Bafang Ultra frame build - Steel

[ErikYoung89]

I want to modify a steel frame for a Bafang Ultra. You can buy an aluminum housing for the motor to weld onto an aluminum frame but I question my ability to do that and don't want to pay someone to do it ( I want this to be MY build). I also want to be able to repair and modify the frame as I see fit and I feel much more comfortable doing that on a steel frame.

So I need to make a steel motor housing.

Does anyone have or know where I could get CAD models for the M510 housing?

https://www.bafang-e.com/en/components/component/accessoires/fp-g510.html

If not I think I'll have to resort to buying one from Luna and just making my own model for my housing fabrication.

These were the other threads that I could find loosely related to this:

https://electricbike.com/forum/forum/builds/new-builder-questions/57878-want-to-modify-steel-surly-big-dummy-frame-for-bafang-ultra

https://electricbike.com/forum/forum/builds/customer-gallery/70437-bafang-ultra-fatbike-build

[ncmired]

Maybe Rodriguez could help you out - looks like they custom-built the bracket on this bike:

https://www.rodbikes.com/images/gallery/gallery.php?id=440

[ErikYoung89]

Thanks!! I shot them an email!

[ErikYoung89]

They weren't able to help me out. Understandably, they didn't want to hand out proprietary drawings of their in-house frame.

Logan was very polite and suggested I check if other frame manufactures provided steel mounts for it as he knows that there are some available for some Shimano motors. I haven't been able to find one.

I just emailed Luna to see if they have anything they can share but am not holding my breath.

While it would be nice to have drawings provided, I can always just buy the aluminum mount and use it for dimensions.

[ncmired]

... sure would be nice if there was a e-motor mount standard, like the standards in place for most bicycle components.

[ErikYoung89]

I'm not surprised at all given the number of bottom bracket standards there are.

It does not surprise me at all that every motor requires a different bracket. I just wish I could get ahold of any sort of mechanical drawings.

[ErikYoung89]

Just ordered the Magnesium Ultra from Luna.

I guess this is less of a question thread and more of a build thread, now.

[Daxxie]

Does anyone have or know where I could get CAD models for the M510 housing?

My frame came with some drawings. It's a dxf Qcad file.
Don't know how accurate it is.

[ErikYoung89]

Sweet!! Could you send that dxf to me?

I shot you a PM and it looks like you can upload attachments.

[ErikYoung89]

Got my Ultra kit in today. It seems to be all there but the mount just doesn't quite fit the motor.

More specifically the tollerances are off just enough such that I can have either the back and middle bolts inserted or the front and middle bolts, but not all three. It's not a matter of the holes being wide enough but rather their placement.

The easy solution is just to drill slightly wider holes one either the front or rear bolt holes on the mount to accommodate the tolerance.

[commuter ebikes]

Got my Ultra kit in today. It seems to be all there but the mount just doesn't quite fit the motor.

More specifically the tollerances are off just enough such that I can have either the back and middle bolts inserted or the front and middle bolts, but not all three. It's not a matter of the holes being wide enough but rather their placement.

The easy solution is just to drill slightly wider holes one either the front or rear bolt holes on the mount to accommodate the tolerance.

You could (1) minimize the number of locations where you will expand the bolt holes, and (2) enlarge the holes in as small of increments as the selection of drill bits manufactured will allow (appears to be 1/128" increments, worth buying on the net and waiting for the drill bits). Then, when you just get it, stop there, even if it is a really tight fit. Rigidity is a good thing.

In addition to this, you could also consider using washers (bolt shank length permitting) in order to maximize the clamping surface area for the bolt, and use blue Loctite on the threads of the bolts. This is my favorite: https://www.parktool.com/product/med...adlocker-tlr-1

I often upgrade my bolts, washers and nuts to Grade 8 (US) or Grade 12.9 (metric), readily available on eBay in any size and style that you would ever need.

[ErikYoung89]

These are all options that I'll explore for my steel motor mount. I honestly just ordered the aluminum mount to use as a template! If I ever do weld it onto an aluminum frame I would just need to slightly expand either the front or back holes.

As always, your post was very helpful!

[ErikYoung89]

Used a plasma cutter to cut a dummy part out of aluminum.

[ErikYoung89]

I think I'm going to build a steel mount like the one used in the Rodriguez build in the second post of this thread.

Only I'll use angle bends instead of curved. Won't be as pretty, but much easier to build and weld.

[ncmired]

After shredding up my jeans twice in the last few months (which REALLY SUCKS when it happens), I'm also eyeing that chain guard - or, well, some sort of guard anyway. For now I'm velcro strapping - the same kind I use to hogtie the shark battery down.