Broken Axle Inspection Bafang Hub Motor. Regen Braking Gone Wrong
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- เผยแพร่เมื่อ 29 ม.ค. 2025
- buymeacoffee.c... I broke the AXLE (!!) on my Bafang G62 hub motor! Let's look at this terrible catastrophe that occurred on my e-bike. I inspect the damaged motor, and install a spare motor. I contemplate mortality, divine miracles from above, and thank the heavens to be alive
![Winter Had Mercy This Day [2025 Ebike Vlog #2]](http://i.ytimg.com/vi/tanPfzKF1uM/mqdefault.jpg)
I thought breaking a crank arm was a strange thing to break, this beat it. Seen a guy waiting for traffic, soon as it was clear he tries to bolt and started pedaling so hard a crank arm snapped, he ended up on his face.
@@Ro-Bucks that’s some Hambini stuff!! its dangerous for crank arms to break on a bike you’re pedaling. There have been big recalls like the shimano one recently where i think water could get into the crank arm and corrosion was occurring from the inside out
Ya I'm thinking regen. is most likely what caused that to shear off like that. Glad you didn't get hurt. Be safe!
Aaron
@@aaronbinder6903 yup the way the axle was twisted into one dropout but the other was still clamped into the v7 torque arm makes me think you need double v7 torque arms. And probably an m14 axle
I've got a couple of these from Grin with the locked clutch and V7 torque arms. On both my fatbike and fat tire recumbent we use these on, the non-torque arm side nut tends to loosen up over time. The axle will then twist ever so slightly going from powered drive to regen, eventually resulting in this. On my setups I've mitigated this with a double-nut and some blue Loctite, though i'm not running as much torque for both forward and regen as you are. In your case I would look at a torque arm on both sides to eliminate the possibility of one side or the other introducing some rotation.
for acceleration i use 60 to 80 phase amps And regen braking i had set lower like 50 to 60 phase amps. But it seemed no matter what, the regen would wiggle something loose, even with one v7 torque arm. If i do it again will be m14 axle and two v7 torque arms for sure. Thanks for sharing your experience, thats very helpful!!
You may have reached the limit of these geared hub motors (particularly with the 12mm axle). I've watched other geared hub fans go through half a dozen failures trying to max them out. I gave up and went DD with a motor similar to a QS205... BUT you need a high discharge battery and suitable controller to make up for the low speed torque loss without the internal gear reduction.
But… i haven’t even tried the steel gears yet! 😭😂😉 I think i might take a break from Regen for now 😅 but i still have some experimentation to do. I wish i had one with an m14 axle. I have a front g61 1000w hub with m14 axle i am saving for some day Maybe I’ll get a m14 axle rear one. I have seen the DD hubs like qs273, but the wheel weights 40 pounds and you need a motorcycle battery and controller, imo qs273 isn’t really an ebike motor And even the 205 is pushing it but i might try one in the future. I just don’t like heavy bikes
@EBikeBuilder_ Will that front g61 with a 14 mm fit in the rear case?
That's so bizarre that it broke out of no where.
Yeah if i ever try regen again its going to be with double v7 torque arms, because it seems the axle was able to twist on the opposite side with the v3 torque arm . Regen is crazy with these things
@EBikeBuilder_ the guys over at Spark said one of the reasons they got rid of regen was because it broke an axle during their testing
Maybe bafang didn't expect someone to pull 250nm out on that motor😂😂😂❤
Scary! I have one bike that uses a G062 running at ~3kw peak and now I'm rethinking those controller settings
@@anthonysuarez7416 yeah i looked up the sheer strength of the m12 axle and its like 170nm… so its possible for this thing to break its own axle if you dial it up enough. I ran my other g62 at 90phase amps for years never had a problem with gears braking or anything until i started doing regen. I think the back and forth of regen torque had a lot to do with it , i probably should have used double v7 regen torque arms. If you have a m14 axle on your motor that one has 59% more sheer strength 280 nm ish. I would feeel a lot more comfortable with the m14 axle
That is one strong torque arm! Maybe you need to flatten the tops of your welds with a file/grinder. If the weld is pressing against the motor housing bearing maybe it's putting sheer stress on the axle. Like kicking the axle on a slight angle compounding the stress on the other end?
I think that one has taken a beating with so many keys sheared and all the crazy stuff you have experienced. Maybe M12 is a bit small for that. So maybe M14 shaft would be better for regen. Good topic man. I wonder if it would be better to have some kind of rubber bushing for the torque arm so it can reduce the impact of the torque on that shaft.
strange that a geared hub motor can do regen. didnt know that existed
@@jay7264 welded clutch on the planetary gear carrier
[Regen + Grin pinch = Twisted Axle] ?? I'm wondering instead of doing a direct weld on the clutch if you could weld one end of a spring to the center piece of the clutch and the other end to the top of the clutch so there's some buffer when going back and forth from regen. Like a big diameter shallow spring?. There's about 1/4" to 3/8" of space between the clutch and motor casing maybe?
It's the (repeated) suddenness of the regen that caused axle failure.
If regen was activated by brakes, perhaps you should use a second thumb throttle instead.
Ive seen a few builds on YT showing regen connected to a thumb throttle so you can modulate the regen intensity - and presumably how fast/hard it ramps up.
Are the axles heat treated at the factory? If so, could the welding have gotten the axle hot enough to damage its heat treatment?
I am having a difficult time finding a Single Speed Cog with 42T.Any suggestions?
Pinion P8200 rear cassette spider and then use a 104 BCD chainring thats 42T
Thanks again
Maybe welding on it tempered the axle so it was too soft?
Holy crp😮
Maybe time to slap the BBSHD and Flipsky on that bike instead of the hub :)
@@Hybrid600 this bike with the bbshd was my first diy build in 2020 . I never tried it with high voltage tho 🤔 it has crossed my mind many times 😈
Hey Bro,quick question.I just set up my bike with single speed and the chain keeps Skipping.Is this because the Chain is too long?I have a tensioner on.BBSHD
@@JOHNDENVER4848 if the gearing is too high and you run it too hard it can skip, happens frequently with small rear sprockets - like 11t or 12t rear sprocket, where it only has a small amount of teeth. For example on 48v my bbshd would always skip in 7th gear because the 11t sprocket. The chain will have to be slightly too long on a single speed, or you can’t join the chain. If its too long shouldnt matter as long as the tension is there. What is the gearing on your bike? The bbshd likes it geared lower with a fast pedal cadence (its always kind of ghost pedaling with the HD on full power) My bbshd on 72v with the 42T rear sprocket never skips. its the chain tensioner that is the hardest part to get right. If your chain tensioner doesnt have a spring or a clutch like a derailleur then it can come loose easy. When i was using a junky tensioner it always came loose. But usually the chain drops not skips
BBSHD
I'm running 52V BBSHD 42T up front & 18T in the rear with a 2 wheeled tensioner with a spring.I think my 18T may be a little off center it's really hard to tell.im going to get that centered and if that doesn't fix it I will use you Suggestions.Thank you so much for responding and just FYI you have Great Videos your a Ton of Help!!!!!!!Thanks again
@@JOHNDENVER4848 are you using a stock controller or external? I'd imagine it would put too much load on the motor going up hills with only an 18 in the back? I'd go with a 42 rear so you have a 1:1 ratio and put on an external sine wave controller with a clutch rear derailleur. That would make it pretty bomb proof and keep the motor in the upper rpm's where it naturally works better.
Ok will surely take your advice.I have this BBSHD Modified Controler that puts out 60Amps
Is that the Haoqi Cheetah motor you broke or another one? I was thinking of getting a Cheetah as it's on the CA CARB Ebike Incentive program I'm waiting on my voucher to get issued in Feb I hope. I think it must be the regen that snapped that axel & the "Freegen" motors shouldn't do that. Ah so that's a bicyle conversion of a Walmart bike? I think regen braking would cause more torque than accelerating & the cold makes steel much more brittle. Low temp steel is used in artic construction for just that reason. Maybe you can do a Cheetah review update for us CA voucher users trying to find the best ebikes on CA's approved list to pick from.
duuude what are u doing ! xD