CBP is blocking import of my e-bike parts?!


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@kmccune a cargo bike would be no better at hauling plate steel, and actually worse, as there is no place for a 3'x5' piece of plate steel to fit and that would exceed the bike's GVW. Those cargo bikes also have the same Bosch Performance CX motor my bike does. As with cars and trucks, you can tow a lot more than you can haul directly in the vehicle. The cargo e-bikes are basically the crossover SUVs of e-bikes. Towing with a properly designed bike trailer is perfectly safe. Note that the photo was taken after I got home and removed the ratchet straps and kayak straps securing it and two other pieces of steel. It was not just resting on that wood frame like that, it would have slid off as soon as I started pedaling, plate steel is very slippery.

That said, I have to wave people off of my Gorilla Mode mad cyclist experiment. I had written a lengthy explanation, but my browser randomly closed and I don't have the heart to re-write the whole thing. Suffice to say, high center of gravity and independently turning front wheels are an issue.


Active Member
Making more headway; finally have the front wheel assembled (sort of). Still need to fix my spacers, lock in the star fangled nut, attach my torque arm, et cetera, et cetera. I have a ton of work to do on the back, shift cables, parking brake, disc brakes, derailleurs wiring, cable management and the like as well, and some fabbing for a deck under my rear rack for the 2nd battery (which is why it is sitting so high), but it's finally starting to feel like a bike. Have to put it up in storage for a bit while I await yet more parts and hardware.




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Thanks! Feels good to finally be making progress instead of sighing at a pile of parts every time I pass through the garage :).
How much is "Beastie Boy" going to weigh when you are done? On the other hand congratulations for "Chasing the Devil", you are learning and others are learning from your experience( perhaps maybe you can open a "Gas Monkey" or "Electric Chimp" bike shop- there is a bit of stimulus money floating around that needs to be put back in circulation)


Active Member
Making more headway; finally have the front wheel assembled (sort of). Still need to fix my spacers, lock in the star fangled nut, attach my torque arm, et cetera, et cetera. I have a ton of work to do on the back, shift cables, parking brake, disc brakes, derailleurs wiring, cable management and the like as well, and some fabbing for a deck under my rear rack for the 2nd battery (which is why it is sitting so high), but it's finally starting to feel like a bike. Have to put it up in storage for a bit while I await yet more parts and hardware.

View attachment 77821
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Nothing is going to stop that machine !
Are you planning to put a 4 inch tire on the rear too?


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Nothing is going to stop that machine !
Are you planning to put a 4 inch tire on the rear too?
No room. About 26"x2.1" is all that will fit in the frame, as it is an old 1990's stump jumper with 135mm spacing. I actually tried a 26x2.5" tire at first but it rubbed; it currently has a 26"x46c tire, and I have slightly wider 26x2.1" tires on order (Schwalbe Pick-Ups, which have the insane weight capacity of 155kg).

Having a bigger tire in the front is by design, much like cargo bikes with 26" in the front and 20" in the back (Yuba Spice Curry), or a 69er or 76er MTB (29/26 and 650b/26, respectively). The idea is that you have more traction/wheel strength in the back and more rollover/suspension/manueverability in the front. Some bikes, like The R&M Load 60, go the other direction and have a bigger tire in the back and a smaller one in the front (20/26 on the Load). In the case of the Load, it makes sense to flip it from a cargo perspective because the most weight is in the front. On the Yuba Spice Curry, a long tail, all the cargo weight is in the back so they put the smaller wheel back there because smaller wheels are stronger. On MTBs, it's more about rear wheel traction (the Load and Spice Curry are both mid-drive e-bikes and long, so I don't think traction is effected much, especially under a load).

Mine is unique in that the height I'm gaining in the front is all from tire size, rather than wheel size, and also that in addition to being taller in the front, I am wider. Since it is a very short bike--about 43" axle to axle, ~3" less than our R&M Homage--I should get the traction benefits, all the more so because the wheel is powered. That's also the wheel with the cassette on it, which in this case is a high-range, 10-51T cassette. This is basically built to be a cargo hauler (via trailer, of course) and monster hill climber. In its lowest gear it will have more torque off the line pointed up a steep grade than e-bikes with several thousand more kW of power (which are generally built purely for speed). It looks ridiculous, but it serves a very specific and intentional purpose.

Included some pics of the aforementioned bikes below to give you an idea what I'm talking about.

Yuba Spice Curry
R&M Load 60


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How much is "Beastie Boy" going to weigh when you are done? On the other hand congratulations for "Chasing the Devil", you are learning and others are learning from your experience( perhaps maybe you can open a "Gas Monkey" or "Electric Chimp" bike shop- there is a bit of stimulus money floating around that needs to be put back in circulation)
Ha. It actually has 3 or 4 nicknames already. It was originally dubbed 'Bruce' in it's traditional configuration; it's now Hyper-Bruce, AKA "Bruce the Moose" (on account of the handlebars), AKA "The Bat Bike".

It will definitely be heavy compared to a traditional e-bike since it is dual motor and dual battery. I was curious about this myself so I weighed our Homage and Bruce this morning. I found the Homage weighs about 66 lbs. Our HPV Scorpion weighs about 85 lbs. according to the mechanic who retrofitted it. Bruce currently weighs about 82 lbs. So with the 2nd 11 lb. battery and about a pound of additional small parts and components remaining, he should come out to around 94 lbs. Heavy, to be sure, but not more than I would expect given that it is a dual motor bike. The batteries are completely in line with the frame and the rear battery will be low over the rear wheel, which I believe will actually improve handling and traction characteristics. It's a hardtail as well (although I threw a suspension dropper post on there for a little bit of relief).

I'm definitely learning things on this build, but mainly regarding this specific build, not any new bike mechanic or fab skills I didn't already possess. I don't really have any interest in making money off of bike wrenching, the main impetus is reducing my carbon footprint by replacing car trips, which I've already done for about 3 years with the Homage, and having fun tinkering in the garage. It's similar to how I feel about cooking--a friend, completely seriously, suggested I should start a restaurant. I'm flattered he and his wife (and mine) feel that way, but I don't want to make money cooking (which is extremely hard work)--I want to make delicious food and eat it.

This bike is inspired by everything I've learned with the Homage, one lesson of which being that a 250W Bosch CX will get the job done if you are towing 300 lbs. of cargo up 12% grades, but just barely and with the additional input of Herculean amounts of human power. Having to sometimes push a bike like that up the same grades because it doesn't have enough power is not very fun. 250 lbs. is exponentially easier, and 200 lbs. is about the max that is still difficult but within a reasonable range of human effort. Bruce is built to be a beast in terms of hill climbing, not weight. In comparison to the Homage, Bruce's power-to-weight ratio is 1100W/94 lbs. (based on nominal power), or 25.8W/kg; the Homage's is 8.35W/kg. Our Scorpion's PWR is 6.48W/kg. Bruce's PWR turns out to be roughly equivalent to the Rungu Dualie with the standard package, which has a PWR of 28.94W/kg (although with the 'rugged' package it drops to 23.93). It's only slightly less than the Ubco 2x2 with a 2.1 kWh battery, which has a PWR of 31.44W/kg. All of that in a package with more torque, a higher top speed and roughly equivalent cargo capacity to the Ubco 2x2 WRK, and probably the Rungu Dualie (the company claims to have an unbelievably high maximum torque, not sure how they calculated it). Here's a comparison of those two bikes with Bruce:

Rungu Dualie (Standard)Ubco 2x2 WRK + 2.1 kW batteryBat Bike
Max power1.4kWN/A2.2kW
Cargo capacity350 lbs. incl. rider, 300 lbs. towing330 lbs. incl. rider300 lbs. incl. rider, 300 lbs. towing
Weight, PWR87.2 lbs., 28.94W/kg111.6 lbs., 31.44W/kg94 lbs., 25.8W/kg
Max torque (unloaded from a stop, 0% grade)352.51 Nm (so they claim, not sure I believe it)90 Nm170.83 Nm (according to the Grin motor simulator)
Max speed24 MPH30 MPH32 MPH

I'm curious to see if I can get real-world torque numbers out of the Cycle Analyst when the bike is finished and see how they compare to the Grin motor simulator and the Rungu's claimed maximum of ~352 Nm. The Rungu does have a mid-drive motor, and has a 30T chainring, which should produce a lot of torque, but that still seems ridiculous to me. That said, the Grin simulator doesn't take into account the 51T cog on my rear cassette, which should increase that figure quite a bit.

I sure wouldn't mind owning either the Rungu Dualie or the Ubco 2x2, btw.

Links below; I actually found an old catalogue with the model/rough year of my frame, a Gary Fisher Supercaliber.

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Looks good, you know things are crazy, a 350 watt 48 volt bike woldnt take me up a similar maybe steeper grade with me pedaling, it was actually harder to pedal than an unpowered bike, got in touch with the company and they offered to rip me off on a 16 amp controller( selling this bike and not going to do any more trade with this company( Eahora)They have actually have helped others perhaps my sincerity threw them off( Honesty seems to bother some)


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So I made a ton of progress this past week and the bike is almost finished. Today I finished up some fab work for the rear battery deck, and ended up having to re-solder my previous re-wiring attempt for the Baserunner controller, because I had the wiring coming out the sides of the mounting base, which of course the battery has to slide over, so that didn't work. I had to drill new holes in the bottom of the mounting unit and into the marine plastic beneath that for my custom battery platform, then re-solder the connections and reassemble everything. I had to re-work a few other last minute details as well. Having hooked everything up in parallel, I finally had a chance to power it on and see that everything turns on properly. Now I can focus on cable management, hydraulic brake lines, the parking brake cable, derailleur cabling and tuning, wiring the horns and then other small finishing touches like waterproofing. I've included photos of some of the trickiest/most technical details. I apologize that some of them are a little blurry, they were taken in haste before dinner. Some salient points:

- The wiring is in parallel, so both motors and all accessories draw from both batteries evenly and simultaneously.
- The horns will be wired into a fusebox and a buck converter, so they have a somewhat complicated wiring diagram and will wait until the last.
- You can see a close-up of the Chasertech adapter I used on the rear; it usually bolts onto the post mount, which I am using, so I have it attached to a Grin frame clamp instead.
- Unfortunately owing to the size of the frame I can only run a 140 in the back, with the side effect that I cannot get the brake seated fully on the rotor without rubbing the motor housing. This will cause some pad rubbing eventually, so I'll have to figure something out for that. It was the only thing I couldn't get to work perfectly in my admittedly gonzo build.
- I couldn't fit the 2nd battery under the downtube, but the Airzound works great in a bottle cage attached to a Grin Triple Bob.
- There are some close-ups of how I attached the front rack, which is actually a Surly Rear Rack identical to the one in the back. I used hose clamps and motorcycle headlight brackets.
- I had a spacer on the front disc rotor but had to remove it and take the unorthodox step of spacing the brake adapter instead, because it was rubbing the motor cable every 60 degrees as a rotor bolt passed it.
- I used Ortlieb QR pannier mounts to make lower rails for the racks since they are so high. Most major brands of pannier will hook onto these plastic rails and I have found them quite sturdy in the past on our R&M.
- I included a photo (blurry, sorry) with front and rear panniers mounted.
- I drilled some large holes in the marine board on the top piece that forms my custom rear battery mount to access the rack tubing. The marine board looks great, I think. Right now I have it assembled with threaded rod and connector nuts, but I have some case hardened, threaded linear motion rods on order from McMaster-Carr that will make it both simpler to assemble and disassemble and hopefully more grinder proof. The top is currently secured with zip ties until I get some low-profile p-clamps in.
- I changed out the rear tire for the Schwalbe Pick-up. It is the sturdiest bike tire I have ever fitted, and paradoxically also the easiest despite the very thick and stiff wire bead. It went on like butter. I included a photo of the crazy 155kg load capacity printed on the sidewall. I will probably switch to a Schwalbe Jumbo Jim in the front in the future once my Surly Knard wears out; I've found Surly tires difficult to source, and they are produced by Innova, which produces surprisingly quality tires for a generic brand, but not as good as Schwalbe.
- Still waiting on a HiGo B2B (2-pin) y-splitter cable for the brakes, which I need because I have dual motors. I discovered that Grin sells 2-pin HiGo's on their brakes (I didn't buy my brakes from them, but got brakes with the same connectors on their explicit advice), but the Cycle Analyst 3.1 has a 4-pin JST-SM connector. It is not explained in their manual that rewiring the HiGo, either by re-terminating it or removing the barrel connector, is mandatory. I got scolded by them to RTFM, even though I already had and the relevant info wasn't contained therein. A trivial detail, but important. Just know that regen braking is not plug-and-play, out-of-the-box ready with some of their kits (Bafang kits will work fine, AFAIK). Any kit with a Cycle Analyst will require a bit of wiring to get that feature working.



Active Member
I'm still making progress on the build; I have a particular issue the inverted fork, which for some reason will no hold air. It is a brand new fork with no apparent defects and zero mileage, so I can't imagine dirt in the seals is an issue. I replaced the valve core but that did nothing. If anyone has any experience with USD forks and can offer advice that would be great; most of the advice online seems to apply to RSU forks.


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I'm not posting anymore photos until the bike is 100% complete, which now seems like it will be a while due to issues with the fork, the bottom bracket, the front tire and the torque arm for the front motor. There are also some minor cosmetic issues with things like the plates for the rear deck. I have discovered these issues on a series of short test rides around town. Because of the bottom bracket issue, I cannot fit a chain, so I've just been riding it around as a moped with the throttle only. TBH, it's kind of scary in throttle only mode. It will actually catch a little bit of air on small bumps in the road when travelling uphill at full throttle. Top speed seems to be about 29 MPH, which is precisely what the Grin Motor Simulator predicted, so kudos to them for that. With a human powered transmission finally installed, the top speed should be a little faster. The front tire might need to be reconsidered due to safety issues; Surly bills it as an 'all-rounder' tire but it seems to be more of an 'all-around on your ass' tire. Posting details below in case it helps anybody with their own DIY build:

- Fork was defective and won't hold air. I ordered a replacement from another vendor and will RMA the old fork once it arrives. The Amazon seller of the original fork, Cycling Deal, has offered a full refund but we will see what happens. According to my purchase history I have ordered maybe half a dozen other components from them before, and they have a very high customer rating, but I suspect this fork may be an example of dumping defective or returned stock, which Amazon sellers are increasingly known to do. Cycling Deal has mostly cornered the market in NA for my fork, a DNM USD-6 Fat inverted fork, but thankfully I found another vendor. I also noticed that while you can't find the fork on ebay or walmart.com from anyone other than Cycling Deal, it appears to be an abundant item on aliexpress.

- I ordered the wrong bottom bracket torque sensor from Grin, an Erider 68mm T9N. I actually have a 73mm bottom bracket, which means the spindles slides back and forth in the shell, which is why I can't run a chain yet. Grin is out of stock and informed me that new stock just shipped from Taiwan, and that means it will take another 2-3 months to get to them by boat! I ordered one from a company called Sol Mobil, but they are apparently supplied by Grin, and despite the claim that the item was 'in stock' when I purchased it, they are out of stock as well. I found that, like my DNM fork, Erider BB torque sensors are abundant on aliexpress, so after creating an account and working my way through the site's horrid interface, managed to order one directly from Taiwan. Grin seems to have cornered the NA market; this seems to be a common state of affairs for certain foreign components. As soon as it arrives, I will cancel the Sol Mobil order. I'm keeping the other order alive until I get the other one just because aliexpress transactions are often the target of some sort of fraud, like generating false tracking numbers and never shipping an actual product.

- The front tire in combination with fully powered throttle-only mode is kind of dangerous. I was accelerating from a stop yesterday, which was lightly wetted by a median sprinkler, wiped out and scraped my knee up. The brush guards, which look admittedly absurd, saved my knuckles. The handlebars and seat were twisted in the fall and I had to effect a small roadside repair. I am considering a fat road tire like a Vee. Alternatively, because fat road tires are few and far between, I might try a Schwalbe Jumbo Jim because they are supposed to have lower rolling resistance and better road traction.

- The front motor torque arm. Oy vey. It has failed on me twice now. The first time, it nearly wrapped the motor cable around the axle, but the smooth axle spacer, some zip ties and additional cable wrap I put on the cable saved it from any real damage. I re-engineered it with a second bolt, threaded coupling nuts, reinforced it with a metal furniture strap, liberally applied threadlock and torqued everything to about 20 Nm. On my most recent ride yesterday it failed again, thankfully with me off the bike. While I was testing off the bike to make sure a front pannier didn't rub the front wheel by lightly triggering the throttle, no less. The odd thing is that all of the new hardware was still tight and orthogonal, so this should have been impossible. It seems as if the first bolt in my assembly, nearest the fork, is getting a lot of heat transferred to it under acceleration and I think it bent enough to escape the swing arm on the Grin frame clamp, then sprang back into a straight shape once free due to the coupling nuts. I'm going to upgrade from these M5 bolts and multiple aluminum coupling nuts to a single stainless steel coupling nut and M8 black oxide bolts held on with stainless steel locking Fuji nuts torqued to 40 Nm, replace the swing arm with a piece of 1/8" x 1" x 1" stainless angle iron with a hole drilled in it so the bolt is fully captured and cannot escape, and replace the furniture galvanized furniture strap with a 1/8" x 1" x 6" stainless knife blank.

- You would think that 1/4" marine board would be able to handle a 12 pound battery, but both pieces are warping, so I'm going to replace them with a solution using 1/8" stainless steel flat bars on top and a plate below.

- The wiring is really hairy in the back with all of the excess battery cable. I've temporarily covered it up with neoprene sleeves cut to length, but I'll probably have to trim them down and either solder or re-crimp.

- I finally put together a decent wiring diagram for the horns.

- The Fisher Fabhouse light terminates in an XT30 connector with fairly thin gauge wire, making connecting it to the Cycle Analyst a little bit of fab. I ended up soldering a DC barrel connector to an XT30 cable. One issue I am having with the light, which Grin so far cannot explain, is that when the light turns on, a currently unused Anderson tap in the rear of the bike makes whining noises at different pitches depending on the brightness setting.

- I was originally getting weird speedo results, it turns out because the default number of poles is was programmed with, 23, corresponds to the front motor and controller, whereas I am using the rear motor and its controller as the default controller, and the GMAC has 6 poles.

- Getting a good battery reading out of the setup with a dual-battery parallel wiring configuration is a bit counterintuitive. You have to set the amp hours to double, but leave the number of cells the same as for a single battery. Once you do that, it works perfectly.

- Switching between road-legal and non-road-legal modes is very easy but not as straightforward as I would like. What I would like to do is limit the nominal power, but that isn't possible. You can only limit the maximum power, the minimum for which is 1.5 kW. Since nominal power is almost always half of maximum power, that's about as close you can get to being explicitly legal. You can also change between up to 3 presets in a matter of seconds with a couple button presses. So the way I have it set up is that I have power wired to my potentiometer, and 3 presets, 'Eco', 'Speed' and 'Unlimited'. The strings are hard-coded in a list, you can't type your own label. Eco is speed limited to 20 MPH; Speed is limited to 28 MPH; and of course Unlimited is unlimited, although that only gives you an extra MPH (plus a few more once it has a chain). So if I select the Eco preset, and dial the potentiometer down to the minimum, it's road-legal. I can do the same with the Speed preset if I don't use the throttle. Or I can ride illegally in Unlimited mode, or use the throttle in Speed mode. These are technically illegal, but not likely to generate much attention from law enforcement since I will not be travelling much faster than 30 MPH.

All in all, it's working well. I calculated an MPGe of about 691 on a 4.31 mile round trip to the grocery store yesterday. Given that I was using full power most of that time, had 5 panniers of cargo, and had to travel up a hill to get back home, that seems pretty good to me. I have to admit that although it isn't that much faster, traveling 29 MPH or so on a bike is a completely different experience than traveling at 20 MPH. It's going to take some getting used to, and it may be something I can only do with no cargo and even then only occasionally to get around or escape traffic.

20210208_201749 (1).jpg
Front torque arm v1, prior to the first failure. Artifacts of the failure included a bent bolt and that the swing arm had swung in towards the wheel.
Front torque arm v2, prior to the 2nd failure. This still wasn't enough. The only artifact of the failure was that the threaded couplers on the inner bolt were loose. Everything else was straight and tight, including the swing arm.
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Active Member
Alright, as promised, here's a final raft of photos now that this bad boy is finally complete... mostly. I'd say it's about 95% finished, but the remaining tasks are mostly polish and refinement: Things like a righthand mirror, thief-proofing the hose clamps for the downtube battery with transparent PVC and pipe clamps, fitting a temporary fat bike front fender because the metal one I ordered from Germany is lost in shipping hell, et cetera. The unfortunate thing just now is that the spouse has a migraine so although I just tightened up the build, I can't test ride until tomorrow :confused:. Probably won't post much more about it unless people have specific questions. I might post a bit more once I get some miles on it and see what it can do. Having already tested it in full-throttle-hang-on-for-dear-life mode, I know it's going to kick ass at it's job of hauling lots of stuff as a bike semi with my Surly trailer. We may also try to do some local touring with it, since it can carry 5 panniers plus whatever we can fit on both racks, and also since it turns out to be very versatile in terms of efficiency. It has a potentiometer tied to the maximum power output, in addition to the usual assist levels (using the 5 default levels, can be easily re-programmed to another number), and the 3 aforementioned presets. The presets also allow me to switch between legal and not-so-legal configurations in a matter of seconds.

I will be very interested to see what kinds of torque readings I see out of the logger on hill climbs, as well as what the top speed will be when adding human power into the mix. I've had brief moments of buyer's remorse when reading about and watching videos of crazy HPC kits and 2000W+ factory e-bikes like the Monarch AWD (not legally registered mopeds, so technically illegal to operate on roads). However, after my throttle-only test rides and the spill I took, not to mention watching more of those videos, those doubts have been erased. Even people testing 50+ MPH e-bikes, like Electrek, admit that those speeds are insane, and they only achieved them to find the limits of the bike; in almost every case, as soon as someone hits those speeds, they wisely back down to something more reasonable like 25 or 30. Moreover, those bikes have really terrible range if you intend to hot rod them around--they are, in fact, referred to as 'hot-rodded' e-bikes. And despite their massive power, the bike I built actually manages to have more torque than just about anything on the road, more in line with a small car. This is because I chose the slow-wind version of both motors, which have more torque, and because of the high-range cassette (really hope to get that 11th gear working some day). So while it's fast compared to 99% of the e-bikes on the road, it's actually slow compared to what it would be with faster windings. Within that lower speed limit, though, it has crazy torque, as two failed torque arms can attest, so the acceleration up to that limit is pretty intense. You can get up to a max speed of about 30 MPH in a couple of seconds on flat ground. There is a light near my house where the problem on my existing bikes is people getting annoyed because they are stuck behind you and passing unsafely. On my first or second test run I noticed I no longer have that problem due to Bruce's acceleration, but funnily enough a new problem cropped up: Namely that once in the protected bike lane on the other side of the light, the car in the lane to my left sped up to 50 to beat me to the next light so they could cut me off from the sharrows lane and bike lane past that light. The extra 10 MPH is a substantial change though, so I'll probably ride with elbow and knee guards on this bike. I've had a few spills on e-bikes now (all 13 MPH or slower!) and I'm kind of tired of cheese-grater elbows and knees.

So I'm pretty satisfied at the moment; time will tell if I stay that way, but having built the whole thing, I'm confident I can repair, or re-engineer and replace, anything that goes wrong. It will probably take a while to get the hang of riding it. For now I'm looking forward to being able to haul heaver loads up hills, pass indecisive/slow drivers that I currently am too slow to pass on the R&M, and pull away from annoying cyclist traffic during heavy traffic. The latter consists mostly of unassisted cyclists leap-frogging me at lights and then riding much slower than my top speed, forcing me to take the lane to pass.

Oh, and one other detail that is great is that both motors have geared clutches so they have always-on brake regen. On my most recent 4 mile round trip, I regenerated about 13% of the power I used, which is pretty amazing for regen on an e-bike.

The most salient points in this mostly final build are:

- RMA'ed the defective front fork and fitted the new one, which in addition to not being defective, is a better fork (different/newer generation) 👍
- Finished v3 of a torque arm solution for the front motor with M8 hardware, locking Fuji nuts (commonly used on motorcycles), orange threadlock (3x stronger than blue), and 1/8" stainless steel plate and angle iron
- Replaced the death trap front tire, which was a Surly Knard 26"x4.8", with an Origin8 Supercell 26"x4.0" which has siping for wet conditions, better road traction, and lower rolling resistance; and also added Tannus armor and Stan's No Flat
- Rebuilt the rear battery deck out of 1/8" stainless steel plate, as the marine board version sagged and deformed under the weight and tension; also theft-proofed the hanging hardware a bit by replacing it with case hardened linear motion rods, and attaching them with red threadlock at the bottom plate
- Shortened the cables going to and from the rear controller, which is housed in the rear battery mount, which cleans things up in the back quite a bit; probably removed 6 feet of cable
- Rigged up a more stable/useful set up for the lefthand mirror
- Finally got the correct bottom bracket and fitted it (ordered directly from China via Aliexpress as Grin has a 3 month delay on the part), so I was finally able to fit the chain and tune the drive train

Mostly final cockpit view and comparison next to the R&M:

The new tire in close-up and compared to the Schwalbe Super Moto-X's on our R&M Homage. It's still a huge tire, but looks tiny to me compared to the Surly Knard. It does take 2 inches off the height, but the downtube angle is still good. The length from the saddle to the pedal and the handlebar height are identical to what I'm used to on the R&M:

A chain! Tuning has been a bit of a bear: Cannot get the 11th gear in the rear into the tune, I might have to take it to the LBS and see if they can get it working. I tightened the cable as much as I can and shortened the chain as much as I dare, but can't get the rear derailleur into a low/outside enough position to shift into that gear. The mechanism still has enough play to get there, though.

Details views of cable management and an additional pair of Surly rack stays I added near the bottom of the rack to stabilize it; on my wipe out on a test ride of the earlier iteration, I found that the rack sagged down onto the rear fender, causing it to rub the rear tire. After fixing that issue, I had to replace and re-cut the rear fender stays as well to get it back off the tire:

Top and side views of the new battery deck. Everything is countersunk to be nice and low profile and the stainless steel is very stiff so there is no flexing whatsoever now. As mentioned, I also replaced the vertical struts, or whatever you want to call them, with case hardened stainless steel linear motion rods of the kind usually used in industrial printing applications. They were a bit pricey at almost $50 a pop, but between those, Hexlock inserts I intend to add to a couple of the top bolts, red threadlock on the bottom bolts and another plate in the back (1/4" aluminum), my nearly $1000 rear battery is safe and secure on the bike (not perfectly, but enough to leave it locked up outside for a few hours in a visible area):

Different views of front torque arm V3 (also, a functioning fork!). The other nice thing about the new fork is that it is the proper racing version designed for dual front brake rotors, so I was able to mount my custom torque arm extension directly into the post mounts for the righthand brake rather than into a Grin frame clamp secured with hose clamps:


Active Member
So I've put about 20 miles on torque arm v3 now and I'm pleased to report that it is absolutely rock solid. The bike has now been tested in the rain on a grocery run, with full panniers on a pet store/package run and towing my Surly Bill and has passed all with flying colors.

I can also report that I am getting more confident and comfortable riding this strange new beast. It definitely requires its own custom skillset to operate, being less heavy than a motorcycle but heavier than most e-bikes. I hit a new speed record today on flat ground of about 32 MPH while pedaling. I was also able to maintain 15-20 MPH on a hill with 15% grades hauling about 60 lbs. As intuited, tailgaters and slower bicycle traffic sort of just melted away into the background.


Well-Known Member
"Pride goeth before destruction", what you are doing is nice and somewhat practical, you must remember a crash with cargo at 30 mph vs 15 mph will have 4 times the energy, the time you mentioned plate steel gave me the shudders. "Do as thou wilt" tempered with caution, your experiences have brought a lot of novel and good ideas to this forum.One thing to keep in mind is this there are mini electric trucks appearing on the market in various places( electric) that can be acquired for a few thousand( Icarus never understood His limits) Cheers and keep on innovating( myself am contemplating a "standard" 3 wheel build- low speed gives so much freedom of design)


Active Member
@kmccune I hear you, safety is on my mind all the time. I ride this bike with a full face DH helmet, an armored shirt, and elbow pads, and I'm planning on adding knee pads when I can find a pair that are comfortable while pedaling. I bought a pair typically used for motocross, but they dig into my shins even when not pedaling. The 32 MPH speed was achieved on a dry, clean patch of road with no debris on a sunny, dry day with very little wind, and there happened to be no traffic in front of me or behind me, which is rare. I'm still pretty timid riding it compared to the R&M; for instance, I'm not any wider, but I'm not comfortable lane-splitting with this bike yet.

When I was towing the steel, keep in mind that was with a 250W e-bike and my average speed on that trip was maybe 8 MPH. This new bike will likely be able to go faster than that even with such a large load, so you're right, I will definitely need to keep an eye on speed when hauling that much, as with any vehicle when hauling or towing a large load. Thanks for your concern for my safety, I appreciate it 👍.


Well-Known Member
You might reinforce a comfortable pair of jeans in the knee area, at least that would save your skin.I understand in warm weather serious safety stuff is hot'


Active Member
You might reinforce a comfortable pair of jeans in the knee area, at least that would save your skin.I understand in warm weather serious safety stuff is hot'
I've looked into riding jeans, they make a lot of them for motorcycle riding with inserts for pads, and some of them even have gusseted knees. I might try those in the future, but in general I find jeans too binding and hot for riding. I prefer to wear twill biker joggers, as they look like normal pants and are light and relatively rugged, and allow a full range of motion like tac pants, but unlike those they have an elastic cuff and ruching near the ankle, which keeps debris out and also fits well over various boots (when I wear boots). I have a couple pair that I've cut down into long shorts for summer riding as well.

I've got some miles now with some Leatt 3DF 6.0 elbow guards, a Leatt Stealth armored tee and my 100% full face DH helmet. I also got some Leatt Dual Axis moto knee guards, but they were too stiff for pedaling, so I had to return them. I ordered the Stealth tee based on their size chart, which is height based, and it's honestly probably a size too large. It also chafes at the collar, so while it is intended to be worn in a tank or under a regular shirt, I just wear it over a t-shirt now. I haven't been entirely satisfied with the elbow guards, which seem to move around more than I like. I did put in a ride with them yesterday though and found they move around less if you push them up a little higher so my elbow is below the cup a little. So I've sprung for some TLD elbow guards and knee guards, as well as some of their Gambit gloves for more knuckle and finger protection. I also sprung for some Leatt EXT guards and their moto gloves, both for comparison and because it's good to have a couple of sets of safety gear in case one set gets chewed up or is drying out, et cetera. I'll try to chime in with a review of the above gear after I put some miles in. The Stealth tee and 3DF 6.0 elbow guards from Leatt definitely get a little hot and sweaty, but not egregiously; they seem to breath pretty well and reviewers experienced with this kind of gear tend to say Leatt gear wears cool compared to other brands, so I'll just chalk it up to normalcy for wearing additional safety gear. I'll have to compare to the TLD gear when it comes in. One thing I've learned is to keep the tags on and try everything on with the assumption it won't fit and will need to be returned, as most return policies are pretty strict and this kind of gear seems to be all over the place in terms of fit, more so than clothes.


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I've put in about 85 miles on the bike now and I'm getting very comfortable with it, having learned to 'speak its language'. I'm getting conditioned as I ride it to handle the additional weight; I'm finding it actually takes more leg strength to ride this bike to balance the extra weight, particularly when standing on the pedals to coast downhill of all things. I've put in 39.6 miles over the last two rides and have some interesting stats to share, which are features of the Cycle Analyst 3.1 computer in case anyone is interested in a Cycle Analyst build (a number of kits, and even factory bikes, use this computer). Some of these were features I didn't even realize it had until today. The first ride was a 16.6 mile ride with the SO around town towing our dog. They were on the R&M, and I obviously did not want to abandon them, so I 'nerfed' it--I put it in Economy mode, which restricts it to 20 MPH, dialed maximum power down to 1.3 kW (which gives it a nominal power of ~500-650W), and used lower assist settings. The 23 mile ride I went on yesterday was an unlimited mode ride from our house to Sausalito and back, which I round-tripped in an hour and 43 minutes with an average speed of 14.2 MPH including a 10 minute stop and the previous 16.6 mile nerf ride, which is pretty fast. I mostly pedaled the whole way in Unlimited mode with a couple of brief throttle sections and a 'full nerf' crossing the GGB back and forth, which has a speed limit of 20 for bicycles and is fairly tight--defining full nerf as like above, but never going above assist level 1.

So I didn't realize max speed was available on the CA; apparently my max speed so far is 34.2 MPH. I don't know yet if that is for the total life of the bike, like it is on the Bosch system, or just until I reset the trip. I also don't know if it includes coasting speed or only powered speed--the top speed I've clocked on the R&M was 45 MPH descending Portal Ave., a long downhill road in SF.

I also didn't realize that min/max amperage and minimum voltage were available. Based on max amps and min volts from the CA, it appears my peak power (amps * volts) so far was 3,190.34W! Actually, max volts aren't shown, so it could even be a little higher. I've seen volts as high as 58.8 on the display before, which would come out to 3,486.84W. That's a lot higher than advertised peak of roughly 2,200W advertised for the two motors combined. Of course, I have no way of knowing whether max volts and amps happened at the same time, so I have to go with minimum voltage for a reliable figure.

Combined regen for these two trips is 12.7%, recouping 2.7952 Ah out of 24.771 forward Ah. On the earlier nerf ride however, I saw this go as high as 27%. The CA also tracks Human Wh and average W of power from human input. Apparently out of the 1336.7 Wh used on the last two trips, I contributed 498.4 Wh, with an average input of 334W of pedaling power, and average RPM of 87.2, which is a fairly optimal cadence. Wh/mi over the past two trips is 29.8. With two batteries, each with 1,029.6 Wh of capacity, giving a total battery capacity of 2,059.2, that gives a range of about 69.1 miles. I've seen Wh/mi as high as 45 and as low as 17 on different rides, however, so the range of ranges seems to be 45.76 miles in full Unlimited mode, and 121.13 miles in nerf mode (possibly a little more in full nerf). Honestly, I'm pretty pleased with all of that.

On my most recent ride I learned that while you need to pedal for full speed on flat ground, on certain grades throttle is slightly faster. On an uphill stretch coming up out of Sausalito heading home I was doing about 25-30 MPH. Pedaling feels safer, because you have better balance on the bike, so the throttle is definitely an occasional thing. I caught up and passed a road biker on Arguello Blvd. back in town, who was honestly ripping it at probably 32 MPH--he asked to draft a bit on the last stretch up to GGP, which worked great. If they aren't doing so already, I honestly think cycling coaching teams should switch to e-bikes for both draft pacers and chase vehicles. Using them to chase takes up less room on the road and is better for the environment, and a draft pacer would be able to target more consistent speeds for training riders in the draft.

I've also graduated hate levels it seems. On the R&M I get occasional comments of 'cheater' or 'sissy' or something like that. On Bruce the Moose the hater comments are "That's a motorcycle" or "That's not a bike", both of which statements are false. Apparently there are a lot of people who don't realize that above e-bikes in the 2-wheeled hierarchy are mopeds, scooters, and then motorcycles. No one has said "That's a moped", and I've only gotten one comment of "That's a scooter." I haven't gotten any 'cheater' comments, I guess because it's so obviously a 'cheater bike' that no one feels compelled to say so. And paradoxically, since I'm 'cheating' more, at least ostensibly from the uneducated POV (based on cadence I'm probably burning the same amount of calories on the R&M, and I think I'm getting more leg exercise due to needing to control the extra weight), I don't get 'sissy' comments because I guess I look sufficiently manly in my full face DH helmet (which people call a 'motorcycle' helmet, which it is not), and on a bike that looks like a 'motorcycle'. Most people just think it's cool, though.:cool: Surprisingly I get less hate now from the roadie and hipster cycling purist crowds now. I guess over a certain threshold of cheating you transcend it in their minds? I don't really understand the logic, but I like the generally positive vibes the bike seems to generate.

I also logged the last two trips on the CA logger I have installed, which writes a bunch of parameters to an SD card. It looks like this:


I don't know if there is a standard way to parse it, like with an app; if not, I will probably write my own at some point, being a coder. It includes GPS data, which is kind of nifty.

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Active Member
So Grin apparently makes an excellent online visualization tool for the logger, of course: https://ebikes.ca/tools/trip-analyzer.html. I've attached my log files for anyone who wants to check it out. My fastest speed on the uphill section out of Sausalito was 31.65 MPH, which I believe was under throttle only at that point, although I may have been pedaling again by then. Select the CALog~.txt file for the CA log input and the GPSLog~.txt file for the GPS log input, select your choice of metric or imperial units, and hit the submit button.


  • CAlog_0034 (30 Mar 2021 01 16 UTC).txt
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  • GPSlog_0034 (30 Mar 2021 01 16 UTC).txt
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