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2019 Crust Evasion, BBS02 or BBSHD, Shimano Alfine 8 IGH

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    2019 Crust Evasion, BBS02 or BBSHD, Shimano Alfine 8 IGH

    This will be a frame-up, spokes-up build, using a medium sized Crust Evasion frame:
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    Initial Specs: BBSHD 68mm motor with the Eclipse 42 chain ring on a 73mm bottom bracket, should end up with a 48mm chain line. I'd have used a BBS02 motor on this build but the Alfine IGH demands a tight chain line. If only Luna made a BBS02 Eclipse 2-piece chain ring ...

    UPDATE: The chain line for the Lekkie BBS02 40 tooth ring, mounted flat (no chain ring or motor spacers), on a 73mm BB measures 48mm, so that's the motor I'm using for now. For reference, the Lekkie 42 tooth ring doesn't come in as close - it's probably out at 54mm or so in the same situation.

    UPDATE #2: The Lekkie 40 tooth is a wonder of "tightness" - it tucks so tight to the left that it won't clear the master link on an 1/8 inch chain (ticks the outer chain guard). So, I've set the chain up "endless".

    Otherwise, the specs and retro silver color components are:
    • steel frame tubes, fattish tire clearance with a narrowish Q
    • adjustable, replaceable 135mm rear dropouts with an inboard (within the frame triangle) disk caliper mount
    • 17AH downtube tray-mount removable battery
    • BBS02 mid drive
    • Lekkie 160mm crank arms
    • Lekkie 40 tooth chain ring
    • Shimano Alfine 8 IGH with a shift sensor - very nice shifting and just enough ratio
    • 1/8 inch chain
    • 24T Sturmey Archer rear sprocket, dish facing out
    • 26 by 2.35 Schwalbe Fat Franks tires
    • Velocity Blunt 35 disc rims
    • TRP Spyre cable brake calipers
    • Nitto flat bars
    I considered randonneur bars, but the resultant control issues aren't worth the cost.
    Last edited by ncmired; 03-07-2020, 11:53 PM.

    Ok, it's finished ... Next!

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      Great build, looks good, nice you don`t have to use a tensioner there.
      I have a similar setup on an old mtb frame. You say you have a 24T Sturmey Archer rear sprocket? That SA fits on the Alfine hub ok?
      I could only get a Nexus type to fit on there.


        Hi, thanks for the note. Yes, the Sturmey Archer 24 tooth. HSL-876 1/8 chromed sprockets have fit on my Alfine and Nexus 3 and 8 speed hubs, no issue, using the Shimano square edge retaining ring. It's an exact fit, so everything has to be clean and no burrs.

        I buy the sprockets on eBay for $10-ish.
        Last edited by ncmired; 02-28-2021, 06:39 AM.


          I re-geared up a little to a 21 tooth sprocket, positioning the 1:1 5th gear at the flat ground, motor RPM topping out sweet spot. Eighth gear won't be useful - oh well. 1st gear is low enough to not tax the motor, staying well within the rated power on steep hills. The road speeds are approx:
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          • Cezar
            Cezar commented
            Editing a comment
            I will start with the cadence speed - so it is not higher than 70 rpm, and more often closer to 60 rpm. Definitely rather flat. I have 28 "wheels and Alfine 8. I use the factory sprocket in the front, i.e. 46t, I tried 18t in the back - it was difficult to drive only in the fastest 8th gear, but it was possible with this cadence - the speed is about 38 km / h. With these ratios, i.e. 46 / 18 (gear ratio 2,555), the transmission becomes more usable - I manage to use much more gears more often. When I changed the rear gear to 22t - I started to use only 6 gears rarely, and more often only 7 and 8, I hear you use 40/24 gears , on 26 "wheels - it seems that you are standing still or just using your thumb. Even a 40/21 gear ratio seems to be useless. What speeds do you use. I usually drive at a traveling speed of 25-28 km / h - more can be done but it's hard to keep up with the cadence. This speed in gears 46/18 can be kept in 7th gear, and in gears 46/22 to 8. When I go to the mountains I will probably put on 46/22 (gear 2.09) to make it easier for the engine and me. So that I do not quite understand gear ratios such as 40/21. I also have problems with my knees (2 operations after a ski injury) and I can't press too hard on the pedals.
            Last edited by Cezar; 05-03-2020, 01:58 AM.

          • ncmired
            ncmired commented
            Editing a comment
            My terrain is mixed with some nasty hills, so I've geared the two Evasion / BBS02 builds very low. I also use the throttle too much.

            Speed wise this bike cruises (throttle only) at 33kmh in the 1:1 gear (fifth). On level ground this means that the motor is maxed out RPM-wise and sipping about 200-300 watts. You can feel the motor clutch engaging and disengaging softly.

            My 70 year old sister rides the bike in 7-8 gear, in assist 1, to get a good workout - she manages about 27KMH doing this. She's a "stomper", or low cadence rider.

            This is a BBS02, which doesn't have the grunt the BBSHD does. I wanted lighter weight, cooler running, long range, and greater component longevity - hence the real low gearing (although upped a little on this bike from 24 to 21).
            Last edited by ncmired; 05-24-2020, 01:33 AM.