February 29, 2024

While poking around on Twitter today I came across the following thread:

say no

I started to think hard about this graph and started wondering if I agreed with his theory that adding an electric motor to the bike would increase the overall load on the bike by 708%. Since most of my time over the past 8 years has been spent fixing broken high powered e-bikes (1000-4000 watts) I had to really take this chart into account and start thinking about whether it is really a good idea to install a high powered electric mid drive motor What is causing all this extra time spent fixing e-bikes.

When I think about the main issues I have with high powered e-bikes vs bikes, it actually falls into the following categories (in order of severity):

  • Frame Fatigue and Breakage
  • hub damage
  • Driveline problems (chain, link and cassette problems)
  • brake
  • broken spoke
  • tire wear

I want to discuss these individually, since they all deserve their own descriptions. This article won’t discuss motor and battery maintenance, but these items themselves require a lot of maintenance, which is beyond the scope of this article.

Frame fatigue

One of the biggest problems with all metal frame bikes has to do with metal fatigue. It’s something no manufacturer wants to talk about, but it’s a real problem.

Very typical mid drive frame breakage, I’ve seen this on several e-bikes

Where do I start dealing with metal fatigue and those flimsy steel and alloy bike frames? Well, metal fatigue is like a monster hiding in your closet. It’s always there, lurking in the shadows, waiting to pounce and wreak utter chaos.

When a metal component, such as a steel or alloy bicycle frame, is repeatedly stressed from being stepped on, rough handled and driven over stakes, it develops tiny cracks over time. Before you know it, those tiny cracks have grown into full-blown metal failure, and your trusty steed is gone.

I have done weld repairs on alloy frames but they are not durable

So, what is the solution? Well, folks, there isn’t one. Metal fatigue is an inevitable part of life. All you can do is try to limit your exposure, don’t ride like a lunatic, and don’t mount the motor incorrectly.If you install a high powered mid drive, make sure Secondary reduction gears won’t hit your chainstays (You should be able to pass a piece of paper freely between the motor and the chainstay).Another big problem I had was Using a Seatpost Adapter (Just get the correct size saddle post). I’ve broken frames on just about every e-bike and regular bike I own, so I’m not in a position to make comparisons between the two. The only frame I have that is not damaged is the steel frame I have. That being said, the only solid advice I can give is that if you can equip your e-bike with a steel frame, it will be less likely to break.

If you are using a hub motor on any bike frame then you should be using a torque arm, this will really keep your frame from fatigue over time.

Typical seat tube failure, which is caused by using a seat post spacer (don’t do it)

I’ve had no luck welding alloy bike frames for repairs. I’ve tried this several times and most of the time it ends up broken. The problem is that you do need to heat treat the entire frame after welding, otherwise you only get about 30-40% of the original strength of the frame. I’m now trying to insert aluminum tubing or hardwood carvings inside the frame and then apply JB Weld epoxy on the inside and outside of the break. So far I have not had a failed repair with JB Weld Epoxy.

Hub Flubs

If you ride a high powered mid drive, eventually you’ll have the problem of a blown rear driver body, which will allow you to pedal as much as you want, but the bike just won’t move. A hub is a ratcheting mechanism that keeps your bike going, but also allows it to spin freely without pedaling.

An example of a failed freehub body where the steel pawls push into the aluminum body, deforming the metal until the pawls fall off

Most of my mid drives draw over 1500 watts, and the new Ludicrous 2 controller has a peak power of 4000 watts. When using a 750W BBS02 with a peak of about 1200 watts, I have had no serious problems with driver body failure. For 1500W and above, hub failure seems inevitable. The higher the wattage, the faster the driver body will fail, but on average it takes about 1-2 years of use and abuse to fail.The solution I came up with was to re-fix with one rear wheel DT Swiss Hub. DT Swiss hubs are extremely durable and have a ratchet system that can be changed in about 5 minutes without any tools. I’ve only had one set of ratchets fail in the past 5 years, and it’s easy and cheap to replace. I encourage people to use the 18-tooth ratchet replacements, because the fewer ratchet teeth there are, the stronger each ratchet will be.

18 tooth star ratchets for DT Swiss hubs, I carry a set with me on the trail so I can replace them if they fail on the trail

drivetrain damage

The chain breaks. There’s not much you can do about it, other than realize that the fewer rear cogs, the less often the chain will break. 8sp chains break much less frequently than 12sp chains, and single speed chains seem to break less often than any other bike chain you can use. Unless you’re running an internally geared hub (IGH) in the rear, you’re probably running with multiple cogs and a narrower chain. If you have a mid drive, all of the motor’s power will go through your chainrings, chain and cassette. These are designed to handle around 200 watts of power, so if you’re using them on a 1000-4000 watt mid-range drive, it goes without saying that the lifespan of these products will be significantly reduced. I always have a power link on my bike so that even if the chain breaks, I can keep riding. In order to install the power linkage you also have to carry a chain breaker, so you also have to carry a bike tool with a chain breaker with you. I use Topeak 18 mini sells for about $35 It has 99% of what I need on the road, including the all important chain breaker.

I found 9sp powerlinks to work with 10sp and 8sp chains, so that’s what I use

For the front chainring, if you can use a steel chainring, it will last the longest and be most resistant to excessive wear.For misaligned chainlines you really need a narrow/wide chainring and the ones I’ve found to work best and last the longest are Race Face series chainrings.this Luna Eclipse chainring For BBS02/HD and Lecky chainring They’re also extremely tough, long-lasting, and create a better chainline than using Raceface sprockets with adapters.

Cassettes can also be extremely problematic for powerful mid drives. I tend to move to the tape that holds most of the gear together. The problem with cassettes that have separate gears is that over time the gears sink into the alloy cassette base, creating deep gouges in the splines and making cassette installation and removal very difficult.

Here you can see which gears are free floating, the last 2 granny’s are strapped into a spider gear so it doesn’t get stuck in the tower base

broken brake

Brake wear is the bane of every cyclist. You know what they say, the only constant in life is change, and brake pads are no exception. Ten years ago I was just riding bikes and they kept screaming away, eventually wearing out the pads and cylinders too, which was much harder than replacing the pads when they started screaming like nails on a chalkboard.

Misalignment of brakes to rotors can cause uneven wear

Now, when it comes to e-bikes vs bikes, let’s just say that brake wear is like the difference between a nap and a full 8 hours of sleep. On a regular bike, the brake pads wear out slowly, like taking a light nap in the afternoon sun. But on e-bikes, it’s a completely different story. Those heavy high-powered beasts require more stopping power, so the brake pads wear out much faster, like a marathon overnight race. Usually when I’m riding an e-bike I’ll even keep some brakes on while throttling the motor because if I want to hit the brakes before I crash badly, I can stop faster if I have the brakes covered and have them I usually buy a bunch of the cheapest sintered brake pads on amazon and stock a few more at my bike shop. I write down the brake type (BB5, BB7, Juicy, etc.) grab them.

Brake wear is easy to fix, just replace those whining pads and you’ll be back on the road and ready to stop in no time. Or a nickel. Or any little coin you need stuck in a car seat.

broken spoke

When I change wheels I tend to use 13 gauge spokes, but most of my pedal powered bikes tend to use 14 gauge spokes. Some e-bikes I’ve bought in the past have had 12 gauge spokes. In general, I’d say the 14 gauge spokes on my pedal powered bike are more likely to break than the 13 gauge spokes on my e-bike, and I haven’t had any 12 gauge spokes break. If I have to replace a damaged spoke, I usually replace it with a thicker gauge spoke so it doesn’t break again, and I tend to check the wheel once a year, unplug each spoke and tune to tune. Higher-pitched spokes are more likely to break when toggled than lower-pitched spokes. Spokes get looser over time, which means their neighbors get tighter.

These spoke wrenches work better than spoke wrenches with multiple sized spokes on the same tool

tired tires

For riding on trails and in the snow, I haven’t noticed excessive tire wear on my e-bike, especially compared to my pedal-powered bike. This is not the case for many of my friends who ride e-bikes on sidewalks. They seem to burn through tires at an alarming rate. When I was a teenager, I biked to school every day, about 20 miles a day. I don’t think I can recall changing the tires on that bike during three or four years of daily commuting. At normal speeds on a pedal powered bike, I don’t think most bike tires will wear out that quickly. Tire wear does seem to be a bigger problem when you double your speed and ride faster and farther.

So, going back to the original tweet that sparked the idea for this article, do I agree or disagree that an e-bike needs about 700% more wear and tear for the same amount of riding? Even though I spend a lot of time pedaling and riding e-bikes, I don’t think his assumption is correct. Overall, I’d say a high powered e-bike requires about twice as much maintenance and repairs as a regular pedal powered off-road bike. There are plenty of e-bike haters out there who want people to think e-bikes are harder to keep working than regular bikes. The reality is that while e-bikes do require about twice as much maintenance, they also let you ride about twice as far in the same amount of time, so my feeling is that it’s really just a wash. Buying an e-bike is usually more expensive than a regular bike, but for many people, a good cargo bike can replace their car, so an e-bike ends up being cheaper than any car.

You can find me on Twitter: @efatbike Watch me trying to learn how to tweet.


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