I've been considering building an ebike

I live in SLC, UT (USA), I weigh ~235#, and I might be building an ebike just for fun. I live near mills/mountains and I visit the desert - I imagine this will be mostly used on the road.

I'm thinking of using a Specialized Rockhopper (~$549) with 29" wheels & a large frame. Thinking of a hard tail so there's more room for batteries, & I'm used to my road bicycle's hard tail, so bigger tires will be softer than that already.
https://www.specialized.com/us/en/rockhopper-29/p/115566

Probably going to go with a rear hub motor, not sure if I'll go with lipo or 18650s, I have a hitec x4 (& x1) charger but I also know lipos require more care.

Any guidance on controllers, packages/kits, advice on motors etc?

I've been following ES on fb for the last few years after I ran into a member who showed me his bike @ a store, so I've been watching people building battery packs etc.

Looks like the regulations (in 2016) said something about 28mph, I'd like to be able to go faster than that sometimes, but I don't seem to like going much over 40mph on my current bicycles.

I've been reading quite a bit & watching a bunch of youtube videos. Not sure that I'll even build it, but I've been thinking about it for a while.

would a mid drive like this be easy to install in that specialized rockhopper linked above? And how would it compare to the rear wheel hub motor? I watched a couple comparison videos & a build someone did using RC parts

https://www.empoweredcycles.com/collections/complete-electric-bike-kit/products/complete-electric-bike-kit-8fun-bafang-bbs02-48-volts-750-watts

Dragon-Shout said:

would a mid drive like this be easy to install in that specialized rockhopper linked above? And how would it compare to the rear wheel hub motor? I watched a couple comparison videos & a build someone did using RC parts

https://www.empoweredcycles.com/collections/complete-electric-bike-kit/products/complete-electric-bike-kit-8fun-bafang-bbs02-48-volts-750-watts

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Read this, if a frame you're thinking of using has a press fit bottom bracket you'd need to order an adapter to make it work. Read the link below and also look at the "blog" section of EMPowered's website and you'll see an entry about the adapters too:

https://www.empoweredcycles.com/blogs/news/101474694-bottom-bracket-standards-and-bafang-mid-drive-motors

I've been looking at that - I have a 2007 stumpjumper & replaced the bottom bracket bearings & they were threaded, I watched a video on the bottom bracket that's spec'd on the bike "BOTTOM BRACKET Square taper, 73mm, internal bearings" and the one the guy took apart was threaded too, so I might be in luck.

I'm not sold on mid-drive though,,,,,but if it's easier to deal with flats, why not go mid drive. I'm watching reviews of the mid drive system on youtube rt now..........really have no clue, and no rush, but that's kind of how I work - once it works in my head I might just have an ebike

The kit comes with the brake levers that cut power to the motor, & the rockhopper comes with "mechanical disc brakes" which I assume are cable (not hydraulic), so this might be a perfect fit.

This might be an easy entry into ebikes for me...
https://youtu.be/CLngOq7jWnM

raisedeyebrows - did you post build threads? Do you like your rockhopper or should I do something else? I've just had 3 specialized bikes & they've all been decent. I have a 2007 stumpjumper & a 2006 allez (roadie) rt now.

For the speeds you want to go you will have to forget about that Befang mid-drive , and get something that will run on much more Watts and Amps.

To decide on a mid-drive or a rear hub motor, post the steepness of the HIlls you want to go up and how long are those hills.

There are good mid-drives, look at the other e-bike section here on E.S. just two down from this section.

You will want at least 1,500 watts continous with higher peak wattage capability for any motor that will work for the speeds you want.

Dragon-Shout said:

raisedeyebrows - did you post build threads? Do you like your rockhopper or should I do something else? I've just had 3 specialized bikes & they've all been decent. I have a 2007 stumpjumper & a 2006 allez (roadie) rt now.

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Looks like SLC has about a half dozen shops selling and renting ebikes including some offering free test rides on any of their bikes. Might be a good idea to try a few hubmotor bikes and mid-drive ones and see what fits your style of riding and needs before you sink a pile of money into a kit or parts and of course good batteries are quite expensive.

29" wheels are awesome in some ways, but they bring the worst qualities out of hub motors. Lower acceleration/climbing, lower efficiency/range, more heat. If I were to use a hub motor, I'd probably choose a 26" wheeled bike and then lace the hub into a 24" wheel. What you lose in ride quality you more than make up for in motor performance.

Looks like I should go with the BBSHD mid drive kit, it seems to be the biggest, that I've seen so far anyway.

Probably get a half-twist right grip for the throttle:
https://www.empoweredcycles.com/collections/8fun-bafang-bbs02-accessories/products/8fun-bafang-bbs02-electric-bike-kit-right-1-2-twist-throttle

Now I'm looking at building a battery pack or just buying theirs.

These samsung q30s might be good:
https://www.imrbatteries.com/samsung-30q-18650-3000mah-15a-flat-top-battery/

And I'm wondering if one of these Dolphin cases are a good choice for me. I'll have to read a bunch into batteries next.
https://www.greenbikekit.com/ebike-dolphin-frame-battery-case-with-5v-usb-output.html

I took a quick look at the local classifieds & found an upgraded model of the specialized that might be better, & cheaper @ $350. It has hydraulic brakes so the brake switches from bafang won't work, I'll have to look at something else.
https://www.ksl.com/classifieds/listing/51593455

Cyclone 3000W mid drive is (potentially) much more powerful than BBSHD. Since it's not a tightly defined system, you can use a wide range of battery voltage and power with it. But's also much cruder than BBSHD and much more destructive to bicycle drive parts.