How To Ride a Mid Drive Ebike Without Breaking it

With few exceptions, everyone who can ride a bicycle already knows how to ride a hub drive ebike. Not so if it comes with a mid drive. Particularly a powerful one that can tear your chain apart. Here is how you flatten the slope of that learning curve.

“Mid Drives For Dummies”

This article is based on a portion of this post where I discuss the strength and weaknesses of different types of ebike motors. I link that article many times in help discussions, but usually only for the part about how to ride a mid drive without excess drivetrain wear, mechanical failures etc… so I am creating this standalone post on the subject… and stealing liberally from the original.

Mid drive motors on ebikes are very common in the production-line, name-brand-manufacturer ebike world. Its safe to say they dominate the industry for eMTBs for example. Why is this? Well, hub motors power the bike thru the axle, so they are single-speed. That means they are not particularly effective climbing hills… unless you throw the rule book out the window and run gobs of power thru them.

Unlike hub motors, mid-drives power the bike thru the drivetrain. That means they can thus use the gears. Just like you do – to get up a hill. This is a good thing for all the reasons its a good thing for you, trying to fight your way up that hill. You’d be nuts to try and do it on a single speed bike. So how is it desirable to try and do that with an electric motor? Well of course it’s not. Unlike with leg muscles, a hub motor is often strong enough to get you some benefit up that hill. But its not happy doing it, and its not good for the motor or (if it has them) the gears inside of it.

If you have only had a hub drive ebike you won’t realize just HOW unhappy until you take your first proper ride up a steep hill on a mid drive ebike.

The benefit is multiplied when you look at a mid drive’s motor specs. Usually they are more powerful than a hub drive by a wide margin. A typical hub puts out 40-60 Nm of torque, with a few going up to 80 Nm. Production mid drives usually start there as the bottom end. Aftermarket motors commonly put out 120-180Nm.

The Cyc X1 powering this Guerrilla Gravity Smash delivers 180Nm of torque to the drivetrain. Couple that to the small front chainring and steel gear cluster in back: you can climb a tree with this thing.

So What?

Well, if you aren’t familiar with what it means to have X Newton Meters of torque going thru your drivetrain, lets use the more common (but functionally useless) measure of watts. That 180Nm motor pictured above has a peak output of 3000 watts. A BBSHD or a Bafang Ultra peaks at 1750 watts (peak power on the BBSHD can also be maintained continuously so its REALLY a beast). A 48v BBS02 is about a thousand watts. And your typical street-legal pissant EU motor is rated for 250 watts (pssst… the manufacturers are now cheating on this. Don’t tell anybody).

Now put those numbers above into perspective: A normal cyclist on an analog bike is capable of putting out roughly 300 watts over the span of a few minutes. A professional sprinter/mutant can hold almost a thousand watts, but only for a minute or two (thats not enough to make a slice of toast).

ohhhhh…

Yeah ‘oh’ is right. Your mid drive is pumping a metric shipload of power thru your drivetrain. That power is likely more than standard bicycle parts were meant to handle. So how do you have a motor this powerful (its not as much of a boost as the math makes it sound like) and not bend, break or snap stuff?

It Ain’t Hard To Do Right…

…but you gotta do it. Here then are the rules of the game when riding a powerful mid drive motor.

The Short Version: Keep the motor spinning.

Now the Long Version:

Keep The Motor Spinning

Here’s a basic tenet that is true of all electric motors: Electrical power goes towards turning the motor and producing forward momentum. If there is resistance – which keeps the motor from free-spinning – then instead of forward rotation, the electrical energy is converted to heat. Mid drives have so much power that they can get really hot, really quick if not allowed to spin up. But they are so powerful, they might not just stop at generating heat.

Lug a powerful mid drive and the torque that is pouring out of it could tear your chain apart, if it can’t rotate it thanks to resistance. Barring that, you might discover what it means to ‘taco’ your front chainring, or rear cog. If your sins are not quite that egregious, and you just lug it gently enough to not tear something apart, then it can within the span of a single ride ‘peanut butter’ the nylon gears inside your motor; bricking it and potentially requiring you to carry the bike anywhere you plan for it to go. 

Thats very, very bad. So don’t let it happen. Here’s how we do that:

When Coming To A Stoplight, Downshift!

Always. Either that or stay in a gear that is in the middle of your cluster so when you start up again, the motor does not lug itself you spin up quickly, without any brutality being visited on the drivetrain. From a standing start, a mid drive will slowly tear into the cassette body, or damage the pawls inside. this will eventually tear the freehub apart and kill the hub. Which means you get to build a new wheel.

But if you downshift so the motor doesn’t tear into your drivetrain when you start back up again, you’ll be fine. So remember: downshift before you come to a stop.

When You Want to Go Faster, Upshift

When working a mid drive, just like driving a classic sports car, you have to ‘row’ thru the gears, both slowing down and speeding up. Wait until your motor is maxed out before you kick it up a gear. Chances are good its going to be smarter to stay one gear down from what you would have used without a motor as your bike will spin up to the same top speed on its next-highest gear as it will the highest one: But it will get there faster. Mid drives are like that especially when going fast on the street. Here again we are going back to not lugging the motor, and letting the mid drive spin faster than you ever would

Again thinking of your mid drive ebike as if its an exotic sports car with a manual transmission: In between each gear you need to let off the power (i.e. the clutch), shift and hit the accelerator (the throttle). If you have a gear sensor you will not have to worry (officially) about the ‘clutch’ part as that will be safely done for you.

Note that above, I am talking exclusively about when you are using the throttle. If you want to pedal the bike thats no problem… just use pedal assist and set your power level to a lower setting; taking care not to overdo the boost and keeping your gearing so you never lug the bike with slow pedaling up a steep hill (if pedaling slow on flat ground, or downhill, there’s no issue to worry about as you are not providing resistance to the motor).

Do Not Shift Under Power

Even if you have a gear sensor. Thats right I said it. Don’t trust the gear sensor unless you are forced to. Lift for just a sec and do your shift.

Shifting while pouring huge watts into your chain is an ugly thing.  You will recognize your mistake the instant the result hits your ears.  It won’t kill the chain outright, but as you hear that chain smash from one cog to another you will know your bike hates you very, very much.

If you treat the gear sensor as a fail-safe rather than taking it for granted, you will be much more likely to avoid disaster. Now, as you become familiar with riding your mid drive and how it behaves, you will naturally figure out how to push it to its limits and minimize that power blip when you shift. You may even get smart enough to do without the blip entirely and just shift full throttle. But for your first few weeks of riding this thing… treat the gear sensor as a backup, not the default.

Here’s a technique you want to learn as part of your education on operating a mid drive: Using your brake lever motor cutoffs as your clutch: Just slightly actuate the levers so the cutoff kicks in, but the pads don’t engage. Lift when the shift is finished. You can stay on the throttle or keep pedaling while doing this so the process is near-seamless.

Many ebike levers have this ability built into them. Magura MT5e levers have a mid-lever hinge that lets you touch the brakes and engage the cutoff without any pressure making it to the caliper.

Check out the little pin in the middle of this ebike brake lever. That is a hinge to give the lever a *touch* of give so you can cut the motor off without engaging the brakes.

Keep Chain Alignment As Straight As You Can

Mid drive motors tend to work in a lot wider range than humans do.  So you can leave the motor in a gear that would be too low for your cadence and let it spin away like crazy… it actually likes it that way.  So, this piece of advice is partly about how you ride the bike (i.e. what gears you let it sit in) but also about how you build it if its a DIY effort.  You really only need three or four gears in the middle of your cluster on a mid-drive-powered ebike.  You want them to be the ones that let the motor spin fast.  You also want the cogs the bike is happiest in rpm-wise to not be cockeyed, front to back (i.e. bad chain alignment). So regardless of whether you built this bike or you just bought it, when hammering on the power don’t do it when the chain is yawed to an extreme.

On an analog bike you can get away with a lot, since you are only feeding back 150 watts to it.  Feed it 1500 and that sideways-skewed chain will become a saw and chew right through your front chainring and rear cog teeth.  Be smart when you shift your gears and go for high power output (or when you build the bike in the first place). If this is a DIY build, learn in your first outing or two whether there are any problem gears you should stay away from.  There are all sorts of offset chainrings (and 1mm and 2mm shims) available on the market. They cost money, but spending that money now means not spending it later after you have walked home.

Build Smart

If you bought your bike manufactured with a mid drive installed from the factory, this part has already been taken care of. If you are building an aftermarket conversion, you will have to buy components that are strong enough to handle the punishment your 1500w+ motor will mete out. Almost 100% of internet whining about mid drive reliability is from builders who fail at this stage.

While a lot of this article is repetition as I stated at the beginning, this is one place where I will just refer you to what I have already written elsewhere. Its only applicable to DIY builders so if thats you, go to this link and scroll down to the Mid Drive Motors section.

Wrapping it up

If you build with appropriate components, and ride it smart, even a high powered mid drive will essentially last forever.  Yeah sure you will wear out the chain and rear cluster in say three thousand miles, the smallest cog in half that, and the chainrings in 10.  But thats peanuts considering how many miles you put on the bike.

And you will have an absolute blast doing it.

Quick Release, Easy-Carry Ebike Battery Setup

Parking your ebike outdoors all alone? When shopping, my cargo bikes are locked but out on the street… but the battery goes in with me. Here’s how I do it without people thinking I am carrying a bomb.

Yes You Can Take ‘it’ With You

An ebike used for utility purposes is, by its nature, going to be left out a lot. You go to the store, load up a shopping cart, come back and fill up your saddlebags. You really want all the parts on the bike when you left to still be there. Especially after loading on 50 lbs of cat food, Oreos and diapers.

The most obvious way you keep the bike itself is to use a good locking strategy. I’ll save that for a different discussion. This time I will focus on how I protect the single most-expensive component on any ebike – the battery. Not by locking it up, but by making it so I can do a quick grab and carry it in with me.

By removing that battery, we are making that big heavy ebike into a boat anchor, which we can hope makes it at least a little less attractive to thieves.

Size (and Shape) Matters

What I am describing can be made to work with any shape battery, kept anywhere on your bike. What you see here works best with a squarish, oblong battery. In the pics below I am using a 17.5ah Luna Storm battery, which is pretty big and heavy (in part thanks to its powerful but not-so-energy-dense 25R cells). More likely, if you have a similar heat-shrink battery pack like this one, its quite a bit smaller and lighter.

I also keep a Luna Wolf Pack battery like this and do not use its magnetic mount. The battery is easy to quickly get off that mount, but leaving it inside of a bag like I describe here is, overall, easier than stuffing it in every time, taking it back out and so on. For packs like this (Wolf, Shark, Dolphin etc.) you could certainly bring a small pack and put it in/take it out as a part of your routine.

There’s more than one way to skin this cat, so what you see here is just a jumping off point.

Lets Get to It

This is the battery in its bag, just like it would be if I rolled up to the local Costco.

Ignore the charger cable in the front. I took this pic at work in my ebike garage.

If we zip open the bag, we don’t see a battery. We see an inner bag, along with that charger cable extending thru to the rear. The controller cable is in there too just out of sight (look closely and you can see it)

If we look inside the bag, we see the battery charge cable is in fact an extension running from the rear of the interior bag up and out the front. The motor cable – an XT90S connector – also has a short extension between the battery cable and the motor cable. The idea is this: when routinely, frequently detaching and reattaching the cable, if there is any wear its on a cheap, replaceable extension and not a critical, live/hot cable coming directly off the battery.

Disconnect the cables and give a tug to the inner bag. Here its shown halfway out but you will just pull the thing out in one motion.

When I leave, I generally put the cables back inside and zip it only halfway-ish, so its obvious there’s nothing worthwhile to steal inside. Move along.

Annnd here we are. the cables are shown sticking out of the inner bag. You will want to cap those for safety’s sake. I use cheap plugs I got a bagful of on Fleabay for a couple bucks.

And yes… as-is I have had someone ask me “what is that a bomb?” … only half joking and ready to clock me if I make a sudden move. So stuff the wires in the bag so they don’t stick out.

Tell the Bomb Squad to cut the red wire

Done! Wires are capped and stuffed into the bag in 5 seconds. The sling strap goes over your shoulder for easy carry. I just lug it to the nearest shopping cart and put it in the bottom rack with my helmet and off I go.

This is just a 3L hydration bladder pouch, the sling strap that comes with it and a shoulder pad I swiped off another strap I wasn’t using.

Parts

Its a really short list with one item on it.

Hydration Carrier

You see above the Blackhawk S.T.R.I.K.E. carrier in use. Purchase link is here. Yes, the name is a tad ridiculous. But this pack is minimalist and is just durable cloth with no insulation or padding. Its easier to stuff into a confined space. Mine came with a super sturdy velcro sling strap.

Another that is well made (and a tad smaller for a tighter fit is sold by Voodoo Tactical. It comes with thin backpack-style shoulder straps that don’t take up *too* much space in your triangle bag and are not enormously fiddly when stuffing back in there.

Another one I use (with my Luna Wolf pack) is this government-issue USMC carrier. The link is to a brand new unit. I got mine surplus and cheaper on Fleabay. This pouch has no straps (you can clip on your own from a duffel bag if you like) and it is the opposite of the Blackhawk carrier: Its thick and padded. I can still stuff it into any triangle bag I have despite this. Its great as a protective layer over a battery.

Wrapping It Up

There are lots of ways to do this. How I do it is no big deal. Key takeaway here is to find a method that works for you so you can swiftly grab the battery, go off to your next adventure and then come back and plug right back in again.