Nervagon's Directionless, and Doomed Build

[nervagon]

This is my first sunk cost fallacy hate build. It all started with an incident of domestic violence against my bottom bracket. There's no turning back... I must complete... My first angry build.

This is a mid drive build using a not-heavy DIY kit from a Mediterranean country known for hot, dry summers and a rich history of diverse culture, art, and cuisine.

 

[neptronix]

Following!

 

[scianiac]

Oh yes, I've done this before, honestly worked out great. I did it for chainline not Q factor and some self convincing was required before I (very carefully) took an angle grinder to my BB.

Weird how that country that may or may not be shaped like a boot has an, uh, interesting history with engineering. What is this forum for if not making things work in spite of manufacturers best efforts to stop us.

 

[nervagon]

Oh yes, I've done this before, honestly worked out great. I did it for chainline not Q factor and some self convincing was required before I (very carefully) took an angle grinder to my BB.

Weird how that country that may or may not be shaped like a boot has an, uh, interesting history with engineering. What is this forum for if not making things work in spite of manufacturers best efforts to stop us.

In my case, my indiegogo mid drive kit came with a custom square taper BB and crankset which is quite heavy. 1.21kg without the crank bolts.

I'll be replacing that junk with an HXR Easy Shift:

But in order to get the HXR freewheeling crankset to fit over the motor mounting plates that straddle the BB shell, I'll have to shave my BB shell down to 68mm. The HXR crankset uses 94 BCD chainrings.

Shaving down my 73mm BB to 68mm will allow me to use any 73mm crankset/BB with the indiegogo mid drive installed. Also a lot of modern BB/cranksets just come with spacers to be used on 68mm shells, so this is not a mod that lowers the value or usefulness of my bike frame... if I don't f*ck it up.

 

[nervagon]

After removing the bulk of the material from both sides of the BB last night, today I dropped off the Kona Safariland at the LBS to get properly faced. Should be ready in a couple days. The rare, elusive HXR Easy Shift is slated to arrive on friday.

 

[nervagon]

And the HXR crankset has arrived... with missing parts. A couple seemingly essential plastic washers and a spring washer is missing as well as the BB cups. The spindle is 30mm, so hopefully any 30mm axle cups will work.

 

[nervagon]

Feeling even more deflated on this build. When I went to pick up my bike from the LBS, they hadn't even started on it, so I took it to another shop to get faced. And they f*cked it up. The BB shell face on the drive side is skewed so much that is visible just by looking at it. The front-facing side of the BB shell is over 1mm longer than the back end. I'm going to have to go back and see their facing tool just so I can figure out how something like this can happen.

I really want to support local bike shops, but that is becoming increasingly more difficult. Now I'm going to have to buy a bottom bracket facing tool.

The ebay seller refunded half of the HXR crankset price due to the missing parts. I was able to hunt down an email for the CEO of the now defunct HXR to ask him for guidance on finding good replacements, but he didn't reply. It looks like I need BSA30 cups and some assorted washers. BSA30 cups require a very good facing (tolerance of .2mm at the worst), which I did not get.

Photon... it calls me.

 

[neptronix]

Damn bro. Major bad bike luck.

Worst case scenario, grab a frame off ebay?

 

[gromike]

Maybe a flat file and some determination might be able to fix the BB. Washers/shims to get to where you need to go.

 

[nervagon]

I ordered a facing tool. If I do end up with BSA 30mm cups, they really need well-faced BB shells. Because of the huge 30mm diameter spindle, the threaded portions of the cups that interface with the frame are very thin. What prevents those outboard bearings from snapping off is how snug and slush they are with the BB face.

The frame isn't destroyed. The narrowest part of the BB shell is 67.5mm. That is fixable. But I won't trust a bike shop again.

 

[nervagon]

The BB facing tool I bought is from UNIOR, a tool company in Slovenia. They seem to have a good reputation and good prices. What I like about their tool is the guide bushings that thread in from the right and left side. This seems much better than the facing tools that only thread into the side opposite the cutter. That would allow for a lot of play

 

[nervagon]

I have decided on the bottom bracket. These are stainless steel BSA30 cups from ROTOR. These look like the strongest cups available for fitting a 30mm spindle in an english threaded BB shell. I feel confident these can securely hold the motor mounts.


And since I have the short mounts, I've ordered a 94bcd 36T SRAM narrow-wide chainring from ebay to mount to the HXR freewheel spider. This is not my ideal gearing, but I will make due for now because if I go to 42T and dual chainring I will lose torque sensing.

 

[neptronix]

Damn, nice bottom bracket cups!

Do you have a cassette with a 10T rear sprocket?

 

[nervagon]

Damn, nice bottom bracket cups!

Do you have a cassette with a 10T rear sprocket?

I could be mistaken, but I thought I read in the manual that the smallest cog permitted to be paired with the Non-Heavy Mediterranean Mid Drive is 11T. My rear cassette will be a Box three prime 9 11-50 from the parts bin.

 

[neptronix]

You could be right!

 

[neptronix]

I'm also having bad bike luck.

Took the BSO over to the bike shop to have them extract the shitty stock BB that requires some oddball tool
They end up having to manhandle it and face one side of the bottom bracket.
They say i didn't lose even a millimeter. we'll see when i pick it up!

 

[nervagon]

I'm also having bad bike luck.

Took the BSO over to the bike shop to have them extract the shitty stock BB that requires some oddball tool
They end up having to manhandle it and face one side of the bottom bracket.
They say i didn't lose even a millimeter. we'll see when i pick it up!

I think you'll be OK. Even if they faced it down to 67mm, that will still work fine with the motor kit mounting plates.

67 + 3 + 3 = 73mm

Maybe you should just have them face the other side too?

Edit: worst case would be .5mm spacer between one of your cups and the shell.

 

[nervagon]

Update: project suspended, or changing course. I forgot that I have to pay an additional $135 for a "superhero" unlock code. This unlock code allows the use of accessories like throttle and brake cutoffs, allows the battery settings to be changed to 52V, and allows speed limit governors to be turned off, and off-road mode to be enabled.

I was never quite clear on what the "superhero" thing was exactly, but it seems I indeed needed it. So I will switch gears, and go Photon, or analog for this bike.

Edit: My Plan A is now for sale:

**Not Available** Lightest.bike 750W High Torque Mid Drive Kit

Over $1,172 value for only $450 USD! Bikee and I... we are like milk and vegetable oil... we just don't mix. Hopefully this little motor can find a home where it will be loved. Does not have the "superhero" unlock code! You will need to purchase the unlock direct from Bikee to get the full...

endless-sphere.com

Now figuring out my Plan B.

 

[nervagon]

The UNIOR facing tool is wonderful. Such a great design.



I ended up right at 67mm after fixing the horrible facing job done by the bike shop. Both sides were wonky. But the UNIOR tool sorted the situation right out. I just used some magura royal blood brake fluid for the cutting fluid, and it works!



The stainless BSA30 cups are definitely sturdy, but I'm not in the clear yet. The motor mount plates have a countersunk recess for the BB cups, but the recess is too narrow in diameter for external bearing cups to sit in. This is something I hadn't foreseen. Now the motor mounts will definitely need to be modified. I will need to overbore the cup recess.



Look at that huge 30mm spindle!

 

[neptronix]

You can't flip the motor brackets around? I think if you did, it would just be a matter of using different spacers for the drive unit. You would also get more of those cups' threads into the BB.

I don't think all these little holes in the short mount connect to anything so the order which you place the brackets shouldn't matter.
Also it should fix that issue you had with the bolt sticking out on the other side.

 

[nervagon]

You can't flip the motor brackets around? I think if you did, it would just be a matter of using different spacers for the drive unit. You would also get more of those cups' threads into the BB.

I don't think all these little holes in the short mount connect to anything so the order which you place the brackets shouldn't matter.
Also it should fix that issue you had with the bolt sticking out on the other side.

The welds of my chainstay yoke interfere with flipping the plates. I don't have clearance. I'll have to modify them. The short mounts are countersunk on the drive-side, which is good.

 

[neptronix]

Damn, i see that now..

mm, the joys of a modified frame! you may also have to flip the position of the chainring, so we don't have a collision with the frame.

...yeah, i would personally put an edge on that plate.. i'm told those slidey bits are for an additional tensioner.. i can't see you using that feature.

That BB should be pretty damn strong if you can get those last bits of cup strength. I'm kind of dazzled at how much nicer of an interface you have.. you may have inspired me to buy a modern bike, lol.

 

[amberwolf]

The welds of my chainstay yoke interfere with flipping the plates. I don't have clearance.

Pshaw. Welds. What are they good for, anyway?

 

[nervagon]

I'm not worried about chainring clearance. That can be flipped to the outside of the spider, but I don't think it'll be necessary. We'll see.

Those grooves on the bottom of the drive-side plate are for the pulley that improves the rear chainring chain-wrap (I think). It should be used if you can.

I'm kind of dazzled at how much nicer of an interface you have.. you may have inspired me to buy a modern bike, lol.

This isn't a modern bike, haha. This is a retired cop bike from 2012. The only thing modern-ish on it is the tapered head tube. It's just a regular english threaded bottom bracket... which are suddenly modern. Which interface are you referring to?

I think Bikee should have done it the way I'm doing it: outboard bearing cups. You can do that with ISIS spindles, as CYC seem to be doing. It would be more robust than using tiny bearings internally with the ISIS spindles.

FSA once made an ISIS bottom bracket with outboard bearings:

It was called the FSA MegaExo ISIS.

 

[nervagon]

Strangely enough, there is an awesome maker space just a few minutes away. They have everything, even a lathe and a mill.



Everyone there was super awesome and they helped me machine my motor brackets down to fit my external bearing cups.



These will look great after some spray paint.