Mounting a BBSHD in an Ultra frame?

CCroft

CCroft

Member
Long story short: I searched long and hard for a unicorn of a bike (fat tire, step-through or low stepover frame, belt drive/IGH, Ebike already or Ebike-capable with a motor powerful enough to push ~ 300lbs of rider and gear through mostly off-road terrain) and ended up with a bike that checked all of my boxes, running a M620 Ultra. I had never ridden an Ultra and assumed it wouldn’t be that much louder than my 2017 BBSHD fat bike build. I was wrong about that. It’s just too loud for me and my riding, even after disassembly/liberally greasing with Mobil SHC 100 as I did with my 2017 BBSHD bike.

I really like everything about the bike except the Ultra. How possible/crazy of an idea is it to mount a BBSHD on it instead of the Ultra? I don’t have a spare BBSHD lying around to hold up to my frame to eyeball how one might accomplish this, so it may be a non-starter. I realize it wouldn't be nicely integrated into the frame like the Ultra is, but I'm just thinking out loud a little before Plan B (= sell the bike and start looking around for a belt-drive/IGH fat bike frame that would take a BBSHD).

Thanks, Colin
 
The BBSHD needs a bottom bracket housing in which to mount. With the Ultra frame you don’t have that mounting option.
 
Ive considered this before, I think a simple bracket bolted into the ultra mounts either side and a tube between them in the right place, once tightened up it would be plenty strong enough and youre free to adjust the crank position for the best fit and virtual seat tube angle
 
Thanks for the feedback; that's what I was suspecting. Ventana sells a BBSHD-ready fat bike frame ("El Gordo") that Cycle Monkey used to create a build very similar to what I'm looking for--sans the step-through frame (although it looks like it has a lower top tube than my existing BBSHD fat bike bike). The step-through/lower TT factor may be the one I have to compromise on. Although if I'm not gaining much in terms of a lower TT compared to my BBSHD fat bike, it might be worth exploring if converting that to the Gates drive/Rohloff is possible depending on its frame (?)
 
That seems a bit extreme to me? I have an M620 that was loud also and greased it with John Deere Cornhead and it is super quiet at all levels of engagement? There also are "quiet" gears available but I have no experience with them nor need now.
 
Because there's a lot more in terms of refinement of power delivery... Well worth the price of admission.
After 4000 mi I'm smitten and you couldn't give me another BBS no matter the weight /noise /cost.
The mobil SHC100 did help a little and it did get quieter over time. Cornhead grease is in the batters box.
 
Yes, but I use throttle only and that is a game changer in power delivery, no pas can compete with the symphony of feet and thumb :)
 
il Munduato said:
Besides an appropriately tuned BBS* or Ultra will do what ever you want via pedals... even if lazy is your game.
Click to expand...
Exactly. Key words are 'appropriately tuned'. On another forum I just read an experienced bicycle mechanic who has worked on and tuned many BBSHDs (or at least thats what they claim on the internet) and this person was pooh-pooh'ing the motors because she couldn't get rid of the overrun and latency effects of the motor when starting and stopping pedaling. As far as I am concerned thats the first and easiest thing to fix. So...
 
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CCroft said:
Long story short: I searched long and hard for a unicorn of a bike (fat tire, step-through or low stepover frame, belt drive/IGH, Ebike already or Ebike-capable with a motor powerful enough to push ~ 300lbs of rider and gear through mostly off-road terrain) and ended up with a bike that checked all of my boxes, running a M620 Ultra. I had never ridden an Ultra and assumed it wouldn’t be that much louder than my 2017 BBSHD fat bike build. I was wrong about that. It’s just too loud for me and my riding, even after disassembly/liberally greasing with Mobil SHC 100 as I did with my 2017 BBSHD bike.

I really like everything about the bike except the Ultra. How possible/crazy of an idea is it to mount a BBSHD on it instead of the Ultra? I don’t have a spare BBSHD lying around to hold up to my frame to eyeball how one might accomplish this, so it may be a non-starter. I realize it wouldn't be nicely integrated into the frame like the Ultra is, but I'm just thinking out loud a little before Plan B (= sell the bike and start looking around for a belt-drive/IGH fat bike frame that would take a BBSHD).

Thanks, Colin
Click to expand...
My friend just this weekend installed the quiet gears in his Ultra (CANBUS) which was very noisy. Now his Ultra runs near silent. YMMV.
 
Tom@WashDC said:
My friend just this weekend installed the quiet gears in his Ultra (CANBUS) which was very noisy. Now his Ultra runs near silent. YMMV.
Click to expand...
"quiet gears"...? Do you mean what is discussed here/sold by GBK? My Ultra/bike was built and shipped to me in May of this year, so I assumed it had these newer/quieter gears. When I had it apart for greasing, I'm pretty sure my third steel gear looked the "New version (B)" showing on GBK. I'm assuming this is one of the newer "quiet gears"?

That said--and admitting that I'm real knowledgeable about these electric motors--it seems to me that the noise I'm hearing and finding hard to ignore compared to the BBSHD isn't mainly from the gears/gearbox, but the higher-pitched whine coming from the motor itself (noise from interaction between motor's coils and magnets).
 
CCroft said:
"quiet gears"...? Do you mean what is discussed here/sold by GBK? My Ultra/bike was built and shipped to me in May of this year, so I assumed it had these newer/quieter gears. When I had it apart for greasing, I'm pretty sure my third steel gear looked the "New version (B)" showing on GBK. I'm assuming this is one of the newer "quiet gears"?

That said--and admitting that I'm real knowledgeable about these electric motors--it seems to me that the noise I'm hearing and finding hard to ignore compared to the BBSHD isn't mainly from the gears/gearbox, but the higher-pitched whine coming from the motor itself (noise from interaction between motor's coils and magnets).
Click to expand...
He did purchase the steel gears from GBK.
 
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