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

[ncmired]

This will be a frame-up, spokes-up build, using a medium sized Crust Evasion frame:

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
• MKS quick-release pedals
• Shimano Alfine 8 IGH with a shift sensor - very nice shifting and just enough ratio
• 1/8 inch chain
• 21T 1/8 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.

[ncmired]

Ok, it's finished ... Next!

[tommie]

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.

[ncmired]

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.

[ncmired]

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:

[Cezar]

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.

[ncmired]

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).

[ncmired]

This build is no more - everything was stripped and applied to other builds. Don't know what I'll end up doing with the frameset - maybe an analog build (which I've got the parts to do on hand).

[yds]

Question about the chainline you had on this build. With the 73mm BB and the 40T Lekkie ring, was it a perfect chainline? Or good enough? I'm currently looking to convert my Surly Troll with the BBS02 kit. I've dry-fit the motor and it looked to me like even with an 11mm offset of the Lekkie (which I haven't ordered yet), that the chainline is still off. Were you running any special cog on the Alfine? Mine is a standard 16T shimano cog.

[ncmired]

Hi, welcome to the forum - it's nice to see another Alfine build.

As mentioned, this build was torn down, but most of the parts went over onto a step-thru Evasion. which has the same rear frame dimensions as this frame and the same 73mm BB. I measured the front chain line - 49mm ( (29mm seat post diameter / 2) + from the side of the seat tube out 34.5mm to the center of the Lekkie 40 chainring). My components are:

• Lekkie 40 tooth chain ring with included 2mm spacer
• Connex 108 1/8 inch chain
• Sturmey Archer 1/8 offset (to the right) rear sprocket (approx. 49mm rear chain line)
• Lekkie left offset / right straight crank arms

Visually, the chainline looks perfect and there appears to enough clearance between the chain and the controller cover, so I probably could have left off the spacer. But, I found that on some builds the chain can "waggle" a little too close to the motor and cut a mild groove (via the chain pins).

I've standardized using the same brand chain across my fleet, but in IMO the 1/8 width chains are not really needed with the milder BBS02. I've also standardized on the SA 1/8 sprockets, which are a tight fit on the Shimano hubs.

I mentioned the Lekkie crank arms because left side crank arm / ankle clearance is sometimes an issue with the BBS02, which has a shorter spindle than the BBSHD. I eyeballed approx. 20mm from the left crank arm tip to the corresponding stay. The right side clearance is not usually a problem. I've stopped using the Lekkie crank arms and now use much less expensive, but still nicely made Shimano STEPS FC-E5010 crank arms ($30 via eBay).

For a 73mm versus 68mm BB comparison, my two Neutrino BBS02 builds have 68mm BBs and their chainline is slightly too inset up front, which is almost unheard of in the BBS world.

On measurements, I've tried to make a spreadsheet calculator to pre-guess, but I think some of the available online measurements are off a touch. For example Luna's BBSHD chainring chart is slightly off, as it measures to the edge of the ring, not to the ring's chain line.

Hope the above helps, and good luck with your build.

[yds]

Thanks so much for the detailed info! With the price of the Lekkie 40T set being north of $210CAD with shipping, I wanted to get as much confirmation as I could before pulling the trigger. Now if I could only find it with a black motor cover, rather than red which is what most places seem to stock, it would be ideal.

[ncmired]

I cleaned up and organized my bicycle parts pile and built two analog bikes. Here's the rebirth of the leftover medium size Crust Evasion frame that has worn both a BBS02 and BBSHD motor. For those wondering whether the BB threads were damaged, no, they didn't seem to be, but I did run a thread cleaning tap before running in the spindle cups. Here's the (re)build component list:

From the parts bins:

• SAS Halo rims, DT spokes, Shimano Nexus 3-speed and SRAM hubs, and Schwalbe Fat Frank 26" tires
• SRAM 34T crank, Connex 1/8 108 chain
• 203mm front & 160mm rear rotors, TRP Spyre cable brake calipers, with Jagwire Compressionless brake housing
• Velo Orange Klunker Bar, Brooks B17 saddle, Nitto tombstone rack (for randonneur bags)

New:

• brake calipers

I chopped a cable clearance hole in the back of the bell housing, which made setting up the shift cable length much easier.

[ncmired]

I converted this frameset into a 3-speed analog bike, using a leftover wheelset, and it sat unused - 3-speeds don't fit my terrain, and my legs aren't up for analog riding.

After staring at the bike for a while, I decided to convert it yet again - this time to a K.I.S.S. CYC Photon-powered assist-only bike:

• DS103 display
• display-only main harness
• no throttle
• no brake cutoffs
• probably no speed sensor
• 27.5 2.0" Origin-8 tired wheelset
• 34T chainring
• microSHIFT Advent 11-38 9-speed cassette
• microSHIFT Advent Super Short Flatbar Groupset

The Photon will be the third motor mounted on this frame - the other motors being a BBS02 and BBSHD. Most of the generic bike components were already in hand, now I'm just waiting for the motor (July, August - best guess). Before analog crank removal:

This bike was originally set up with 26" x 2.35mm tires, and was a bit of a low rider - you can tell by the exposed seat post. I should have gone the next frame size up, but oh well. Going to 27.5" x 2.0mm tires will only raise the bike up about 3mm, per Bike Insights.

With the frame's 73mm BB, the chain line won't be great, but not out of the mid-drive norm - 50.3mm front chain line versus the rear freehub 45.5mm center cog. Gear inches and 75 cadence speeds follow:

[ncmired]

Nah, gear inches - I'm not used to using the more current gain ratios.

[AZguy]

I see - I'm lazy and just do all this kind of stuff in excel

[ncmired]

but you're right, the numbers in the top chart could also be used as a 335 cadence MPH chart.

When I need a new dropdown value, I go into the HTML and add another row, and wham bam thank you ma'am! Sort of the same idea, but different. I use Excel for financial stuff Quicken can't do very well.

Abacus anyone?

[ncmired]

Oh, what the hell ...

While I wait for the official CYC sampan to crawl across the Pacific (given favorable winds and a strong sculling arm), I'll bolt on a bbs-fw'ed BBS02, update the fw to the latest & greatest, and get the bike at least rideable so I can finish tweaking the ergonomic changes also made.

Nothing better to do on this rained-out day.

[73Eldo]

Mmmmmm steel frame. Nice and comfy.

Is that just a 205 rotor up front? It looks huge.

[ncmired]

Mmmmmm steel frame. Nice and comfy.

Is that just a 205 rotor up front? It looks huge.

Yep - 203mm front & 160mm rear, clamped on via standard "good enough" road TRP Spyre calipers which, for me, are a light pull pressure match with either generic Bafang brake levers or in this case, some leftover Paul canti levers. And cabled right lever to front caliper, motorcycle style.

The display-only rigged BBS02 motor is in place, configured, and stand-tested.

[ncmired]

Finally a dryish day, so I made a short but rolling and kinda hilly, must-pedal 10-mile trail ride, to get the ergonomics settled. My arse has some getting-used-to to do, regarding the Brooks B17, but it wasn't too bad - especially ridden in good-old jeans. I've got one of the new(er) Brooks Cambium C19 carved profile all-weather seats on the Amtrak bike.

I don't recall now just how old the BBS02 design is - IMO it has aged very well for what it is: a simple, reliable, well-supported, and priced right little workhorse. I've got it set up as the Photon will be, with just a (500C) display to turn it on & off and fiddle with the PAS. The motor is now running version 1.3.1 of the open-source BBS-FW firmware, which has a few more options over the stock Bafang firmware.

Nope, still not a cadence-based only sensor fan. Meanwhile, I'm hoping the CYC Sampan has reached, oh, maybe Midway Atoll by now.