What is the radius (or diameter) of the 44t Tongsheng TSDZ2 chainring and how far out does it extend from the edge of the bottom bracket?

BuddaWhat

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Jul 22, 2022
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What is the radius (or diameter) of the 44t Tongsheng TSDZ2 chainring (measured at its widest points) and how far out does it extend from the edge of the bottom bracket at its center? I'm trying to figure out if will clear my chain stay before I buy it. I've seen a downloadable actual size printout of a chainring for a Banfang you can cutout and position it next to your bottom bracket to see if their motor will fit an indivdual bicycle frame, but I haven't found the same for the Tongsheng. Thanks in advance.
 

matthewslack

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Nov 26, 2021
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What is the radius (or diameter) of the 44t Tongsheng TSDZ2 chainring (measured at its widest points) and how far out does it extend from the edge of the bottom bracket at its center? I'm trying to figure out if will clear my chain stay before I buy it. I've seen a downloadable actual size printout of a chainring for a Banfang you can cutout and position it next to your bottom bracket to see if their motor will fit an indivdual bicycle frame, but I haven't found the same for the Tongsheng. Thanks in advance.
Chain is half inch links, so circumference at centre of chain pins is 22 inches, divide by Pi for diameter.

Lots of detail including measurements here:

 
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Bikes4two

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Feb 21, 2020
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  • I have a spare EDIT 44T chainring and I've just measured it and it is 175mm diameter.
  • My mistake, I measured a 42T chainring - durgh. As @Woosh says in another post, go for 184.6mm for a 44T chainring.
  • The motor casing covers the edge of the bottom bracket so I can't measure precisely, but I would estimate that from the edge of my 68mm BB to the standard 'as supplied' chainring teeth is about 12mm.
  • The supplied chainring is dished towards the BB to improve chainline. If you fitted an ordinary flat chainring then this dimension goes to about 20mm. (I've done this on one of my bikes as it has an internal gear hub so chainline is fine).
  • From the chainline perspective for derailleur gears, 20mm is probably ok when on the smallest rear casette sprockets but I would imagine it'd be a problem in the lower gears/bigger sprockets.
 
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Bikes4two

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Feb 21, 2020
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you have to measure it with the chain.
I see what you're saying but I think the OP is concerned about the chainring teeth touching the chainstay and at that point the chain isn't of course on the chainring :cool:.

And I'm about to correct my post as the chainring I measured is 42T not 44T - durgh - so your other post giving 184.6m for 44T is the one to stick with.
 
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Woosh

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I usually check the current largest chainring on the bike. If it's 38T or more, then the TSDZ2 will fit. You still have to move any cables running below the bottom bracket.
 
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