New Carbon Frame Built with Bafang M500

[pelle]

Hi,
I'm a newbie on ebike. I have built a number of bikes from scratch with carbon frames from china, rims from WTB and DT-swiss, spokes from DT-swiss, gears and brakes from Shimano and tires from Schwalbe. Being a senior (74) I do not engage in any technically advanced mtb-ing, but prefer to bike around on trails in the forest and along the beaches. Typically ride 100-200km a weeks along tracks with 200-400m in accumulated climbs. Now I thought to build an emtb to extend my tracks a discover new tracks in more distant areas. Here are my considerations and questions in light of the new emtb build.

I will aim for a light weight bike with a carbon hardtail and a ridged carbon fork (which I have on my present builds). Target weight is around 18kg. My currents builds weigh around 9kg, so a Bafang MM G520.250 would add around 2,8kg (with deduction made for the current crank 0.6kg) and a Bafang BT-F04.600 adds 3.5kg and the carbon frame being adds around 1.2kg heavier than my Airwolf carbon frame.

As said I am considering a Bafang G520.250 considering the Swedish legislation, which limits the power to 250w and max speed to 25km/h. Speed is not an issue for me and I guess the low 250w power restriction kind of aligns with my goal to keep the weight low. The frame I currently have in mind is a LCE1066 from Xiamen Lightcarbon Composite (Ebike Frame Bafang M500 Or M600 Hardtail Full Carbon Electric Mtb Frameset 12*148mm Lce1066 - Buy Carbon Fiber Ebike Frame,Ebike Bafang,Carbon Ebike Frame Mtb Product on Alibaba.com).

1. Any experiences applying to this choice of frame?

What about the considerations for an appropriate battery size. I guess a higher voltage means lower current and hence lower loss to heat. So a 48V volt battery would be more advantageous over a 36V.

2. I notice that Bafang uses the term "Nominal 43V" and interpret that as 48V battery under load. Is that correct ?

3. The BT F04.600 is only 0.5kg heavier than the BT F03.450, but provides 150Wh in energy. Are there other considerations than weight and price to weigh in here?

4. Do I need the brake sensors for my disc brake levers?

5. Do I need the gear sensor to protect against hard shifting?

I have a Shimano 10-51T cassette and a 32T chainring today, maybe a bit to the light side (but I am an old man). I thought I would keep that gear ratio so the bike would feel about the same if the battery ran out of juice while I was still far from home.

6. Any comments on that rational about gear ratio?

7. If I interpret the g520.250 specification correct, a 32T chainwheel is standard to that motor, correct?

8. In the manual for the G420.250 there is mentioned a "Special tool" for tightening the chainring. Is it a standard socket for a Shimano chainwheel?

Many questions but I hope they are within the scope of this forum.

Best Regards,
Pelle

 

[Neeko DeVinchi]

Hi,
I'm a newbie on ebike. I have built a number of bikes from scratch with carbon frames from china, rims from WTB and DT-swiss, spokes from DT-swiss, gears and brakes from Shimano and tires from Schwalbe. Being a senior (74) I do not engage in any technically advanced mtb-ing, but prefer to bike around on trails in the forest and along the beaches. Typically ride 100-200km a weeks along tracks with 200-400m in accumulated climbs. Now I thought to build an emtb to extend my tracks a discover new tracks in more distant areas. Here are my considerations and questions in light of the new emtb build.

I will aim for a light weight bike with a carbon hardtail and a ridged carbon fork (which I have on my present builds). Target weight is around 18kg. My currents builds weigh around 9kg, so a Bafang MM G520.250 would add around 2,8kg (with deduction made for the current crank 0.6kg) and a Bafang BT-F04.600 adds 3.5kg and the carbon frame being adds around 1.2kg heavier than my Airwolf carbon frame.

As said I am considering a Bafang G520.250 considering the Swedish legislation, which limits the power to 250w and max speed to 25km/h. Speed is not an issue for me and I guess the low 250w power restriction kind of aligns with my goal to keep the weight low. The frame I currently have in mind is a LCE1066 from Xiamen Lightcarbon Composite (Ebike Frame Bafang M500 Or M600 Hardtail Full Carbon Electric Mtb Frameset 12*148mm Lce1066 - Buy Carbon Fiber Ebike Frame,Ebike Bafang,Carbon Ebike Frame Mtb Product on Alibaba.com).

1. Any experiences applying to this choice of frame?

What about the considerations for an appropriate battery size. I guess a higher voltage means lower current and hence lower loss to heat. So a 48V volt battery would be more advantageous over a 36V.

2. I notice that Bafang uses the term "Nominal 43V" and interpret that as 48V battery under load. Is that correct ?

3. The BT F04.600 is only 0.5kg heavier than the BT F03.450, but provides 150Wh in energy. Are there other considerations than weight and price to weigh in here?

4. Do I need the brake sensors for my disc brake levers?

5. Do I need the gear sensor to protect against hard shifting?

I have a Shimano 10-51T cassette and a 32T chainring today, maybe a bit to the light side (but I am an old man). I thought I would keep that gear ratio so the bike would feel about the same if the battery ran out of juice while I was still far from home.

6. Any comments on that rational about gear ratio?

7. If I interpret the g520.250 specification correct, a 32T chainwheel is standard to that motor, correct?

8. In the manual for the G420.250 there is mentioned a "Special tool" for tightening the chainring. Is it a standard socket for a Shimano chainwheel?

Many questions but I hope they are within the scope of this forum.

Best Regards,
Pelle

Hi Pelle,
I'll do my best to answer but I suspect that others may need to chime in concerning the tolerances of Carbon. Strictly speaking, all bafang emtb specific frames I've built up are 661 Hydroformed alloy.
Anywho, here we go,
1. Traditionally, bafang have always been against 'over-vaulting their products to ensure longevity. In terms of vaults vs amps, The rule with Bafang (with the exception of the G510), the higher the vaults, the less amps you need. E.g. 36v 17amp, 48v 15amp, 52v 13amp etc. By increasing the vaults, you are ensuring the efficiency of the motor in conjunction with discharge rate which are not detrimental to the cell bank and not over working the BMS (Battery Management System). It is worth mentioning that sadly, Bafang have made it more difficult to reprogram the controller within the newer units. However, I am aware that a third party has stepped in to give riders this option but I have no information at this point as to this product. Naturally, I'll keep all who are interested updated.

2. Nominal voltage refers to the power required to engage the motor. In this case, its 36v (I know its weird). To cut a long story short (subject to the programming of the controller), Bafang motors can only recognize current but struggles to recognize vaults and amps. Only by using Bafang's propriety battery, do you have the ability to view each cell bank and discharge rate per cell (depending on the display you use). Case and point, running either 36v or 48v is fine.

3. This is where I ask others to chime in. Again, I'm more familiar with the Alloy frames.

4. Motor cut offs (brake sensors) are only required in the following examples
A. The motor in question is not torque sensing and instead is Cadence sensing
B. You choose to use the ebike as a speed pedelec+

If you're intended use is for emtb use, you don't need motor cut offs. If you choose to use the bike as a speed pedelec (up to 28mph) or faster or, wish to use a throttle as well, then you'll need motor cut offs. Personally, I use both Shimano levers with the cut offs and Magura levers with cut offs. The calipers however are all 4 piston front and rear.

5. TBH, the only reason why Bafang developed the gear sensor was to try and compete against Bosch. As much as I like Bafang, I will gladly give Bosch the edge due to its shift detection.
In my opinion, it's not necessary. Just be mindful when shifting gears (or consider Shimano's Link glide system).

6. The better question you should ask is 'how can I use a 104bcd?'. Bafang have always spec'd their motors with big chainrings. If you can get a smaller one or, replace the spider to a smaller one with a smaller bcd, then you'll find you can benefit from a conventional mtb/emtb set up. My Bafang ultra M620 M620 emtb's use 38tooth chainrings each and a gear ratio of 11-42. I would love to go to 50t in the rear but a 38t chainring due to the 130bcd makes is impractical.

7. Going back to point 6. Its unclear what the bcd of the chainring/spider is. However, anything less than 110bcd and your safe to assume that you can run a 32t chainring.

8. It'll either be the tool you are referring to or, a a shimano centre lock removal tool. Unfortunately, the method of removing Spiders on Bafang motors do differ on models and generations. Regardless, these tools are easily and readily available at any LBS.

Hopefully that's helped but if you need any advice, I'm sure there is a dedicated thread on the forum which may also help.

Good luck ?

 

[pelle]

Thanks for a prompt response. Understand that the torque sensor will kind of suffice for the gear sensor by just going easy on the pedals while shifting. I believe I would get brakesensors for my brake levers as part of a complete motor kit. As you write either they supply me a 32T chainring as part of the kit or I will need a spider with an appropriate bcd.
The frame would fit a bafang bt f03 or f04 so i guess I am stuck with that battery form factor, which limits the battery capacity to 600wH.
What is the chainline for the MM G520.250 ?
Is a DP C18.CAN compatible with the G520.250?

 

[savas]

why don't you buy the dengfu e10 and the m800 motor and do the mod which has been done by Karakoenig.You will achieve 17 18 kg with as far as i remember 600wh battery.Just look at this thread m800 build
this is what i plan for my dengfu with m600 but ill buy the motor later .
greets sava

 

[Jon A]

5. TBH, the only reason why Bafang developed the gear sensor was to try and compete against Bosch. As much as I like Bafang, I will gladly give Bosch the edge due to its shift detection.
In my opinion, it's not necessary. Just be mindful when shifting gears (or consider Shimano's Link glide system).

Are you saying your Bafang builds do not use a shift sensor? Or that even with the sensors, the Bosch system works better?

 

[Neeko DeVinchi]

Are you saying your Bafang builds do not use a shift sensor? Or that even with the sensors, the Bosch system works better?

The systems work differently. Where as the Bafang system detects tension in the cable via a sensor, Bosch detects cadence/torque/vibration. By contrast, Bosch is better as it will back off power the moment you shift and initiate quicker. Where as Bafang will back off power before the chain jumps up or down the cassette, resulting in a moment of loss of power.
Only one of my Ultra emtb's runs bafang's gear sensors now (oddly enough, the hardtail). The rest (full suspension), dont.
Honestly, it's not detrimental to a build if you use it or not but I guarantee, you'll notice the gear sensors flaws when up shifting on a technical climb.

 

[Jon A]

Good info. Thanks.

 

[pelle]

That's a viable option. The downside from my objective is that the e10 is not a hardtail, but that is only a weight consideration and I don't perform the kind of riding that require a rear damper. Feels kind of weird with a rigid front fork and an rear damper. Just checked the spect of Defung e10 and it stats m500 and m600 batteries, which are the BT F03 (450WA) and BT F04 (600WA). The E10 (full suspension) is also 500g heavier than the LCE1066 hardtail.
However since I am aiming for range a larger capacity batteriy than the F04 (600WA) would be preferable, so I still have some research to do. An alternative could also be to modify a F04with more cells, or simply carry a spare battery in my rugsack.
Maybe I am going down the wrong alley by adding a motor. I am intending to do a great amount of pedalling, just going longer distances and maybe get a little assist on the toughest hills. Hence the added weight of some 8-10kg might just be a penalty ????

 

[pelle]

The hardtail Dengfu E14 might be pretty good choice, it fits a M500 and a 48V (768WA) battery.

 

[pelle]

Has the Dengfu 48V 768WA battery the same form factor as the Bafang F03/F04 batteries?

 

[pelle]

why don't you buy the dengfu e10 and the m800 motor and do the mod which has been done by Karakoenig.You will achieve 17 18 kg with as far as i remember 600wh battery.Just look at this thread m800 build
this is what i plan for my dengfu with m600 but ill buy the motor later .
greets sava

Do the Dengfu frames come with an empty battery case? I cannot find anybody offering Dengfu batteries. Who offers the mentioned Dengfu 48v 768WA battery?

 

[3S1985]

Hi, when you order the dengfu frame it's a option to deliver the battery and motor with the frame.

Greatings

 

[pelle]

Hi, when you order the dengfu frame it's a option to deliver the battery and motor with the frame.

Greatings

Thanks, It appear the Dengfu E14 is pretty close to my target especially if I can get the 768wa battery. Do you order directly from Dengfu Sports Equipment Co., Ltd ?

 

[3S1985]

Thanks, It appear the Dengfu E14 is pretty close to my target especially if I can get the 768wa battery. Do you order directly from Dengfu Sports Equipment Co., Ltd ?

Yes i have ordered a e10 frame battery + motor directly so have several others on this forum. You just send a email to [email protected] specify what you want and where you are living and they will send you a quotation. More info is here in the forum just look for thé dengfu e10 threads?

Good luck

 

[pelle]

Yes i have ordered a e10 frame battery + motor directly so have several others on this forum. You just send a email to [email protected] specify what you want and where you are living and they will send you a quotation. More info is here in the forum just look for thé dengfu e10 threads?

Good luck

Thanks

 

[savas]

Do the Dengfu frames come with an empty battery case? I cannot find anybody offering Dengfu batteries. Who offers the mentioned Dengfu 48v 768WA battery?

you can buy only frame and battery box

 

[pelle]

Hi Pelle,
I'll do my best to answer but I suspect that others may need to chime in concerning the tolerances of Carbon. Strictly speaking, all bafang emtb specific frames I've built up are 661 Hydroformed alloy.
Anywho, here we go,
1. Traditionally, bafang have always been against 'over-vaulting their products to ensure longevity. In terms of vaults vs amps, The rule with Bafang (with the exception of the G510), the higher the vaults, the less amps you need. E.g. 36v 17amp, 48v 15amp, 52v 13amp etc. By increasing the vaults, you are ensuring the efficiency of the motor in conjunction with discharge rate which are not detrimental to the cell bank and not over working the BMS (Battery Management System). It is worth mentioning that sadly, Bafang have made it more difficult to reprogram the controller within the newer units. However, I am aware that a third party has stepped in to give riders this option but I have no information at this point as to this product. Naturally, I'll keep all who are interested updated.

2. Nominal voltage refers to the power required to engage the motor. In this case, its 36v (I know its weird). To cut a long story short (subject to the programming of the controller), Bafang motors can only recognize current but struggles to recognize vaults and amps. Only by using Bafang's propriety battery, do you have the ability to view each cell bank and discharge rate per cell (depending on the display you use). Case and point, running either 36v or 48v is fine.

3. This is where I ask others to chime in. Again, I'm more familiar with the Alloy frames.

4. Motor cut offs (brake sensors) are only required in the following examples
A. The motor in question is not torque sensing and instead is Cadence sensing
B. You choose to use the ebike as a speed pedelec+

If you're intended use is for emtb use, you don't need motor cut offs. If you choose to use the bike as a speed pedelec (up to 28mph) or faster or, wish to use a throttle as well, then you'll need motor cut offs. Personally, I use both Shimano levers with the cut offs and Magura levers with cut offs. The calipers however are all 4 piston front and rear.

5. TBH, the only reason why Bafang developed the gear sensor was to try and compete against Bosch. As much as I like Bafang, I will gladly give Bosch the edge due to its shift detection.
In my opinion, it's not necessary. Just be mindful when shifting gears (or consider Shimano's Link glide system).

6. The better question you should ask is 'how can I use a 104bcd?'. Bafang have always spec'd their motors with big chainrings. If you can get a smaller one or, replace the spider to a smaller one with a smaller bcd, then you'll find you can benefit from a conventional mtb/emtb set up. My Bafang ultra M620 M620 emtb's use 38tooth chainrings each and a gear ratio of 11-42. I would love to go to 50t in the rear but a 38t chainring due to the 130bcd makes is impractical.

7. Going back to point 6. Its unclear what the bcd of the chainring/spider is. However, anything less than 110bcd and your safe to assume that you can run a 32t chainring.

8. It'll either be the tool you are referring to or, a a shimano centre lock removal tool. Unfortunately, the method of removing Spiders on Bafang motors do differ on models and generations. Regardless, these tools are easily and readily available at any LBS.

Hopefully that's helped but if you need any advice, I'm sure there is a dedicated thread on the forum which may also help.

Good luck ?

Does Bafang make the 32T chainring they specify under the "M500 Drive System"? If so, who would market them. I think I have figured out the rest of the components so I could place an order on the Dengfu E14 frame with the 48V 768WA battery and the M500 engine. But I will will not budge on my requirement to have the (in my opinion) proper chainring. Is'nt it odd that them specify 32T/40T as the proper sizes and then not supply them?

 

[3S1985]

Does Bafang make the 32T chainring they specify under the "M500 Drive System"? If so, who would market them. I think I have figured out the rest of the components so I could place an order on the Dengfu E14 frame with the 48V 768WA battery and the M500 engine. But I will will not budge on my requirement to have the (in my opinion) proper chainring. Is'nt it odd that them specify 32T/40T as the proper sizes and then not supply them?

The motor is delivered with a steel chainring from bafang. Don't know the tooth count for a m500 motor maybe other members can give you this information.

The chainring is mounted on a spider 104 bcd size so you can fit aftermarket parts no problem...

 

[pelle]

The motor is delivered with a steel chainring from bafang. Don't know the tooth count for a m500 motor maybe other members can give you this information.

The chainring is mounted on a spider 104 bcd size so you can fit aftermarket parts no problem...

I am buying the whole package with frame, battery and M500 motor from Dengfu. They say they can only supply 38T or 44T chainrings. Shall I interpret what you write their 38T chainring is attached to a 104 BCD spider, which will enable me to detach the 38T ring and attach an other chainring of my prefered 32T choice?

 

[Neeko DeVinchi]

I am buying the whole package with frame, battery and M500 motor from Dengfu. They say they can only supply 38T or 44T chainrings. Shall I interpret what you write their 38T chainring is attached to a 104 BCD spider, which will enable me to detach the 38T ring and attach an other chainring of my prefered 32T choice?

I could be wrong but a 38t - 44t suggests a 110bcd.
Are you able to screenshot the chainring so I can view it in case I'm looking at something else @pelle ?

 

[pelle]

I could be wrong but a 38t - 44t suggests a 110bcd.
Are you able to screenshot the chainring so I can view it in case I'm looking at something else @pelle ?

These are screenshoots from Bafang components spects and the photo is what I got from Dengfu when I asked "What's in the M500 motor box", with the comment like "Something like this, M600 box". So the problem is that Dengfu doesn't really know (in detail) what he is supplying. They said we only have 38T and 44T chainwheels. We don't know the weight of the frame because we don't weigh the frame separately. It sound like the frame comes from an other source than Dengfu.

Could you tell from the photo if there are provisions to connect brake sensors or whould I not care about the brake sensors. A rear light maybe nice but there seems to be no provisions for that.

Regards,
Pelle

 

[patdam]

I am buying the whole package with frame, battery and M500 motor from Dengfu. They say they can only supply 38T or 44T chainrings. Shall I interpret what you write their 38T chainring is attached to a 104 BCD spider, which will enable me to detach the 38T ring and attach an other chainring of my prefered 32T choice?

right, as you can see in your pics, it is an 32

 

[pelle]

right, as you can see in your pics, it is an 32

Unfortunately what you see in the photo is only "Kind of " what they say they deliver, but explicitly state that they ONLY carry 38T and 44T chainrings......

 

[patdam]

Unfortunately what you see in the photo is only "Kind of " what they say they deliver, but explicitly state that they ONLY carry 38T and 44T chainrings......

i think we have misuderstanding. The motor is delivered with 38T or 44T, no mater because you put it in the trash (or you turn it into a work of art). because it is in heavy steel and it is a shameful to use it on a carbon frame. you replace it by a beautiful 104BCD narrow wide alloy plate in 32 , 38 or other you want.

 

[pelle]

i think we have misuderstanding. The motor is delivered with 38T or 44T, no mater because you put it in the trash (or you turn it into a work of art). because it is in heavy steel and it is a shameful to use it on a carbon frame. you replace it by a beautiful 104BCD narrow wide alloy plate in 32 , 38 or other you want.

I don't mind steel component on a carbon frame if they fullfill their mission and I will probably keep a 38T for hard times. Hopefully I can use the 104 BCD spider as you suggested and then everything might be resolved. Thanks for your response.
Regards,
Pelle

 

[thaeber]

I don't mind steel component on a carbon frame if they fullfill their mission and I will probably keep a 38T for hard times. Hopefully I can use the 104 BCD spider as you suggested and then everything might be resolved. Thanks for your response.
Regards,
Pelle

Like Patdam mentioned, You can use any 104 BCD Chainring. I‘m runnuing a 32 T Garabruk narrow/wide myself on the M500 cranks/spyder.

 

[pelle]

Like Patdam mentioned, You can use any 104 BCD Chainring. I‘m runnuing a 32 T Garabruk narrow/wide myself on the M500 cranks/spyder.

Absolutely if I get a a 104BCD spider I will be fine, nice to hear that you are also using a 32T chainring. Which motor and gear/cassette are you using.
Melody from Dengfu, approached me and offered to answer ANY questions, which sound encouraging.
Ebike is a new world to me, so I want to understand where the culprits are. Given long delivery times from China I find it important to base decisions on established facts rather than to find out by trial and error.
This will be my fourth carbon frame build. I bought my earlier frames from Airwolf in China. Established a very nice relation with a sales person which rendered him a lot of sales and me all the information I wanted. Unfortunately Airwolf doesn’t carry e-bike carbon frames.

 

[thaeber]

Absolutely if I get a a 104BCD spider I will be fine, nice to hear that you are also using a 32T chainring. Which motor and gear/cassette are you using.
Melody from Dengfu, approached me and offered to answer ANY questions, which sound encouraging.
Ebike is a new world to me, so I want to understand where the culprits are. Given long delivery times from China I find it important to base decisions on established facts rather than to find out by trial and error.
This will be my fourth carbon frame build. I bought my earlier frames from Airwolf in China. Established a very nice relation with a sales person which rendered him a lot of sales and me all the information I wanted. Unfortunately Airwolf doesn’t carry e-bike carbon frames.

I‘m sure You will get the crankset with 104 BCD spider. I‘m running a 11-46 10-speed Shimano SLX Cassette, same as Rob in the Cheeb uild thread. I‘m very happy with the gear ratio, fits perfect to the M500 behaviour. I need the 46 T sprocket only at extreme steep climbs, mostly the 2nd sprocket at 42 T is sufficient. Using the fastest gear ratio 11-32 You can pedal the bike up to 36-38 km/h.

 

[pelle]

I‘m sure You will get the crankset with 104 BCD spider. I‘m running a 11-46 10-speed Shimano SLX Cassette, same as Rob in the Cheeb uild thread. I‘m very happy with the gear ratio, fits perfect to the M500 behaviour. I need the 46 T sprocket only at extreme steep climbs, mostly the 2nd sprocket at 42 T is sufficient. Using the fastest gear ratio 11-32 You can pedal the bike up to 36-38 km/h.

Thanks for your response. I was thinking about the same gear set up.
Now I have a XT-12p 10-51 cassette and 32T chainring on my current mtb, that I considered shifting to the new build.Maybe I just keep the current bike intact and buy new 10p gear for the emtb. How easy is the pedalling when you tuen off the motor? Do you have to turn any parts of the motor when you are pedalling with power turned off. What charger do you use for the Dengfu battery?
Regards,
Pelle

 

[thaeber]

Thanks for your response. I was thinking about the same gear set up.
Now I have a XT-12p 10-51 cassette and 32T chainring on my current mtb, that I considered shifting to the new build.Maybe I just keep the current bike intact and buy new 10p gear for the emtb. How easy is the pedalling when you tuen off the motor? Do you have to turn any parts of the motor when you are pedalling with power turned off. What charger do you use for the Dengfu battery?
Regards,
Pelle

My pleasure ? I would recommend 10 speed with much cheeper cassette an cheeper / stronger chain. Wear is very high with the Ebike, and You dont need 12 speed with motor. I use the charger delivered with the motor/battery. He‘s a bit loud (fan noise) but I charge the bike in the basement. Pedaling without motor is ok, more efficient / less drag then the EP 8, also over 25 km/h. But You feel the weight of the bike....