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Single Front Chainring - Chain falls off

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Single Front Chainring - Chain falls off

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Old 06-22-20, 08:57 AM
  #1  
mogulman
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Single Front Chainring - Chain falls off

Got my wife an Electra Townie Go 8D e-bike so she can ride with me. She has MS and hasn't been able to ride in a long time. It has a Bosch 38T FSA chainring up front. SRAM PG-820 11-32 8-speed in the back. Shimano Acera rear derailler.

Anyway.. the last few times she was riding, the chain came off the front chain ring and got wedged between the chainring and the frame. The first time, she kept peddling because she didn't know what happened. It took me a long time to get the chain dislodged and back on the chainring.

Second time it was easier because she stopped peddling (I told her to stop after the first time). Still it was hard because this bike has a chainguard that makes it tricky to get in and move the chain around while riding. My wife said she wasn't switching gears when this happened.

I brought it to the lsb, and they said it looked ok. They are going to check it again, later this week.

Just wondering what could cause this to happen on a single speed front chainring?


Last edited by mogulman; 06-22-20 at 09:00 AM.
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Old 06-22-20, 09:30 AM
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Shifting the rear derailleur also shifts the angle of the chain as it approaches the front chainring. Combine with a bump at the wrong time, and the chain might come off.
A simple "chain catcher" mounted next to the chainring might help.
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Old 06-22-20, 09:33 AM
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There are a lot of typical stuff like chain worn, chainring wear, gunked up chain etc. that can cause chain dropping but one issue with crank forward bikes is the enormously long chain.

I would look to have a chain keeper installed and be done with it. Maybe a narrow-wide chain ring.

John
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Old 06-22-20, 11:40 AM
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Cause? I was not there to watch.. There are chain keepers , they go on the upper side of the chainring ..

You could put 2 toothless disc chain-rings on either side of the toothed one..
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Old 06-30-20, 07:10 PM
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So this bike is only 2 months old. The chain falling off happened now twice in the middle of two different rides. Luckily both times I was with my wife who was riding the bike. We got this so she could keep riding, as she has balance issues due to MS.

I brought the bike back to the LBS twice. They told me they have seen this on this bike before because of the long chain. They also said there is nothing wrong with the bike. They said they could put a narrow wide chain ring on the bike, but that would cost $70. They said a clutch Derailleur would be better but they don't make one for this bike.

I don't really want my wife to get stuck somewhere because of this. I also don't feel like we should have to pay extra to get a bike where the chain doesn't fall off.

The LBS isn't responding to my phone calls or emails. Probably because they are busy from the virus, etc. They knew my wife had MS when we bought the bike and liked it because it seemed like an easy to use bike. The bike is currently at the LBS.

I feel like they should be able to make the bike work without the chain falling off, and without me paying extra.

Am I wrong? It's a $2000 bike.

Should I ask them to fix it or get a refund or credit or something or am I being too extreme?
​​​​​​any other suggestions?

​​Also. I tried calling Electra, but they didn't answer or respond to my vmail.

Last edited by mogulman; 06-30-20 at 07:13 PM.
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Old 06-30-20, 07:27 PM
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On a new $2000 bike, I would expect the chain should stay on the chainring. You are not being unreasonable.
What the LBS can do about it, I don't know. A refund or store credit (more likely) would be a good resolution for me.
Good luck.
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Old 06-30-20, 07:34 PM
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It's a $2000 bike, yes, but probably more than half of that is the name-brand Bosch system.

Unfortunately there are no 8-speed clutch derailleurs or NW chain rings. All of those are for 10 speed and higher systems. Such a system would fit on this bike but you are right, you really shouldn't have to. Inexpensive 1x bikes usually have some measures to keep the chain on. Many of them have a guard on both sides of the chain ring. My kid's Hotrock came with an idler that also incorporated an upper guard. If Trek forgot to do anything about this you can regard it as a design failure on their part. Perhaps willful.

This or something like it might help. https://mrpbike.com/products/1x-cx?v...14342583943210
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Old 06-30-20, 07:43 PM
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What about something like a deda dog fang? Not sure if any of these chain retainers will fit though because of the Bosch motor and thickness of the cruiser frame.
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Old 06-30-20, 11:06 PM
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A narrow wide chainring is going to help greatly and yes it is another expense but that is why you bought the Electra to spend a little less initially so you have money left over to upgrade all the foibles they left you with from the factory. Tourney derailleurs and e-bikes aren't a good combination for decent shifting and chain retention.

Certainly yes the bike is better than the crap online and yes the motor says Bosch on it but it also underneath says Active Line which is their entry into motors. It is like Bluepoint is to Snap On, yes technically Snap On but not really anything close to Snap On quality wise but OK enough for the occasional user.

I would be very very very nice and polite and ask if you can trade in the bike and look at the Specialized Como line, yes you will spend more initially but shouldn't need to spend a lot down the road and you will likely be getting slightly more powerful motor as well as parts that will better handle the stressors of being on an e-bike and work better. I think your wife like many many many many many others will love that bike.

Also just for those curious anyone saying a 400wh battery on a 50+ pound bike is going to give you 100 miles of range is clearly smoking or injecting something that the federal government would consider illegal. At best you may get 50 miles in eco mode but I wouldn't count on it. Same thing with fast charging on the 2ah charger, it is functional and for most people who are going to charge overnight, just fine but 6.5 hours is not fast.
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Old 06-30-20, 11:18 PM
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Originally Posted by veganbikes
A narrow wide chainring is going to help greatly and yes it is another expense but that is why you bought the Electra to spend a little less initially so you have money left over to upgrade all the foibles they left you with from the factory. Tourney derailleurs and e-bikes aren't a good combination for decent shifting and chain retention.
.
Actually we bought the bike because my wife liked the style, how it rode, the laid back seating of the Electra and the color. It has been good for her except for the chain issue. I don't know if any of the other manufacturers have a bike that has the same frame style where the seat is behind the pedals. This dealer is a trek dealer so they only have trek and Electra
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Old 06-30-20, 11:21 PM
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The LBS finally got back to me later tonight. They are going to try the narrow wide front chainring without charging us. They said it fixed the issue for another customer. If that doesn't work we may end up swapping for a Townie Go 8i which is similar but uses a Nexus internal gear. I'm assuming this would allow the chain to be tighter. I'll update the forum after we get it back and try it.
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Old 06-30-20, 11:46 PM
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Originally Posted by mogulman
Actually we bought the bike because my wife liked the style, how it rode, the laid back seating of the Electra and the color. It has been good for her except for the chain issue. I don't know if any of the other manufacturers have a bike that has the same frame style where the seat is behind the pedals. This dealer is a trek dealer so they only have trek and Electra
Most Trek dealers are like that, they don't want you to have freedom of choice because you probably won't end up on a Trek. I think the wife will love the Specialized Como so if you have an opportunity to ride one, you should take it. I didn't want to like it at first but then I rode it and can't complain. It is super comfortable and easy to ride and not super heavy and with the 4.0 and 5.0 I have plenty of good motor power and can go 28mph so I can better keep up in traffic and in urban stop start environs.

The color is nice though a lot of low cost bikes tend to go with nice colors to entice you, I see it on a lot of brands. Specialized made their Sirrus X 2.0 in a really awesome color but you cannot get it as just a frame.

From when the Simpsons went to Brazil (I don't remember the episode name):
Marge: What a charming neighborhood
Lisa: Mom, these are slums. The government just painted them bright colors so the tourists wouldn't be offended.
Marge: Works for me.
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Old 07-14-20, 05:23 PM
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Finally the LBS said they had the bike ready with the narrow wide chainring. I went in, and the bike shop tech told me they had to replace the 38T front chainring with a 36T. I'm thinking that isn't a huge deal. Then he tells me that the chainring bolts rub against the inside screws for the chainguard which is attached to the bosch motor.

They didn't tell me anything about the cassette, but it looks like the rear cassette is different too.

I left the bike there and they said they were going to work on it. I'm getting pretty nervous about this now and wondering if I should just try getting my money back.

I tried calling Electra a few times but they never answer or return my calls. I sent them an email today.

Also..now it looks like the Townie Go 8d isn't available anymore.
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Old 07-15-20, 04:40 AM
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Dropping the front chain is a pretty common problem with the Bafang mid drive kits. The 100% solution is a narrow wide chain ring.

Give the bike shop a chance to get the new ring installed properly and then see how if feels

The slightly smaller sprocket is probably a good thing. You might lose a bit of top speed but my guess that isn't an issue with the way you ride

Also make sure you wife knows to ease off on the pedal effort when shifting. Not sure if the motor automatically kicks off during shifts on that particular bike.
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Old 07-26-20, 05:53 PM
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LBS was unable to get this fixed. I found a few places that had the Townie Go 8i with Nexus 8 speed. Costs about $500 more. The LBS couldn't get me one, so they offered to give me my money back. I bought the new bike from REI.

I do really appreciate the LBS really trying to fix it or make it right.
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