6000+ Road miles on my BBSHD and I finally had to replace the Nylon Pinion drive gear. Not because of heat damage but because of wear. I don't climb any really steep hills with it(it's an Urban warrior/commuter in a relatively flat city) so I spin a lot of RPM to stay around 30-35mph on the busier streets. Replaced it with the PEEK gear just to help extend it's life because of wear... and piece of mind. Specifics: It started life driving an 8 speed cassette(Shimano HG51-bf group) with a 42t Bafang chain ring. Around 4000 miles on the motor I changed it up. Now it drives a Nexus Inter-5e with 27t Sprocket and a Lekkie 40t HD chain ring(2mm spacer behind it). The switch to the Lekkie was to correct the chain line to the IGH and keep the same 1st gear ratio. Chain line is strait as an arrow now. 1st gear on the Nexus Inter-5e is 1:1, so for those doing the math that puts me at 1.48:1 ratio in 1st gear. Which interestingly enough is nearly the same starting ratio I used in 1st gear on my HG51 cassette/42t setup which was 1.5:1. 5th gear on the IGH however is a HUGE 3.9:1 final ratio. I never use it... unless I'm riding down grade. It's larger than the 8th gear ratio(42:11, that I never used) on my cassette setup. 7th gear was 3.5:1 as it was and could easily hold me at 30mph with power set to 90% on 52v. Yes, I've reprogrammed the power levels in the stock controller.

The amount of experience and knowledge that is conveyed on this channel is incredibly useful and helpful and it has saved me from making some very costly mistakes (time and money) that I otherwise would have made if I hadn’t watched the related videos on this channel first. If you have a question or a problem related to mid drive motors, chances are it’s been discussed on this channel. It’s really appreciated and thank you, great channel!!

Words from the wise. 👍

It is better to replace a nylon gear than replace a motor, good old nylon fuse :)

Crucial information for current and future owners. Thanks team! 🥰🥰

I appreciate your explanation, it's simple enough most I think can understand this. I'll definitely forward your video to others in my community, the human body analogy is a good one.

Great video John!👍

My bbshd is also more than 5 years old and still ok, 2 times I opened it to clean and grease. Mileage is about 9000-10000 km per year, full throttle all the time, 52v battery.

Good video, John. You have a good radio voice, and you explain things clearly. Problem with Bafang mid drives is getting a small enough chain wheel on the front and having a decent chainline. I have a 42 tooth lekkie knockoff on the front, anything smaller gives a horrendous chain line. It would be nice to have a 32 or smaller on the front for trail riding. Not really interested in speed, it s a bicycle not a motorcycle.

I finally built my KTM fatbike and went for my first ride, blew the nylon gear after 10 minutes. 2800 Watts, full throttle, 80km/h BBSHD 46T up front and 14 in the back...LOL, I didn't know about this video, now I do.....

Great video John. I have a BBS02 with 44 front and 14 34 rear and a BBSHD with 42 front and 11 42 rear. no problems at all with overheating or the nylon gear but I do as you advise use the gears correctly and keep it spinning uphills. Both running 48 V so not overstressing at all. Still important to be in the correct gear mind you.

Just as a side comment this video is mostly useful for those people who are using a controller which allows for field weakening of the motor. Normally motors don't spin up to 13000 rpm so a one to one gear ratio is really only useful if field weakening is used! I know you mentioned this in the video but it is important and bears repeating! I set up the high voltage kit on a shimano Alfine geared hub and the first time I rode it I could hardly keep the wheel on the ground. The Alfine in the lowest gear is very low! Besides the fact I think I broke two spokes in the process I quickly changed it out for a cassette which I locked to the lowest gear as the Alfine would not take that kind of power without destroying itself! This video is really for single speed setup as far as a drivetrain goes! Keep up the good work!

Hi John, I'm glad you mentioned that you still have your nylon gear. I was quite concerned about this on my recumbent trike as I have the HV upgrade kit without the peek gear. I will take my BBSHD motor apart and regrease it before putting the trike back on the road. Great video, by the way.

Thanks!

Excellent. This video is timely I am about to rebuild up my Surley Krampus with my BBSHD. Thank-you.

A 42 to 42 is impossible to peddle the cadences is much to high that why I use hubmotor a can peddle along at 45 km to 50km hour easy with a 50 tooth on the front and a 12 tooth on the back

hey man thanks for all the good info in your videos. im converting a -05 bighit with a bbshd and have 42t front and have ordered a 30t singlespeed for the rear running with a 24" rear wheel. i dont have the money for a bac800 yet so i bought a fsesc 75100 and will add extra cooling. thinking of running 50 battery amps and 80-90 phase amps at 72v and some field weakening but im unsure if my gearing will be an issue do you have any input on this? keep up the good work cheers!

Nice video John..if only some one could Bolt à 3 speed gearbox on the BBSHD and have a gates belt life would be perfect..ps next time talk about stress on the drive chain...anyway keep up the good work many newbies will learn from our mistakes. 👌👌👍👍

Good video, thanks for the info.. I’m waiting to get my cyc x1 gen4 and I’m trying to get as much knowledge about it as possible before installing it. I don’t want to be the reason something happens lol

10t

I run a bling ring 42 up front 9 speed on back or my 29er 11 smallest 800 miles on my BBSHD 52 never had a problem so far been great

I have a 46 tooth in the front and 16 tooth on the back with my 8 speed i.g.h i keep it in 4 gear or 5 gear and its good i have had my bbshd 3 years and i have a 3300 watt controller on it.

I only use smaller cogs on the flat or going downhill, while pedaling as fast as I can. I use it as I would a standard shift automobile.

I've finally got my build together enough to test it and see how it runs but for now I'm stuck with a 46 tooth crank gear that came with the motor. Any other gear that sits any closer or is a smaller diameter will hit the frame. The bike Ive installed it on has a 7 speed shimano with the largest gear being a 28 T. Something has to be changed. I took it for a quick spin and hit 45 mph and put it away. It was plenty warm

Awesome video. I understand how important gearing is now, but had to learn the hard way. Wish you had started your site sooner;) Interestingly I burned out my stock controller before wearing out any mechanichal parts. Have since switched out my stock controller for a Ludicrous (was scared to go external then but regret my ignorance) & the 8 speed cassette for a wide ratio 10. I'm also running 42:42 for a granny gear. I like that your controller set up allows for gentle use of the throttle in 1st, mine bucks the bike in lower gears (good thing I usually pedal). The 42:42 may not be "fast" (with most controllers) but will climb anything the wheels can grip, without hurting the motor. May I assume that you're running 72 volts to achieve a reasonable top spead in 1st gear? If I used my BBSHD, at 52 volts, only in 1st gear my top speed wouldn't make "class 1".

Always check you Watts on climbing when it's too high it's time to gear down

Thanks for that explanation. I ride a recumbent trike on a regular basis. I started with a Bionx Hub Motor which lasted me about 6 years of trouble-free riding. Then I fitted a Bafang BBS02B Mid Drive motor which blew my mind with its power and acceleration. But it only lasted for about 4000 km and kept getting very hot. Now the acceleration was such that I tended to change up gears by 2 or 3 at a time to keep up and after a few minutes, I was in top gear and doing about 35kph. I was still pedalling only because I used a 65T chainring which allowed me to pedal up to say 50kph. As my small (top gear) was about 11t, you are going to tell me that I blew up the motor because of my large chainring! Well, what is the answer if I want high-speed cruising and pedalling at the same time? Should I go back to a quiet hub motor with no gears or is there an IGH which can handle gear changes electronically better than I can manually and maybe employ a speed drive on the front? I am now trying a BBSHD 1000w which I was told is more bullet-proof than the BBS02B but it is still annoying the hell out of me with derailleur noises of clanging and banging and a slipping chain. I have since found a chainlink with a serious kink which is probably causing a lot of that noise and can be fixed by elimination but what is the solution to my problem?

My bbshd is still good 4 years later and i still have nylon gear and it has 3000 watt controller. It does not heat up that much it will hit 40 degrees but its winter here

AM Racing AMR 250-90 Single AC Motor - Liquid Cooled, Permanent Magnet - Remy Cartridge [AMR 250-90] Price: $10,900.00 Motor Diameter: 10.5 Inches Motor Case Length: 11.25 Inches Motor Shaft Length End to End: 12.25 Inches Peak Torque: 280 Lb Ft Peak (w/150kW controller) Peak Power: 210 HP Peak (w/150kW controller) Max RPM: 10,000 you crash that you going home in a bucket we just need 1 megawatt batts in aaa size 🚴

Need help with my Trike Project gearing.

What would be a good ratio if you are using a Enviolo 380 hub? Now with "human power", I use a 24 up front and a 17 in the rear. Have a 34 also up front to, but it hasn't enough bottom end.

I liked the way you broke this down, but I find it crazy that this isn't common sense in this day and age

Ride your ebike like you would a non ebike - always be in the correct gear. As he said: low motor RPM = inefficient (heat) - it is also is still putting out a load of torque, ready to break anything that's been weakened. The heat soaks into all the components, to the point that it can soften the plastic gear (=failure), demagnetise the magnets in the motor (=failure/permanently reduced power), it can even melt the glue holding the magnets in (normally a CYC thing). It's a bicycle with some electrical assistance, not a f'ing electric moped - ride it as such! Oh, It can go the other way too............... Motor spinning too fast = making its own magnetic field, that gets strong enough to interfere with the working of the motor = loss of power (over simplified) There's a thing called "Field weakening" to deal with this, but not all motors have it.

Original nylon gear on mine and not a single issue. Just remember to gear for torque as much as possible, especially if you are on less than a 72v setup.

Hello John! I want to ask you something I haven't seen anyone talk about in the diy ebike world. I want to build an ebike with a cyc x1 stealth gen 3 motor and a 52v battery and since I've always wanted to have a wheelie machine, that's exactly what I'm planning on doing quite often with my ebike. I'm planning on using 38t drive train, a 12 gear cassette and wheelie in 1st or 2nd lowest gear and very often use throttle only, even for commuting. My question is, is it possible to do that without burning the throttle (I'm planning on using a motorcycle Domino throttle soldered to a female 3 pin so it can work on the ebike) and without burning/braking the motor ?

Has anyone changed gearing ratios internal to motors. EG, alloy a higher rotor RPM relative to crank RPM. I find my body generally prefers a low pedal cadence. And this then tends to lug the motor more. If you could adjust the internal gear ratio between the motor rotor, and the cranks/output. Then you could spin that motor up higher, for any given pedal cadence.

How can I figure out gear ratio for a trike with jackshaft? I'm running the CYC X1 Pro Gen 2 with stock spoke. Going to jackshaft. From jackshaft to differential axle

I've been trying to destroy my bbshd since 2019! Wrong gear, full throttle up hills that I can hardly climb on foot and my motor is still killing it! 2800 watts of Boss power. Nylon gear. I do usually run 42 x 30 minimum. Yet when I ride my fixed gear road bike by leg power I run 52 x 16.

hello, I'm running a bbshd stock with a lekkie 52t and 21t at the back with a shimano nexus 8, sould I replace the rear cog? which size?

If I only want 3 gearsin the back, what other 2 should I use besides a 1:1 42? an HD and bac800 setup?

So does this mean the optimal human and motor powerbands are mutually exclusive? You'd be spinning at an incredible cadence running 42t-28t at 60kph. Does this not also mean that gearing for pedal assist at human cadences means lugging the motor to some degree?

If the motor is designed to operate at a speed/rpm that is above the optimum cadence for efficient human muscle operation then it seems to me that quite apart from the fact that the system will be biomechanically inefficient torque and cadence sensors will also not work effectively since you will not be able to spin the cranks fast enough or apply sufficient torque via the cranks. I assume that in such a situation one needs tou use the throttle and peddeling becomes effectively useless. What of the situation where you want the motor to work at maximum eficiency so as not to get hot but you also want to make a contribution via peddeling? In this case would it be better not to overvolt the system and for that matter what rpm are ebike motors designed to work eficiently at? Anything more than about 60rpm at the cranks would seem to be wasteful of muscle power since if I recall correctly muscles work best at about 60 rpm. Surely a motor that can break it's gears is a badly designed one since it's gears should be designed to withstand the maximum torque that the motor is rated to supply. If you try to force the motor to supply more torque than it was designed to supply then would not a fuse safeguard from both broken gears and burned out windings?

Yes, but what is the max speed using 1:1? Using 26" wheels? Edit; with a BBSHD

You did the subtitles it seems much better to me...... And nice to see you in first person with the new backdrop remains only one thing, if you allow me The light that illuminates you from the front is too strong. I think you make your face as white as a sheet of paper. Don't get me wrong, it looks good, but seeing it from your phone, with the effect of the view, seems to blind you dazzled by a ship's lighthouse. Your eyes then, suffer extremely the Cap, it can barely protect you a little. And just a thought that I see through the smartphone, if everything is OK for you pretend not to have read. 👍❤️😉💯

A 1 to 1 gear ratio would mean a 26 inch bike with 2meter tire circumference that goes 30 km/h needs a tire rpm 250x and therefore a cadence of 250 per minute. Who can do a 250 cadence? Answer: No one can! So you got a 1000 Watt Motor that should be good for at least 40 km/h but you are not allowed to use a gear ratio that enables the rider to pedal with the motor in an acceptable and doable cadence. An acceptable pedal cadence at 40 km/h would be 90 rpm so the suitable gear ratio would be 1 to 3,7. In your theory this would damage the motor. If this is true all these mid drive motors are completely trash.

Abruptly ended there

Well i did a total of 17.2 miles on my brand new Bafang 750w correctly using the gears and also fitted with a gear sensor and on the last six miles of my journey and also the flattest part on a smooth road for 6 miles and flat out 32mph the motor started to whining like a dog on heat, i get home check the motor, wtf, you could have cooked a full english breakfast on it, it was that hot, i checked things out and it seems some part of the internal workings are bevelled and under pressure push a gear/cog outwards that starts to rub the inside of the motor housing, on that note and after another two similar episodes i sold the badly engineered piece of shit motor.