery brand but not a universal one.

Edited June 16, 20214 yr by Nealh

thanks, I have found this which might work. Thinking of getting the 6.4 aH version

 

https://www.aliexpress.com/item/32827328248.html?spm=a2g0o.productlist.0.0.777d75a6LSS8Ca&algo_pvid=b16a5d81-ad31-492e-98c1-1802ea058987&algo_expid=b16a5d81-ad31-492e-98c1-1802ea058987-21&btsid=0b0a01f816233132585937716ee110&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

 

now i just would need to know which cable versions (picture 3) to order, and which is the conntroller from topbikekit which would work in the system (the smallest version, as there is not much space to fit it)

If buying the battery on AliExp might as well get the KT controller and display as well.

Fir the battery connection the bullets can be a bit crappy and the shroud protectors eventually melt because the bullets tbh can't handle the heat.

For battery connection opt for #2 Anderson Powerpole or the XT in pic 3 or 4 but first order the controller and get the battery with the opposing correct connection.

 

Are you looking for all WP connectors or SM block connector's ?

I use Ofkeet with no issues.

 

KT Controller 36V 48V 250W 350W 500W 750W 1000W 1500W Waterproof Brushless Electric Bicycle Controller with Light Function|Electric Bicycle Accessories| - AliExpress

 

For fully WP connectors opt for #4 controller with the Black/Red Anderson power pole connectors and #2 on the battery pic.

From Ofkeet store select your display, an 1T5 cable and PAS with 3 pin yellow connector. For PAS we need to know which BB the bike has.

 

With WP connectors it is very hard to fault diagnose, so a lot of us use the SM Block connectors. It all boils down to how neat or how you hide the wires.

Thanks Nealh, will have a look at all these!