Recent content by Flash-FX

Christini offerers a "Boost" offset for 104BCD. Get a straighter chainline. Ultra road guys might need this...

Here's some missing pictures from this thread, for those that might be interested...

Check out Karls post. https://electricbike-blog.com/2019/09/02/christini-bcd-104-ultra-max-adapter-unleashes-the-torque-monster-on-your-trail-snow-ebike/#more-7556

Hey, some answers -Sorry no video as of yet... -Welding the dissimilar thickness aluminum can be tricky, pre-heat the thick piece first. I have a Miller Dynasty 350 that welds that thick stuff pretty easy. -The "Trex" fixture can be moved to another frame if I want to build another. It just...

The standard supplied Bafang chain ring has 5 arms, or 130 BCD. The 130BCD 38T ring is the smallest one you can get to fit your setup. The chain ring I made is a 4 arm, 104 BCD, to accept much smaller sprockets. These are plenty strong. Sounds like you need one too. Sorry, I am not making any more.

Ok, since there are none commercially available yet (Luna Cycle?), I had to make my own. The lower gearing really helps in off road conditions. Also reduces current draw. Here are a couple pictures (also posted over on my fatbike build).

The motor tilt probably doesn't matter where it ends up. Mine ended up so that the tubes are somewhat adjacent to the mounting bolts. I wanted that extra ground clearance too. Remember that there will be a lot of heat when it is welded and there will be some distortion. Final filing/reaming will...

As far as the question regarding the BB in the same exact location, probably not. I thought about that too. lowering helps in stability. But after pedaling the "stock" bike around and trying to imagine where a change would be an improvement, I left it alone (same location). With the "fixture", I...

I wonder how long it will be before you can just go out and buy one??

Before welding, I had attached the disc to the "tube" for test fit. The crank arms have a short offset and hit the sprocket support in the center ID. The tube was trimmed down just enough for final clearance. I was hoping for no chain ring spacers in the end but, it didn't work out like that...

The output drive spline on the Ultra motor has 34T. That was fun to make....

Ok, time for some fine tuning...in the sprocket department. The 44T Bafang supplied chainring was just a tad too big for this bike. I need smaller. I've seen early ultra motors with the 104bcd 4 arm spiders but can not find any. So, here we go....I just so happened to have the parts lying around...

Ha! this came to mind when I saw the barrel ....https://www.youtube.com/watch?v=GSbigjiKLoU

You might have to physically TYPE your com# in the box. Like in this case "COM3". It didn't seem to be case sensitive.