Leisesturm

Exactly. Even the All Axle Motor has to produce torque, or ... what's the point. So ... 'lesser' motors, equipped with torque arms are not suddenly obsoleted by the existence of the AAM. The point of the AAM is its adaptability to different use scenarios. It is still a hub motor at the end of the day. All hub motors produce their torque around the axle centerpoint. There is no way possible to get around that.

Rick

The engineering of both the All Axle hub Motor and the Gmac/Grin version of the Mac motor are designed so the fit to the bicycle is not haphazard. This in itself reduces the stress on the stays. Grins Phaserunner and Baserunner controllers allow you to control startup torque and other parameters that other controllers don't . The mounting of the torque arm for both these motors does not allow any movement. Justin has put allot of time and effort into making changes for the better in an industry that has made little progress since the late 1800s.

Alcanbrad

We may all be saying the same thing here. That the AAM is still nothing but a hub motor that improves on several of the fitment issues. It, by itself, does not improve on any of the motors basic intended function - i.e. make bike go. Grin has spent a fair amount of time and effort improving many of these short comings, but in the end, it still is hub motor. I think the weight is the real Achilles heal of these ebike motors, and that is limited by physics and materials. Only one of those limitation has the possibility of improving further and I doubt Grin will exceed the worlds motor technology manufacturers and make a better motor before anyone else does.

Armto mentioned their Cyntronix (sp?) solution. I looked at that when I started my journey and was concerned about the low power dissipation motor. Also, they were out of stock and weren't sure when they would have more (this was last fall). Sounds like that solution works well for them. I am going to go back and see if I can tell exactly what they are offering to see if there might be a better trade-off components wise for the type of riding we hope to leverage ebike conversion for.

Rick

The All Axle Hub Motor is around two kilos lighter than its nearest competitor. It does not surprise me that someone hasn't replaced cast steel with aluminum before. Grin also put more powerful magnets in there motor. As with the All Axle Hub Motor the GMac motor has the wiring coming out from the side instead out the center of the axle. The GMag has a 10mm solid axle. The GMac also has mowerful regen. This has only ben experimented with up to now.

I have looked at the Cyntroni. It is a small geared motor with the controller and other electronics built into the battery case. It also allows you to run some lights with there battery. I'm not worried about burning up their small motor because they probably have a thermistor in it so you will get thermal roll back if you work it to hard. Grin also has a small motor but it has the wiring coming out the side instead of the middle of the axle. A round solid 10mm axle. Very little filing to fit on a front fork. They give quite a bit of info on it also. Using there Baserunner or Phaserunner controller would increase the power without added heat. I would use a torque arm if I used a 48v or 52v battery with it. Cyntroni does not give allot of info on there system. Grin also has spare parts and a tear down video for the G31X Mini Geared Hubs. I would use the EZEE motor If they would come out with a solid axle version. I have disk brakes and don't like the idea of having to file half the diameter difference of that 12mm axle to align the height equally.

kayakindude

Getting back to the basic question posed by the OP. I went with Swytch. 250 watt front hub system that adds 6 pounds, 4 of which is a quick release battery that mounts on the front handlebar. This is peddle assist only, though a throttle can be purchased.

Charges in about 2 hours and assists for roughly 25-30 miles depending on demand. The system was just under $500 and takes 4 months to ship from England.



No issues with overheating or fork twisting and that is with a dog trailer attached.

Mlcdc1

any pics available?

kayakindude

Pics and a breakdown of the process posted here:

Swytch

Leisesturm

Dude, that story sounds like sheer misery to me. You got hosed big time and learning that you put that kit on a tandem??!! Seriously? 250W on a freaking tandem? A tandem that pulls a trailer no less. There would be know way of knowing if a 250W motor was working or not on our tandem. My wife by herself is good for that when she is in the mood. And four months for delivery is NOT something to get excited about. Your expectations and needs might be very, very basic but this is not the only thread where you have offered up this Swytch thing as some kind of better way for the rest of us. I'm not seeing it.

kayakindude

I am really sorry you seem so negative about something my wife and I have really been enjoying for the past six months. Maybe not everyone wants so much power you barely have to pedal, maybe some of us just want a little assist on hills, point being enjoy riding your way and maybe judge others a tad less.

We can tell that 250w does make an impact based on the data of the same rides year over year.

My experience was not miserable, I learned a lot and imagine a 1st timer is going to have to figure things out...PAS is PAS and will require adjustments depending on the bike you are installing it on. Some of us just want to dip our toes into electric and I stand by that for a newbie this gave me what I was looking for.

Not everyone needs to have something right now, I was in such a rush that I still have the 2nd kit in a box and you know what when I get to it, I get to it. Same with the universal mount they sent me for free...clearly a terrible company.

Looking forward to a nice ride out there today.

Alcanbrad

I believe that the above quote and the post just before illustrate the challenges of sizing a system to a bike. The big issue is that the manufacturers motor power ratings are inconsistently applied making it almost impossible to compare one system vs. another when all you get is "250 watt motor". A 250W and a 1500W motor may give the same feeling of "power" to the user. What really matters is the torque a motor can put out, and it's ability to dissipate heat. I am sure Kayakindude is experiencing satisfactory performance with their setup, and I agree with Leisesterm's point that 250W is too small for a tandem.

In general, (and I emphasize "general") you cannot compare two motors without having the rated torque data provided. You can, however, in "general" compare the thermal performance based on the motors size/mass.

On relatively flat terrain, a small light weight lower power motor (e.g. 250W) is probably very adequate by offering pedal assist without overheating. If your demands are higher, you need a motor that has greater thermal mass to dissipate the excess heat that will be produced. I know that Rick will extol the thermal advantages of the Grin all axle motor, and to many extents he is correct, however, it still weighs around 9 lbs.

Looking at the Swytch set up, it is a physically small motor. For the demands that we put on our e-set up, this motor a way too small. It may be just fine for lighter team and relatively flat rides, but not for heavier team and hilly terrain, it is way undersized.

The smaller mass motors can overheat and burn up under load in the matter of a few minutes. A larger mass motor can last longer. It all depends on the load profile demanded of the motor. Taken together, the motor, battery, and controller can be engineered to achieve some desired performance behavior while also protecting the motor from overheating. All of this is good, however, if your controller rolls back the power to the motor to protect it just when you need it the most, you have lost a large part of the benefit you were counting on the motor to provide.

You can get a better understanding of motor power from this article https://ebikes.ca/learn/power-ratings.html . The further into the article you read, the deeper into the weeds you get, but the first few paragraphs are a good introduction.

One thing to keep in mind: The bicycle hub motors, controllers, and battery packs are all engineered for a single bike/single rider. By their very design, they are undersized for application on a tandem. Depending on the system make up and intended usage, that limitation may manifest itself in different ways: Limited range, rapid overheating/power roll back, slower acceleration, or excess weight. I know that not everyone is able to engineer their own system and have to rely on the marketing promises of the vendor, and that is fine for many people. I would hope that as ebikes become more mainstream, the industry will harmonize on meaningful rating and comparison metrics to allow for better choice options for the consumer.

Artmo 

I agree with you about the apparent misery with the ordering system for Swytch, but you are wrong about 250W on a tandem. As I’ve probably mentioned elsewhere, we bought our Cytronex system to enable us oldies (162 years combined) to keep up with our group at 16-18 mph for 20-25 miles and it does the job even on the lowest power setting which is about 80W. I almost never use max or even medium power ..........but we do live in Florida. It never ceases to amaze me how much that 80W boost gives when needed.
When I see people mention here about 750 and even 1000W I wonder why they don’t buy a motorcycle! How big are the batteries?? To me, more important than power is battery capacity and, therefore, range, and transportability. The Cytronex C1 has 180Wh battery capacity, is so neat, and simple to fit and does exactly what it is designed to do. For transport, I simply remove the front wheel and put the very light tandem inside our BMW 535i GT. For longer rides, we carry the rapid charger and top up at coffee stops.
in the UK we have a Circe Helios with Shimano STEPS motor, which provides 250W with 408Wh capacity. That tandem is about twice as heavy as our Macchiato with Cytronex and the range is only slightly greater.
Please don’t dismiss 250W without having experienced it, although, in your case, it seems as though you have a very heavy tandem to begin with.

Rick

Even though top racers can physically push around 400watts for short periods of time during a race. The average person rides with about 80watts. So if you are using the hub motor for an assist than in most cases 250watts can be enough. If you are riding up a steep grade In very hot weather then not so much. I live in the high dessert and there is a girl with a proclaimed 750 watt assist with a throttle. She has to stop at a local park for the motor to cool down. She doesn't like to pedal. I watched some YouTube videos of the sun race for bicycles. It is held once a year. They use solar panels and are only allowed up to a certain battery capacity. The English guy that came in forth place had four 75watt solar panels and used a BBSHD mid drive motor. This motor can handle allot of watts. He set it up with an aftermarket control system by Grin and ran it at mostly 200watts. Motors heat up at slower speeds and if he had used the 750watt version of the motor that is 3 pounds lighter he might not have finished the race. I plan on doing this with a Yuba Mundo. I will haul grocery's and haul my touring bicycle to the start of far away rides. Limiting the watts will allow it to still be a pedal bike and the heaver motor will handle heat better.

kayakindude

A lot of good feedback on motors and wattage. It makes asking the OP what kind of rider they are and type of terrain pertinent.

On indoor rides I'm an average 220 watts and the wife 95 watts, so maybe that's why a 250 motor is adequate for us? I definitely don't need assist when riding solo and don't track watts outside. Also up in coastal New England so overheating would rarely be an issue.