SHARKBITEATTACK
10 W
I want a rear 2812 9c motor in a 26in rim that's disc brake compatible. Does anybody make this or would I need to lace it myself?
Where to buy a 9c 2812 motor?
- Thread starter SHARKBITEATTACK
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docnjoj
1 GW
Methods used to have those motors.
http://endless-sphere.com/forums/viewtopic.php?f=31&t=31146&start=45
otherDoc
http://endless-sphere.com/forums/viewtopic.php?f=31&t=31146&start=45
otherDoc
dogman dan
1 PW
He's only got the 2812 in front hub 20" rim nowdays.
You can get a 2810 in 26" rear motor.
Look for it in the for sale new section, in the wife kit thread. 2810 is still a very slow motor, and makes almost as good a dirt hill climber as the 2810 on 72v. It will be faster, about 30 mph on 72v, which many consider a plus. I consider the 2810 the ideal motor for my longtail. Perfect for hauling some weight up steep hills.
I love my 2812, but it is awful slow for most folks. To get it in 26", I just slapped the stator into a rotor from a burnt 26" motor.
You can get a 2810 in 26" rear motor.
Look for it in the for sale new section, in the wife kit thread. 2810 is still a very slow motor, and makes almost as good a dirt hill climber as the 2810 on 72v. It will be faster, about 30 mph on 72v, which many consider a plus. I consider the 2810 the ideal motor for my longtail. Perfect for hauling some weight up steep hills.
I love my 2812, but it is awful slow for most folks. To get it in 26", I just slapped the stator into a rotor from a burnt 26" motor.
itchynackers
100 kW
Dog,
I've just ordered a 2810r from methods. Figured I'd try a bit more hill ability. I currently have a 9x7, and an 8x8 (which are both fantastic). I've upgraded to 10awg phases into the motors, and plan on that with the 2810. Can you give us some performance limits of the 2810 compared to the 2812?
I've just ordered a 2810r from methods. Figured I'd try a bit more hill ability. I currently have a 9x7, and an 8x8 (which are both fantastic). I've upgraded to 10awg phases into the motors, and plan on that with the 2810. Can you give us some performance limits of the 2810 compared to the 2812?
Ha. what are you gonna do, run 200v on it? that thing is probably slower per volt than my magic pie, which i need 120v ( 30S ) just to get to 42mph.. the 2810 is slow enough as it is!
120v is about the upper limit of what infineon controllers are capable of handling.
I bet you will only hit 20-25mph on 72v with the 2812. It'll get there fast, but that's a pathetic top speed.
120v is about the upper limit of what infineon controllers are capable of handling.
I bet you will only hit 20-25mph on 72v with the 2812. It'll get there fast, but that's a pathetic top speed.
French
10 mW
neptronix said:
Not if you're riding steep, technical dirt trails.
dogman dan
1 PW
Different strokes for different folks.
Personally the 25 mph top speed of my 2812 in 26" is just about the same as the top speed I can stand going over the bars. Thing is, it's rocky on them trails hearabouts. Others have routes much better suited to faster, bikes that can stand it etc.
Performance, no real difference with any winding of 9c. 1000w is nice, 1500w is about the sweet spot, and by 3000w you sure better have a temp sensor on that motor. They can cook off nice and quick at 3000w.
Nice thing about the slow motors though, is they tend to be unable to pull that much watts for long. Once you hit 25 mph, the watts back right down saving your motor. Good for foolish riders like myself.
The 2810 will hit about 30 mph on 72v.
Personally the 25 mph top speed of my 2812 in 26" is just about the same as the top speed I can stand going over the bars. Thing is, it's rocky on them trails hearabouts. Others have routes much better suited to faster, bikes that can stand it etc.
Performance, no real difference with any winding of 9c. 1000w is nice, 1500w is about the sweet spot, and by 3000w you sure better have a temp sensor on that motor. They can cook off nice and quick at 3000w.
Nice thing about the slow motors though, is they tend to be unable to pull that much watts for long. Once you hit 25 mph, the watts back right down saving your motor. Good for foolish riders like myself.
The 2810 will hit about 30 mph on 72v.
MadRhino
100 GW
Those slow motors are perfect for bad trails. At this time of the year, as the melting trails are a mix of ice, slush and mud with fallen branches everywhere; I use the 5306 on my bike and have a much better ride than with the fast motors. When you can't ride fast, enjoy the complete throttle range and efficiency of a slower setup.
John in CR
100 TW
The problem is that they can't make the power required for really steep stuff. If a motor's top speed is 30 on the flats, then it needs to maintain at least 15mph to dream of survival. Take a specific example, a fairly lightweight rider at 160lbs with a 70lb bike requires 1500W to climb a 20% grade and these motors can only do that in very short spurts with plenty of 0 grade riding at speed to cool off afterward. The bottom line is that real trail riding requires more power or variable gears to get down closer to pedal bike speeds on climbs.
MadRhino
100 GW
Yep, but riding a bad trail is never very long anyway. If I have to slow down some sections to 20 due to bad trail conditions, I ride up and down the mountain once and have enough. My faster motors have a very twitchy throttle and overheat quickly at that speed, using the slow winding makes it a better ride.
Most of the summer, the trails are nice and I can speed with a faster setup, that is when my motors are at risk because I am tempted to ride them much longer. Yet, a lap here is 10 to 15 Km and I am at the bottom of the trails. I can use a 2nd bike to ride again and let the other one cool. For me it works, but I don't live in the Alps where I would have to climb long uninterrupted stretches.
Driving the gears makes a much better dirt bike, but having to shift doesn't make as good a ride, and bicycle shifting is not up to the task for power. I will drive the chain with my trial bike, no pedals and a drive train made for power.
Most of the summer, the trails are nice and I can speed with a faster setup, that is when my motors are at risk because I am tempted to ride them much longer. Yet, a lap here is 10 to 15 Km and I am at the bottom of the trails. I can use a 2nd bike to ride again and let the other one cool. For me it works, but I don't live in the Alps where I would have to climb long uninterrupted stretches.
Driving the gears makes a much better dirt bike, but having to shift doesn't make as good a ride, and bicycle shifting is not up to the task for power. I will drive the chain with my trial bike, no pedals and a drive train made for power.
dogman dan
1 PW
John is quite correct. The 9c motor has to be kept below 1500w for most of the ride or they will go up in smoke. I oughta know, I've smoked a few of em. I don't feel the motor sucks, just that smoking a motor from time to time is part of the experience if you push the 9c's. Get the motors cheap enough, and smoking one a year is cheap thrills. I like the lower weight of them too. After a year of hard trail riding, your rim and spokes may be about done too anyway.
Somehow there is a myth that the low speed windings have more torque, and can take more watts. Wrong on both counts. But a low speed winding does tend to naturaly drop to a low wattage sooner than a fast winding. They have a slower stall speed, so if your avaliable watts allows only 10mph, it's stalling less and making less heat than a fast winding. Since less heat is being made, more of the avaliable power is making torque, so that is what the rider feels. On the watts, a given motor design can take x watts. That doesn't change any by using a different winding.
For the record, a 9c 2810 is quite capable of climbing 15% grades no pedaling for at least a mile, if run on a controller limited to 1500w. Thats 72v 20 amp. Yes it's going to get hot, but it will survive it. Two years of trail riding has taught me that. A 2812 can do short stretches of 20%. Short, because by then you are stalling the motor at 5 mph up a grade like that.
For sure, a clyte 5306 would be able to take the heating a bit longer, and have a higher watt limit. Long enough to get up most trails.
Trails built specificly for mountain bikes very often are not much above 10% grade, since pedalers hate it. Or they may have a switchbacked up route, and a nice bomb on the return allowing a rider to avoid ascending 20% grades. But if you start riding other roads or trails, you can get into motor smoking grades quite easily. Mine roads, or horse trails can have very steep grades that can kill most hubmotors designed for a bicycle.
So to get up some of the really tough trails, you do need a much more robust motor than a 9c of any winding.
Luckily, I have miles and miles of desert mesa, and desert mountain riding where the trails are a grade the slow 9c winding can tolerate just fine. The steep bits are just short enough that I can climb for 4-5 miles no problems, since most of the trail is graded 7-10%, rather than 20%.
Somehow there is a myth that the low speed windings have more torque, and can take more watts. Wrong on both counts. But a low speed winding does tend to naturaly drop to a low wattage sooner than a fast winding. They have a slower stall speed, so if your avaliable watts allows only 10mph, it's stalling less and making less heat than a fast winding. Since less heat is being made, more of the avaliable power is making torque, so that is what the rider feels. On the watts, a given motor design can take x watts. That doesn't change any by using a different winding.
For the record, a 9c 2810 is quite capable of climbing 15% grades no pedaling for at least a mile, if run on a controller limited to 1500w. Thats 72v 20 amp. Yes it's going to get hot, but it will survive it. Two years of trail riding has taught me that. A 2812 can do short stretches of 20%. Short, because by then you are stalling the motor at 5 mph up a grade like that.
For sure, a clyte 5306 would be able to take the heating a bit longer, and have a higher watt limit. Long enough to get up most trails.
Trails built specificly for mountain bikes very often are not much above 10% grade, since pedalers hate it. Or they may have a switchbacked up route, and a nice bomb on the return allowing a rider to avoid ascending 20% grades. But if you start riding other roads or trails, you can get into motor smoking grades quite easily. Mine roads, or horse trails can have very steep grades that can kill most hubmotors designed for a bicycle.
So to get up some of the really tough trails, you do need a much more robust motor than a 9c of any winding.
Luckily, I have miles and miles of desert mesa, and desert mountain riding where the trails are a grade the slow 9c winding can tolerate just fine. The steep bits are just short enough that I can climb for 4-5 miles no problems, since most of the trail is graded 7-10%, rather than 20%.
John in CR
100 TW
MadRhino said:
MadRhino,
Like you I want to be able to just go for it up the mountains with battery as my limitation. For a trail bike I figure my high efficiency 2 speed in a mid-drive and geared down 2:1 going to a 26" wheel will do the trick. That would give a top speed in high of 35-40mph and in low about 20, so the motor is perfectly safe in it's prime efficiency band loaded all the way down to about 10mph and several Kw. In low in a 17" wheel it powers 250lb me + 110lb bike up 25% grade silently giggling on the way up, so imagine what you could do. I need to get on the stick and do a mid-drive to demonstrate with me as the ultimate stress test rider.
John
MadRhino
100 GW
Yep, I find better to shift Kv than gears, and I'd like to see it drive the left side to leave the crank alone. Yet, it is not an easy task to fit such a hub motor in frame while retaining DH compatible geometry, suspension and width. If you succeed, it sure will have the potential of a good jumper.John in CR said:For a trail bike I figure my high efficiency 2 speed in a mid-drive and geared down 2:1 going to a 26" wheel will do the trick. That would give a top speed in high of 35-40mph and in low about 20, so the motor is perfectly safe in it's prime efficiency band loaded all the way down to about 10mph and several Kw. In low in a 17" wheel it powers 250lb me + 110lb bike up 25% grade silently giggling on the way up, so imagine what you could do. I need to get on the stick and do a mid-drive to demonstrate with me as the ultimate stress test rider.
John
SHARKBITEATTACK
10 W
neptronix said:
I was planning on running it at 72v for a top speed of 25mph. I like to explore remote areas in deep terrain. Lower speeds with high torque on demand would help me navigate this terrain. Mud, logs, ditches etc... Also I liked the idea that I can do a delta wye conversion in the future to achieve a 35+ mph top speed for street riding.
dogman dan
1 PW
Mabye the 2810 on 18s then? Just watch your heat if you run more than 20 amps.
^-- yeah seriously.. lower voltage.. less cells to worry about.
I like the higher speed wind motors mainly because i've only got 10 or 12 cells to worry 'bout. Need more torque? increase the amps..!
The 2810 is a nice compromise..
I like the higher speed wind motors mainly because i've only got 10 or 12 cells to worry 'bout. Need more torque? increase the amps..!
The 2810 is a nice compromise..
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