Hallelujah : The BBSHD Steel Gear Is Finally Here

For years I’ve been anxiously awaiting someone getting their act together and mass-produce a steel gear to replace the crappy nylon gear in the BBSHD. The mad scientists at Lunacycle have designed and machined a replacement steel gear and are selling it for $42 here. This gear is slightly smaller than the nylon gear it replaces and comes pre-lubed with the quietest lube they could find. This article is about all the reasons I hate nylon gears (they fail) and why this steel gear is a must-have option for anyone who is running their BBSHD at the limits of its ability. If you are rocking a Ludicrous 60 amp controller or plowing through deep snow, whenever you get around to peanut buttering your nylon gear do yourself a favor and buy this replacement gear and not the nylon one.

You can see the steel gear is slightly shorter which cuts way down on weight and noise

The original nylon gear is a weak point in both the BBS02 and the BBSHD drive units. I understand why Bafang chose to use the nylon gear, since it is a failure point on the drive unit, if there is a serious issue with heat or stress it is much more likely that the nylon gear will fail rather than the motor getting destroyed. On top of that, the nylon gear is also much quieter than a steel gear would be.

The original nylon gear weighs in at 98g so adding a steel gear will add about 70g

Lunacycle sent me an earlier steel gear to test that was much heavier at 340g which worked well. They decided that the gear was just too big and machined down not only the size but also a good deal of the steel inside the gear which was unnecessary. This extra effort shaves a 175g of weight off the gear effectively cutting the weight in half. Since there is less metal in contact with the motor the gear is also quite a bit quieter. These steel gears can be noisy when you first put them in, but they get quieter quickly as the gears ‘break-in’. The steel gear also ships in a plastic bag full of grease (be careful not to get the grease inside the gear where the bearing clutch is).

This shows the weight of the gear with the grease and a foam plug to protect the bearing clutch (claimed weight for gear only is 165g)

The nylon gear installation is relatively straightforward and involves pulling off the controller and the motor. Although you can do this with the BBSHD on the bike, I feel that it is much tougher to do it that way and I recommend pulling the motor off the bike to replace this gear. For full instructions on replacing the nylon gear on the BBSHD you can reference this old article. I’ve replaced about 5 nylon gears on BBSHDs and 3 of them on BBS02’s in the last 4 years but I also beat the hell out of my drive units in deep snow. Even with all that experience it still takes me about 40 minutes to replace the gears and often I end up stripping the insulation off the motor wires when pulling the motor out. I find that just putting heat shrink tubing over the phase wires where the insulation rips is the easiest fix for torn insulation.

I am currently testing this gear and will post any updates to this article if I have issues. It is slightly louder than the nylon gear, but I expect that like my M600 with steel gears, it will quiet down quite a bit after the first 100 miles or so.

Here you can see the original prototype of the steel gear which is full size, what you get will be much smaller

This steel gear has been in the works for years now, and I’ve been chomping at the bit to try them. I find it crazy that it has taken this long to get this product to market, as it seems like there would be a huge demand for them. I bet that the BBSHD with a steel gear can easily produce 100 Amps peak without self-destructing, now it’s time for someone to design an even more Ludicrous controller which puts the 60 amp Ludicrous controller to shame.

Maybe we can hit plaid.

Ride On.

30 thoughts on “Hallelujah : The BBSHD Steel Gear Is Finally Here

  1. But just as you mentioned, the nylon gear is designed to fail first to protect other parts of the BBSHD. Using this steel gear, won’t it just push the failure point somewhere else?


    • Ik ben het met u eens. De Bafang motoren zijn niet begrensd, daarom kunnen ze makkelijk overbelast worden. Vooral in de US gebeurd dit omdat de wet dit toelaat. Hier in Nederland mag je niet harder rijden dan 25 km per uur. Alle e-bike fabrikanten zoals yamaha, bosch, Shimano, Impulse, Brose, hebben hun motoren begrensd. Voordelen zijn; langere levensduur, minder onderhoud en grotere actieradius. In de US doen ze ook andere dingen met de Bafang, zware belasting door bergop rijden en terrein rijden. Ik had nu 20.000 kilometer gereden met mijn Bafang BBS02 750W 48V en moest de hele motor demonteren, nieuwe stuwlagers gemonteerd omdat er veel speling op de trapas zat. De Bafang maakte lawaai, dit kwam door het meedraaien van de rotor as in de lager behuizing. Schoon gemaakt en vast gelijmd met loctite 641. Ook de accu was versleten, nu een accu van 48V en 17.5 Ah. Ook de spaken, assen en velgen van de wielen vervangen. De V-brakes hadden de velgen doorgesleten. Mijn ebike is nu weer in top conditie.


  2. Will it fit ELux bafang motors as I have already melted the nylon gear? Thx

    On Wed, Nov 20, 2019, 7:24 AM ElectricBike-Blog.com wrote:

    > Karl Gesslein posted: “For years I’ve been anxiously awaiting someone > getting their act together and mass-produce a steel gear to replace the > crappy nylon gear in the BBSHD. The mad scientists at Lunacycle have > designed and machined a replacement steel gear and are selling it f” >


  3. Thank you, for your article sir!. I am going to get that before I put my bbshd together on my catlike. Often people don’t find out until sometimes to late about benefits to their projects, I guess good luck is a waiting game. You, and Luna cycles have created justice, all over again. Thank you.


  4. Hier in Nederland mag de Bafang niet zwaarder zijn dan 250 Watt. Ik heb de Bafang BBS02 750 W, hetgeen eigenlijk niet toegestaan is. Ik heb een smeerpunt gemaakt zodat ik het nylon tandwiel van buiten af kan smeren met white grease spray, een keer per jaar is voldoende. De Bafang BBS02 heeft twee kwalen. 1. De lagering van de rotoras gaat rammelen in de behuizing, oplossing ? zie You Tube bij: Bafang 8fun BBS02 BBS01 motor shaft noise or missing o’ring = Loctite 641 procedure. De autur is BrunoPOWEEER. Kwaal 2 zijn de druklagertjes/ stuwkracht lagers in de hoofdas van de clutch. Als je hard mee trapt op de pedalen, dan komt er veel druk op deze kleine kooi lagertjes, de kogels lopen uit het lager omdat de kooi verslijt. Deze kleine stuwkracht lagers bestaan uit drie delen, te weten twee lager schalen en een kooikogelkrans. Te koop bij Aliexpress.com Bafang spare parts . Opmerking: bij het smeren van het nylon wiel, mag geen vet bij de uiteinden van de rotor as komen, anders gaat deze as in de lager behuizing mee draaien. Maar ik heb de uiteinden van de as, vast gelijmd in de behuizing met loctite 641, het gevaar van meedraaien is daarmee uitgesloten.


  5. As you say – about time👍🏻

    Point taken re: the nylon gear being sacrificed. I have 3 BBSHD’s but do not ride them hard in MTB mode. I swap my units on 6 available bikes including an MTB, road bike, beach cruiser and 2 folding Bromptons. I might buy one but not 3 and even then they would have to be available in the UK which they probably wont be🤔 For now i will stick with the softy-ridden Nylon ones but look forward to updates on the Steely👍🏻

    Laurie –


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  7. As being associated with the gear makers for longer than comfortable….I can tell you why it’s taken so long.
    They are generally a pain in the ass…..


  8. The nylon gear is meant to shear before you break something else, replacing it with steel is a fools errand. It’s also nice to have for liability (of the original company) if the motor is running, and say someone gets their hand stuck in a spinning wheel under power. It’s a passive safety that’s always there Phenolic and nylon gears are typical in machines with rotating components that can eat operators.

    Also, that to me clearly looks like a COTS gear they found and will work for the application, not custom machined gear. Properly spec the motor or leave the gear in place….


      • I run mine at 72 volts 50 amps… but I use a gear ratio that is kind to the motor. I run my bbshd 50kph up 10% hills. It gets warm but not nearly hot enough to need the steel gear. I bought one cause a spare is sensible. I don’t expect to need it any time soon though.


  9. There already is a more “ludicrous” controller. Its called the bac800 and it beats the crap out of the Luna controller. I will try the steel gear if I wreck the nylon one. But so far I have had no issues either at 50 amps 52 volts or 72 volts. If you are wrecking nylon gears regularly then I’d take a look at your riding style and gearing!!!


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  11. Hallo Captain Codswallop, It is important that you kick along well in a light gear, so a large gear of your cassette. I put the support on position 2 or 3. Then you use little power and the engine does not get hot. I also climb 10% slopes in the Alps. If you are in a hurry and you let the engine work very hard, you will go more than 20 km pro hour, but the engine will become blood hot. I prefer to keep it whole, it costs enough.


    • You make a very good point, the right way “use a big gear on the cassette”.
      Many people swear by Running a 30T on the BBSHD to reduce load on the Nylon gears. In itself this does nothing! If the motor makes a large amount of power, then that is the amount of power applied to the Nylon gear before it leaves the crank hub, and before any secondary gear selection.
      Flat out is flat out and full load on the motor is full load On the Nylon gear regardless of what bicycle gearing is selected.
      In fact a 30T front driving a straight chain Lind to a 15T rear is the exact same ratio as a 42T front driving a straight chain line to a 21T rear.
      I’m not playing with the big boys for power but I can ride straight up 100 metres of stairs in 40T to 36T Gearing on a 52v HD set at 25A.
      on any Steep dirt surface I find any lower gearing just creates wheel spin that reduces how far one can get up a hill.

      Liked by 1 person

  12. Rij sinds een paar weken een BBSHD zelfbouw MTB met 8 versnellingen. Bevalt goed en twijfel over aanpassen interne gears en mosfets. Heb er nog maar 800Km mee gereden en veel tijd besteed in het africhten van de PAS ondersteuning. De motor voelt niet warm maar lauw aan, trek gemiddeld 800~1300W constant in me dagelijkse woon-werk verkeer. inhouden met snelheid doe ik niet (zomaar) aan. Zelfs niet bij een helling a 7% voor 1,1KM lang, 50km/h zie ik veelvuldig op me LCD scherm. Wel veel meer bezig met schakelen (dan e-bike met 1500W front hub) tijdens rijden maar gaat steeds meer vanzelf.

    Rijgedrag is meer vergelijkbaar met een opgefokte scooter (Trek ze eruit bij stoplicht)

    Vreemd genoeg heeft me Bafang 46T crank als eerste gefaald, en niet de versnelling casette of ketting. Dat grote lompe ding is al scheef getrokken op enkele tandjes bij standaard uitrusting?! Gelukkig van metaal dus heb het maar terug gebogen. Loopt sindsdien weer goed!

    Hoe kan het dat een Nylon gear dan langer meegaat? Heb ik wel een metalen tandwiel nodig…
    2000Watt lijkt mij ideaal voor deze motor zonder schade op lange termijn.
    Iemand ervaring?

    Liked by 1 person

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