MAC motor + Trek 4300 build

[neptronix]

Ah, too bad you had no time to visit. It's lonely out here in Utah, I have lived here for 8 months and despite really hunting, never found anyone who's interested in building EVs :\

I miss Portland because i could go to an EV meetup every month and see forum members there..

Yeah, some parts of Salt Lake City are really bikeable. Long stretches of bike lanes plus bike path that goes all the way from the north end of the state to Provo ( ~100 miles ). Only problem is the bugs in the northern half. Time for a velomobile..

 

[John Bozi]

cool beans.

Probably due to the geometry of my bike, i don't have that problem on my Treks. I can fit a 60T on the suckers and it doesn't interfere with the falconEV bag either ( but it's a close call )

^-- my Trek 4300

I am interested in your chainring, do you have any guides, does the chain fall off?, what did you buy to get that set up... What's the actual diameter of 60t - Id like to measure to see if it would even fit on my bike because of the swiingarm.

I can't see quite clearly but I am guessing you have no front or rear shifters installed. I imagine if you were ever in trouble where the electrics stopped you could just use your hand to change into a smaller cog at the back.

Unfortunately I have a 4 bolt 3 chainrings at the front of mine and dream of having your set up... so I guess I will have to get a whole new crankset - is that right?

thanks

 

[neptronix]

Chain never falls off, you just nee the right tension on it and you won't have problems.
It's a vueltausa chainring, not hard to find
Diameter is crazy and you will have to get a wide bottom bracket to support it and rely on maybe 2-3 gears tops because the chain angle will be wonky otherwise. Show me a pic of your swingarm and i may be able to tell you if it is even possible and give you a measurement.

I did not have any shifters.. why bother if the electrics quit, i'm boned. But that's how you get a setup to pedal at ~35mph on a 20" wheel - you have to compromise.

There's another thread for that bike in my sig.

I am interested in your chainring, do you have any guides, does the chain fall off?, what did you buy to get that set up... What's the actual diameter of 60t - Id like to measure to see if it would even fit on my bike because of the swiingarm.

I can't see quite clearly but I am guessing you have no front or rear shifters installed. I imagine if you were ever in trouble where the electrics stopped you could just use your hand to change into a smaller cog at the back.

Unfortunately I have a 4 bolt 3 chainrings at the front of mine and dream of having your set up... so I guess I will have to get a whole new crankset - is that right?

thanks

 

[John Bozi]

thanks, for the info I had look through your build for that bike thanks, I will keep this all for reference for a future bike - I really dont want to change more than a chainring because I build was a full brand new bike.

NEXT TIME I WILL BUILD MY BIKE FROM A FRAME UP!

 

[gensem]

Neptronix,

What temperature do think its safe to keep the motor alive? Like 150c celcius?

 

[neptronix]

150c and it's ready to cook, i am sure. Most motors can't tolerate that so well O_O

I wish i knew. I never put a temp sensor in the motor. What i know is that if you ever manage to get the side covers hot, you've either demagnetized it already, or you are just about to.

 

[cal3thousand]

Hall sensors are at risk at about 120 Celsius

 

[gensem]

150c and it's ready to cook, i am sure. Most motors can't tolerate that so well O_O

I wish i knew. I never put a temp sensor in the motor. What i know is that if you ever manage to get the side covers hot, you've either demagnetized it already, or you are just about to.

I see.. mine came with the sensor (thanks Paul). I did ask because Its not that hard to get the temp sensor to 120c

 

[neptronix]

Yeah, the MACs have great power output, but suck at dissipating the heat. Same with any geared motor. Pretty unfortunate.

I just run mine at 36v these days since mine's an ol' dog from seeing so much abuse

 

[Ringmaster]

Hello, I think this is my first post here .

I see nice ideas here (good bikes!) , but I don't like using foam to absorb shocks, it doen't help to remove the heat.

I preferred to use aluminum profiles for holding the batteries on the center; the bicycle this way is very well gravity-centered, and more robust, and the water and heat are not a problem:

http://crecimiento-sostenible.blogspot.com.es/2014/10/diy-turn-your-bike-into-ebike-with-kit-Preparing-box.html

Is basically an 8 years old BH bike with a 10s9p li-ion pack (18Ah 36V) from old laptop batteries and a prokit 901 from GoldenMotor. I am very sattisfied with smooth riding, power to help climbing, duration (between 30-50 kms depending on demand).
To avoid the most punctures on the rear wheel, I used fundax leather protector bands (excuse my english level, I'm spanish).

http://crecimiento-sostenible.blogspot.com.es/2014/11/avoiding-punctures-on-bike-leather.html

Cheers,

Ringmaster

 

[The Toecutter]

I've read through most of this topic and still have a few unanswered questions for those here who have abused their MAC motors.

Is cell_man still the go-to guy for these motors to get them into the U.S. or are better options available? I'd prefer a MAC8T integrated into a double-walled 26" rim with 14ga spokes, and it needs to be strong enough to be "bulletproof" for long trips.

How many miles of use did you get out of the MAC motors before they needed repair/replacement? How long do the new composite clutches/gears last under the abuse you have put them through?

What I've got in mind:

I am planning to put together an electric-assist tadpole-layout velomobile using a PAS and THUN torque-sensing bottom bracket with Cycle Analyst v3. I currently have a KMX frame with adam333's front suspension kit. There is no rear suspension, but most of the mass will be over the front axle line anyway. The rear wheel is 26" and I have a Schwalbe Marathon Plus on it. Fully laden weight with myself plus clothing/tools/food/water/camping gear is expected to be 300 lbs, and I expect my first body shell to have a CdA of around 1.5 ft^2. The velomobile itself will weigh no more than 100 lbs.

I want it to be able to operate on pedal-only mode if the battery runs dead, and I will also have a thumb switch for a throttle, limited to 20 mph, in case I break the chain. This will minimize the risk of ever being left stranded due to any motor/drivetrain component failure. I'm looking at perhaps 300W at the rear wheel to cruise at 30 mph on the flat with a pedal cadence of 90, with a top end of 40 mph or so at 120 cadence. I have in mind setting a MAC8T up with a Sunrace 9sp 11-40T gear cluster in the rear with a single 46T cog up front and running the motor/controller at 60V/40A.

The idea is to have a wide enough gearing range that with the motor off, I could still pedal it up fairly steep hills at ~5 mph, and with the motor on, cruise at 30 mph at a comfortable cadence with 100-150W pedal output with the motor doing the rest(maybe 250-300W electrical input), and top out at 40 mph. Best of all, it will be 100% legal as an electric "bicycle" in the state that I reside under this setup, and in states where it is not legal, the motor will be hidden by both the sprocket set and a rear disc brake and I can fully disengage the clutch and pedal it like a normal "bicycle" when needed, and still probably reach the same 40 mph top speed on the flat with no electric assist while pedaling my ass off.

I think the MAC motor will work for this application.

Theoretically I could accelerate from 0-30 mph in about 6.5 seconds pedaling with 500W and letting the motor throw in the rest being fed 2.4 kW from the controller, with the max primary current as well as the phase current both set at 40A(so as not to damage the clutch or gears on launch). This acceleration would match some of the slowest automobiles on the road, and while I would like more acceleration than that, I still do value reliability over performance.

Maybe one day I'll have to try to re-design this motor to get what I want out of it(5+ kW peak on a regular basis without damage would be nice), but that's not even going to be a possibility unless/until I make the purchase and do some testing of my own. I'm tempted to plunk down $1200 for a LightningRod's middrive for trikes along with $1500 for a Rohloff 500/14 internal gear hub instead, but this MAC8T would allow me to avoid most of that expense/headache for now while allowing this vehicle to be a practical form of transportation with a lot less components to break.

Think the MAC is a good choice for my application?

 

[ScooterMan101]

Toecutter,
You have so many questions, I can only answer a few.

I had 700 miles on my 2013 Mac 6T on a 27.5 inch wheel at 48 volts, running at 22 amps before it needed work, and that is , Only , because I road up a steep mountain that was dirt and gravel on the steepest last 1.6 or so miles of it.
It over heated, but did I did seem like it did since when it stopped I got off and felt the motor and it did not feel hot.
I thought I stripped the gears, or the clutch , but after a couple of months I did some tests and found out that one of the Hall Sensors was not working. ( I had melted the solder of that one Hall Sensor )
I got it repaired and am riding and loving it now .
So Gears not a problem, clutch not a problem, just over heated the solder .

The likely hood of you doing the same thing is much less now Because ...

The new Mac Motor has a white wire that is a temp sensor, and when hooked up to a Cycle Analyst V3 , through a Infineon Controller, the vendor that sells you the C.A. V3 can adjust it to shut off the motor before it over heats ( not on C.A. V2.3 model ) just the V3 one .
So now you have a , almost , bullet proof Hub Motor when the Three Parts are used together. You still should be careful if you go up long and or long and steep hills, if so get the 12 t or 10 t for more speed.
With the New Mac motor you can also spend $ 30 more and get the one that accepts cassettes .

I have a smaller motor, but have gone back to riding the Mac, for more speed, and less stress , on the smaller motor I am always pushing it to its limits, on the Mac there is plenty of spare power .
Mac's are said to be able to handle 1200-1500 watts for long periods.
Not much cogging / resistance when not under power and just using leg power, however heaver weight of a motor/battery etc is not much fun.
I can and often run the Mac on just a few hundred watts as well to get longer range.
* Note , if you get a Mac Motor that accepts the older freewheel then you could be getting a previous version Mac with, No , white temp sensor wire , get the New Mac that accepts a cassette to get the white temp sensor wire *
Mac motor, Infineon 12 fet controller, Cycle Analyst V.3 . Good Battery able to handle 25 + amps.

I've read through most of this topic and still have a few unanswered questions for those here who have abused their MAC motors.

Is cell_man still the go-to guy for these motors to get them into the U.S. or are better options available? I'd prefer a MAC8T integrated into a double-walled 26" rim with 14ga spokes, and it needs to be strong enough to be "bulletproof" for long trips.

How many miles of use did you get out of the MAC motors before they needed repair/replacement? How long do the new composite clutches/gears last under the abuse you have put them through?

What I've got in mind:

I am planning to put together an electric-assist tadpole-layout velomobile using a PAS and THUN torque-sensing bottom bracket with Cycle Analyst v3. I currently have a KMX frame with adam333's front suspension kit. There is no rear suspension, but most of the mass will be over the front axle line anyway. The rear wheel is 26" and I have a Schwalbe Marathon Plus on it. Fully laden weight with myself plus clothing/tools/food/water/camping gear is expected to be 300 lbs, and I expect my first body shell to have a CdA of around 1.5 ft^2. The velomobile itself will weigh no more than 100 lbs.

I want it to be able to operate on pedal-only mode if the battery runs dead, and I will also have a thumb switch for a throttle, limited to 20 mph, in case I break the chain. This will minimize the risk of ever being left stranded due to any motor/drivetrain component failure. I'm looking at perhaps 300W at the rear wheel to cruise at 30 mph on the flat with a pedal cadence of 90, with a top end of 40 mph or so at 120 cadence. I have in mind setting a MAC8T up with a Sunrace 9sp 11-40T gear cluster in the rear with a single 46T cog up front and running the motor/controller at 60V/40A.

The idea is to have a wide enough gearing range that with the motor off, I could still pedal it up fairly steep hills at ~5 mph, and with the motor on, cruise at 30 mph at a comfortable cadence with 100-150W pedal output with the motor doing the rest(maybe 250-300W electrical input), and top out at 40 mph. Best of all, it will be 100% legal as an electric "bicycle" in the state that I reside under this setup, and in states where it is not legal, the motor will be hidden by both the sprocket set and a rear disc brake and I can fully disengage the clutch and pedal it like a normal "bicycle" when needed, and still probably reach the same 40 mph top speed on the flat with no electric assist while pedaling my ass off.

I think the MAC motor will work for this application.

Theoretically I could accelerate from 0-30 mph in about 6.5 seconds pedaling with 500W and letting the motor throw in the rest being fed 2.4 kW from the controller, with the max primary current as well as the phase current both set at 40A(so as not to damage the clutch or gears on launch). This acceleration would match some of the slowest automobiles on the road, and while I would like more acceleration than that, I still do value reliability over performance.

Maybe one day I'll have to try to re-design this motor to get what I want out of it(5+ kW peak on a regular basis without damage would be nice), but that's not even going to be a possibility unless/until I make the purchase and do some testing of my own. I'm tempted to plunk down $1200 for a LightningRod's middrive for trikes along with $1500 for a Rohloff 500/14 internal gear hub instead, but this MAC8T would allow me to avoid most of that expense/headache for now while allowing this vehicle to be a practical form of transportation with a lot less components to break.

Think the MAC is a good choice for my application?

 

[The Toecutter]

Here's more questions, in case anyone else has answers:

How about max torque/rpm before the gears/clutch become subject to a significant amount of wear?

Is fitting a rear disc brake rotor possible?

I am currently considering purchasing this motor within the next month or two. Maybe a MAC8T set up for 60V/35A would be a good idea. With a MAC12T, would 72V/25A be pushing it too hard? 72V/25A in a MAC12T would give a very similar torque vs rpm curve as a MAC8T at 60V/35A with a similar peak power output, but a higher efficiency in the preferred operating ranges, and it would be less stressed on hills.

Long distance cruising on the flat at 30-35 mph is really what I have in mind though. I just need to be able to handle the occasional 10%+ hill at lower speeds, even if it stretches on for miles. In a velomobile, it seems that this motor will be under-used except on hills or hard accelerations.

With a 26" wheel, I'm looking at 520 rpm to do 40 mph. In a velomobile with sufficient drag reduction, 40 mph can easily be maintained on < 750W, on flat ground or down hills. A significant fraction of that < 750W will be provided by the rider. I'm hoping that under that load and rpm, I can avoid damaging the gears/clutch. The rear of the trike lacking a suspension won't help things, so keeping the rear wheel out of potholes will be important.

Pushing the trike up hills is where this system will be at its most vulnerable. 1500W electrically input into the motor to yield ~1000W mechanical from the motor and 250W rider input would theoretically allow me to go up a 10% gradient at almost 20 mph if the total laden weight is 300 lbs with a 0.15 sq m CdA. At 66% efficiency, it would take 10 minutes to overheat. I would probably want a speed switch set up to vary the applied voltage for the terrain in order to reduce heat output, but it sounds like a very usable configuration, regardless of any attention to that detail.

 

[neptronix]

For your app where weight isn't super critical, i would go with the leafmotor 1500w, as it has all kinds of spare capacity to shed heat and produce power. The peak efficiency point ( ~90.5% ) of that motor is around 1000w continuous and you will be closer to that on a velomobile at 40mph than i am on my mountain bike ... and you'll have nice regen capabilities which are great on a velomobile which can tend to be heavier, and thus demand more braking power.

The MAC is a fantastic motor when low weight is desired, and is still the #1 hub after all these years for that application. I ran one of the older ones from 2011 that had thicker laminations and lower performance and was impressed as hell with it when i was 85lbs heavier and was using it to climb hills.

Okay, so the secret to MAC motor longevity, based on my experiences with the older 2011 model is this..

1) If you can feel heat on the outside, that stator is scorching on the inside and you need to give it less power. The MAC can dish out a lot of power but is famous for shedding heat poorly, like most gearmotors. The stator has a super poor thermal path and generally sheds heat through the axle. Excessive heat is what kills the halls and the gears for most people, based on what i've seen.

2) Clutches and gears get hurt by peak torque spikes the most. The MAC motor, due to it's high pole count, naturally has a crapton of low end torque.. moreso than other geared motors. When taking this motor to 1500W peak and beyond, it is useful to soften the low end torque by whatever means your controller has available. On infineon clone controllers ( em3ev, lyen, etc ), this means limiting the phase amp to battery amp ratio to 2.25:1 - 2.5:1.
Example: if you have your battery amps set to 40A, to get a 2.25:1 ratio, you want your phase amps set to 90A.

This phase amp to battery amp ratio essentially determines what your powerband looks like. The higher the ratio, the more peaky the initial torque is. If you go too low, like 2:1, you will have the motor choking and sputtering the second you hit the throttle because there is not enough torque in the low end.

Most controllers out there have a high phase amp to battery amp ratio, because their default tune is centered around getting a direct drive motor spinning from a stall. I would never trust the default tune of any controller if you are pushing above say, 1500w, because your initial torque is going to be way too high.

 

[The Toecutter]

Thanks for the info. Do you know of anyone who has fit a rear brake disc rotor to a MAC?

I like the leafmotor except for one problem: there is no way to mechanically decouple the motor from the rider input. I need to be able to operate this on pedal-only if my battery runs dead or if I'm in a different state where my electric "bicycle" is now considered a "moped" or "motorcycle". What are the cogging losses like on a leafmotor with no power input? Most of the larger hubmotors would lock up.

The MAC is also much easier to keep hidden.

Weight is somewhat critical to my application. I need to keep the total weight of the unladen vehicle with batteries and body at under 100 lbs. Fitting my 140 lb self plus 60 lbs of gear will bring the laden weight to 300 lbs. Every extra pound of motor is a pound of battery I won't have. The efficiency gain of a leafmotor over a MAC will negate this somewhat, but if the battery runs dead, I also do not want to be left stranded.

 

[neptronix]

Thanks for the info. Do you know of anyone who has fit a rear brake disc rotor to a MAC?

You can do it, but i think you need a larger rotor ( 203mm ) to clear the hub.. i am not sure if that statement applies to the newer style.

I like the leafmotor except for one problem: there is no way to mechanically decouple the motor from the rider input. I need to be able to operate this on pedal-only if my battery runs dead or if I'm in a different state where my electric "bicycle" is now considered a "moped" or "motorcycle". What are the cogging losses like on a leafmotor with no power input? Most of the larger hubmotors would lock up.

Read the leafmotor thread started by me. Cogging is very minimal for a DD due to the thin laminations. The permanent coupling and regeneration capability are the exact reasons i have that motor as my daily driver.

Weight is somewhat critical to my application. I need to keep the total weight of the unladen vehicle with batteries and body at under 100 lbs. Fitting my 140 lb self plus 60 lbs of gear will bring the laden weight to 300 lbs. Every extra pound of motor is a pound of battery I won't have. The efficiency gain of a leafmotor over a MAC will negate this somewhat, but if the battery runs dead, I also do not want to be left stranded.

Well, we are talking about a 5-7% continuous increase in efficiency, plus dramatically higher efficiency while starting off from a stall, or heading up a hill. Plus, you can also get another 50 to 10% of your energy back through regen.
This could translate into you needing 6lbs less of battery, depending on how big your battery is.

The bigger DD hub will also pretty easily push 20 ft-lbs more continuously, if not more than that. A DD does make up for it's heavier weight, one way or another!

 

[The Toecutter]

Read the leafmotor thread started by me. Cogging is very minimal for a DD due to the thin laminations. The permanent coupling and regeneration capability are the exact reasons i have that motor as my daily driver.

Whoa. I remember reading it almost 2 years ago, but didn't keep up with it afterward due to time constraints. I regret not doing so. I think you've convinced me to buy a motor.

I remember thinking 1500W was its recommended continuous power when I saw that chart, and saw that it was permanently mechanically coupled to the rear wheel. I didn't hold high hopes for it, especially because of a hub motor's worst weakness for my application: cogging. If I was willing to tolerate that, the CroMotor was in my future. My previous trike was a lot heavier and weight was also more critical for my application(I was considering a middrive kit before I broke the frame).

Going through what I haven't kept up with in your thread, I've read through Page 8 of 48 so far and have also read Page 48, and here are my thoughts:

So you can put 6 kW peak to this thing and NOT kill it? I ran a simulation for 48V/92A just now, and got 0-30 mph in 4.5 seconds, 0-40 mph in 11.8 seconds, with me pedaling at 500W. I haven't run one for 6 kW since I have to re-input the torque curve data, but I already like where this is going. :lol:

Since you were able to pedal a 65 lb bike to 20 mph with the motor off, with its cogging fully in effect(which is very minimal), it seems a sure bet that if the motor is shut off, more than 90% of the mechanical input from the rear freewheel/freehub provided by the rider will still power the rear wheel, accounting for the motor losses. All of that additional rotating mass versus the MAC wouldn't be pleasant to overcome with the motor off, but I could accept that compromise given that velomobiles can make great use of their momentum because of their low drag.

Regen is awesome for saving brakes. A brake lever setup to use the motor regen as a rear brake would aid the purpose of reducing front brake pad and cable wear, and negate the need for a rear brake disc. I need to be able to coast though, so it is imperative that I either be able to set the regen up to be user-activated, or alternatively, install a rear disc brake and caliper.

Being able to go 30 mph up hills without overheating would make this much safer to use in traffic.

The 88-90% peak efficiency is a really nice bonus. It may not be a Lynch motor, but it is more than good enough considering I was willing to settle for a MAC that peaked at 75-80%.

It's legality in places where ebikes are outlawed, when operated with the motor assist off, will range from "gray" to illegal. The MAC would have had the same problem.Which brings me to my remaining concern: noise. A sinewave controller could allow silent operation when the motor is in use, but does the motor make any noise when the electric drive system is turned off? I imagine it would make little or none. Silent operation is crucial for stealth. My build needs to pass as unassisted when passing through a state or municipality where ebikes aren't legal as "bicycles" and require all the associated paperwork and bureaucracy. I will ride with the motor assist off in areas where it is not legal, but silence is critical to avoid providing any evidence of its motored status. With a MAC, I just disengage the clutch, and hope no law enforcement officer cares enough to take the whole trike apart to prove there's a motor there. If it's making this awesome noise, it's only going to arouse unwanted attention, which it will get enough of being a strange looking vehicle as it is. I'll try to go through more of your videos and see what you've done and how this motor operates.

With this being said, the MAC would be "enough" for my needs, but since I haven't put forth the money for a motor yet anyway, I may as well consider the alternatives.

Your build is a very practical, inexpensive, and fast build. Thanks for sharing what you have about it along with your experiences. I have more reading to do. I must have researched the specs of more than 30 ebike motors by now, and hadn't looked at the Leafmotor in-depth. I'm glad I didn't buy anything yet.

 

[Bullfrog]

IMO the MAC is the most awesome motor known to man as long as you don't exceed its ability to reject excess heat .

The torque per amp is higher than any motor in the Grin Tech Motor Simulator...but the MAC does have its limitations. Roughly 50A and a 14S (52v) battery...you can go way over both of those but the amount of power you get for the increase starts to diminish rapidly and you end up just producing heat.

If you want to run the MAC steady state for very long I wouldn't go over 50A/58.8v but you can push it waaaay beyond that for short periods of time. I have run my 12T MAC at 60A battery and 180A phase currents with a 58.8v battery for a little while with no issues and that includes wide open throttle starts. Used an Infineon 18 FET 4110 FET controller. The new style gears in the motor did fine and the freewheel clutch never slipped. AND I had a 29" Maxxis Hookworm installed at the time with an OD of 750mm .

One limitation that most don't experience is that IF you take a MAC off road and beat the heck out of it going over roots and rocks, you can displace the little springs in the freewheel clutch that keep the rollers in place. It happened to me and the clutch still engaged just fine but it would not freewheel.

Remember just because the simulation says it is possible, it doesn't mean it is a good idea :lol: .

I just ordered an 8T MAC and want to get the same acceleration I have with my 12T and I am wondering if my controller can handle 50A/150A battery/phase current without damage.

Anybody running an Infineon 12 FET IRFB3077 controller...what is the maximum battery and phase amperage you have pushed through the controller?

Thank You

 

[Bullfrog]

Yes you can run a 203mm rotor on the new MAC...the rear freewheel motor anyway, that is what I have and been running the 203mm rotor for a long time.

I have it all in a Mongoose Terrex from Walmart. Other frames may be different but the MAC Rear Freewheel Motor handles it just fine.

Just another tidbit...talked with Justin at Grin Tech and they ran a MAC at 145C on the dyno with no adverse effects. I use the Grin Tech Motor Simulator to check my temps and use "1.5" for the incline because it matches my actual conditions fairly close. You can go with a smaller diameter tire to drop the temps or a larger diameter to increase speed. I program my CAv3 to start rolling back the power at 135C and to shut the motor off at 145C...just to be safe.

Neptronix has some really good info/recommendations in this thread. I'd highly recommend anyone running a MAC read through it.

The MAC...is famous for shedding heat poorly. That is putting it mildly :lol: . You can liquid cool it but that has its own unique challenges...I'd recommend limiting the power so you don't have to liquid cool it or go with a 10T/12T instead of an 8T...depending on your weight, tire diameter and the hills you plan to climb. I tried the liquid cooling and I would NOT recommend it as a solution. Just use the Grin Tech Simulator to figure it out .

 

[Bullfrog]

Neptronix,

What temperature do think its safe to keep the motor alive? Like 150c celcius?

Based on what Justin told me about the MAC they ran on the dyno, I program mine to start rolling back the power at 135C and shut down if it reaches 145C. I just like to live dangerously plus I have a new motor on the way :lol: . Another motor may be completely different.

EM3eV recommends power roll back at 110C and shut down at 120C for the MAC...probably the safe alternative .

 

[pguk]

I just nipped out back to check - yep, this is a 200mm disc I ran on a MAC a few years back. The Kona Stab frame had no disc mount bracket so I added one with aluminium welding. Would recommend a 203mm rotor, but 200mm was what I had to hand and it did run well
Great to hear the motor is respected even today.