Kona Ute tsdz2 conversion

guerney

Esteemed Pedelecer
Sep 7, 2021
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A new axle which works like the TS, connected to a raspberry pi which rewrites the wheel size setting in the controller firmware continuously to suit varying levels of torque? It's unlikely to work lol. Bafang seem to bemoving on and uninterested in developing the bbs series. The cadence sensored bike does take a little getting used to, but IMHO it's bearable.
It'd be easier for a device to deliver motor power via the throttle control, responding to a torque sensor. But it'd probably ride like cr*p without a lot of fine tuning, and even then.
 

Nealh

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Aug 7, 2014
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West Sx RH
Stanecoke yes that's the one, I didn't find it on ES but came across it on pedelec.de where his user name is Hochsitzcola.
 
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guerney

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Sep 7, 2021
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Stanecoke yes that's the one, I didn't find it on ES but came across it on pedelec.de where his user name is Hochsitzcola.
Aha? And hmmm... (translated)


 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
Back with an update. After 60 miles of shakedown riding I lent the bike to a friend to use for a bit whilst my kid grows enough to fit the seat :)

Said friend has zero mechanical sympathy or interest in maintenance so I figured it would be a good test to make sure it was proof against my wife using it.

It's come back with another 160 miles on the clock, a big old creak and a cheesed thread on the axle. I guess most of it's my fault, I didn't gorilla up the crank arm bolt enough during the initial assembly and it rode lose, and once these ride loose once, you're stuffed in my experience.

New axle time for me and see if I can find the source of the creak on the way through, sounds like a dead BB bearing would on a normal bike.
 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
After disassembling it, it was apparent the motor + bearings were fine, just loose crank bolt on the square taper axle had completely nuked the crank arm. I only had a small torque wrench (up to 24nm) so guessed, and seemingly I didn't guess very well.

That said.. one new crank arm later, and a torque wrench with the appropriate range, did it up to 40nm and the cranks are so tight on they won't even turn! hmmmm. Can't see that I could have cocked up anything in the reassembly on - black spacer plate, castle nut using the supplied tool, then crank arm...

Any thoughts? I'm going to back it undo it and try it again at whatever turns out to be the highest torque setting I can manage without it binding.
 

peter.c

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Apr 24, 2018
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thurrock essex
The crank arm castings are poor on the square taper, once it has come loose [a very common problem] they tighten on to far up the shaft
Try to remove /file the rear of the crank arm to gain clearance if its the non drive side try a different arm
 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
The crank arm castings are poor on the square taper, once it has come loose [a very common problem] they tighten on to far up the shaft
Try to remove /file the rear of the crank arm to gain clearance if its the non drive side try a different arm
Hmm. It's the non drive side arm I've replaced. I hope I haven't over torqued it and goosed the new arm! If the tolerance on the axle is the issue maybe a smear of loctite or grease might cause it to nip up just that fraction earlier.. Thinking aloud
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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After disassembling it, it was apparent the motor + bearings were fine, just loose crank bolt on the square taper axle had completely nuked the crank arm. I only had a small torque wrench (up to 24nm) so guessed, and seemingly I didn't guess very well.

That said.. one new crank arm later, and a torque wrench with the appropriate range, did it up to 40nm and the cranks are so tight on they won't even turn! hmmmm. Can't see that I could have cocked up anything in the reassembly on - black spacer plate, castle nut using the supplied tool, then crank arm...

Any thoughts? I'm going to back it undo it and try it again at whatever turns out to be the highest torque setting I can manage without it binding.
If there's binding then there is contact in the wrong place, assuming axle not bent. Find and resolve the contact, hopefully amicably, and then full proper torque. Shouldn't be any need for less, if proper clearances have been restored.
 

guerney

Esteemed Pedelecer
Sep 7, 2021
11,252
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After disassembling it, it was apparent the motor + bearings were fine, just loose crank bolt on the square taper axle had completely nuked the crank arm. I only had a small torque wrench (up to 24nm) so guessed, and seemingly I didn't guess very well.

That said.. one new crank arm later, and a torque wrench with the appropriate range, did it up to 40nm and the cranks are so tight on they won't even turn! hmmmm. Can't see that I could have cocked up anything in the reassembly on - black spacer plate, castle nut using the supplied tool, then crank arm...

Any thoughts? I'm going to back it undo it and try it again at whatever turns out to be the highest torque setting I can manage without it binding.
??? "TongSheng TSDZ2 cranks have a lot of offset which increases the q factor well beyond what was intended for most bikes. "

 

Bikes4two

Esteemed Pedelecer
Feb 21, 2020
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  • When I did my first TSDZ2 conversion (on my own bike) I tightened the cranks by hand to what I considered as tight enough but as experienced by others, they still periodically required re-tightening.
  • One recommendation was to try Bafang cranks which I did but they loosened up after a while too, albeit maybe not so often.
  • And then I bought a torque wrench and realised that 'my tight' was quite a bit short of the recommended 40nm torque. Now they are tightened properly: I checked the tightness after a further 1500km-ish (this is still with the Bafang cranks fitted) and I needed to give them a bit of a tweak, but otherwise OK
Q- factor:
  • Most casual cyclist don't know about this parameter and in practical terms I wouldn't think they need to as the factor is IMHO only likely to be a consideration for performance cyclists i.e. road racers.
  • Of the 4 other TSDZ2 conversions I've now done (a) I've stuck with the original cranks and (b) I've tightened them up to 40nm and none of the riders have (yet?) to get loose cranks or any physiological issues that could be put down to Q factor.
The TSDZ2 is made to a low price point so it is likely that some motors will suffer from indiferent manufacturing tolerances, but of the kits I've used, I've not encountered anything untoward.
 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
Fresh look at it today and it all becomes clear, I have a friday afternoon axle.

Drive side - fine


Slightly blurry non drive side - no flats for the arm to seat onto before it binds.


Not impressed with the quality of this kit so far with the original crank arms not being threaded correctly and now this.
 
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Bikes4two

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Feb 21, 2020
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  • Clearly @potato you are having some issues with your TSDZ2 :(
  • Your observations got me curious as to what my axle tapered ends looked like so I took the TSDZ2 crank arms of my wife's conversion (I've removed them several times as I've moved the motor between three different bikes).
  • As per your own observation, the taper on the non-drive side didn't have a 'shoulder' either but I've not had a crank arm problem.
  • I don't think the presence or absence of a 'shoulder' is relevant - as long as the taper is machined to the correct angle and is long enough to allow the crank to be pulled onto the taper far enough that is tight, then all should be fine.
  • In the two pics below you can see that the cranks on both sides have a small clearance between the motor body and the crank which supports my view that the shoulder (or its absence) might not be the issue.
  • In your post #66 you mentioned that you'd tightened up to 40nm and the crank wouldn't turn.
  • That experience rings a bell with me in that on one of my motors I thought the sprag clutch was playing up (it turned out to be fine - the probelm was the free-hub on the wheel), so I dismantled that side of the motor.
  • On re-assembly I got something out of kilter and I had the same 'crank arm binding' issue that you describe and this was due to something I'd not got right in the re-assembly process (can't remember what it was though!) meaning the axle wasn't protruding from the motor body enough to allow full tightening on the taper (does that make sesne?).
46465

46464
 

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potato

Finding my (electric) wheels
Nov 5, 2021
21
12
  • Clearly @potato you are having some issues with your TSDZ2 :(
  • Your observations got me curious as to what my axle tapered ends looked like so I took the TSDZ2 crank arms of my wife's conversion (I've removed them several times as I've moved the motor between three different bikes).
  • As per your own observation, the taper on the non-drive side didn't have a 'shoulder' either but I've not had a crank arm problem.
  • I don't think the presence or absence of a 'shoulder' is relevant - as long as the taper is machined to the correct angle and is long enough to allow the crank to be pulled onto the taper far enough that is tight, then all should be fine.
  • In the two pics below you can see that the cranks on both sides have a small clearance between the motor body and the crank which supports my view that the shoulder (or its absence) might not be the issue.
  • In your post #66 you mentioned that you'd tightened up to 40nm and the crank wouldn't turn.
  • That experience rings a bell with me in that on one of my motors I thought the sprag clutch was playing up (it turned out to be fine - the probelm was the free-hub on the wheel), so I dismantled that side of the motor.
  • On re-assembly I got something out of kilter and I had the same 'crank arm binding' issue that you describe and this was due to something I'd not got right in the re-assembly process (can't remember what it was though!) meaning the axle wasn't protruding from the motor body enough to allow full tightening on the taper (does that make sesne?).
View attachment 46465

View attachment 46464
 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
Thank you for going to that effort, I appreciate it. I agree that the presence or not of a shoulder is irrelevant so long as the taper is correct. I measured the largest exposed bit of the axle on the non drive side as 31.8mm. The other side I didn't measure as I thought I'd cracked it with the absence of a shoulder. Time for me to have another look and as you say, see if there's anything to get more axle showing on the non drive side
 
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Bikes4two

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Feb 21, 2020
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Hi @potato

I've just reviewed how I did the sprag clutch work/inspection (as per how the guy did it in this youtube clip here) and the dis-assembly is on the drive side of the motor so my earlier comment about having crank binding on the NDS after re-assembly is incorrect - my crank binding was on the drive side - durgh!

Apologies for any misdirection :cool:
 

potato

Finding my (electric) wheels
Nov 5, 2021
21
12
I sent a video of the issue to the seller and they've said its because I'm using steps crank arms rather than the originals (which arrived with virtually no thread in the pedal holes). I don't really buy this as an answer unless they decided to make up their own axle standard, but with the language barrier making it hard to escalate, I'm waiting on a replacement set of cranks to try. Fair play to them they have sent the replacements out promptly, and without any extra cost for shipping or anything
 
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guerney

Esteemed Pedelecer
Sep 7, 2021
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This is all rather horrendous. Would it be safe to thin the end of the crank arm, which goes up too high along the axle? Or maybe add some material so that the square in that crank arm is slightly smaller? (Bodges and probably not worth contemplating)
 
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potato

Finding my (electric) wheels
Nov 5, 2021
21
12
If I had a welder I would have considered adding a dot of weld to the axle for the crank arms to seat against before binding. Probably for the best I have to be patient for a proper solution than such bodges!
 

guerney

Esteemed Pedelecer
Sep 7, 2021
11,252
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It's too early for bodges, hope the newcrank arms work out... but if they don't - adding a dot of weld to the axle could leave that crank arm loose, which over time would wear away the axle and square hole in the crank arm. Also the heat from welding could affect the axle steel, depending on how much carbon it contains (and whether it's been folded and battered 200 times ;), Samurai sword style) and how it's cooled afterards - quenched in water could make it more brittle, which could lead to it breaking under stress. Allowing it to cool slowly could it leave it soft, which could lead to it bending. Filling in the square in the crank arm with weld to drill and file to form a smaller square, could also lead to bending, breaking or excessive wear problems, depending on how it was cooled afterwards. If those new crank arm didn't fit properly, I'd file off about 1mm from the motor facing side of that crank arm, hoping that it wouldn't make too much of a difference to it's strength. A somewhat risky bodge.
 
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