lightweight assistance and proportional power

[Tom Doughty]

Hello
I'm about to buy a kit and here asking those of you (all of you) who know far more than I.
My two most important requirements are low weight and an assistance that allows pedal cadence to remain as constant as possible when load increases and the motor assists. I would also need a high proportional level of help from the motor as I'm not strong and my cadence is slow. Speed is not important, but torque is.
Reliability is too and ideally a geared motor as I won't always use the assistance but don't want to drag a motor around in the hub.
So far, i've enquired about Keyde who impress with weight and would offer me rpm of 195rpm. but I've read concerns about their reliability and once I buy the thing and install it, I don't want to do it all again.
The motor would be in the rear wheel, fit with a disc brake and a cassette.
Any thoughts out there?

 

[D8ve]

Crank drives let you trade speed for torque. Dropping to first and turning the pedals gets you up steep hills that only the best hub drives can manage.
Assuming you have bad days when you can't assist at all.
Others know more about the hub motors than me.
But there are two speed motors that have good low down torque and acceptable top end as well.
Weight difference is now really in the battery, bigger tank weighs more.

 

[Kenny]

Hi Tom, Unfortunately there doesn't appear to be any UK based suppliers of lightweight motors like the the Tongxin, Q100, and Keyde.

UK kit sellers opt for beefier motors like the Bafang CST which are very capable, but around 3 to 4kg.

Suppliers probably have less issues with these motors as the very light motors are more prone to failure if over stressed.

 

[flecc]

The shortly to arrive Cytronex kit might interest you Tom, the announcement of that is on this link.

To see the sort of bikes they already fit this to as complete e-bikes, see this link.
.

 

[Yamdude]

The shortly to arrive Cytronex kit might interest you Tom, the announcement of that is on this link.

To see the sort of bikes they already fit this to as complete e-bikes, see this link.
.

I'll be interested myself to see what this Cytronex lightweight kit will be like..... but judging from their ready made Ebikes, i bet it'll be well overpriced.
Hopefully more of these lightweight kits will become available, as they're quite rare at the moment.

 

[KirstinS]

The shortly to arrive Cytronex kit might interest you Tom, the announcement of that is on this link.

To see the sort of bikes they already fit this to as complete e-bikes, see this link.
.

Do you know it is coming please ? Only it's been "nearly ready" for four years !!

 

[Yamdude]

Do you know it is coming please ? Only it's been "nearly ready" for four years !!

I didn't realise that...... I wont hold my breath then.

 

[flecc]

Do you know it is coming please ? Only it's been "nearly ready" for four years !!

I'm just living in hope!

One day they'll get to the point when it is actually available, probably when the sale of their complete e-bikes slows down enough. They are a small outfit.
.

 

[KirstinS]

Well I email them every new year since 2011 (i just checked)

This year they said it would be out this year for sure as he was ordering tooling

So ... Maybe ?

 

[anotherkiwi]

What about the Q100 CST from bmsbattery? 2.1 kg is about as light as you can go in a "normal" rear hub cassette motor. You are about a Kg lighter than a bafang. d8veh had quite good things to say about these motors performance wise and apparently had success running with a 48 V battery which would give you the torque you need in the 201 rpm version.

 

[KirstinS]

To bring this back to op requirements

I think maybe crank drive with torque sensor working through the gears is a better idea

I think you should try crank vs hub first , if you can

 

[Tom Doughty]

To bring this back to op requirements

I think maybe crank drive with torque sensor working through the gears is a better idea

I think you should try crank vs hub first , if you can

thanks..Can you suggest any crank drives that are as light as poss to start with. I'll go hunting. Quite close to buying a Keyde as its so light and looks like it will do what I want BUT there are some reliability and quality concerns.

 

[Tom Doughty]

Well I email them every new year since 2011 (i just checked)

This year they said it would be out this year for sure as he was ordering tooling

So ... Maybe ?

wow guys, I just e mailed tham and asked the question....when? Looks like I might have quite a wait. I'm close to buying a Keyde as its so light and looks like it will do what I want BUT there are some reliability and quality concerns. Its a risk.

 

[flecc]

thanks..Can you suggest any crank drives that are as light as poss to start with.

The Japanese Sunstar crank drive is quite light and typically high Japanese quality. There are three links for you to see what they are in this previous post.

N.B. The critical post below isn't referring to the Sunstar but to the top post on another product.
.

 

[neopot3864]

Cytronex sounds like an excellent bit of kit, it's taken a long time to develop but it's now available and looks to be well worth the wait. A to B reviewed it recently and they reckon this is by far the best power assistance kit on the market, and perhaps the best electric bike solution full stop. They even predict we will be looking back nostalgically at the heavy German electric bikes of today, now we have lightweight and precisely tailored travel solutions... Worth having a look I think!

(links removed by admin)

 

[Nealh]

Cytronex sounds like an excellent bit of kit, it's taken a long time to develop but it's now available and looks to be well worth the wait. A to B reviewed it recently and they reckon this is by far the best power assistance kit on the market, and perhaps the best electric bike solution full stop. They even predict we will be looking back nostalgically at the heavy German electric bikes of today, now we have lightweight and precisely tailored travel solutions... Worth having a look I think!
Check out the A to B review - http://www.atob.org.uk/product/a-to-b-118-digital-edition/
Here's a link to their site - https://www.cytronex.com/

Four posts only to date and the same recommend on four threads, Hmmm !!!!
You should show your hand and clarify that you are not spamming on a product you have a financial interest in.

 

[anotherkiwi]

I have reported the posts as SPAM. Same post copy/pasted...

 

[cwah]

To bring this back to op requirements

I think maybe crank drive with torque sensor working through the gears is a better idea

I think you should try crank vs hub first , if you can

I tried 3 bbs02 in the past. All 3 developped some level of failure after some time.

I didn't even overvolt them.

I believe crank drive for some reason are not as reliable as hub drive.

They are also more expensive to replace.


For me, I'd choose a hub hands down. Buying a hub around £100 and change it after failure is much cheaper than a crank drive at £350!

 

[anotherkiwi]

I tried 3 bbs02 in the past. All 3 developped some level of failure after some time.

I didn't even overvolt them.

I believe crank drive for some reason are not as reliable as hub drive.

They are also more expensive to replace.


For me, I'd choose a hub hands down. Buying a hub around £100 and change it after failure is much cheaper than a crank drive at £350!

You can't over-volt a BBS0x. They require you to be in the right gear. I am guessing you stalled them and fried the controllers. A new controller costs 76€.

 

[cwah]

You can't over-volt a BBS0x. They require you to be in the right gear. I am guessing you stalled them and fried the controllers. A new controller costs 76€.

No I didn't fried the controller as I didn't overvolt them.

The fault were the following amongst the 3 bbs02:
- intermittent acceleration when raining
- all 3 had a broken LCD display for various reasons (bike felt on the floor, a small drop on the display, etc)
- one had a small click sound when pedalling
- currently the last one has an error 30 on the cracked LCD. I don't have time to diagnose.