So, are these DIY electric kits for regular bikes worth it? Or just go for a pre-built one?

[e9999]

Been toying with the idea of buying a kit to electrify my Giant mountain bike. I like the bike, it's all I needed so far. Quality and performance are decent but it's probably worth only $200 or $300 on Craigslist, so not a huge value that I must keep at all cost, but I have it on hand, ready to go.
I'm thinking about a kit because you can get higher power than what you'd find on an electric bike in a store; can customize it, it'd be fun to do, and also because the electric bikes in store seem very expensive for what they are. I am also very reluctant to end up with a proprietary battery built in the frame that won't be able to replace in 4 or 5 years. Seems like for less than $1000 I'd have a much better bike with a kit than I could buy for $2 or $3K in a store. I may be wrong on that.
What's the consensus about whether one or the other is the better way to go in general? Yes, I realize, "it depends", but any general thoughts?

 

[on the rocks]

A lot of factors in this and you never know until you try I'm trying to convince my buddy to get a cheap Costco fat bike and add a Bafang motor. He's not biting yet... For that reason I like the idea. That and if your just using the bike for cruising or maybe a gravel bike? I don't know I would go that route for a enduro or serious tail bike. It would be a fun project tho.
Some of the reasons(may outweigh any positives)not to.
- A lot of states are offering E-bike rebates. This would not apply and the new bike fully set up would be a much better route.
- The bike industry overbuilt during Covid years and is now flopping. My guess is you would get a much more smoking deal on a new bike if you shop, especially tagging it to a rebate.
- Avoid a Chinese bike and go a setup that offers a mainstream battery/ motor setup(like Shamano) where they use a common replacable battery. Avoid one off setups if possible(battery proprietary to bike manufacture). This would likely solve the dead, non replacable battery issue along with a house fire... I have a 900WH Shimano and 3 years deep its holding strong, very few issues.
- Even though a fun project, DO YOUR HOMEWORK! Bikes have so many variables. Especially if an older bike. Make sure your research ALL replacement parts in a kit. If an older bike and anything but an easy bolt on motor and battery it will be likely something wont fit or work with your bike. There are so many variables when dealing with Bottom Brackets, axles and drive terrains.
- Before you spend a dime, research trails. Find out what you can ride with a motor. Likely unless state approved or private trail, you can't ride it unless a designated motorcycle(motorized) trail, then you might as well buy a dirt bike... Even when you do the homework and know your good, you will be stopped and harassed all the time, it gets old....

GOOD LUCK!

 

[e9999]

good points there, thanks.

I was indeed thinking mid-drive Bafang to be able to use gears as I have a very steep hill I need to go over to get to my house. I think the bottom bracket size was OK but will need to double check. The bike is probably 15 yo. And thinking 750W, should be plenty, if allowed. The relatively inexpensive brand name bikes I saw were all 250W, that seems low.

Didn't think too much about rebates, will need to check that, that could make a difference indeed.

Ideally, I would prefer a generic battery pack you hang from the frame, not a built-in one, so easier to replace. Can't handle planned obsolescence too well.

Will be primarily for asphalt, maybe a bit on light trails nearby or in the desert where everything goes.

 

[on the rocks]

And thinking 750W, should be plenty, if allowed. The relatively inexpensive brand name bikes I saw were all 250W, that seems low.

750w is pretty common. I only went 900 because I know I would be targeting 20+ miles with vertical, a very heavy bike, big fat tires causing more drag and 6" + of fresh snow expected in some cases, for normal casual riding it would be way overkill. I use every bit on the long rides and always ride full boost power but for a planned asphalt maybe mild single track 750 should be more than enough. With 250 your likely going to limit your rides to battery but it all depends on how much you want the bike to pedal for you. If your willing to ride in eco mode you might get by. Just a guess tho.

I think you would be good with a Bafang setup for what your looking at and it would be a good entry level experience with the abilty to move it to another bike later on or just pull it and sell it, again, just an opinion with never riding one. I don't know a ton about them but they seem pretty reputable. I can tell you riding an e-bike is a blast. It just takes the experience to a whole other level for those that really don't love the misery of the uphill climbs.

If you find you have any rebates available and considering that route, look into a shop that may rent a entry level bike and try it out first. Most shops apply that rental charge against a purchase. You may also make sure you understand the bike classes. Anything other than Class1 will be tough to ride anywhere due to political restrictions.

You best bet is probably search other forums, not alot of knowledge here on bikes, especially E-bikes. I know there are probably better sites but this one has some useful info.

E-Bikes

Electric bikes for trails, commuting, road.

www.mtbr.com

 

[e9999]

thanks. Yes, been leaning to a DIY kit but not too confident it could be resold easily, lots of parts involved. I know that personally I would be needing a bunch of time to assess if a used kit is complete and suitable if I were contemplating buying one, so that hassle is a deterrent to resale I think. Plus unknown battery condition issue too.

I did look a while back at the local bike paths and yes, there were issues nominally with what classes are allowed. That is indeed important. I would like to be able to use bike paths to commute since some are separate and therefore safer. OTOH, from talking to riders, it seems like nobody cares or checks what bike classes are on those paths, so who knows.

I'm thinking mid-drive. These don't play havoc on the derailleur and gears, like with grinding and shock stresses, do they?

 

[on the rocks]

I'm thinking mid-drive. These don't play havoc on the derailleur and gears, like with grinding and shock stresses, do they?

I ride the fat bike pretty hard and the drive terrain is holding up well after 2 years. Just like an analog pedal bike, try not to shift up hill under load, but not the end of the world if you do. Ultimately it will depends on what motor you go with, The Ep8 I run is a whopping 250 watts LOL , it's not like it's a 25KW E-MOTO motor. Keep in mind a Class1 is pedal assist and speed limited to 27MPH if that I think. These things are fun but far from a twist throttle hold on to your seat power. It involves quite a bit of pedaling still. This is why I don't get there is so much hate for them and they are actually slower downhill due to the added weight.
I would suggest avoiding hub drive as it is added unspring weight. If just a cruiser tho, it's not as big of a deal.

 

[little_joe]

I suspect you'll find mid-drive is harder on the drivetrain than a rear hub motor. Mid-drive is putting all of the power into the chain, and thereby the chainring, cassette. My experience with both torque-based mid-drive and cadence-based hub confirm this: 2500mi on my mid-drive's cassette before replacement, on 3rd chain, 2nd chainring. Hub bike didn't need anything when I sold it with over 1500mi. I'll never go back to hub drive or cadence-based assist regardless.

To me, the absolutely essential question is: torque-sensing pedal assist or cadence-based? I found cadence-based to really suck on hills, as you have to spin like a wildman to get the power; whereas torque-based amplifies your actual input and feels natural. Seems this would be a deal killer for an eMTB; and it sucks when you need to get moving in a hurry (unless it has a throttle). I'd suggest test-riding both styles just to see the difference for yourself, then consider everything else...

 

[jebb]

I did the Tongsheng TSDZ2 conversion to my wife's bike a couple years ago. Mostly because I agree w/ little_joe: torque-sensing pedal assist is so much better, and Tongsheng was the only torque sensing middrive I could find at the time.

Anyway, for your actual question about whether or not it's worth it, I don't think on a straight dollars basis it is anymore, outside of some very unusual situations.

The prices for the parts have gone up a fair amount where you gotta be thinking about $1k.

I bought an ebike at REI a couple months ago for $800. It's not the nicest bike in the world but it's not one of those DTC ebike brands where none of the parts are real bike parts. It has a Bafang 350W hub drive motor and Tektro hydraulic disc brakes, mostly shimano altus components.

I bought another new bike at a bike shop a couple months ago: has four piston shimano hydro discs, Bosch mid-drive power, like overall relatively high end components. it was $2k, marked down from $5k.

I think the bike market is going through some crazy post-COVID-shortage adjustments.

It's super fun to do the ebike conversions, and I kind of wish it still made sense because I just like doing it. I will also say with custom firmware etc my homebrew ebike is by far the most powerful, most responsive etc of the now four I have. But just thinking about cost, there's a couple things that keep me from doing it again:
* The market is flooded with ebikes. There's absolutely no way I could put together an ebike like the one I bought at REI for $800 with Bafang/Tongsheng etc. parts. It's like I got the bike for free.
* The homebrew bike is homebrew. There's fiddly stuff about it. It's not maintenance-free. Of course, no bike is, but it's definitely not as trouble-free as the 'real' ebikes and you can't really rely on shops to be able to work on them.
* I'm more aware now of how much faster and harder ebikes wear everything. You really want better brakes, stiffer frame, tires rated for higher speed, etc. on an ebike, especially a home brew one that has no speed limitation. It's like building a car, you don't want to just upgrade the engine.When I was first building it I was thinking "eh my wife will ride this pretty slow, it's not any more dangerous than a normal bike, she'll just do less work." But it's not really true: she carries way more stuff because it's easier, she rides a little faster because she's used to it, she rides much, much, much farther. Those are all great things, but you really need to upgrade every aspect of the bike to handle it, certainly the brakes and tires, and you really want to start with an overbuilt frame, but also realistically the drivetrain.

I could see doing it for some sort of novelty builds, or unusual situations, like if I had a longtail or something, I could imagine upgrade it. Or just because I thought it was fun. But I don't think it really makes financial sense anymore like it used to.

 

[e9999]

interesting take on this, thanks. Food for thought indeed.

 

[Houser]

Well since you asked. I think building your own ebike will be a huge waste of your money. Because you will really like ebiking and you will have a junkey home made ebike. You will then go to the cheep China made ebike store and buy a better but still cheep and budgety ebike. It will work fine but will not be as nice as your new riding friends not cheep-skate ebikes. After suffering for another season with a still not good enough ebike you will finally take out a bank loan because you are now broke from buying your cheep ebikes, go down to the Trek bike shop and buy a really nice Trek Powerfly E-bike that you will love and enjoy riding for many years.

 

[nonstopbike]

Mid-drive bafang worked out well enough when electrifying an older larry vs harry bulllitt bike.

Aside from that, go used and readily available. Radpower are 2 of our e-bikes, and canyon is the e-,mtb.

having a throttle is very nice. anything above 25mph (class 2 i think) start to feel pretty fast. think specialized globe haul.