A way to Stabilize Bafang BBSHD motor

[Stavros]

Since I had already found a lot of reports about the fixed holder slipping down with time ( I thing this is a construction weakness of the system), I decided to take measures before having to deal with the problem and stabilize BBSHD from the beginning of the build: http://electricbike.com/forum/forum/...my-first-build.

In a boat shop I found a stainless steel Jaw/Jaw Tubular Turnbuckle T Toggle used in sailing and using washers I managed to fit it between the upper hole of the motor and the lower water bottle hole at the seat tube.







Check the clearance with the Battery in this last picture.



This turnbuckle provides very strong and presentable support for the weight of the motor, is adjustable in length and its movable joints makes it very versatile. Many bikes have already installed 5mm rivnuts at the seat tube or the down tube and if not it is very easy to install one at a convenient place in order to avoid using any hose clamps.

[Fred]

Very creative! I haven't had any problem with mine slipping but will keep that solution in mind in case I see it down the road.

[Stavros]

About 600km and 4 months after initial installation I noticed a slight up-down movement of my BBSHD motor.

I checked the outer aluminum ring nut, I could unscrew it by hand! The same for the inner steel ring nut!

The movement of the motor was insignificant and there was no damage to my aluminum frame by the teeth of the Y shaped fix holder of the BBSHD motor thanks to my motor stabilizer!

I removed the crank screw and the crank and tighten the ring nuts using Blue locktite a corresponding torque wrench and the special tool for each ring nut.

[joeaverage]

GREAT idea. I just ordered one from EBay for $20. I ordered a Viadana Marine AISI 316 Stainless Steel 6mm 1/4" Turnbuckle. I saw other options at "West Marine" online but they were more expensive than I wanted to spend (~$50).

[joeaverage]

I can confirm that the Viadana size turnbuckle is the right one. Really nice <$20 solution to motor droop on my BBSHD. Makes the motor feel really solid where there was always a little rocking motion while pedaling before. I could tighten the motor with the Bafang bracket and it always worked loose over time. I wasn't real fond of the aftermarket brackets. The one I bought didn't fit my bike anyhow without alot of re-engineering. This turnbuckle fit same as the original poster using existing bolts for the water bottle and on the motor. Wish I could add a second one to the right side of the motor for OCD symmetry! ;)

[joost]

I used the full suspension bracket sold by Luna, I also still used the supplied bafang bracket.https://lunacycle.com/bsbf-1-stabili...s02-and-bbshd/ I have an asi bac 800 controller running some serious watts through here. https://lunacycle.com/bsb-1-stabiliz...s02-and-bbshd/. The other verticle stabilization bracket bent.

[joeaverage]

Looking at my motor - I might try to move the turnbuckle to the next bolt hole forward. Would give the turnbuckle more leverage on the motor. Don't know if it is clear my downtube battery. We'll see.

Joost - THAT'S why my Lunacycle bracket didn't fit - its supposed to bolt to the bottom of the downtube. I don't have bolts there. Cool. Might double up on the turnbuckle and Lunacycle bracket. I have since purchased a nutsert kit. Thanks for the picture.

[joost]

I wasn't sure if a waterbottle boss would hold it, but it's worked fine and hasn't moved. Those luna brackets are designed for pipe clamps which can look ok if you wrap them in heat shrink tubing. One thing i will point out... if the lock nut loosens at all, the torsion will pull the motor toward the drive side chain stay. My motor runs 2000w so it's something i always have to keep an eye on. I haven't used loctite, but I am planning to put blue loctite on this weekend.

[JeffSouthworth113]

That looks nice. I had the same problem. I had to order a 100mm bbshd for my 73mm Specialized 6fattie. When I got the motor I was horrified about how the threads didn’t continue to tighten the mounting bracket flush against the bb. I came up with a solution using two mounting brackets and two mounting nuts. I ground out the threads on the nuts so that I could use them as spacers. Next I welded them together and the welded the to a mounting bracket with the nubs pointing down. I ground off one of the arms of the mounting bracket, positioned it on the bike and put the other bracket on top of that. I welded it together and it works perfect— no slippage. I left one arm on the first bottom bracket just in case it did slip. If I need to I can bolt it to the frame.

[JeffSouthworth113]

[MiKrOuLiS]

Καλησπέρα, θυμάσαι το μήκος του τεντωτήρα;
Σκέφτομαι επίσης εναλλακτικά αυτά :

[Harold]

I used 1/8" x 1" aluminum to make a strap that wraps around the bottom tube and bolts to the motor using the existing motor bolts.

[Sabre13]

Hi is this a Step through frame that you put the Bafang motor on if so did you find that there was enough ground clearance?
Interested as looking to put a Bafang motor on a low step frame. Thanks.

[Gremlin]

Some cool ideas here, MiKrOuLiS that looks like a track rod end used in karting? Most seem to be M8 . Can you name your source, please?
There are some of these on eBay, either stainless or tenifer finish, mostly around +/-200mm, but could be shortened and re-tapped.

[Gremlin]

OK, just thinking out of the box on this, and probably a dumb idea, but just for discussion:
How about drilling & tapping throught the BB tube from underneath before installation, and inserting a large grubscrew(s) to bite into the Bafang 1” tube?
Length and torque would need to be carefully thought about to avoid damage, I suppose.
Maybe that tube is only thin wall, so it’s a bad idea?

[cwinning]

Hello @stravos,

My apologies for resurrecting and old post like this, but I was curious how your use of the "Turnbuckle" worked out long term? Anyone else try this?

Looks like a genius solution.

Best regards,
cwinning

[cwinning]

I ordered a Viadana Marine AISI 316 Stainless Steel 6mm 1/4" Turnbuckle Jaw/Jaw 3,306 LBS from Ebay. It was cheap so I don't mind the gamble. I'll have to fine longer bolts and washers, but that shouldn't be an issue. I'll test fitment once it arrive later this week. I'm also going to add blue locktite just in case.

[AZguy]

Are you trying to address a real problem or is this just insurance?

Do you have a typical installation where the motor torque pushes it against the frame?

[cwinning]

Insurance. I ride off road a lot so there will is a lot of harsh riding. I'd be less worried if my bike was a commuter only. (plus, I like to over build things)