MAC motor worth it?

[Manbeer]

Back and forth between a 6t Mac or gng 3kw mid drive for the wifes super 73. 30mph consistently seems good, would like to be able to hit 40 or so for like a min or two just to hang with traffic on main st rather than on the sides when people sometimes park sticking out too far, etc

Am i correct in thinking 6t would be the correct choice for this on a 20x4 on 60v? alternatively i could do an 8t @
72v which looks like i should be able to get about 36-37 out of

 

[Chalo]

It's a bad idea to use a mid drive for a Super 73 or any other unpedalable bike. You'd be getting all the shortcomings without the main benefits. Any motor powerful enough to go 40 mph will wreck bike gears quickly and regularly anyway.

 

[Bullfrog]

Can anyone tell me what the function of the six embedded magnets is and can I use an older hub that doesn't have the magnets with a newer MAC motor that came with a hub that had the magnets?

The 6 magnets rotate past the speed (hall) sensor on the PCB. Mine has the indents but no magnets or sensor.
I'm not 100% sure, but I imagine you can swap shells so long as the axle fits thru the bearing.

Thanks colsaunders2. Just FYI, also got the same answer you provided from Grin Tech.

Mounted the new 10T motor in an old hub that does not have the embedded magnets and so far everything is working OK. Running a Schwalbe Super Moto-X 27.5x2.8 tire and plan to charge my battery to 58.8v later today and see what I get for a top speed on flat ground. I am hoping for about 29 mph with the battery at 100%.

 

[Bullfrog]

Back and forth between a 6t Mac or gng 3kw mid drive for the wifes super 73. 30mph consistently seems good, would like to be able to hit 40 or so for like a min or two just to hang with traffic on main st rather than on the sides when people sometimes park sticking out too far, etc

Am i correct in thinking 6t would be the correct choice for this on a 20x4 on 60v? alternatively i could do an 8t @
72v which looks like i should be able to get about 36-37 out of

If you want to do 40 mph, your best option is a Direct Drive motor. Something like a QS205.

A MAC will over heat if you run 40 mph for extended periods of time and a mid drive will wear chain/sprockets quickly.

Use the Grin Tech Motor Simulator and use a 2% grade with the appropriate rider weight and aerodynamic drag to see what the MAC motor temps will do. Stay below 140C with 2% and you should be OK. I ride where it is pretty flat and 2% matches the real world temperatures I see pretty good.

Are you trying to get rid of your wife :lol: ? 40 mph on a Super 73 is going to be scary and dangerous. Keep it below 30 mph and use an 8T MAC for a small wheel or a 10T MAC in a larger wheel with a 14s/52v battery and you might be OK.

 

[Manbeer]

Back and forth between a 6t Mac or gng 3kw mid drive for the wifes super 73. 30mph consistently seems good, would like to be able to hit 40 or so for like a min or two just to hang with traffic on main st rather than on the sides when people sometimes park sticking out too far, etc

Am i correct in thinking 6t would be the correct choice for this on a 20x4 on 60v? alternatively i could do an 8t @
72v which looks like i should be able to get about 36-37 out of

If you want to do 40 mph, your best option is a Direct Drive motor. Something like a QS205.

A MAC will over heat if you run 40 mph for extended periods of time and a mid drive will wear chain/sprockets quickly.

Use the Grin Tech Motor Simulator and use a 2% grade with the appropriate rider weight and aerodynamic drag to see what the MAC motor temps will do. Stay below 140C with 2% and you should be OK. I ride where it is pretty flat and 2% matches the real world temperatures I see pretty good.

Are you trying to get rid of your wife :lol: ? 40 mph on a Super 73 is going to be scary and dangerous. Keep it below 30 mph and use an 8T MAC for a small wheel or a 10T MAC in a larger wheel with a 14s/52v battery and you might be OK.

Lol, Weird as it sounds possibly because I am so low to the ground it feels so much slower going the same speed's as my 27.5 inch hardtail. Already have upgraded to 48v From stock 36 V set up. it can Cruise pretty consistently around 30, And that's perfectly fine. It's pretty much just for short distances of a mile or so a along main streets Where people parallel park I'd like the ability to go with the traffic rather than next to it. So 40 would likely only be used for a minute or two. Not wanting to go direct drive as I prefer the lighter weight of a geared setup That's capable of what im going 98% of the time.

Plus, I liked her so much I just got one for myself. The scramblers keep multiplying here

It's a bad idea to use a mid drive for a Super 73 or any other unpedalable bike. You'd be getting all the shortcomings without the main benefits. Any motor powerful enough to go 40 mph will wreck bike gears quickly and regularly anyway.

I was actually thinking of going with a three speed internal gear hub just to keep the motor in the happy and efficient range. This way I can gear it for say, 20mph in 1st, 30 in 2nd or whatever And basically have an overdrive for the few rare instances I do want to bump up the speed (Or whatever the ratios are on the RK3, can't remember)

 

[donn]

It's a bad idea to use a mid drive for a Super 73 or any other unpedalable bike. You'd be getting all the shortcomings without the main benefits. Any motor powerful enough to go 40 mph will wreck bike gears quickly and regularly anyway.

Electric motorcycles use mid drives, am I right? Typical bicycle version piggybacks on the cranks, but of course not on a motorcycle and not necessarily on a bicycle either? Do the putative bicycle versions have multiple gears, or does the motor connect directly to the left side of the hub?

 

[Bullfrog]

Back and forth between a 6t Mac or gng 3kw mid drive for the wifes super 73. 30mph consistently seems good, would like to be able to hit 40 or so for like a min or two just to hang with traffic on main st rather than on the sides when people sometimes park sticking out too far, etc

Am i correct in thinking 6t would be the correct choice for this on a 20x4 on 60v? alternatively i could do an 8t @
72v which looks like i should be able to get about 36-37 out of

If you want to do 40 mph, your best option is a Direct Drive motor. Something like a QS205.

A MAC will over heat if you run 40 mph for extended periods of time and a mid drive will wear chain/sprockets quickly.

Use the Grin Tech Motor Simulator and use a 2% grade with the appropriate rider weight and aerodynamic drag to see what the MAC motor temps will do. Stay below 140C with 2% and you should be OK. I ride where it is pretty flat and 2% matches the real world temperatures I see pretty good.

Are you trying to get rid of your wife :lol: ? 40 mph on a Super 73 is going to be scary and dangerous. Keep it below 30 mph and use an 8T MAC for a small wheel or a 10T MAC in a larger wheel with a 14s/52v battery and you might be OK.

Lol, Weird as it sounds possibly because I am so low to the ground it feels so much slower going the same speed's as my 27.5 inch hardtail. Already have upgraded to 48v From stock 36 V set up. it can Cruise pretty consistently around 30, And that's perfectly fine. It's pretty much just for short distances of a mile or so a along main streets Where people parallel park I'd like the ability to go with the traffic rather than next to it. So 40 would likely only be used for a minute or two. Not wanting to go direct drive as I prefer the lighter weight of a geared setup That's capable of what im going 98% of the time.

Plus, I liked her so much I just got one for myself. The scramblers keep multiplying here

It's a bad idea to use a mid drive for a Super 73 or any other unpedalable bike. You'd be getting all the shortcomings without the main benefits. Any motor powerful enough to go 40 mph will wreck bike gears quickly and regularly anyway.

I was actually thinking of going with a three speed internal gear hub just to keep the motor in the happy and efficient range. This way I can gear it for say, 20mph in 1st, 30 in 2nd or whatever And basically have an overdrive for the few rare instances I do want to bump up the speed (Or whatever the ratios are on the RK3, can't remember)

I agree with you completely on the lightweight and small size of the MAC/GMAC plus you can get higher acceleration per amp than any motor currently available. You can also run a lot of power to a MAC for short periods of time without over heating...just don't do it for very long. The Grin Tech Motor Simulator will give you a good idea how long it will take to over heat.

 

[Chalo]

It's a bad idea to use a mid drive for a Super 73 or any other unpedalable bike. You'd be getting all the shortcomings without the main benefits. Any motor powerful enough to go 40 mph will wreck bike gears quickly and regularly anyway.

I was actually thinking of going with a three speed internal gear hub just to keep the motor in the happy and efficient range. This way I can gear it for say, 20mph in 1st, 30 in 2nd or whatever

If you have enough motor power for 40mph, you will lunch a 3 speed hub even faster than you'd waste derailleur gears. When geared and maintained appropriately, they are reliable for the amount of power that one person can make with pedals.

Most of them are spaced about 116mm anyway. There's a 135mm Shimano Nexus 3 with a disc mount, and there's a 170mm Sturmey Archer hub for fat tire bikes. I wouldn't bet on being able to find either one right now.

 

[Manbeer]

According to the simulator, if I can give it 72 V it will give more than I would even want from it. Hopefully I don't shit the bed for torque going with a 6t But I put in an inquiry on Alibaba.

and Chalo- Yes it was the sturmey archer i was looking at. One of those guys affiliated with Luna at one point had done a review on it and said it seems to handle the power of the mid drives fairly well. To be honest, the primary purpose was to have some sort of overdrive for the times I need to speed it up a bit and something geared down For those times when I'm taking it easy going home with a fairly flat battery and I'd rather keep the motor spinning than load it too hard

Anyway, if the pricing on Alibaba is pretty close to accurate the sample will be a bargain and I can transfer from one bike to the other if I decide I want to go to a different route. Probably going to go with a 72v 50a KT controller as i already have an lcd8 on the one bike

 

[The Toecutter]

The Sturmey-Archer 3-speed is perhaps the most robust IGH you will find. If it can't handle your proposed power output, there's likely nothing on the market that will. A Rolhoff is probably almost as strong, with a very wide gear range, much higher price tag, and more maintenance requirements, and I wouldn't trust it to handle the 2 kW or so it would take to bring that bike to 40 mph.

Oddly enough, there IS a 6 kW mid-drive powered KMX trike out there running a 10-speed cassette and a derailleur, but the operator has to keep the pedal cadence at ~140 rpm to keep from destroying the $250 chain he bought to handle the mid drive as well as to prevent destruction of the mechanicals in the rear. He keeps torque down and rpm high to pull it off, and has placed more than 10,000 miles on that system without breakage. He also cleaned the chain after EVERY ride. He's taken it to 65 mph a few times.

 

[Manbeer]

The Sturmey-Archer 3-speed is perhaps the most robust IGH you will find. If it can't handle your proposed power output, there's likely nothing on the market that will. A Rolhoff is probably almost as strong, with a very wide gear range, much higher price tag, and more maintenance requirements, and I wouldn't trust it to handle the 2 kW or so it would take to bring that bike to 40 mph.

Oddly enough, there IS a 6 kW mid-drive powered KMX trike out there running a 10-speed cassette and a derailleur, but the operator has to keep the pedal cadence at ~140 rpm to keep from destroying the $250 chain he bought to handle the mid drive as well as to prevent destruction of the mechanicals in the rear. He keeps torque down and rpm high to pull it off, and has placed more than 10,000 miles on that system without breakage. He also cleaned the chain after EVERY ride. He's taken it to 65 mph a few times.

I actually considered having a custom dropout/derailleur hanger made. In theory anyway, even some thing like a seven speed 11 to 28 would be more than adequate For my purpose since the wheels are small and the terrain is pretty flat anyway so I'm not trying to lug 29x2.5s up a slope or anything. The problem is most of the decent hubs I see for fat bikes Have 32 holes, then most of these little fat bikes and hub motors have 36, and I don't really see many rims for inch flat tire in 32- Otherwise I would build up a wheelset with some hopes or dt swiss.

Figuring I can get the mac for something like 300 all in, I will build up a wheel with it and see if it suits my purposes, which I think it will.

Is anyone who has done the sample order familiar with what typical shipping rates are?

 

[Bullfrog]

According to the simulator, if I can give it 72 V it will give more than I would even want from it. Hopefully I don't shit the bed for torque going with a 6t But I put in an inquiry on Alibaba.

and Chalo- Yes it was the sturmey archer i was looking at. One of those guys affiliated with Luna at one point had done a review on it and said it seems to handle the power of the mid drives fairly well. To be honest, the primary purpose was to have some sort of overdrive for the times I need to speed it up a bit and something geared down For those times when I'm taking it easy going home with a fairly flat battery and I'd rather keep the motor spinning than load it too hard

Anyway, if the pricing on Alibaba is pretty close to accurate the sample will be a bargain and I can transfer from one bike to the other if I decide I want to go to a different route. Probably going to go with a 72v 50a KT controller as i already have an lcd8 on the one bike

2EDFD386-1514-422C-A736-B49079E18640.jpeg

When I run your set up in the Grin Tech Motor Simulator, I get 172C in 16 minutes assuming 0% incline, 72v, 50A battery, Mt Bike Upright drag, and no energy from the rider (no pedaling). That is way too hot for a MAC. So make sure you have the capability to monitor the motor temperature...you can run a MAC at 140C all day but I wouldn't go much higher.

Remember you need to use the overall diameter of your tire...the bead seat diameter on a 20" tire is 406mm and a 4" tire adds 100mm per side so the total OD is about 606mm.

A 6T MAC and a 12T MAC will put out the same torque per battery amp for all practical purposes...one is not a "torque" motor or a "speed" motor. To the first order, the torque is a function of the stator diameter/width, the number of poles...and of course the supplied battery amperage. Or to put it very simply, the physical size of the motor.

 

[Bullfrog]

Chalo posted some VERY good info on 3 speed hubs...I agree with him but I'd put it more simply: if you are going to push a lot of torque through one, they will break. Plus the only manufacturer that still produces a 3 speed IGH is Sturmey Archer. Shimano, SRAM, and everybody else has stopped making them because they are too expensive and less capable when compared to a freewheel/cassette.

A Rohloff hub is one of the more capable hubs as far as the torque it can transmit without breaking but WHY even use anything but a single speed? The max torque an electric motor can produce is at zero rpms...so it is perfectly designed to get you moving and then the power required drops as you go faster until you reach the synchronous speed of the motor. All of my mid drive ebikes (I have four) are single speed. I use a Surly Singleator chain tensioner and I gear them so I get the desired top speed.

 

[Chalo]

All of my mid drive ebikes (I have four) are single speed.

Why do that to a chain drive when you get the same results from a hub motor-- with better reliability, less wear, and greater fault tolerance?

 

[Bullfrog]

All of my mid drive ebikes (I have four) are single speed.

Why do that to a chain drive when you get the same results from a hub motor-- with better reliability, less wear, and greater fault tolerance?

The mid drives are BBSHD powered and used off road.

My road bike is powered by a 10T MAC.

The MAC over heats when used off road at low speeds with repeated full throttle acceleration. Only way to change the gearing for a MAC or a Direct Drive motor is to change the diameter of the wheel and even a 20" wheel was not enough.

 

[Manbeer]

According to the simulator, if I can give it 72 V it will give more than I would even want from it. Hopefully I don't shit the bed for torque going with a 6t But I put in an inquiry on Alibaba.

and Chalo- Yes it was the sturmey archer i was looking at. One of those guys affiliated with Luna at one point had done a review on it and said it seems to handle the power of the mid drives fairly well. To be honest, the primary purpose was to have some sort of overdrive for the times I need to speed it up a bit and something geared down For those times when I'm taking it easy going home with a fairly flat battery and I'd rather keep the motor spinning than load it too hard

Anyway, if the pricing on Alibaba is pretty close to accurate the sample will be a bargain and I can transfer from one bike to the other if I decide I want to go to a different route. Probably going to go with a 72v 50a KT controller as i already have an lcd8 on the one bike

2EDFD386-1514-422C-A736-B49079E18640.jpeg

When I run your set up in the Grin Tech Motor Simulator, I get 172C in 16 minutes assuming 0% incline, 72v, 50A battery, Mt Bike Upright drag, and no energy from the rider (no pedaling). That is way too hot for a MAC. So make sure you have the capability to monitor the motor temperature...you can run a MAC at 140C all day but I wouldn't go much higher.

Remember you need to use the overall diameter of your tire...the bead seat diameter on a 20" tire is 406mm and a 4" tire adds 100mm per side so the total OD is about 606mm.

A 6T MAC and a 12T MAC will put out the same torque per battery amp for all practical purposes...one is not a "torque" motor or a "speed" motor. To the first order, the torque is a function of the stator diameter/width, the number of poles...and of course the supplied battery amperage. Or to put it very simply, the physical size of the motor.

I ran the calculator as well, but for the speeds where it would reach those temperatures I would only be using for it most the moment or two. If I back down to the 30 mph cruising range or even 35 it comes up as overheat never.

The problem is speed is addictive. I know how it is when it's capable of going faster- you think you will rarely be making use of those speeds and before you know it you're cruising at full clip and wanting more.

Fortunately, or unfortunately… Power usage goes up like crazy at those speeds. The only places I could really open it up for long are far enough away we are I'd already be somewhat down on battery getting there and have to keep an eye it getting back. So pretty much cruising at moderate speeds most of the time, with the capability of throwing it into hooligan mode for a mile or two along the way

What's interesting is that the motor on the bike pretty well replicates the characteristics of the 6t mac on the calculator in the real world.
Apparently they use some sort of crappy knock off hengtai or something but people are throwing 3000 W at them. Makes me question if I should do the battery and controller upgrade first and see how long this thing holds up

 

[Bullfrog]

Maximum amperage for a MAC...well I have been hitting mine with 60A battery and 180A phase for a couple years now without any problems i.e. no clutch problems and no gear problems. I really like the acceleration the MAC provides since it will accelerate faster than ANY ebike motor assuming you supply the same battery amperage. I use a 14s6p 52v battery with -25R cells so the 60A is not a problem for the battery and my limitation is the BMS which won't go over 60A without flipping a circuit breaker.

Steady state you can't run a MAC at more than about 1,000 watts for long periods of time or about 2,600 watts for 5 minutes: https://ebikes.ca/product-info/grin-kits/gmac.html. From the time I start until the motor temperature stabilizes, it takes me about 30 minutes so I can exceed the "2,600 watts" during the first 30 minutes without worrying.

Maximum temperature...I have my CA set to roll back the temperature if I exceed 140C and to shut down the motor if I reach 150C. Only issue is once you exceed about 135C, the resistance of the windings goes up and the temperature rise can be pretty quick if you aren't careful but I regularly run my MAC at 140C for hours on end and have no damage as a result.

The best set up with a MAC IMO is a 10T motor in a 26" or a 27.5" wheel running a 52v battery and a controller capable of 40-50A battery and 140-180A phase current. Going over about 50A battery doesn't do much for you since magnetic saturation begins to occur and you don't do much more than produce heat. That gives you good acceleration, a top speed of 30-32 mph, and little worry about over heating.

Thanks to Justin at Grin Tech for helping me find the limits of a MAC and my experiments have matched his findings on the dyno as well as his advice.

 

[Kajman]

Anyone had chance to compare MAC10T to Mxus XF19r?

 

[kudos]

The best set up with a MAC IMO is a 10T motor in a 26"

This is exactly the setup I use and I agree.

I wish I could purchase more Mac motors with controllers, any one have any leads it would be much appreciated. I went straight to MacMotorTech but comms with them is awful and I haven't been able to progress an order.

 

[Kajman]

What speed on what voltage/amps do you have with 10T? How loud is it?

 

[kudos]

I use 14S so 58.8V hot off charger, 40A controller, I get around 31mph.

Motor noise is minimal, you don't hear anything once you get going anyway.

 

[Bullfrog]

What speed on what voltage/amps do you have with 10T? How loud is it?

I am running a 10T MAC on a 14s battery i.e. 58.8v fully charged and my controller is set for 55A battery amperage max...I get about 30 mph and the amperage is fairly low once I get rolling.

Just FYI, the MAC will accelerate quicker than ANY motor in the drop down menu of the Grin Tech Motor Simulator assuming you feed both motors equal battery amperage and your controller is not limiting the amperage to the motor.

You can buy directly from the factory and you can buy one motor if it is your first time. They also sell the 12 and 18 FET controllers. After your first order you have to buy eight pieces minimum on your second order.

 

[kudos]

Hey bullfrog, are you using the new 18fet controller from Mac?

If not what controller are you using to feed the 55A ?

 

[Triketech]

Maximum amperage for a MAC...well I have been hitting mine with 60A battery and 180A phase for a couple years now without any problems i.e. no clutch problems and no gear problems. I really like the acceleration the MAC provides since it will accelerate faster than ANY ebike motor assuming you supply the same battery amperage. I use a 14s6p 52v battery with -25R cells so the 60A is not a problem for the battery and my limitation is the BMS which won't go over 60A without flipping a circuit breaker.

Steady state you can't run a MAC at more than about 1,000 watts for long periods of time or about 2,600 watts for 5 minutes: https://ebikes.ca/product-info/grin-kits/gmac.html. From the time I start until the motor temperature stabilizes, it takes me about 30 minutes so I can exceed the "2,600 watts" during the first 30 minutes without worrying.

Maximum temperature...I have my CA set to roll back the temperature if I exceed 140C and to shut down the motor if I reach 150C. Only issue is once you exceed about 135C, the resistance of the windings goes up and the temperature rise can be pretty quick if you aren't careful but I regularly run my MAC at 140C for hours on end and have no damage as a result.

The best set up with a MAC IMO is a 10T motor in a 26" or a 27.5" wheel running a 52v battery and a controller capable of 40-50A battery and 140-180A phase current. Going over about 50A battery doesn't do much for you since magnetic saturation begins to occur and you don't do much more than produce heat. That gives you good acceleration, a top speed of 30-32 mph, and little worry about over heating.

Thanks to Justin at Grin Tech for helping me find the limits of a MAC and my experiments have matched his findings on the dyno as well as his advice.

That is very close to my experiences with the early Gen 2 MAC 10T I have from late 2016, it's on a Scorpion FS26 trike with one of the earlier Phaserunners, I think 2nd production batch. Previously ran with a Gen 1 MAC 12T. About 7500+ miles to date, no problems other than a battery replacement.

Originally 50A, than 40A, and now run 30A Battery Limit to prolong battery life anymore and most of my riding involves long steep hills on paved roads averaging 10-15 WH/Mile, typically about 15 MPH average rolling speed. It gets hot in the desert so early morning rides with a 15 MPH breeze keeps me dry, yet I still get a good 160 BPM workout.

As a MAC not GMAC, it has the clutch & gears. At 5000 miles the gears & clutch were inspected with well over 50% life remaining.
It's just an incredibly well designed motor. While I prefer the freewheeling component for the human only experience, the GMAC is a better layout for mounting and connecting.

This is from 6 years ago when the MAC was new, later battery upgrade not shown. I ride it daily about 10 miles.
http://www.triketech.com/Drivetrain/PowerAssist/HPV-MAC-V2.html

 

[Kajman]

I just bought 10T, it will replace my Mxus XF19r, interesting which one will be stronger