BBSHD installation position.

[Haystacks]

Hi folks so ive gone and ordered a bbshd kit from EM3ev to replace my rear hub, now i'm kinda wondering if it was the right thing to do due to the design of my bike. I've done loads of research, feels like i've read the entire BBSHD content of the interweb which led me to the conclusion that it would be fine to mount - however - i'm now having second thoughts about the motor moving.

Theres quite a few installations which have faced similar circumstances and gone fine (mainly recumbents), the OP and other commenters stating the plate that grips the BB shell will hold the motor fine but something inside me is doubting that.

This is the problem

No bottom bar.

So 2 questions really, what are peoples experiences with motor movement and secondly could i mount it vertically against the downtube/rear shock brace?

 

[Dewey]

I'd try a stabilizer bar, it's basically a torque arm for a BBS motor. I fitted the lighter BSB-1 version for my BBS01 and there is no more motor movement. The issue for you is it is designed to attach to the chain stay of a hard tail bike but yours is a full suspension, you might try reversing it and trying to attach it to the seatpost tube. Your bike does not have a downtube so you will not be able to fit the version for full suspension bikes. I found it easy to bend the BSB-1 version to attach to my bike's chain stay so you might want to try getting that version, reversing it, and bend it (off the bike) to a shape that will let you attach it to your seatpost. I recommend wrapping a short piece of inner tube under a hose clamp so as not to scratch your bike. It's a bit hard to tell from the photo if it will be long enough to let you attach it with a hose clamp, but there is a hole at the end that could fit an M6 bolt if you don't mind drilling a hole in your seatpost tube and buying a rivnut tool to install a rivnut. Plus added bonus I found it therapeutic to hit a bike part with a hammer ;-)

 

[Haystacks]

I'd try a stabilizer bar, it's basically a torque arm for a BBS motor. I fitted the lighter version for my BBS01 and there is no more motor movement, my favorite Bafang BBS ebike accessory purchase this year by far. The issue for you is it is designed for hard tail bikes and yours is a full suspension, you might try reversing it and trying to attach it to the seatpost tube, you will need to bend it though and your bike does not have a downtube so you will not be able to fit the version for full suspension bikes. I found it easy to bend the lighter version to attach to my bike's chain stay so you might want to try getting the lighter version first and trying to make it work with your seatpost. Plus added bonus I found it therapeutic to hit a bike part with a hammer ;-)

Yeah sorry meant seat tube and i think you might be right about some impact maintenance therapy lol

The closest frame ive found that have been converted are the montagues but they have a small cross brace which some seem to butt up against, most of the recumbents are not butted up against anything they just float out front, wonder if they have issues, might have to join one of their forums to find out.

The recieved wisdom is that if i make sure the plate bites properly and loctite the first ring then it aint going nowhere, but we all know what those niggling doubts are like when we have no experience of something. I think with that stabiliser bar it could work, but im still wondering if mounting it vertical against the seatpost tube might also work. Decisions decisions decisions

 

[Dewey]

Every bike is different, but my experience with the stock Bafang mounting plate is it sucks. It moves after only a few rides even on my less powerful BBS01, a BBSHD you might have to remove the left crank arm to tighten down the lock ring after every ride, which would suck as Bafang aluminum crank arms are crap - I replaced mine with steel unicycle cranks after replacing the left crank arm 3 times in 4 years, who TF made the design decision to have a soft aluminum crank on a hard steel spindle... so I recommend trying the stabilizer bar, though I understand if you don't want to drill your seat tube.

 

[Haystacks]

Which way does the motor move? Down or up? if it goes down then there may be a solution integrated into the bb shell - theres a stand under the bb designed to protect the chainring when the bikes folded. I'm trying to avoid buying a new frame or this bike is going to be like triggers broom (likely only uk peeps would that reference lol)

Oh and the stabilizer is only available in 68mm i need 100mm as its a fatbike

 

[Dewey]

Ho ho, I am an expat Brit in the US, my American wife sometimes tells me my DIY ebike is triggers broom with the amount of mods I've done to it.
The motor moves up.
The stabilizer goes on one side of the bottom bracket so the BB width doesn't matter except for the issue of whether it can be bent enough to attach to your seat post. Your bike appears to have some additional hardware around the bottom bracket that makes the pivot behind the seat post, that might be problematic with regards to bending the stabilizer enough to reach the seat tube, but looking closer I see a crank guard under the bottom bracket that would need to be removed in order for the motor to fit at the angle the stabilizer would position the motor under the BB shell, should be easy enough to hacksaw off.

 

[harryS]

I put a BBS02 on an old aluminum frame bike in 2016. It slipped loose after a week, so I got the special wrench, tightened it, and it's been fine.

I believe the motor, if loose, will rotate up, because I recall posts from people who have dented their lower frame tubes.

 

[Clyde]

I've got a downtube, but the BBSHD doesn't quite touch it when using the stock motor mount. I found it had loosened up after the first 50 miles and a nice crash, so I torqued everything down again and have seen no movement at all for the next 25 mi. I may go with a sturdier bracket down the road, but for now it seems to be holding well.

 

[harryS]

Should be able to use the aux bracket like people use torque arms, If it doesn't line up with your frame, drill a hole in the bracket and fab a second arm to grab it. Cut off what you don't need.

 

[Haystacks]

I've just started the installation process and although i cannot complete it tonight due to new rear wheel and drivetrain not being here til tomorrow, it is going absolutely AWESOME.

IT FITS. PERFECTLY. YAY.......

Theres a little nub where the reinforcing struts are which the motor sits against, even when loose there is very little play, maybe 5mm. Didnt need to cut the little stand off either, a little impact maintenance to bend it slightly and it slid straight in.

Will continue with the electronics now and will be ready to roll tomorrow when ive installed the rear wheel etc. wooohoooooo

 

[tomjasz]

I put a BBS02 on an old aluminum frame bike in 2016. It slipped loose after a week, so I got the special wrench, tightened it, and it's been fine.

I believe the motor, if loose, will rotate up, because I recall posts from people who have dented their lower frame tubes.

Yes. You made a good point regarding the right tool. I've had every BBSxx series motor with thousands of miles. No loose motors.
1/2 inch drive breaker bar and blue Loctite. I actually prefer two primary lock rings and forget about the aluminum secondary lockring
ring.