Newbie wants to build torque sensor bike

I have driven my friends (Bosch) torque sensing bike, and then a 'standard' paddle assist (or thumb lever) bike.
The paddle assist was scary to drive; making a U turn in our street and starting to just paddle a bit to keep some speed, the bike JUMPED applying FULL POWER as soon as it detected paddle movement.

The Bosch drive on the hand felt as if it wasn't even there, VERY natural, completely maintaining the 'biking' feeling. Just being able to go a little faster than normal with the same amount of muscle power, with the 'little faster' adjustable via the 'how much support to you want' setting.

So torque sensing is for me the only e bike I am considering. BUT, I don't have and certainly cannot justify the high price.

Being a DIY through and through, I started to look into kits for making one of my bikes a torque sensing E bike, and came across the Tongsheng TSDZ2 (or its non-infringing names it is offered under). Based no initial searching, I would like the 48 Volt, 750W motor, add a thumb lever control (in addition, when just in case), lights, and 2 high capacity (18 or up Ah) batteries (ideally for frame and rear rack mounting)

At this point my questions are (I will measure the dimensions of my existing bike as outline in most sales listings):
a) do I need to make sure i get the latest version of the controller (I read the newer version is better 'tuned')?
b) what seller (domestic, china; dealer or ebay) if any difference?
c) any recommended kits (completeness, quality of parts, price)?
d) what sprocket size (standard it seems is 42?)
e) other features, accessories, etc to make use and install easier?

FWIW, you can use the Cycle Analyst v3.x from http://ebikes.ca to turn any "dumb" controller with a throttle input into whatever kind of control input you want--torque sensor (at pedals, at rear wheel, whatever), cadence-controlled PAS (which I use on my SB Cruiser trike to get more speed the faster I pedal, with barely any response at the lowest pedal speed), or a combination of both, and even have a separate throttle (or other analog-voltage-output control) (which I also have, in case my legs are hurting too much to do the pedalling and/or something goes wrong, or I simply can't start pedalling because of slope, load, etc and have ot use the throttle to get started, and then just pedal to control it after that).


Also, there are at least three Open-Source FirmWare projects for the TSDZ2 that give you more options than the original firmware from the OEM. They're listed over here:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=116355#p1717519
and there are many threads discussing them in various builds, etc.

Note that it has been reported the latest controller versions use a different hardware setup that cannot be reprogrammed to the OSFW, so see the threads for the OSFW and TSDZ2 systems for details on which is the best one to get for this purpose.


Also be aware that there are mechanical design problems with the TSDZ2 itself that can lead to broken crankshaft (which could cause you to crash and be injured depending on when it breaks under you as you're pedalling) unless you do various modifications to it before you use it; there's details on that in the various TSDZ2 threads.


Front sprocket (chainring) sizes will depend on the speed and torque you need out of it when shifted to various gears on your rear wheel, and what sprocket sizes are used on those gears on that rear wheel. Larger front sprockets give faster speed but lower torque.

TSDZ2 is hot garbage. Read all the trouble threads about it in this forum if you doubt it.

Add-on torque sensors for other systems are fragile and fussy, but at least they won't snap off and hurt you. They'll let you down in other ways.

My advice is to don your man pants and get used to cadence PAS or throttle or both. Or else ride the proven pedal torque solution: a regular bike.

Do not blow your shekels on a Bosch bike. That's a chump's game that will keep taking big bites of money until you either give up, or buy another one and repeat the cycle.

Chalo said:

Add-on torque sensors for other systems are fragile and fussy, but at least they won't snap off and hurt you. They'll let you down in other ways.

Click to expand...

If you have on top of your head, what ways they will let down ?

afzal said:

Chalo said:

Add-on torque sensors for other systems are fragile and fussy, but at least they won't snap off and hurt you. They'll let you down in other ways.

Click to expand...

If you have on top of your head, what ways they will let down ?

Click to expand...

Many bottom bracket torque sensors replace the crankshaft with a fancy stress strain sensor.. and it is a small digital electrical signal that comes for them. This is not a good place for tiny, fragile sensors that might not like water, dirt, and mud from the bike. Inside the bottom bracket.. So without care ( riding through streams, ect) they will eventually short out, and cause other problems in the system.

They are a fragile form in my experience.. but.. when they work.. Yes they are wonderful and it is like riding on a cloud. I have used the Ca3 system and it is very nice if set up correctly.

I use a BB torque sensor and for commuting it is fine. For off road use, you want the Bosch system which is actually very reliable contrary to what is being written here.

I think that diy ebike is only meaningful if you find this sort of thing interesting. Elsewise, you should just buy an ebike and ride it.

To trigger some more inputs/opinions, I want to phrase my quesiton a little different:
If you have under $1,000 and must have torque sensing (NOT cadence or thumb lever), what is the best way to go about (open to DIY suggestions/kits if good instruction are provide for an able DIY (but not a bike expert).

Chalo said:

My advice is to don your man pants and get used to cadence PAS or throttle or both.

Click to expand...

Not for me. It is like riding a moped. Not much to do with biking.

Vbruun said:

For off road use, you want the Bosch system which is actually very reliable contrary to what is being written here.

Click to expand...

Nobody said Bosch wasn't reliable. I said it was expensive and would continue to be expensive to maintain. That's the nature of a pricey system that's specifically made to be inoperable with third party components.

If you're a contented Apple customer, it will be familiar to you. If you're one of us who thinks it's crazy to throw your money away on Apple products, you'll hate it.

vtraudt said:

Chalo said:

My advice is to don your man pants and get used to cadence PAS or throttle or both.

Click to expand...

Not for me. It is like riding a moped. Not much to do with biking.

Click to expand...

Pretty narrow view of biking. But we all have to live with the hangups we have, I guess.

I use throttle only for simplicity and robustness, and my e-bikes are absolutely bicycles first. I think commercial torque sensing e-bikes are much more appliance-like than what I ride.

vtraudt said:

To trigger some more inputs/opinions, I want to phrase my quesiton a little different:
If you have under $1,000 and must have torque sensing (NOT cadence or thumb lever), what is the best way to go about (open to DIY suggestions/kits if good instruction are provide for an able DIY (but not a bike expert).

Click to expand...

save more money

buy one of these, with the appropriate spindle length for your donor bike:
https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/ncte-120.html
buy the CA-SA:
https://ebikes.ca/shop/electric-bicycle-parts/cycle-analysts.html

use the remaimning ~$600 to get a kit that meets your needs.

These two items will turn any ebike into a tork sensing ebike.

Cycle analyst display / brain - 105$
Tork sensing bottom bracket that is plug and play with teh CA3 - 150$

There you go. GOOD, tork sensing controller manipulation. use any controller i the world and any throttle i the world.

255$.

25.5% of 1000$.

74.5% to spend on other things. ( 745$).



https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/ncte-120.html

https://ebikes.ca/shop/electric-bicycle-parts/cycle-analysts.html

DogDipstick said:

These two items will turn any ebike into a tork sensing ebike.

Cycle analyst display / brain - 105$
Tork sensing bottom bracket that is plug and play with teh CA3 - 150$

There you go. GOOD, tork sensing controller manipulation. use any controller i the world and any throttle i the world.

255$.

25.5% of 1000$.

74.5% to spend on other things. ( 745$).



https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/ncte-120.html

https://ebikes.ca/shop/electric-bicycle-parts/cycle-analysts.html

Click to expand...

Don't forget shipping and accessories; the OP may want to control the PAS levels in some way, besides navigating the CA menus, etc.

E-HP said:

buy one of these, with the appropriate spindle length for your donor bike:
https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/ncte-120.html
buy the CA-SA:
https://ebikes.ca/shop/electric-bicycle-parts/cycle-analysts.html

use the remaimning ~$600 to get a kit that meets your needs.

Click to expand...

Now we are talking. But also read that 'some' (?) controllers don't like (or not easily) inputs from torque sensor?

E-HP said:

Don't forget shipping and accessories; the OP may want to control the PAS levels in some way, besides navigating the CA menus, etc.

Click to expand...

PAS stands for ?? (I assume amount of assist based on input torque)?
What do I need to control that level ?

vtraudt said:

E-HP said:

buy one of these, with the appropriate spindle length for your donor bike:
https://ebikes.ca/shop/electric-bicycle-parts/torque-sensors/ncte-120.html
buy the CA-SA:
https://ebikes.ca/shop/electric-bicycle-parts/cycle-analysts.html

use the remaimning ~$600 to get a kit that meets your needs.

Click to expand...

Now we are talking. But also read that 'some' (?) controllers don't like (or not easily) inputs from torque sensor?

Click to expand...

The torque sensor connects to the CA not the controller. The CA converts the signal from the torque sensor into a throttle signal, so it can be used to add the capability to any controller that has a throttle input. PAS stands for pedal assist sensor; which there are two basic types, torque sensor PAS or cadence sensor PAS; some setups support both torque and cadence inputs/outputs.

It appeas to me that the Op when discribing the pedal cadence senosr bike tested, likely used a speed control controller so hence maybe the full power that took him by surprise. Using a current control controller one doesn't get the same power affect and alarming take off.

Oh yeah. to get the FULL Cycle Analyst experience, you will want a power metering shunt like this. This will turn your bike into a power meter too... and can manipulate the output even more based on real time power levels.

https://ebikes.ca/shunt-ca3.html

hemo said:

It appeas to me that the Op when discribing the pedal cadence senosr bike tested, likely used a speed control controller so hence maybe the full power that took him by surprise. Using a current control controller one doesn't get the same power affect and alarming take off.

Click to expand...

Ya, can't comment on the validity of making a determination of two PAS types purely on a single ride from both types. There's nothing "natural" about pedaling and having electric assist, unless you want to fool yourself into thinking you are stronger or younger. If you're OK with owning an ebike, and not pretending it's a pedal bike, then KT cadence PAS is pretty good.

Chalo said:

Vbruun said:

For off road use, you want the Bosch system which is actually very reliable contrary to what is being written here.

Click to expand...

Nobody said Bosch wasn't reliable. I said it was expensive and would continue to be expensive to maintain. That's the nature of a pricey system that's specifically made to be inoperable with third party components.

If you're a contented Apple customer, it will be familiar to you. If you're one of us who thinks it's crazy to throw your money away on Apple products, you'll hate it.

Click to expand...

What are the expenses of maintaining the Bosch system? Chains, casettes and chainwheels are cheap and last OK even under middrive power. As far as i'm aware that is all that seperates their system from a hub motor one.
The motors need no maintenance..

Vbruun said:

Chalo said:

Vbruun said:

For off road use, you want the Bosch system which is actually very reliable contrary to what is being written here.

Click to expand...

Nobody said Bosch wasn't reliable. I said it was expensive and would continue to be expensive to maintain. That's the nature of a pricey system that's specifically made to be inoperable with third party components.

If you're a contented Apple customer, it will be familiar to you. If you're one of us who thinks it's crazy to throw your money away on Apple products, you'll hate it.

Click to expand...

What are the expenses of maintaining the Bosch system? Chains, casettes and chainwheels are cheap and last OK even under middrive power. As far as i'm aware that is all that seperates their system from a hub motor one.
The motors need no maintenance..

Click to expand...

Proprietary batteries. Proprietary connectors. Proprietary spare parts. Authorized dealer service.

Like I said, if you're cool with Apple, you'll be cool with Bosch. I'm not, and I expect that a lot of the participants here aren't either.

Vbruun said:

Chalo said:

Vbruun said:

For off road use, you want the Bosch system which is actually very reliable contrary to what is being written here.

Click to expand...

Nobody said Bosch wasn't reliable. I said it was expensive and would continue to be expensive to maintain. That's the nature of a pricey system that's specifically made to be inoperable with third party components.

If you're a contented Apple customer, it will be familiar to you. If you're one of us who thinks it's crazy to throw your money away on Apple products, you'll hate it.

Click to expand...

What are the expenses of maintaining the Bosch system? Chains, casettes and chainwheels are cheap and last OK even under middrive power. As far as i'm aware that is all that seperates their system from a hub motor one.
The motors need no maintenance..

Click to expand...

Direct drive hub motor has zero maintenance. No moving parts except the axle bearings.

I don't disagree that DD hub motors are reliable, but so are mid drive motors. The maintenance costs are not great on either type of bike unless you dont know how to replace a chain and casette (in which case you should not consider a diy bike). I know the proprietary systems are expensive to repair but they don't break a lot either.
I'm just trying to explain to the man that the easiest way to get what he wants is to just buy it. And honestly I think telling him elsewise is a lie.

Also, telling the man to just use a throttle is fine, but as a man that has ridden both throttle and torque sensing extensively, I whole heartedly agree that torque sensing is far superior.

Vbruun said:

I'm just trying to explain to the man that the easiest way to get what he wants is to just buy it. And honestly I think telling him elsewise is a lie.

Click to expand...

Are you suggesting to tell him what he wants, just ignore what he wants, or try to explain how he wants something else? He wants sub $1000 and torque sensing is what I read. "Easiest" depends on how much he has to work to make the extra couple of grand.

Or just do the sensible thing and buy a used one...

Ofc he can build a bike but i'm really sceptical that it will be 1000 dollars and good