The chainring of my TSDZ2 wobbles. Is that normal?

[Busse Woods]

Maybe it's just the nature of this design. On my non electric bikes the chain rings are rock solid. Tong Sheng really needs to improve their tolerance/quality control.

 

[EMGX]

All parts are made to be within a certain tolerance (machining metal with precise, exact sameness from one piece to the next is virtually impossible because the machine tools wear down or move a miniscule amount). So let's say two parts have to fit together, and the machining causes both to be on the high side (slightly larger than 'perfection'); they will fit together very tightly, with no slop whatsoever. But if the opposite occurs and both parts are on the low side, there will be a lot of slop. On average, most parts will fall close to the middle, so when they are mounted against each other there will be a very small bit of room but not enough to really notice.

The amount of the tolerance (and the quality control) will depend on the company. Sometimes a part that's outside of spec won't be caught and tossed, and they'll ship it for assembly anyway. If both parts are on the high side, they won't even fit against each other. On the low side, yikes the slop! But chances are, both won't be out of tolerance on the low side, although one part could be.

I guess the question in your case is, does the slop allow so much wiggle that it binds or throws the chain? If not, then at worst it might cause sidebar wear on the chain at a somewhat faster rate than normal, but other than buying a replacement chain a little more often there's no downside for riding. You could always buy parts to rebuild the assembly, though, and hope you get some from a different batch that will fit more tightly.

My chain ring deflects less than a millimeter under pressure, and there's no detectable "wiggle" in the shaft area. I guess I got a tight set.

It seems to me that correction of loose tolerance is why shims are used on the tsdz2 (shims also used on the motor shaft and small reduction gear if I remember correctly). I'm curious if the OP opens the cover over the large gear if it wobbles on the axle shaft due to inadequate shimming. If that's the problem it should be an easy fix.

 

[Busse Woods]

Thanks. EMGX. That makes sense. I'm not expecting perfection but there should be a way to improve the fit. I'll probably take a look sometime next week. I will report what I find.

 

[kevinmccune]

Thanks. EMGX. That makes sense. I'm not expecting perfection but there should be a way to improve the fit. I'll probably take a look sometime next week. I will report what I find.

you can also find shims at TRACTOR SUPPLY.

 

[Busse Woods]

Thanks! I don't have one of those near me. I am thinking Ace Hardware may be a good source.

 

[PedalUma]

Before I knew better, I re-used the original ring-bolts without the ring-guard and had wobble and scraping of the plastic cover. When I should have slightly heat shaped the cover on the rear side so it was flush and used shorter bolts.

 

[kevinmccune]

Thanks! I don't have one of those near me. I am thinking Ace Hardware may be a good source.

Hardware from Ace is so dang expensive.

 

[Rexlion]

Hardware from Ace is so dang expensive.

Yeah, that's for sure! Years ago (1990) I used to buy 1500 each of a couple sizes of grade 5 bolt and lock nut at one time for my business, so I was accustomed to getting a good price from a wholesaler. Now when I need to go buy two or three bolts or screws from Ace, the price just about gags me! For what I used to resell 250 pieces for, if I now pay the same I'll get about 10 pieces.

 

[kevinmccune]

Yeah, that's for sure! Years ago (1990) I used to buy 1500 each of a couple sizes of grade 5 bolt and lock nut at one time for my business, so I was accustomed to getting a good price from a wholesaler. Now when I need to go buy two or three bolts or screws from Ace, the price just about gags me! For what I used to resell 250 pieces for, if I now pay the same I'll get about 10 pieces.

No excuse for scalping( its the business norm these days) meanwhile what little we have gets worth less and less.

 

[Busse Woods]

This video shows the spacer shims behind the large gear at ~3:30.

You are absolutely right EMGX,my TSDZ2 does not have any of the two (brass?) shims. Although the play seems to be coming from the shaft/torque sensor assembly. I'm not sure if shims will help that. An even bigger concern are the red and black wires that are visible in the video, probably for the torque sensor. I'm afraid if I add shims they may damage those wires. The bearing I added to the drive side appears to be helping so I'm going to leave it at that. For the time being, I'll just keep an eye on things. .

 

[PedalUma]

I have a motor disassembled on the bench. The main gear has a bit of play. It needs a new blue gear because the needle bearings lost their chrome finish and failed. Part of that is the stress the motor was under, full power on Sonoma Mountain trails while lugging it. He never lubed the main gear for 2.5 years and that stressed everything else. It will get a new main gear, one way clutch, spindle with bearing and blue gear. It will all be almost over-packed with fresh grease. That particular motor came from a second tier supplier during the pandemic when sourcing was sometimes difficult. Co-incidence? Or coincidence? I always wondered if components were rated beyond Pass/Fail but on a bell curve. With the better parts going to the upper market and the average to the mass market, with the second lowest quintile (that is passable grade-D but not F) to the low end budget builds. The 'Chine' of Machine has an ancient origin. These are some of the smartest and most experienced makers ever. So, why toss grade 'C' components when someone wants to sell everything from that big average bin?

 

[kevinmccune]

I have a motor disassembled on the bench. The main gear has a bit of play. It needs a new blue gear because the needle bearings lost their chrome finish and failed. Part of that is the stress the motor was under, full power on Sonoma Mountain trails while lugging it. He never lubed the main gear for 2.5 years and that stressed everything else. It will get a new main gear, one way clutch, spindle with bearing and blue gear. It will all be almost over-packed with fresh grease. That particular motor came from a second tier supplier during the pandemic when sourcing was sometimes difficult. Co-incidence? Or coincidence? I always wondered if components were rated beyond Pass/Fail but on a bell curve. With the better parts going to the upper market and the average to the mass market, with the second lowest quintile (that is passable grade-D but not F) to the low end budget builds. The 'Chine' of Machine has an ancient origin. These are some of the smartest and most experienced makers ever. So, why toss grade 'C' components when someone wants to sell everything from that big average bin?

I noticeed that some major manufacturers industrail motors( or engines ) seemed to have above the norm quality and just general construction issues my acquaintence told me the 'industrail" engines were assembled using a lot of the 2nd grade reject parts, do not know if that had anything to do with the vibration issues or not. However as 'Pedaluma" sez[ we have the tech we can rebuild and make it better]

 

[PedalUma]

Most not-style parts are about the same but AMG gets the fifth quintile QC components from Benz to build with.

 

[Art Deco]

I think everyone resells the out of spec parts to someone further down the quality line . We certainly saw some stuff made during the pandemic that wasn't up to normal quality.