Any advice on this build/plan?

[jpwalton]

I'm planning a build using an existing mountain bike (2003 Giant Iguana Disc. Aluminum Frame)

My goals:
* Get up the San Francisco hill I live on without huffing and puffing (2 blocks of est 15-20% grade).
* Buzz around the city in a more or less legal way (take advantage of bike lanes, trains, etc).
* Still have some fun on offroad riding (simple single track, and a little mtn biking). This is a secondary goal.
* 15-30 mile range.
* Top speed of 28mph (I'm not really focused on speed).
* Do it all for under $1K (or as near to that as possible).

Conclusions so far:
I've decided on a mid drive, specifically BBS02. It seems like the right balance of power and price that I'm looking for (BBSHD also attractive but I think I can meet my goals without springing for it). As far as I've seen, Luna Cycles has the best deal on both motor and batteries, so Im planning on getting everything from them.
I was really interested in building my own battery with 18650 cells, but the price after getting spot welder and tools actually makes that seem like a more expensive option (unless I wanted several batteries). Also, I was having a hard time sourcing a hard case for a DIY battery (if anyone has any good tips on that let me know). In general, I want a hard case over a heat-shrunk version (interested in opinions).

Here's my parts list and notes. There are two sheets, one with a DIY Battery, and one without.

Any thoughts are welcome.

 

[docw009]

Where's your combo wrench for the BBS02 fasteners? It works better than channel locks. Looks like the only way to get the Luna combo wrench these days is to pay $10 over the price of the $29 tool kit.

 

[jpwalton]

Where's your combo wrench for the BBS02 fasteners?

are you talking about this? https://lunacycle.com/parts/bafang-parts/bbshd-parts/copy-of-luna-wrench-bbshd-and-bbs02-mid-drive-installation-tool/
I guess I thought it was included in the tool kit...

 

[docw009]

I couldn't find that wrench on their site, but I didn't look hard enough. It worked quite well for me. It's not in the tool kit. You'll need a crank puller, BB socket and maybe a chain breaker (to remove front derailleur). They''re in the kit.

My bike is alloy, but I haven't had any issue with the BBS02 coming loose after I wrenched it properly. Still, if I were installing another, I might get the aux frame bracket too.

I chose not to have a programming cable. I'd either get pulled into endless nights of tweaking or never use it all.

 

[dogman dan]

Looks like you figured out mid drive for the win on grades that steep. SF in places, really is an e-bike hell.

Re the battery enclosures,, Look to the better frame bags to frame carry a DIY triangle pack, if you get to making batteries.

I decided to stick with square batteries, and eventually built a bike specifically to carry them.

 

[Ykick]

Select the smallest stock chain ring possible. The deal with these BB drive's IMO, you want to gear it like a truck with small engine.

I’d also suggest reviewing and perhaps adopting some of the 3-5 speed cassette modifications mentioned in this thread:

https://endless-sphere.com/forums/viewtopic.php?f=28&t=84097&hilit=+cassette

I’m simply in love with a wide range 3 speed customized cassette using the LH 3speed front crank shifter - check out this chain line:



Also, I’d definitely go with the color DPC-14 display. Very nice unit and handlebar switch. Perhaps inquire if they might discount it significantly along with your BBS02 purchase?

I’ve never bought or used the official wrench yet although I might if I keep installing these drives? I just use a brass/aluminum drift and hammer. I know it’s bush-league but that’s worked out pretty well for me.

 

[Alan B]

Welcome to ES.

The BBS02 is a good choice. I decided to use the BBSHD, but they're very similar. The main difference is heat production, the BBS02 makes more heat so it becomes more important to be in the right gear and keep the motor spinning faster.

My BBS is on the Diamondback Overdrive, linked below.

I haven't ridden it in SF, but I've run it on steeper single track in Marin and the East Bay, and it climbs steep enough to get scary. I haven't reached its limit, but I find mine from time to time.

 

[Alan B]

The Shark pack plastic is a bit thin and really packed tight inside, and the size limits the capacity and range (I do have one). I've gone with the triangle bags and battery packs when I can. The Dolphin plastic is stronger but the pack is slightly larger so it may not fit as easily in the triangle.

 

[Alan B]

In the East Bay Hills, riding hard with moderate hills on pavement (1800 feet of climbing) I've seen around 26 miles of range with a 20 amp hour 52V triangle pack on the BBSHD. This was running hard to make a tight schedule, 25-30mph, but that gives you some idea of range. The BBS02 would not reach quite the same speed, it would get much hotter, and the range might be slightly better due to the lower speed. So under these conditions with an 11AH pack the BBS02 range might be 15 miles. Slowing down or less climbing would increase this range.

 

[LewTwo]

The Shark pack plastic is a bit thin and really packed tight inside, and the size limits the capacity and range (I do have one). I've gone with the triangle bags and battery packs when I can. The Dolphin plastic is stronger but the pack is slightly larger so it may not fit as easily in the triangle.

The dolphin also has a keyed power switch. The shark does not have a power switch.

 

[jpwalton]

Thanks for the tips. I've been hearing a lot about the BBS02 heat issues. I also came across this in research. The price difference is significant enough that I'm still leaning that way although BBSHD ~is temping...