Is this bicycle, a Scott Sub 20 hybrid, a good candidate for conversion to E-bike?

[Busse Woods]

Hello everyone, new member. This appears to be a wonderful forum with great information on E-bikes. Can’t wait to learn more and start riding an E-bike.

Is this bicycle, a Scott Sub 20 hybrid, a good candidate for conversion to E-bike?
https://www.bicyclebluebook.com/value-guide/product/10302

I understand it has rim brakes and that may be a negative. My riding is mostly on flat paths/roads and I don’t typically ride in the rain. I’m not looking for high speed, just something to help me turn 15-20 mile rides into 30-40 miles.

I would change the tires to 35-38mm to give me a softer ride and better stability. I’m favoring installing a Bafang or Tongsheng mid drive motor.

Most of the new e-bikes that appeal to me go for $2.5K or above. I love riding my Scott and it fits me well so I think that conversion may be my best option. I have no issues with the mechanical or electrical requirements to perform this conversion. I’m kind of looking forward to doing it.

Guess I’m thinking of turning my Scott Sub 20 into this:
https://cyclingmagazine.ca/sections/gear-reviews/scott-e-sub-evo-running-500-watt-hours-review/

Anything I should be aware of when doing this conversion? I welcome your comments/suggestions.

 

[Busse Woods]

Thanks, I like the idea of keeping the weight down. Should make the bike easier to haul. I saw a video that said many E-bike accidents are similar to motorcycle accidents. So I want my E-Bike to continue to be more like a regular bike as far as speed is concerned. I don't see a reason for a lots of power unless one wants to go fast or tackle steep hills. I'm only looking to make my recreational rides longer and more enjoyable. Not to mention with rim brakes, fairly skinny tires and no suspension I probably don't want too much speed.

The Bafang or Tongsheng mid drive motors both appear to be 750W. Would something lower powered be more appropriate?
Is my Scott hybrid bike a good choice for a conversion?
What is typically the most difficult part of doing a conversion?
Thanks all.

 

[Gionnirocket]

@PedalUma. . . I think this situation is where you reign

 

[Busse Woods]

That is what I am thinking, maybe a 500W motor would be more than enough for my intended use. If it saves a few lbs and a few dollars that's not a bad thing. I understand, I would probably not use max power very often, if at all. My understanding is that a torque sensor is superior and makes the bike feel more natural when riding. So I would probably choose that. I have only begun my research into E-bikes and conversions so still have a lot to learn.

 

[PedalUma]

That is what I am thinking, maybe a 500W motor would be more than enough for my intended use. If it saves a few lbs and a few dollars that's not a bad thing. I understand, I would probably not use max power very often, if at all. My understanding is that a torque sensor is superior and makes the bike feel more natural when riding. So I would probably chose that. I have only begun my research into E-bikes and conversions so still have a lot to learn.

Finally someone who does not want a 3000W bike that weighs in at 106 pounds with 20" tires that are 5" wide!
@Gionnirocket brought me in. I am crazy for the TS at 350W. Six-pin - that means no brake lever cutoffs and no throttle option. Get the small display. Do not install the wheel speed sensor or magnet. Set wheel circumference at 100cm. I am all about less being more. The Zen Garden of less. The lower nominal rate of bleed out on the 350W translates to longer range, so the battery can also be smaller and lighter. I have done some builds in the 35 pound range. These bikes blow away the expensive bikes at bike shops. And they are so much fun. I rode my three-speed today grinning like an idiot. It does not look like an electric bike and I can pass the expensive ones while honking a clown horn and sipping coffee. If you can see some of my builds at www.pedalUma.com. I have a little workshop in Northern California where I work on bikes. This is what an electric bike looks like. Good luck.

 

[EMGX]

That looks like an excellent bike for a conversion. I have two TSDZ2 bikes. One 36v 500w and a 48v 750w version. Both motors cost and weigh the same. I ride both bikes on routes that have flat to hilly/mountainous sections and both motors do well but the 48v 750w version has significantly more power in the highest setting - almost too much for most regular use. Despite what a certain clueless individual "advises" (who admits that he never did a mid drive conversion, having only watched youtube videos) there are virtually no difficulties installing a tsdz2. If you have the ability to remove a bottom bracket assembly and have a few basic bike tools a conversion can be done in an hour or so, I've installed them on 5 different bikes and I've also installed front and rear geared hub motors. The mid drive is just as easy overall and a much neater installation with no separate controller, no brake cut off or throttle with the associated extra wiring needed. Torque sensor is the way to go IMO for a more natural bike riding experience. By the way I have a Yamaha PW-SE powered gravel bike that rarely gets ridden because I prefer my tongsheng converted bikes. Huge heavy batteries aren't needed for 40 mile rides with these efficient mid drives. I rode 24 miles today including 1700 ft elevation gain on a 48v 10ah battery and am still at over 51 volts.

 

[EMGX]

PS.
I find rim brakes fine for my use. I regularly hit mid 30s mph downhill coasting and up to low 40s and I have no issues with the rim brakes on my two conversion bikes. They have similar stopping power as the mechanical discs on my gravel bike, not as good as amazing elixr1 hydraulic discs on my son's old mountain bike but I prefer the simplicity and reliability of mechanical brakes over hydraulics.

 

[Busse Woods]

Thanks PedalUma I will check out your website and the TS at 350W. I agree, I want to keep things light and simple. I don't want to change the characteristics of this bicycle any more than necessary. Just need some assist to make my rides longer and more enjoyable. I may end up getting something purpose built and more substantial in the future but for the time being I think converting my Scott bike will make me plenty happy.

 

[PedalUma]

Rim brakes work fine. I install the ex-long ones and keep the rims clean. @EMXG like to clean rims with acetone, then isopropyl. I bet gin would also work. I don't talk about my site here but in your case it sounds like you want the confidence that this is totally doable. It is. I have done builds with zero zip ties. Clean.

 

[Busse Woods]

Thanks EMGX, now you are really getting me excited about this conversion. I'm going to do more research and am looking at this as maybe being a bit of a winter project as the cycling season in my neck of the woods will end in a month or two. I will surely post once I make some progress.

 

[Busse Woods]

Rim brakes work fine. I install the ex-long ones and keep the rims clean. @EMXG like to clean rims with acetone, then isopropyl. I bet gin would also work. I don't talk about my site here but in your case it sounds like you want the confidence that this is totally doable. It is. I have done builds with zero zip ties. Clean.
View attachment 100940

Upgrading the brake pads and keeping the rims clean sounds like a good idea, will keep that in mind. I appreciate the tip.

 

[Busse Woods]

Finally someone who does not want a 3000W bike that weighs in at 106 pounds with 20" tires that are 5" wide!
@Gionnirocket brought me in. I am crazy for the TS at 350W. Six-pin - that means no brake lever cutoffs and no throttle option. Get the small display. Do not install the wheel speed sensor or magnet. Set wheel circumference at 100cm. I am all about less being more. The Zen Garden of less. The lower nominal rate of bleed out on the 350W translates to longer range, so the battery can also be smaller and lighter. I have done some builds in the 35 pound range. These bikes blow away the expensive bikes at bike shops. And they are so much fun. I rode my three-speed today grinning like an idiot. It does not look like an electric bike and I can pass the expensive ones while honking a clown horn and sipping coffee. If you can see some of my builds at www.pedalUma.com. I have a little workshop in Northern California where I work on bikes. This is what an electric bike looks like. Good luck.

Thanks, I like the idea of keeping the built as simple and clean as possible. I'm fine with no throttle. Love the water bottle batteries. Can I get 30-40 miles out of those if I put decent effort into pedaling?

 

[Gionnirocket]

Thanks, I like the idea of keeping the built as simple and clean as possible. I'm fine with no throttle. Love the water bottle batteries. Can I get 30-40 miles out of those if I put decent effort into pedaling?

There are many variables that determine miles/watt hour... But I don't see why not from everything else you've said. I can easily get 40 miles out of a 10ah battery and my bike is a cheap overweight fsmtb and I have old man wet noodle chicken legs and a bad knee.
I think that you are really going to enjoy this as I did my Bafang BBS02B conversion for much of the same reason you did. And the icing on the cake was it made for an excellent project at the beginning of Covid.
Good luck and your in good hands here with those that have replied ( me being the exception :-D

 

[Busse Woods]

Gionnirocket, thanks for your help with this. I'm really looking forward to this conversion. I like the fact that the conversion can be done without changing the "look and feel" of the bike very much. Is there a reason you chose the Bafang over the Tongsheng mid drive? Is there a recommended supplier for these motors?

 

[Busse Woods]

So I'm leaning toward the TSDZ2 w/ XH18 small display as suggested by PedalUma. Thing is, it looks like it comes in 36, 48 and 52V and in 250, 500, 750W versions? The website states 250-750w but there is no way to select which wattage unit I may want. So I'm confused about that. How do I determine which one is best for my purpose? I guess I rather have a bit too much power than too little. Although I would like to use the most efficient drive and want to keep weight to a minimum. Is there much difference in weight between the various versions?

Edit: In addition the chainring comes in different sizes. I imagine a 42T would be the logical choice?

Looks like this unit in the 48V version is probably the one I want.

TSDZ2 w/ XH-18 - Torque Sensing Pedal Assist (36-52v / 10-18a / 250-750w)

Tongsheng TSDZ2 w/ XH-18 Display - Torque Sensing Pedal Assist Mid Drive E-bike Conversion Kit The TSDZ2 Mid Drive Motor - Torque Sensing Pedal Assist: The harder you pedal - the harder the motor works with you. 4 levels of assist provide smoothly integrated power ranging from +36-300%...

www.eco-ebike.com

And I'm thinking this 48v battery unit. Should be suitable for my requirements.

48v 9ah Bottle Battery w/ Cradle (18a Discharge)

This Bottle Battery is great for making lightweight conversions, and fitting into tight spots that other larger batteries cannot. Featuring an on/off power button, USB port (for charging your mobile device etc.), and a locking cradle, these are typically installed on your downtube, but some...

www.eco-ebike.com

 

[tomjasz]

Rim brakes work fine.

I'm quite happy with Kool-Stop eBike brake pads.

 

[Busse Woods]

Those pads seem perfect. Thanks.

 

[PedalUma]

So I'm leaning toward the TSDZ2 w/ VLCD-5 as suggested by PedalUma. Thing is, it looks like it comes in 36,48 and 52V and in 250, 500, 750W versions. How do I determine which one is best for my purpose? I guess I rather have a bit too much power than too little. Although I would like to use the most efficient drive and want to keep weight to a minimum. Is there much difference in weight between the various versions? Is the torque sensor built in the TSDZ2 or is that purchased separately?


Edit: In addition the chainring comes in different sizes. I imagine a 42T would be the logical choice?

The standard 42-T ring is fine for most applications. An alloy narrow/wide is an upgrade you can do next Summer when you have a better feel for your bike. These are smoother and grab the chain better. You may want a little larger or smaller chainring after clocking up some miles. The BCD is 110mm, that is the 'bolt center distance' on a chainring. 48V, 500W will be a little too much. 48V batteries lean toward being more hefty. A 48V x 10.5Ah gives over 500Watt hours. That will be about 2.5ish hours of ridding time. My butt is done by three hours of ride time. The weight of the motor versions is nearly identical. The motors inside the housings are identical. They are about the size of 1/2 of a can of soup. That is one reason I like to unlock a 36V, 350W. It makes it spike at high power for technical rock garden moves but with a lower nominal draw on the flats, because it is the same motor as the 'bigger' ones. Yes the torque sensor is built in. There is also a hidden compartment for hiding extra wire. Keep in mind that these motors 'like' a high cadence. They also do best when pedaling is smooth, not pounding. Pedal with a back-sweep. One last thing. Do not be tempted to run wires between the motor and the bottom bracket.

 

[Busse Woods]

Thanks PedalUma, I appreciate you taking the time to help me figure this out. I'll go with the standard 42T and consider an upgrade in the future. So you are suggesting a 36V 350W unit will be fine for my intended use and be the most efficient. I'm kind of confused as the Elecycle site only states 250-750W it does not allow me to choose the wattage of the motor. Also, I like the idea of the small display but don't think it would work well with the Ergo handle bars I have on the bike. Looks like the larger display is my only choice.

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[PedalUma]

The small display will be fine. It just cannot fit on the inside of a bend. So put it on top of the bar to the left. You are not going to be looking at the display, just like you don't squint at a shifter. You will be using it by feel.