Hunting mid-drive build - frame choices

I am looking to build a mid-drive hunting/trail bike. I live and play in the mountains of rural NE California. My budget is around $2K, but I can stretch higher. I am unsure if I want a 27.5+ or a fit tire. I think I want a hardtail for simplicity. I will be buying a used bike or frame for the conversion. I know I want hydraulic disc brakes, quality components, the ability to attach/build a rear rack, and the ability to attached a Bob trailer. I am pretty sure I will be using a bbshd for the mid-drive.

What bikes/frames do you recommend I look for in this ebike build? There are so many out there, I am looking for some direction on where to start.

https://sfbay.craigslist.org/nby/bik/d/santa-rosa-kona-mountain-bike/7214766180.html Kona Mountain Bike - $750 (santa rosa)
https://chico.craigslist.org/bik/d/chico-specialized-mtb/7218236015.html Specialized MTB - $400 (Chico)

Will those newer bikes play well with an bbshd install? I read that the bottom bracket compatibility on newer bikes can be an issue? I am new to this and trying to not make many major mistakes.

Frames themselves look good, just need more info on what type of BB it is.

For hunting I would build a cargo bike.

markz said:

Frames themselves look good, just need more info on what type of BB it is.

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I guess that is what my question is asking. How do I determine if a bottom bracket will work with the bbshd mid-drive motor? Is there a list of bike brands/models that work?

MadRhino said:

For hunting I would build a cargo bike.

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I am looking for a standard type bike as I will be doing a lot of scouting and miles in pretty rough terrain. I have been given a Bob trailer, so when hunting with gear (blinds, stands, ect.) I will have that. With no trailer, I will have small pack and emergency kit on the rear rack.

Subject: Hunting
Why ride & carry , strapped , $6K EV, packs, knives, food and lights to the wide open land of truck driving drunkards armed with $100 shotguns?
Have you seen the movie "Deliverance"? Ever tangled with a hillbilly?
You crazy man
Mike V.

Stealth_Chopper said:

Subject: Hunting
Why ride & carry , strapped , $6K EV, packs, knives, food and lights to the wide open land of truck driving drunkards armed with $100 shotguns?
Have you seen the movie "Deliverance"? Ever tangled with a hillbilly?
You crazy man
Mike V.

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Hey now, this is my home! In all seriousness, there are a lot of road hunters. As a public school teacher in a small isolated rural town, I know most of them. There is also a shit ton of private forest land behind locked gates. Those gates mean no vehicles, but they allow bikes and ebikes! I currently hike in, but an ebike opens up a lot of land that has little pressure.

The problem with some newer bike designs is a flat or curved area at the bottom bracket which results in poor clearance with a "BB' mid-drive. Both of the models suggested above have "normal" interfaces, so should work fine, although the Kona doesn't seem like that great a deal (to me). The other thing to consider is the diameter of the chainstays and whether they're curved where they contact the BB. Either could require spacers to keep the motor farther from the BB exacerbating the difference of the right and left arms from their respective chainstays. I had this problem with a Niner scandium frame and ended up using a steel donor hardtail.

I would go fat tire if you have the chance vs 27.5, but there's been a few fat tire frames I set customers up with where the chainrings got too close to the seat stay, and we had to switch to a different frame.
Just an fyi, on one customers aluminum fat bike frame, the pull on the chain from the motor bowed the frame to the right so much it put giant vertical crack about 6 inches long on the left side of the seatpost. That was after only about 3 short test rides too... No heavy thrashing.

Voltron said:

I would go fat tire if you have the chance vs 27.5, but there's been a few fat tire frames I set customers up with where the chainrings got too close to the seat stay, and we had to switch to a different frame.
Just an fyi, on one customers aluminum fat bike frame, the pull on the chain from the motor bowed the frame to the right so much it put giant vertical crack about 6 inches long on the left side of the seatpost. That was after only about 3 short test rides too... No heavy thrashing.

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What are some good fat tire donor bikes that I should be looking at in the $500+ dollar range?

Coach v said:

What are some good fat tire donor bikes that I should be looking at in the $500+ dollar range?

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Used

500$ fat bikes are crap.
Then, first ask yourself if you need one. Loose terrain? Snow? Because any fat bike is crap if you don’t need one.

2,5 to 3.0 tires are best for most off road riding.

There are a ton of Mongoose builds and NO major boo boos . Haven't read anything bad about a build of one yet , just like a fat woman , fun to ride but not to be seen with . Put different stickers on it . :wink:

Hunting hunting what ? I'm hunting I'm hunting for something in a two-piece polka dot bikini. So Cal bro a day at the beach.

I bought a used Biktrix Juggernaut and have been using it both for commuting (10km each way, gravel/pavement mix) and exploring forest trails. It's not the greatest ebike but it does what it does quite well for the $1400 CAD I spent on it.

It's an old model with the exposed BBS02 rather than having it integrated. It's perfectly adequate for puttzing down the trail, but a bit more umph would be nice for long open stretches during the commute (it cruises at 35 km/h) or if I were to be pulling a trailer. I was going to take it elk hunting this fall, but COVID...

I swapped out the rear cassette, derailleur, and shifter for a Box 11-50 9 speed setup. The steel cassette seems to be holding up quite well and the extra low gearing is nice when going slow without loosing that top end gearing or your chainline with an extra small chainring. I also think having a big cassette matched to a standard chainring would result in less wear and stress to the drivetrain than a standard cassette and a small chainring. The standard 11-32 cassette is inadequate if you are going up anything moderately technical.

For $2000 I don't think you can do better than buying something used that is close to what you want already, then upgrade specific parts that aren't quite cutting it.

To me, that last post is magic, it has hit the nail squarely on it's head.

Larger front chainring, larger rear cog, results in less chain pull and less pull force on the bottom bracket bearings, compared to using a small front chainring and normal sized big cog in the rear.

If a hardtail has enough room for a Thudbuster Long Travel suspension seatpost, then it can ride much better than with a rigid seatpost.

A hardtail should make adding a trailer easy, compared to full suspension. Adding a rear rack is easy too.

A throttle would be a must have for me, just use the assist you want, very simple if the throttle is controllable. A Cycle Analyst V3 can tame a throttle, at least sort of. Throttle is a big help when starting on an uphill or when threading your way through tight stuff. Torque sensing is the best pedal assist, again for me.

I have ridden a Chinese full suspension bike that used a Bafang Ultra mid drive. The Ultra is not a conversion, the frame has to be built to use it. This bike had lots of excellent suspension travel and both a throttle and torque sensing pedal assist...that worked very well together, even when using both at the same time.

"Sailing down the Saskatoon, the terror of the sea. If they want to reach the Co-op, they gotta get by me."

I ended up purchasing a 2013 Salsa Beargrease. It is on its way here now. Looking at my bbshd options and choices, but will wait until I can measure the BB.