Care and feeding for your high power mid-drive power train

I love mid-drives, just read any article I’ve ever written and if you don’t come away with anything else, you’ll feel my love for high power mid-drives shine through. By a far margin, I feel like the best mid-drive on the market right now is the BBSHD with the 2500W ludicrous controller is the best deal to be had ($1200 right now at Lunacycle for the Black Friday sale here). Running 2500W of power through a normal bicycle drive train that is designed for 200-350W is going to wear and break things at a frightening rate. This article is about how to keep that from happening and some of the tricks I have learned in the last 5 years that have kept my bikes on the trail and not in the shop.

A properly maintained drive train on any mid-drive will create far fewer headaches for you

Lube the crap out of that chain

There are lots of articles that will say that you’re destroying your drivetrain by over lubing it. I call BS on that, as near as I can tell there is nothing to be lost from lubing your chain before every single ride. I buy chain lube in giant containers and then transfer it into the little expensive squeeze bottles by pouring it into a bowl and sucking it up into the tiny squeeze containers. The lube I always buy is Pedro’s Go! lube in the 1-liter containers available here for <$10 (retail is $45). I’ve tried about a dozen different lubes and this is the one that doesn’t build up on the chains and works well in snow and temps below 0 F.

Crappy sex lube (tastes awful), but great for your chains

Bring your bike inside if it gets below freezing

Nothing causes a looser chain than one that is wet and gets left out in the freezing cold to freeze. That water will expand and cause the chain to get a lot looser pretty fast as well as create problems with cable brakes freezing and freezing up derailleur wheels. Get 3 boot trays and put them in a row and bring your snowy slushy ebike inside the house when it freezes, or at the very least bring it into the garage. Garages will stay about 10 degrees warmer than the outside, generally.

Really, you’re going to leave your ebike outside to freeze in this kind of weather? That is a terrible thing to do to any ebike

Replace your chain and cassette at the same time

A worn chain will wear down the cassette at the same rate so the teeth of your cassette will end up matching your stretched chain. When I swap my chain I generally will swap out the cassette at the same time. If you replace the chain and leave an old cassette it might start skipping, especially in the higher gears. I generally don’t replace the cassette until it starts skipping in 2 gears just because I’m incredibly cheap frugal.

Chains and cassettes wear together and if you replace one without the other you will often end up with a drive train that skips and skips and skips

I only buy all steel cassettes, preferably one-piece ones

There are lots of kinds of cassettes, but I’ve found that the cheaper $30ish all-steel cassettes that are all one piece and not individual cogs last the longest. They are also very heavy, but it’s an ebike, so longevity trumps weight every time. I would also steer away from cassettes with aluminum grannies, as they will quickly taco under serious load and you’ll end up with a giant mess of derailleur, spokes, chain and folded over chainring (true story).

The HG-62 Cassette is one of my favorite 10sp 36T chainrings for durability (reviewed here)

Cheaper chains seem to last longer than the pricy ones

This is something that I’ve noticed, if you spring for a $50 fancy chain it will likely stretch and wear out much faster than getting a $10-15 KMC chain. I’m not sure why this is, but my guess is that the cheap chains are designed for kids bikes that are not ridden that much and left to rust in the lawn, so they are built heavier and more durable rather. KMC seems to make the most durable chains, although sometimes I buy cheap SRAM chains as well. Make sure to use the right size chain for your drivetrain, don’t put an 8-speed chain on a 10-speed drivetrain or it won’t shift right. Single-speed chains seem to last much longer than anything else, which all by itself is a good argument for using an IGH on your ebike.

Most people don’t realize that most bicycle chains are actually made by KMC and just re-branded, save some money and just get a cheap KMC chain

Go narrow\wide on the front chainring

I don’t generally replace the front chairing unless I get broken teeth or when I start getting chain-suck (chain pulls up past the chainstay and gets stuck and you have to force it back out). I prefer using Raceface narrow-wide chainrings or custom alloy chainrings on my mid drives. Both the Luna Eclipse chainrings and the Lekkie both seem extremely durable and long-lasting. I never use a stamped steel chainring on the front chainring, as I’ve found that I often end up with problems with the chain coming off at inopportune times (is there ever really a good time to lose your chain?)

The X9 is the king of derailleurs in my book and can be had for about $100 street price

It’s all about the derailleur

Want a drive train that doesn’t suck? Then its really important to get a good derailleur. I’ve tried a bunch of them and the best derailleur I can find is the SRAM X9 hands down. SRAM keeps trying to replace the 10sp X9 with the GX which I’m not crazy about (although it is a lot cheaper). There are other options out there as well, none of which I can really recommend, even more expensive units. As your shifting cable gets looser over time make sure you twist the adjustment to tighten the cable at the shifter if the bike starts slipping into a higher gear. When you are pumping 2500W though the drive unit, you don’t ever want to be shifting.

Shifting under load puts an extreme strain on the chain and the teeth of your cassette, don’t do it (unless you’re riding someone else’s bike that you don’t like)

Don’t shift under load

Nothing will compromise your drivetrain like shifting while under severe loads. Let up on the throttle, shift, and then start pedaling again. Don’t shift while powering up a steep hill on full throttle. That is just dumb and you will break your ebike.

A ratcheting freehub (no pawls) is the only non-steel unit I can find that can stand up to 2500W of power

Freehubs die under severe load, it’s just what they do

Another problem you will come across is trashing rear freehubs. Many lightweight freehubs on expensive bikes will have an aluminum freehub body that will not stand up to serious abuse. Eventually, the steel pawls will push into the freehub body and cause the rear wheel to not spin anymore when you pedal or run your mid-drive. If you can’t find a replacement freehub body then the only way to deal with this is to replace the entire rear hub. If you want to keep your rim then you’ll have to relace a rear hub into the wheel. I would do some research and try to find an inexpensive steel freehub body, which will never fail or get something with ratcheting steel pawls like the DT Swiss Big Ride 350 (reviewed here). A ratcheting freehub will not be cheap, but it probably won’t die on you in the woods when you are 6 miles from your car in a foot of snow (true story).

Here you can see one of the 4 sad aluminum freehub bodies I have destroyed in the last 5 years

In the immortal words of Amos, Rocinante’s grease monkey,

“You take care of her, she’ll take care of you”

Ride On.

Aluminum freehub bodies + Cassettes that are not one-piece + High power mid drives = Problems

Karl Gesslein is a degenerate hooligan of the highest caliber living in upstate NY. His passion for e-bikes and all things sustainable causes him to be obsessed with climate change and finding solutions that will keep humanity from becoming extinct from our own hubris. His personal blogs include electricbike-blog.com, awaken-spirit.org & chestnutparadise.com.


1 Comments

  1. Karl, I sprung for the BBSHD/ludicrous to put on my Surley ECR pulling a BOB trailer. I have an 18 mile ride once I leave our island to shop. My first e-bike. Will my Rohloff 500 hold up with a light touch? I’m an avid pedaler who doesn’t see using the throttle much until the stacked beer is falling out of BOB.

Leave a Reply

%d bloggers like this: