Now helping a friend!

jfny1978

Active Member
Region
USA
Hey everyone. My ebike is working great...so now of course my friend wants help converting his bike to a mid drive ebike! He has an Electra Townie Balloon 3i and the specs online just say it has a "sealed cartridge" bottom bracket - from the best I can tell that would work well and uses a pretty standard 20 spline crank remover, which I have. Does that sound right? Photos below. (To be clear he sent these photos and he is hundreds of miles from me but I'm visiting him in a few weeks)
 

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tomjasz

Well-Known Member
It’s a standard old school square taper bottom bracket. Back in the day the bearing were loose. Modern bearing are sealed. But there’s no difference in the overall BB specs and design. The typical BB tool for square taper is golden. But the 3i is not a candidate for a mid drive. A good front hub drive maintaining the rear back pedal braking. I’m thinking it has a front rim brake? If correct s DD hub with regen braking is a great build. My most used rrrand shopping bike is set up like I suggest.
 

jfny1978

Active Member
Region
USA
It’s a standard old school square taper bottom bracket. Back in the day the bearing were loose. Modern bearing are sealed. But there’s no difference in the overall BB specs and design. The typical BB tool for square taper is golden. But the 3i is not a candidate for a mid drive. A good front hub drive maintaining the rear back pedal braking. I’m thinking it has a front rim brake? If correct s DD hub with regen braking is a great build. My most used rrrand shopping bike is set up like I suggest.
Thank you. It does have a front rim brake and rear coaster brake. So you can't keep the coaster brakes if you do a mid drive kit?
 

tomjasz

Well-Known Member
So you can't keep the coaster brakes if you do a mid drive kit?
Correct. I made that brain fart mistake on my first ever build 7 years ago. An almost identical bike from Trek, the Pure, before Trek bought out Electra.
 

jfny1978

Active Member
Region
USA
Correct. I made that brain fart mistake on my first ever build 7 years ago. An almost identical bike from Trek, the Pure, before Trek bought out Electra.
Ok interesting. I will see what he wants to do. I imagine he doesn't want to give up the coaster brake. Front brakes only on an ebike sounds dangerous.
 

harryS

Well-Known Member
I fashioned something similar to this for my 26" steel frame fat tire bike, which had (gasp) 4' wide rim brakes,. After spending 30 bucks on a set of metric taps and dies. I should just bought ths gadget. Then again it was a giid excuse to upgrade my tools.

 

tomjasz

Well-Known Member
I fashioned something similar to this for my 26" steel frame fat tire bike, which had (gasp) 4' wide rim brakes,. After spending 30 bucks on a set of metric taps and dies. I should just bought ths gadget. Then again it was a giid excuse to upgrade my tools.

In my experience that solution with higher W motors isn’t ideal. I’d go Nine-Continent with regen braking. Added cooling fins and Statoraide. Regen braking is great and with rear coated brakes very manageable. But of course, no sarcasm, you’re one of the best DIY posters here. And yours is good advice. I’m just another idea.
 

Merle Nelson

Well-Known Member
Region
USA
Thank you. It does have a front rim brake and rear coaster brake. So you can't keep the coaster brakes if you do a mid drive kit?

Post #1281 might have some clues as to a way to make it work.
 

tomjasz

Well-Known Member

Post #1281 might have some clues as to a way to make it work.
Giving up rear brakes with a mid drive is, well, irresponsible.
 

Merle Nelson

Well-Known Member
Region
USA
I wouldn't disagree with you Tom. And I know precious little about ebikes but, if I understand correctly the new owner of that bike valued the ability to apply the rear brake with her leg rather than with her hand.
 

tomjasz

Well-Known Member
I wouldn't disagree with you Tom. And I know precious little about ebikes but, if I understand correctly the new owner of that bike valued the ability to apply the rear brake with her leg rather than with her hand.
Then don’t use a mid drive. I like my boater brake too. A direct drive front motor and a regen capable controller is a nice conversion. A gear drive front hub is also a good conversion but relies only on the coaster rear and front rim brakes. Just fine for a 20-25mph eBike.
 

EMGX

Well-Known Member
There is a coaster brake version of the TSDZ2, which is what Petaluma used on that lady's coaster brake bike conversion.
 

tomjasz

Well-Known Member
There is a coaster brake version of the TSDZ2, which is what Petaluma used on that lady's coaster brake bike conversion.
I’m not a fan of the mounting position or the motor. But I am curious as to how a motor can freewheel with ANY mid drive with a coaster brake. Link me to that Petaluma post?
 

tomjasz

Well-Known Member
OK Google reveals all,

“This model will not freewheel while pedaling in reverse. This feature is a unique TSDZ2 option not found on any other e-bike mid-drive motor. It allows this motor to work with a coaster brake. This motor also works with regular non-coaster brake bikes with both derailleurs and internal gear hubs. Throttles are not available on coaster brake motors for safety reasons. Also, walk-assist is disabled for safety reasons.”
 

EMGX

Well-Known Member
I considered a coaster brake version but decided against it.
Here is a China based source $389 shipped

eco-ebike doesn't have the coaster brake version listed on their web site but they told me they had it in stock (US based in Tennessee), their price was $425, plus shipping, if I remember correctly.

Endless Sphere is populated by many people who have no idea what they are talking about which shows in the thread you referenced. "DRUM" is accurate. The main gear is solid without the sprag clutch as he noted. There is another difference in that the main gear is straight cut instead of spiral cut. I am aware of this because I was thinking of converting my TSDZ2 to a coaster brake version. I think (but not certain) that it could still be done by also changing the reduction gear to a straight cut one to match. total cost to change both the reduction and main gears should be less than $100 - maybe I'll do that someday/maybe not.
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tomjasz

Well-Known Member
TSDZ2 was a disappointment for me. I had an evaluation sample. I ended up giving the KHS Smoothie bike, motor, and battery to a fellow living in a boathouse with an income we’ll under $1000 a month. He loves it. I’ve built around 7 or 8 different motors and kits. I still ride BBS01A motors from 2014. But personally now prefer hubs. MAC and MXUS.
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EMGX

Well-Known Member
TSDZ2 was a disappointment for me. I had an evaluation sample. I ended up giving the KHS Smoothie bike, motor, and battery to a fellow living in a boathouse with an income we’ll under $1000 a month. He loves it. I’ve built around 7 or 8 different motors and kits. I still ride BBS01A motors from 2014. But personally now prefer hubs. MAC and MXUS.
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The guy you gave it to liked it though, right? I've never used a direct drive hub motor but the MXUS geared front hub motor paired with a KT 11/22a controller and display works amazingly well on my wife's Biria bike. Still the TSDZ2 looks like it would be a really good choice for a Electra Townie. It depends on expectations though. I did a 63 mile ride with my Schwinn Hybrid/TSDZ2 on Sunday, along the way I saw a couple with their tank-like Rad bikes. The man never even used the pedals except as foot rests, the woman with him turned the cranks maybe a half dozen times. I suppose they were just out to get some fresh air because for sure they got zero exercise. The Tongsheng is for people who actually ride bicycles, not so much for throttle scooter riders.