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Loud Crack

1540 Views 12 Replies 8 Participants Last post by  Westwolder
Me and my daughter have 2021 Norco Bigfoot VLT 1 e-fatties.

I get a loud crack sometimes from my pedal area when I start pedalling. It often occurs mid-ride, after pedalling backwards a quarter revolution and then laying a bit of power to the pedals. It seems to only occur in colder temps.

My daughter tells me she doesn’t experience it.

Mine is loud. It scares me. It echoes in the trees. I have often checked afterwards to make sure I didn’t crack one or more teeth off my chain ring. That is what it sounds like to me.

My LBS has mentioned that it might be the hub/pawls and that they were going to get in touch with the Norco rep to keep a hub on hand, just in case.

I don’t think that’s what it is. It sounds to me like it is coming from the motor area. It sounds like it’s the chain ring or other part of the drivetrain, but I can’t find anything damaged. I sure hope it’s nothing internal in the motor. Wherever it’s coming from, it’s a horrible noise. Clearly something is in distress.

It has done this since I purchased the bike.

I plan to keep riding and pray nothing $hits the bed 25kms deep in the mountains in minus 15c (or worse) temps.

If anyone has any ideas I would love to hear them. Thanks.
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I feel like anything described as a "loud crack" has to be a sudden violent contact of metal on metal. The only thing that makes any sense to me is a chain sort of riding up on top of a tooth, getting some tension on it as you apply the power and then suddenly snapping back down into its proper place when the force of your pedaling overcomes it. Especially with your description of it being preceded by a slight backpedal.

Do you feel anything through the pedals?
Diagnosing abnormal noises from a bike is almost impossible without experiencing it in person. What type of hub is it? You can easily inspect that yourself. Is your shifting smooth and adjusted correctly? Are your motor bolts all tight? Not sure this would cause a loud noise, but should be checked anyways. And while you are at it, I’d check all the bolt to ensure they are tight.
I wouldn't be surprised if it was the rear hub. A couple of years ago I had a cheapo Trek (brand new) that developed an extremely loud noise in the BB area that we thought was a bad bottom bracket. The LBS replaced the BB twice without curing the problem. It turned out to be a bearing in the rear hub. As we are all aware, unwelcome sounds coming from our bikes aren't always what they appear with the way noise can transmit through the frame.
I wouldn't be surprised if it was the rear hub. A couple of years ago I had a cheapo Trek (brand new) that developed an extremely loud noise in the BB area that we thought was a bad bottom bracket. The LBS replaced the BB twice without curing the problem. It turned out to be a bearing in the rear hub. As we are all aware, unwelcome sounds coming from our bikes aren't always what they appear with the way noise can transmit through the frame.
My LBS is convinced it is the hub. I have no issues with it otherwise.

No issues shifting.

No issues with the motor mount bolts. They creaked before but my LBS was able to eliminate all noise. 100% quiet now.

I guess it’s probably the hub. It’s a cheap POS. I replaced most of the crap components on both bikes, but the hubs remain.
My LBS is convinced it is the hub. I have no issues with it otherwise.

No issues shifting.

No issues with the motor mount bolts. They creaked before but my LBS was able to eliminate all noise. 100% quiet now.

I guess it’s probably the hub. It’s a cheap POS. I replaced most of the crap components on both bikes, but the hubs remain.
You can put a spare wheel on and go for a ride. Tell your shop to let you borrow a wheel if you don’t have one, and if it solves the problem you will give them more business to replace the wheel/hub. Or pull apart the freehub assembly yourself. Once you learn how to work on your own bike, you can save a lot of time and money. YouTube is your friend.
You can put a spare wheel on and go for a ride. Tell your shop to let you borrow a wheel if you don’t have one, and if it solves the problem you will give them more business to replace the wheel/hub. Or pull apart the freehub assembly yourself. Once you learn how to work on your own bike, you can save a lot of time and money. YouTube is your friend.
I have a spare wheel. He11, I have a spare bike!
Tire Wheel Sky Vehicle Automotive tire


My LBS treats me well. They are convinced it’s the hub. I’m going to bring it in and they are going to tear it apart. I suspect there will be no charge.

The problem is that it only does it once maybe every second or third ride. I can’t replicate it. Switching wheels may not be conclusive unless I ride like that for a while. I suppose I can swap the wheels indefinitely and see.
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I would agree with the bike shop that it’s the rear hub that is making the crack sound. I get this all the time with my dtswiss 370 pawl hub on my trail bike. It’s soooo loud that it will echo through the forest when it does make the sound. Normally it happens on first engagement or I stop pedaling then restart and bang it will go.
This is my second dtswiss 370 and they both did it no it’s not isolated to one hub.
if you are getting that sound even after service I would not waste my time with that hub, move on to something like a dtswiss ratchet style hub and avoid low cost pawl hubs. Oem hubs that manufactures put on are normally the cheapest hubs they can find move on to something with decent quality.
Check your chain. Every time I’ve heard a loud crack coming from around the right crank, on my ebike and my regular bike, it’s the chain breaking/splitting the links around the front side of the pins.
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Me and my daughter have 2021 Norco Bigfoot VLT 1 e-fatties.

I get a loud crack sometimes from my pedal area when I start pedalling. It often occurs mid-ride, after pedalling backwards a quarter revolution and then laying a bit of power to the pedals. It seems to only occur in colder temps.

My daughter tells me she doesn’t experience it.

Mine is loud. It scares me. It echoes in the trees. I have often checked afterwards to make sure I didn’t crack one or more teeth off my chain ring. That is what it sounds like to me.

My LBS has mentioned that it might be the hub/pawls and that they were going to get in touch with the Norco rep to keep a hub on hand, just in case.

I don’t think that’s what it is. It sounds to me like it is coming from the motor area. It sounds like it’s the chain ring or other part of the drivetrain, but I can’t find anything damaged. I sure hope it’s nothing internal in the motor. Wherever it’s coming from, it’s a horrible noise. Clearly something is in distress.

It has done this since I purchased the bike.

I plan to keep riding and pray nothing $hits the bed 25kms deep in the mountains in minus 15c (or worse) temps.

If anyone has any ideas I would love to hear them. Thanks.
Me and my daughter have 2021 Norco Bigfoot VLT 1 e-fatties.

I get a loud crack sometimes from my pedal area when I start pedalling. It often occurs mid-ride, after pedalling backwards a quarter revolution and then laying a bit of power to the pedals. It seems to only occur in colder temps.

My daughter tells me she doesn’t experience it.

Mine is loud. It scares me. It echoes in the trees. I have often checked afterwards to make sure I didn’t crack one or more teeth off my chain ring. That is what it sounds like to me.

My LBS has mentioned that it might be the hub/pawls and that they were going to get in touch with the Norco rep to keep a hub on hand, just in case.

I don’t think that’s what it is. It sounds to me like it is coming from the motor area. It sounds like it’s the chain ring or other part of the drivetrain, but I can’t find anything damaged. I sure hope it’s nothing internal in the motor. Wherever it’s coming from, it’s a horrible noise. Clearly something is in distress.

It has done this since I purchased the bike.

I plan to keep riding and pray nothing $hits the bed 25kms deep in the mountains in minus 15c (or worse) temps.

If anyone has any ideas I would love to hear them. Thanks.
My best guess its
Me and my daughter have 2021 Norco Bigfoot VLT 1 e-fatties.

I get a loud crack sometimes from my pedal area when I start pedalling. It often occurs mid-ride, after pedalling backwards a quarter revolution and then laying a bit of power to the pedals. It seems to only occur in colder temps.

My daughter tells me she doesn’t experience it.

Mine is loud. It scares me. It echoes in the trees. I have often checked afterwards to make sure I didn’t crack one or more teeth off my chain ring. That is what it sounds like to me.

My LBS has mentioned that it might be the hub/pawls and that they were going to get in touch with the Norco rep to keep a hub on hand, just in case.

I don’t think that’s what it is. It sounds to me like it is coming from the motor area. It sounds like it’s the chain ring or other part of the drivetrain, but I can’t find anything damaged. I sure hope it’s nothing internal in the motor. Wherever it’s coming from, it’s a horrible noise. Clearly something is in distress.

It has done this since I purchased the bike.

I plan to keep riding and pray nothing $hits the bed 25kms deep in the mountains in minus 15c (or worse) temps.

If anyone has any ideas I would love to hear them. Thanks.
Best guess is its your motor freewheel. It should stop backward pedalling.
My best guess its

Best guess is its your motor freehub ( not your cassette freehub). It should stop backward pedalling. So just stop pedalling backward!

The creeping noise is the interface with your crank/ motor spigot interface. Metal fatigue of your motor spigot may result as per EP8/E13.

Eventually you may find your crank arm falls off leading to serious death or injury or comedy death and serious injury:ROFLMAO:

Otherwise avoid curry, use full sized shorts, sunscreen and lubricants to prevent loud crack problems...
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