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**Rider** · 08-04-2019, 04:57 PM

The BBS02B slid right in the Soma Wolverine 68mm BB and the reduction gear housing cleared the chainstay without any spacers needed (~1mm clearance gap noted by arrow in photo). I used my custom made aluminum torque bracket from the Soma B-Side build. It fit perfectly with the same lower left stay clamp and puts the motor in just the right position with a gap from the downtube; not up against it. The Gates 55T belt ring sits ~10mm from the BBS02B housing (labeled "X") and ~9mm from rear chainstay (labeled "Y"). Because I already know the BBS02B 130BCD front adapter bracket with a Gates 55T mounted to it has a belt line of 55mm, I did the simple calculation to determine the distance in from the right sliding dropout for the Gates 22T rear cog centerline. Here's the calculations:

135mm rear spacing divided by 2 = 67.5mm (distance from center to right rear dropout). 67.5mm - 55.0mm = 12.5mm (distance from the right rear dropout for the centerline to match the front belt ring).

I then spaced the Gates 22T cog 12.5mm in from the right rear dropout on the Sturmey-Archer CS-RK3 3spd cassette hub and done! (photo labeled "Z")

NOTE: There is only ~9mm to work with in moving the centerline inward using a Gates "55T" belt ring on a BBS02B mounted in "this" Soma Wolverine 68mm BB frame. There would only be ~10mm to work with using any smaller Gates belt ring such as the smallest 50T that clears the BBS02B reduction housing "without" facing the BB. A Sturmey-Archer RX-RK5 5spd has a 46mm chain line using their "offset" chain sprockets. I don't know the centerline offset of the Gates belt cogs made for the RX-RK5 5spd, but if it is 46mm then a custom belt ring that moves the centerline in the maximum amount will closely line up. The best way I can envision such a custom belt ring being made is to machine out a Gates 50T belt ring to match the diameter of a 42T Lekkie Bling Ring with the teeth machined off and weld the two together with the absolute minimum clearance from the BBS02B housing in front. What that means is the smallest beltline achievable using a BBS02B on a standard 68mm BB "without" facing the BB is ~46mm; how much you can face the right side on the BB will be dependent on your particular frames chain stay clearances (both reduction gear housing and belt ring); and that is using a completely custom made front belt ring.

For chain drive projects, the 42T Lekkie Bling Ring on a 68mm BB is ~46mm. Smaller chain line needs will require right side BB facing to size; while watching the BBS02B reduction housing and front 42T Lekkie Bling Ring chainstay clearance. Remember, a chain drive project doesn't have to be perfect, but a Gates belt drive project does.

Hope this NOTE helps others a little bit when trying to determine if a Gates belt drive or chain application is doable on their e-bike project. Cheers!

Attached Files

**Rider** · 08-05-2019, 06:51 AM

Got her finished up over the weekend and took her for a 40 mile shakedown ride. Moved the 2.4 to the front and put a new 2.0 in the rear as planned; clearances are fine in the rear. Everything worked great without anything loosening up or causing issues. Glad that was the case, because I forgot my Allen wrench multi-tool on the initial ride. Only adjustments will be slight tweaks to the angles of handlebars, grips, inner bar ends and saddle to fine tune it.

The gearing is nice, but not as fast as I though it would be. That could be because everything I based it on was from my Surly ECR 29+ build speeds and this new ride is a 27.5. It can be operated like a 5spd by starting out in 1st at 4 of 9, increasing to 5 of 9, then shifting to 2nd, increasing to 6 of 9, then shifting into 3rd and cruising at a nice cadence about 21.5-22mph. At 7 of 9 she cruises at about 23-23.5mph with a slightly faster cadence and a reasonable workout. At any of those levels all you have to do is put in the leg effort and the assist slowly backs off and battery power is saved automatically (a wonderful feature of the BBS02B mid-drives). The gearing seems to be a great setup for a reasonably fast commuter without a lot of shifting. Everything is whisper quiet with the belt drive. I didn't know how much I missed that silence until I experienced it once again.

This is now my go to recreational and exercise ride. Can't wait to start logging the miles...

**Rider** · 08-05-2019, 07:06 AM

Oh, I want to add that I switched to Fabric Ergo Lock On Grips combined with the SQlab 411 inner bar ends (on SQlab 311 bars). These grips are silicone, but not spongy soft. They have a ergonomic wing and mid-palm bulge with a smaller diameter at the inward side of the grip. I really liked them on this ride, my first time using them. I have large hands and by placing my hands to the outer side of the grips they fit perfectly. Smaller handed people can use the same grip, just move their hand a little bit more inward. You can lean on the wings for comfort with a light grip. Combined with the SQlab 411 inner bar ends, you can rest you palm on top of the grip wing while your fingers hang free with your thumb on the inner bar end to prevent your hands from slipping off if you hit a bump. This is a very relaxed hand position that is one of my favorites. The wings are small, but not so small that you can't grab the end of the bars like you have outer bars ends and ride that way. The silicone makes them softer than the Ergon grips and the smaller wing makes them better suited for aggressive riding if desired without sacrificing comfort on the trekking portion of your rides. I think the Fabric Ergo Lock On grips will become my new favorite all around grip.

Attached Files

**Rider** · 08-12-2019, 06:17 AM

Second ride out of the gate was a big one. A friend on his light weight carbon road bike joined me for a 62 miler last Saturday. The morning got off to a rough start with his car having a water leak in his driveway, so I swung by and put his bike on my roof rack, while mine was down low in the rear on a trailer hitch rack. On the way to the starting point my car with ~1,000 new tire picked up a nail flat on the freeway. Had to unload my bike and put the cheater spare on to get us there. Now about an hour off our planned schedule, we made it the trailhead that was about 30 miles from the coast. Our ride to the beach and back went flawlessly, with zero issues on either bike. My new adjustments proved comfortable with the only sore spots after the ride on my booty strictly due to the length of the ride. My buddy is about half way through breaking in his new rock hard Brooks leather saddle, so he was worse for wear then I with my comfortable ISM Urbaine no numbness special. Beautiful weather and noted lots of newly paved sections on the trail. It’s wonderful that the cities in my area are keeping up, improving and expanding bike trails constantly. They are even adding gravel dirt walking/jogging trails in sections that are wide enough to separate the bikes from the foot traffic. Wonderful! Looking forward to many more miles on this new comfortable build.

Interestingly, my friend is going to hop a train with another eRoad riding friend to Santa Barbara soon for a ride back to Orange County along the coast -AND- he is going to rent/barrow an eRoad bike to do it. I see another aging convert in the early morning coastal mist!

**greaselyadam** · 08-15-2019, 07:33 AM

Rider,

THIS IS AWESOME!!! I'm looking at building a belt-drive, IGH ebike as well, and I'm also in Socal. Any chance I could swing by and check out your build?

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Soma Wolverine V2.1 Belt Drive BBS02B

Soma Wolverine V2.1 Belt Drive BBS02B

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