first time e-bike conversion surly disc trucker

finn1911 · May 30, 2021

I've been doing some shopping lately on ebikes.ca and general browsing around trying to figure out how best to turn my Surly Disc Trucker into a toddler transport machine and I'm hoping to get some answers to some questions i haven't been able to find. I would likely go with a setup where i have a torque sensing bottom braket of some type (not sure on the model to choose) and then also a throttle in the mix, probably a half-twist.

I am torn between a GMAC motor or going for the quieter but heavier 9c RH-212. I would prefer the smaller size of the GMAC for sure, but I'm not sure if the noise would bother me or not; I also think i would prefer the look since it would look less like "hey i'm an ebike!". Any thoughts there? It's worth mentioning that I live in Vancouver, Canada and my commute of about 30km roundtrip would definitely involve some hills with a max grade of about 3%. I would LOVE to see a video of someone riding the GMAC in normal city conditions so i could hear how it sounds. In addition to this, is there really much concern about stripping gears etc?

The other questions i haven't been able to find answers to are how things like proportional regen works in practice.. like, how does it work physically? Do you pull the brake lever and then do you need to keep holding that slightly pulled while you turn the throttle to modulate the braking force of regen? Related to this, if you're using regen, how or when does the throttle turn back to throttle mode?.. is it when you release the brake, or when you start pedaling again?

To complicate things, I'm wondering about touring weights and hills. As some might know, this bike is meant to be a touring bike and that's what I've used it for in the past. I now have a kid so it's primary function is toddler transport right now, but I could forsee at least some weekend camping trips for myself and maybe with the kid as he gets a bit older. I realize i would need to organize these trips around being at a campsite with power at some point, but I'm wondering if either motor i mentioned would be better for hill climbing with a full load of paniers? What is important here other than just amp hours? is 36V going to provide enough grunt or should i be thinking more in the 52V range.

One final thing, does anyone know how grin's website stock system works? It will let me choose parts for a RTR system but then say something like -147 available, but not tell me what part they don't have. Obviously, I can just call and ask, but just wondering if anyone knows.

Stephen

dogman dan · May 31, 2021

I had not looked at grins website in quite a while. I can't say a thing about how the site works, or how they work regen.

You want 52v for sure. Quicker get out of the way in city, more power to get up that steeper hill in the sticks.

But I do have some experience with heavy loaded bikes, and the rocky mountains. The mac motor looks really cool, but honestly, I found the freewheel the thing that was great about a geared motor. But not for a heavy cargo bike. What really worked well for me on a cargo bike was one of Grins really big motors, circa 2010 or so. It was called the 5304. This was a direct drive motor, 25 pounds in weight, with huge magnets and a ton of copper wire inside to handle 3000w power. I found a very heavy loaded cargo hauler needed only 2000w to get up the 10% grades that go on for miles typical of the rocky mountains in New Mexico. And even without regen, loaded like that you will like a big motor dragging hard on your descent, helping you save your brakes.

Not saying you can't get by with a lot less, just that the big ass direct drive motor really worked great for that camping trip.

For those 3% grades and the kid on the back, no worries at all. But you may have to pedal really hard, to carry a kid and a trailer full of camping gear. Ideally you'd do two bikes. One the city bike, for which the mac motor would be fine. The other bike would be specialized, a longtail with 20" wheel that would climb better with a trailer, with the same motor you used on the city bike. The 20 inch wheel makes the motor run in a lower gear, so the small wheel shines when the grades get steep, and the loads get heavy.

Grin sold a bike like that at one point, maybe they still do. I welded an imitation of it using square steel tubing, and the front half of a very good steel mtb frame. It was a great cargo bike, running a 9 c motor. It was built specifically to haul a huge home made trailer.

As for noise, geared motors make a very soft gear whine, which will annoy the hell out of you if you expect it to be as silent as a regular bike. Direct drive motors make a very soft grunting noise when starting up, that will annoy the hell out of you if you expect it to be as silent as regular bikes. At top speed, geared motors make a lot more noise than DD, but I am talking about at 30 mph. At 20 mph, no motor makes enough noise to bother me. But I don't expect to hear butterflies flapping. No motor noise is going to compare to city noise. Both types sneak up on wildlife just fine, with the tires making twice the noise of the motor on a dirt track.

In short, don't sweat the noise of either type. and if you mind looking like an e bike, get saddle bags covering the motor like my picture.

RunForTheHills · May 31, 2021

I built a Disc Trucker with a GMAC motor. I am actually finishing the project right now as it got put on the backburner for a couple of years since I have been working from home. I was able to buy a prototype GMAC from Grin that has a clutch, so no regen. The motor with the 10mm axle dropped right into the frame with no filing of the dropouts. This won't be true for other motors with larger axles and without the built in torque arm. I did have to drill a hole in the bottom bracket shell for the Sempu torque sensor wire, but the Erider torque sensor they offer now doesn't require that. I bought the TRP Quadiem G-Spec hydraulic brakes (I have upright bars) and the calipers fit between the rotor and the hub with about 2mm clearance with a 160mm rotor in the back.

I have seen another Trucker build on this site that used a mid-drive motor. The BBSxx motors do not have a torque sensor, but the TSDZ2 does. Mid-drives have an advantage on steep or long hills as they use the gearing on the bike.

https://www.endless-sphere.com/forums/viewtopic.php?f=3&t=98802

finn1911 · Jun 1, 2021

dogman dan said:
I had not looked at grins website in quite a while. I can't say a thing about how the site works, or how they work regen.

You want 52v for sure. Quicker get out of the way in city, more power to get up that steeper hill in the sticks.

But I do have some experience with heavy loaded bikes, and the rocky mountains. The mac motor looks really cool, but honestly, I found the freewheel the thing that was great about a geared motor. But not for a heavy cargo bike. What really worked well for me on a cargo bike was one of Grins really big motors, circa 2010 or so. It was called the 5304. This was a direct drive motor, 25 pounds in weight, with huge magnets and a ton of copper wire inside to handle 3000w power. I found a very heavy loaded cargo hauler needed only 2000w to get up the 10% grades that go on for miles typical of the rocky mountains in New Mexico. And even without regen, loaded like that you will like a big motor dragging hard on your descent, helping you save your brakes.

Not saying you can't get by with a lot less, just that the big ass direct drive motor really worked great for that camping trip.

For those 3% grades and the kid on the back, no worries at all. But you may have to pedal really hard, to carry a kid and a trailer full of camping gear. Ideally you'd do two bikes. One the city bike, for which the mac motor would be fine. The other bike would be specialized, a longtail with 20" wheel that would climb better with a trailer, with the same motor you used on the city bike. The 20 inch wheel makes the motor run in a lower gear, so the small wheel shines when the grades get steep, and the loads get heavy.

Grin sold a bike like that at one point, maybe they still do. I welded an imitation of it using square steel tubing, and the front half of a very good steel mtb frame. It was a great cargo bike, running a 9 c motor. It was built specifically to haul a huge home made trailer. Finished cargo mixte..jpg

As for noise, geared motors make a very soft gear whine, which will annoy the hell out of you if you expect it to be as silent as a regular bike. Direct drive motors make a very soft grunting noise when starting up, that will annoy the hell out of you if you expect it to be as silent as regular bikes. At top speed, geared motors make a lot more noise than DD, but I am talking about at 30 mph. At 20 mph, no motor makes enough noise to bother me. But I don't expect to hear butterflies flapping. No motor noise is going to compare to city noise. Both types sneak up on wildlife just fine, with the tires making twice the noise of the motor on a dirt track.

In short, don't sweat the noise of either type. and if you mind looking like an e bike, get saddle bags covering the motor like my picture.

Thanks for the reply! I think i'm leaning now towards the https://ebikes.ca/shop/electric-bicycle-parts/motors/rh212-std.html motor instead of the GMAC. I will probably also go with a big 52V 20aH battery so i have as much capacity as I can get. If I don't like the motor down the line I can always swap out for something else. According to Grin, this would give me 1040Wh. I will probably also install the Erider BB and a throttle as well so i can do modulated regen braking. I'm ready to pull the trigger I think, but it sounds like there is a bit of a wait (a few weeks they say) for the baserunner controller so I'll have to be patient I guess. Thankfully they are local to me (literally less than a 10 minute ride to Grin) so at least I won't need to wait for shipping?

It turns out that the -

RunForTheHills · Jun 1, 2021

finn1911 said:
Thanks for the reply! I think i'm leaning now towards the https://ebikes.ca/shop/electric-bicycle-parts/motors/rh212-std.html motor instead of the GMAC. I will probably also go with a big 52V 20aH battery so i have as much capacity as I can get. If I don't like the motor down the line I can always swap out for something else. According to Grin, this would give me 1040Wh. I will probably also install the Erider BB and a throttle as well so i can do modulated regen braking. I'm ready to pull the trigger I think, but it sounds like there is a bit of a wait (a few weeks they say) for the baserunner controller so I'll have to be patient I guess. Thankfully they are local to me (literally less than a 10 minute ride to Grin) so at least I won't need to wait for shipping?

It turns out that the -

That is an expensive kit. You will have to file your dropouts to install that motor. When I select the kit, it shows the Baserunner in stock and the Phaserunner is greyed out, but it sounds like you called them and confirmed availability.

https://ebikes.ca/shop/electric-bicycle-kits/rh212/rh212-ready-to-roll-kit.html

finn1911 · Jun 1, 2021

RunForTheHills said:
That is an expensive kit. You will have to file your dropouts to install that motor. When I select the kit, it shows the Baserunner in stock and the Phaserunner is greyed out, but it sounds like you called them and confirmed availability.

https://ebikes.ca/shop/electric-bicycle-kits/rh212/rh212-ready-to-roll-kit.html

For sure, not cheap, but thankfully my company provides some spending money that can be used for fitness/green type things and so I'll get a good 60% off. It's still costing me a chunk of change, but it's not quite as painful as it first seems and it'll keep my car off the road for a decent chunk of the year. I've submitted my order now, so we'll see how long it takes to come in.

dogman dan · Jun 2, 2021

Hard to beat dealing with Grin. I wish I was local, just so I could hang out some with Justin. The best e bike stuff I've ever owned was stuff that Justin designed and produced, not just sold. Cycleanalysts, and the Satiator charger.

You are going to be very happy with your bike. You can save a ton of money keeping that car parked. Gas is the tip of the iceberg, every year you put off having to get a new one saves you 5 thou a year, if not more.

first time e-bike conversion surly disc trucker

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