# Loud Crack



## mtnbkrmike (Mar 26, 2015)

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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## nilswalk (Nov 26, 2014)

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?


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## RBoardman (Dec 27, 2014)

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.


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## jimmytang (Nov 13, 2020)

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.


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## springs (May 20, 2017)

Does this bike use a SRAM UDH?


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## mtnbkrmike (Mar 26, 2015)

jimmytang said:


> 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.


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## RBoardman (Dec 27, 2014)

mtnbkrmike said:


> My LBS is convinced it is the hub. I have no issues with it otherwise.
> 
> No issues shifting.
> 
> ...


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.


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## mtnbkrmike (Mar 26, 2015)

RBoardman said:


> 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!









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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## Niko (Feb 2, 2006)

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.


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## MX9799 (Feb 11, 2018)

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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## Westwolder (10 mo ago)

mtnbkrmike said:


> 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.
> 
> ...








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## Westwolder (10 mo ago)

mtnbkrmike said:


> 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 best guess its


mtnbkrmike said:


> 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.
> 
> ...


Best guess is its your motor freewheel. It should stop backward pedalling.


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## Westwolder (10 mo ago)

Westwolder said:


> 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!
> 
> ...


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