MAC motor + Trek 4300 build

[neptronix]

No prob.
Yeah, 48v on the 6T will do about 40mph on a 26" wheel. That's just too much.

I run 57v ( 15S ) on my 8T in a 26" wheel, and yes, it is operating the motor close to it's short term limit. On a 29" sized wheel i would be more concerned.

I think you'd be pretty happy with the 30-32mph speeds that the 8T in a 29" wheel would pull. If you want faster, i'd go to a motor that can handle more power.

The 20" magic pie is a novelty motor, in reality! you can't even hit 30mph on 72v :lol:. I am going to tag team up with gary at golden motor canada and see if we can get them to do a custom winding for approx. 20mph on 36v in the 20" wheel. It would then be more like a 9T MAC motor. The 20" pie, can handle 41-42mph continuous for a good period of time but that requires 125v nominal, which is a bit on the crazy side....

BTW the magic pie cogs like a son of a bitch, so you will definitely want to keep it for another build

The MAC motors don't come with a gear cluster. You'll want a 7 speed 11t DNP freewheel, UNLESS you can find a shimano megarange with an 11t gear, which is far superior.

Forget having custom threaded freewheels made. Not gonna happen. threaded freewheels were marked for extinction in the 1990's and no company is serious about manufacturing them anymore.

Sorry, i don't remember the shipping cost, but i recommend the SAL shipping method. Sea freight can take 2-3 months and there is no guarantee that it will arrive.

Thanks guy. Now that I look a little closer, I think I see what you are saying. You recommend 8T just because of my intention to run 12s correct? Cellman gives a warning of 48V on 6T, but gives a warning of 60V on 8T. I do want another Golden Motor like the 20" molded wheel you have, but that will have to wait for a differnt build. I also want to freewheel with the Rockhopper, putting the controller in batteries like you have in a bag and then just unplug it and remove it to ride the bike regularly.

I assume that the 8T does not come with a 7-speed attached and yall kinda went back and forth in the thread about which one is a good one. Can you recommend who I should get the 7-speed from? What about the torque arms - I dont think I have anyone around here than can custom make them.

Also, what do you think the shipping is approx. from cell_man to New Orleans? I sent him a letter, but as you know it takes a while. Thanks again man. You do us all a great service!

 

[kevo]

Neptronix wrote: The MAC motors don't come with a gear cluster. You'll want a 7 speed 11t DNP freewheel, UNLESS you can find a shimano megarange with an 11t gear, which is far superior.

Can a 9 speed Shimano cluster be used with the MAC if the rear stays are slightly expanded and a spacer is used (like described by Illia on ebikessf for the BMC)

 

[neptronix]

Hm, that's a question for a bike store. I believe the gear spacing is narrower, so the width of the total assembly may be similar. I'm not entirely sure though.

 

[veloman]

I don't see the need to use an 8 or 9speed freewheel. I only use about 3 gears on my 7sp freewheel as it is. Make it easy on yourself and get a 7sp freewheel and get a cheap 7sp rear shifter.

 

[kevo]

To each his own, I like to pedal

 

[neptronix]

Oh, you'll understand the recommendation for a 7 speed freewheel and a huge single front chainring as soon as you get a setup with good power

With my 7 speed, i use about 4 of the speeds. That's at 26mph on the MAC at 36v. I run a 50T chainring. This allows me to pedal along at the motor's top speed, or kick down 2-3 gears to help on super steep hills.

On the magic pie build, i will have a grand total of 1 gear, and will pedal the whole time in that one gear. Some of the biggest hills will drop my speed by i dunno, 2-3mph.... so no need for shifting :lol:

On my lady's 350w MAC tuned to 36v/28A, we do use 6 of the 7 gears for hill climbing.. pushing a peak wattage of about 1000w.

All 3 bikes are pedaled >75% of the time.

 

[GMUseless]

.++

I'm running 50:11 on my MAC 6t and the rear dérailleur only serves as a chain tensioner. I often shift the front rings, but never the rear. Planning on this, I got a good quality Shimano XT front D, and a $10 SRAM x.3 rear D.

The MACs have such good low end torque, you simply won't be using your low gears. If you like pedaling, start with an 11t rear, get the widest bottom bracket you can to allow clearance for the largest front rings that will fit. At 50:11 my input is mostly ghost above 30 mph.

 

[neptronix]

Yeah, 50:11 is basically useless above 30mph, unless you got a 29er or something. The vuelta USA chainrings are great. a 55T could help you out . I have a 60T for my 20" wheeled magic pie.
I can pedal up to, i think, 28mph on 11t-20T.. pretty sad :lol:

http://www.vueltausa.com/components/chainrings/se-flat-chainrings.html

50T barely clears my frame with a standard bottom bracket. The Trek frames are shaped just right for it. If i went to a wide bottom bracket, i'd have chainline issues leading to faster wear. Bummers.

 

[veloman]

Hey hey, my top gear is a tiny 44x11 and I sometimes legit pedal it at 32mph. yeah, it's a fast cadence, but not that bad. I usually drop to the middle ring when coming to a stop, and start in that gear (11 tooth). Sometimes I've move it to the 12 or 13 cog if I am starting on a hill or want to get off the line fast. Mostly it's just to baby the gears on takeoff. The 8T on 1200watts has no problem getting off the line. Absolutely kills a DD at the same power level.

I do have a 53 large ring on my next build, so then I can pedal it slower at fast speeds.

But yeah, I never need more than 3 gears. Of course, i don't ride massive hills either. I'd say 8-10% is the steepest, and they are quite short.

 

[motomech]

Do you have problems with the chain coming off the chainring when shifting the rear? That's what I found, so I keep the front derailleur. I see you got a more normal looking stem now. And front suspension again?

Yes, i do. If i shift while hitting a bump, i'm screwed.
However, a front derailleur is both useless and doesn't jive with a frame bag too well.

I'm sure there's a better solution.

Scorpion: yes, i love having it back in action! But i feel like it's so slow now, in comparison to the 20" pie on 6kW.. :lol:

I had the same problem, the frt. deraileur interfering with the bottom strap of the Falcon EV bag. I was able to get it mounted just above the strap by "locking" it in the big ring position and then moving it up, but it's still close to the bottom of the chain when on my 44/11 gear.
Instead of locking it by clamping the cable on the frame as some have do here, I spread the deraileur open by hand and dropped a sm. 9 mm socket in the open space. The spring tension holds it in there, so I now have a serviceable chain guide.

 

[neptronix]

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

 

[motomech]

Question, "At what point does an Ebike become an Emoto?

Answer, From the rear down tube on back.

 

[neptronix]

:lol: good one, man.

That's totally true. That's the direction my builds are heading in. I think it happens to everyone who really dives into this. The end of this downward spiral is building something like liveforphysics puts together.

I started out in a 250w cell_man MXUS geared motor kit. Now i am pushing 7000w into a magic pie and 2500w peaks into a MAC. I am ordering an eTek ( motenergy ) 22lb motor and am going to run it chain driven on a hardtail or maybe a xtracycle style configuration.

Pray to your selected diety that you are not afflicted this bad

 

[veloman]

:lol: good one, man.

That's totally true. That's the direction my builds are heading in. I think it happens to everyone who really dives into this. The end of this downward spiral is building something like liveforphysics puts together.

I started out in a 250w cell_man MXUS geared motor kit. Now i am pushing 7000w into a magic pie and 2500w peaks into a MAC. I am ordering an eTek ( motenergy ) 22lb motor and am going to run it chain driven on a hardtail or maybe a xtracycle style configuration.

Pray to your selected diety that you are not afflicted this bad

I think I may have hit the sweet spot for the Mac and my riding, at 1200-1300watts on the 8 turn. Acceleration is plenty to stay in front of city traffic with minimal or no pedaling. I don't ride fast roads and so it's pretty rare that I ever want more power. Efficiency still hangs around 19-21wh/mile with minimal pedaling in this heat. I will boost it to 1500watt and see how that goes, but that is nearing the more abuse territory, and I am getting it fairly hot as it is (88 C). It tops out at 33-35mph on a flat road. Yes, sometimes if I'm stupid and ride a fast road i want more speed, but I can avoid those roads nearly all the time.

The 6 turn on a 45lb bike setup with 2000watts was pretty snappy. Does anyone regularly ride their Mac at 2kw and can you report any issues? For me, I hit peak power constantly since I have to stop so often.

 

[nonlineartom]

I ride my 10T at 1600W. Although it only pulls that on hills, cruising top speed is about 800W with no headwind, even on 2 mile long hills it's fine, about 2000 miles so far and only a sticky clutch, sometimes won't freewheel but a speed bump or two gets it working. I'm sure it would handle 2KW forever, but that's the 10T can't speak for the 6T

 

[Gregory]

Same, my 10T MAC peaks at 60V 1600W and I won't increase that. I want at least one reliable, stealthy bike.

 

[veloman]

As far as gear longevity, the 10T should be a considerably harder on the gears than the 6T due to more torque (better off the line). Not sure about the clutch life but the windings would prob last longer on a 10T with less heat built up.

 

[neptronix]

I'll tell you guys a secret about saving the clutch and the gears
If you have a programming cable, you can tune out the initial torque, which will help a ton.

Most infineons are set for a 1:3 battery to phase ratio, meaning that if your battery current limit is 30, then the phase limit is 90. OK, this is fun because it makes for a nice blast of torque from a stall. It's fine for DDs who have low torque too.

But I like to change this to 1:2.5-2.3 .. so for my 40A battery current, that's 40 x 2.4 = 96 phase amps.

This means that you will have more of a flat torque band, and notably less initial kick from a stall - half, or less.. The upside is that at mid-high speed, you retain your hill climbing torque. It also forces you to pedal a bit from a stall, which is good for you as in a high powered setup, there is a tendency to get lazy.

 

[gensem]

Neptronix,

Any news about the big mac?

 

[neptronix]

Neptronix,

Any news about the big mac?

In terms of the hub motor, no.

In terms of the lawnmower motor.. still waiting on parts to arrive and i am in the middle of doing a double move. Magudaman is much more likely to finish his build before me. Sorry for the waiting game.

 

[veloman]

I'll tell you guys a secret about saving the clutch and the gears
If you have a programming cable, you can tune out the initial torque, which will help a ton.

Most infineons are set for a 1:3 battery to phase ratio, meaning that if your battery current limit is 30, then the phase limit is 90. OK, this is fun because it makes for a nice blast of torque from a stall. It's fine for DDs who have low torque too.

But I like to change this to 1:2.5-2.3 .. so for my 40A battery current, that's 40 x 2.4 = 96 phase amps.

This means that you will have more of a flat torque band, and notably less initial kick from a stall - half, or less.. The upside is that at mid-high speed, you retain your hill climbing torque. It also forces you to pedal a bit from a stall, which is good for you as in a high powered setup, there is a tendency to get lazy.

Thanks for reminding me about this, I'm going to reset mine right now. Most of the time I actually wish it was a little slower off the line.

 

[hillzofvalp]

I Really want one of those 60T chainrings.. but for 104mm 4 bolt mtb cranks.. Where did you get your 4 bolt road one? I just may have to CNC the gear I need

 

[neptronix]

I Really want one of those 60T chainrings.. but for 104mm 4 bolt mtb cranks.. Where did you get your 4 bolt road one? I just may have to CNC the gear I need

You're referring to the magic pie build, right? 60T chainring came from Vuelta USA. Good unit too.

http://www.vueltausa.com/

You can always just switch out your cranks if you can't get a 4 bolter from 'em. Might actually be worth it considering the kind of $ they are asking for chainrings these days.

 

[Stryker16]

I'll tell you guys a secret about saving the clutch and the gears
If you have a programming cable, you can tune out the initial torque, which will help a ton.

Most infineons are set for a 1:3 battery to phase ratio, meaning that if your battery current limit is 30, then the phase limit is 90. OK, this is fun because it makes for a nice blast of torque from a stall. It's fine for DDs who have low torque too.

But I like to change this to 1:2.5-2.3 .. so for my 40A battery current, that's 40 x 2.4 = 96 phase amps.

This means that you will have more of a flat torque band, and notably less initial kick from a stall - half, or less.. The upside is that at mid-high speed, you retain your hill climbing torque. It also forces you to pedal a bit from a stall, which is good for you as in a high powered setup, there is a tendency to get lazy.

just ordered a mac kit (thanks mostly to you). playing around with the software and wondering what inputs you are talking about. i want to flatten the torque band for sure so do i simply change 'phase current' and 'rated current' to get a ratio of around 2.5?

 

[neptronix]

I'll tell you guys a secret about saving the clutch and the gears
If you have a programming cable, you can tune out the initial torque, which will help a ton.

Most infineons are set for a 1:3 battery to phase ratio, meaning that if your battery current limit is 30, then the phase limit is 90. OK, this is fun because it makes for a nice blast of torque from a stall. It's fine for DDs who have low torque too.

But I like to change this to 1:2.5-2.3 .. so for my 40A battery current, that's 40 x 2.4 = 96 phase amps.

This means that you will have more of a flat torque band, and notably less initial kick from a stall - half, or less.. The upside is that at mid-high speed, you retain your hill climbing torque. It also forces you to pedal a bit from a stall, which is good for you as in a high powered setup, there is a tendency to get lazy.

just ordered a mac kit (thanks mostly to you). playing around with the software and wondering what inputs you are talking about. i want to flatten the torque band for sure so do i simply change 'phase current' and 'rated current' to get a ratio of around 2.5?

2.5 or less, yeah. 2.3 works too.
The battery current is going to be the lower number.