Chain Snapping on Ebikes

AndySP

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Hi all,

I'm looking to buy myself an Ebike but I've demo'd 4 and snapped all four chains! (Specialized, Santa Cruz, Whyte and YT)

I spoke to the bike shop who said "We get a lot of reports of chains snapping" and then a friend who rides MTB for a living who also mentioned that he has heard of lots of snapped chains on EBikes. The bike shop also said that they tend to use lower end drivetrains (such as SRAM NX/GX) as they are stronger than the top end (XX1 etc) because of the torque the motor puts through. I've also heard that the shifter is forced to be a single gear-at-a-time shift because of this.

I'm probably not riding them correctly, but I've only ever snapped one other chain (non-Ebike) in 30 years of riding, and I never change gears under load. I am right ocd about making sure my own bikes are well set up though.

None of the chains snapped when changing gear, but when I got on the power to climb a steep hill.

Also conscious I've not seen a single EBike review where they have mentioned a snapped chain.

Has anyone seen or can verify this? Are these just poorly setup demo bikes?


Cheers, Andy
 
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I have owned two eMTBs, with thousands of miles on both, and never snapped a single chain. And I ride hard, on rocky terrain.
 

syl3

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the bike shop employees probably reused some non reusable powerlinks so as to keep the spares for themselves.
 

Coyotefred

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I'm relatively new to e-MTBing, and I snapped my chain twice during my "trial rides" (BBSHD conversion of my existing 26" fat bike). Adding "e" to your MTB is definitely going to put more stress on your entire driveline, and any "weak links" in your chain or driveline will become apparent very quickly. In my case I had made some repairs to my chain that worked just fine before my ebike motor was added to the equation, but that extra torque/stress was just enough to reveal that my repair wasn't sufficient. I replaced the chain and am using only a quality *reusable* master link (not all are), and I've had no chain issues whatsoever in several hundred miles of biking since...biking that is mostly off-road/off-trail with around 275lbs of rider, bike and other schwag.
 

AndySP

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Thanks guys, appreciate the replies - I didnt even know about reusable master links!
 

Coyotefred

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FYI: I'm currently running a Shimano CN-HG701 11spd chain and KMC master link (https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1)

I've read where some ebikers prefer lower speed drivetrains/chains due to supposedly greater strength (chain width etc.) and there may be some truth to that. But knock on wood my 11spd setup with this chain has been fine so far. PS I also replaced my old cassette with a Sunrace CSMS8 EAZ 11-46, apparently popular with many ebikers due to its all-steel cogs and design (cogs on spiders) that reduce stress on the freehub body.

I would definitely plan on bringing a spare chain and chain pliers as part of your repair kit--something I never did before. I'd bring chain repair stuff before ebiking, but not a full replacement chain. Maybe overkill, but particularly if you're biking in places where they will be no on-road 'rescue,' getting an ebike out of the backcountry without a chain is not something I'd look forward to ;)
 

motox155

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It's mainly from shifting under power. Even if you don't think you are, chances are you are. On mine shifting in eco mode usually is pretty safe but go up to sport or turbo, shifts really pop. You need to learn to basically stop pedaling while shifting. If all you do is ride ebikes it gets to be pretty easy to do but switching back and forth like I do, I still have a pretty hard shift time to time.
 

Redlands R&C

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Also you mentioned that you did it on 4 demo bikes, so you need to consider all the other people that have ridden the bike and not properly treated the drivetrain. You may just have been the unlucky person that finally broke everyone elses mistakes.

So don't consider the broken chains a deal breaker per se, just realize that if/when you buy one, you will need to be mindful of how YOU treat YOUR drivetrain.
 

matt4x4

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Maybe look at hub motors instead of mid drive ebikes, but I've ridden mid drive ebikes far far far more powerful then any store bought ebike and never broken a chain.
 

Gemini2k05

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Couple points

1. Low end chains are not stronger
2. 11 speed chains are not stronger
Source: https://cyclingtips.com/2019/12/the-...rable-11-speed

3. Power output alone is not enough to break chains. No matter how strong you think you are with your e-bike, you are still probably not putting at the same sustained power that Van Der Poole is. Source: https://cyclingtips.com/2019/04/math...s-amstel-gold/

4. Shifting: If they are breaking it's from constant shifting under super high load, not just high loads. I've seen a lot of people chronically make this mistake on their e-bikes, just dumping 3-4 gears at once as they are climbing under max power up a hill. I'm 220 pounds and a pretty strong pedaler and I can typically get at least 2k miles out of chains on my e-bikes.
 

matt4x4

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I had always thought the smaller chains, like the 12 and 11 speed chains were weaker then say a 8 speed chain because the 8 is wider. With the very close tolerances of the new chains I dont think thats the case from the few articles I read in various bicycle media outlets. The smaller chains (12 and 11 and 10 speed) come at a cost, along with the higher cost of the cassette and any gram weenies out there put the cost exponentially higher. I was shocked to see some of the costs for 12 speed cassette, $150 was quite common.
 

AndySP

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Thanks guys and cheers for linking those articles Gemini. Think the general consensus is it should be ok as long as the bike is well set up with decent quality equipment on the drivetrain.

Youre bang on with the sustained power. I stuck a power meter on my Yeti and average power was around 200w so way way way less than Van Der Poole! Tbh Im not even sure how accurate my power measurement was so may not even be correct. I also did a short ride on a 1st gen Turbo Levo with a power meter which maxed 425w for a very short time with the bike in Turbo mode! His max power is insane...
 
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