Chain pop

[mclydeg]

2019 levo
About 2-3 times per ride as I take off I hear what I believe is a single chain pop.
Bike shifts OK ??
Any ideas?

Thanks in advance
Mcg

 

[wepn]

2019 levo
About 2-3 times per ride as I take off I hear what I believe is a single chain pop.
Bike shifts OK ??
Any ideas?

Thanks in advance
Mcg

The clunk you hear mostly in Turbo, less in Trail & not in Eco?
I believe that's the sound of 100 Nm of rotational force of the Gates belt on the spindle though I could be wrong

 

[Kave]

I hear my chain pop too. But just once in a while.
Makes me consider another drive train than the NX 11 spd.

 

[salko]

By this chain pop you mean the pop like the chain jumps for 1 teeth forward or if cassette will lost connection with a wheel and jump few degrees forward? After about 140km on 2020 TL I also heard this kind of chain pop 1-2 times ...

 

[mclydeg]

Not sure
Just sounds like a single pop maybe a chain binding type sound
Not a skip

 

[Zimmerframe]

Mine makes this sound too .. (Kenevo). Not worked out what it is .. normally either when setting off or when suddenly going hard after going easy.

 

[mclydeg]

Exactly
Mine all are when taking off

 

[Zimmerframe]

Exactly
Mine all are when taking off

I've changed my chainring and checked the guide .. that made no difference. woner if it could be something to do with the quick link slackening off 1mm and then pulling tight ? is that possible ? I know nothing !

 

[GeorgesEBike]

I've gotten the same thing on my 2018, 2019 and 2020 Levos.

 

[Murch]

Happens on mine and everyone I ride with too. We are not sure what causes it but I have gotten used to it. I do know it is coming from the chainring area.

 

[mclydeg]

Bike shop guy said sram cassettes have thin teeth
Going to see if any are slightly tweaked

 

[ebikerider]

It's just the motor taking up slack when you take off or when you have backed off the pressure on the pedals causing the noise. It happens more frequently in trail or turbo mode for me.

 

[Jeff McD]

Happened on both of my 2018 Levos and now on my 2020 S works Levo as well. Only happens in very tight technical terrain when I am pedaling slow in tight turns and really sounds like flex in the drivetrain causing the chain to ride up on one of the chainring teeth and then pop off. Keep waiting for the chain to break but hasn't happened yet ha ha. keeping fingers crossed.

 

[wepn]

Honestly I don’t think this sound would be replicated so exactly by so many if it was the chain but rather transmitted through the chain.

Nobody has reported shifting issues & I don’t think anyone has reported the sound during a gear shift.

I strongly suspect it’s the same sound I’m hearing occasionally and my chainline doesn’t budge with the Rohloff hub. I don't think the chain is the cause - more like a lot Newton metres. I'd be interested to know if it occurs in cadence based Shuttle mode

Also interesting described as a pop. I'd say clunk. Sound transmission through magnesium differs to that of aluminium which could explain it being present but slightly different in Mag S & Alu S.

I tried riding with reduced Peak Power and it’s much less noticeable.

 

[Zimmerframe]

I'd say clunk.

I'd describe mine as a clunk. But maybe "pop" is the technical word ?

Anyway, had a short ride yesterday after converting to tubeless and didn't notice it once. Could be co-incidence but I actually tried to make it clunk once I'd noticed it wasn't doing it, by going from soft to hard several times and it didn't do it. @wepn has a rohloff and still gets it, so it sounds like it's chain related. I changed my front chainring last week and that didn't make any difference.

The only things I did which could make a difference was dropping the back wheel, I span the freewheel a few times whilst the wheel was off and checked things, converted to tubeless and put it back. So unless slackening the chain off completely stopped it somehow ? I had to re-adjust the rear caliper afterwards which seemed odd, you'd think it would all have lined up exactly the same ? So unless it's something unusual with the rear axle bolt, which is unlikely.

 

[laustin956]

Hi i had to add a washer to the chain guide to stop rubbing.

 

[gaba]

Probably unintended/unnatural movement of chain onto or off of teeth in your drivetrain. Could be a stuck/stiff chain link, bent teeth/tooth on your cassette or chainring, or poorly aligned chain line. I had a stuck link in my brand new chain on delivery. I used a chain brake tool to loosen it up and worked lube into it. That fixed my initial pops. Some amount of occasional noise from such a powerful motor is probably unavoidable as you use a flexible system that moves in so many directions, as things aren’t always perfectly aligned. Make sure you keep you drivetrain clean and well lubricated. Work through each link to ensure it’s moving well. Regularly check your cassette and chainring for damage. Try to shift with minimal tension on the chain (let off the pedals before you shift). Shifting in turbo for me took practice.

 

[mclydeg]

I checked my chain, cassette, front ring.
All looks good??

 

[mclydeg]

Any input from Specialized Rider Care ?
Seems they are several experiencing this sound.

 

[brizi2003]

I've changed my chainring and checked the guide .. that made no difference. woner if it could be something to do with the quick link slackening off 1mm and then pulling tight ? is that possible ? I know nothing !

Wouldn't think so unless your reusing a 'use once' quick link - which you shouldn't do.

 

[Zimmerframe]

Wouldn't think so unless your reusing a 'use once' quick link - which you shouldn't do.

Nope. All new. Quiet section, power hard CLUNK..

Second ride yesterday after going tubeless and no clunk....

 

[brizi2003]

I checked my chain, cassette, front ring.
All looks good??

Is it possible your getting a little chain suck? A while ago I fitted new chain, cassette and jockey wheels and the new chain kinda got hung up on the chain ring on the lower run as I pedalled. New ring solved it. Perhaps your getting this with only part of the chain/ring?

 

[brizi2003]

Not sure
Just sounds like a single pop maybe a chain binding type sound
Not a skip

Could also be the freehub, they sometimes make a loud 'crack' from time to time when they are sticking a little. This normally occurs when just starting to pedal. Maybe try stripping the rear wheel freehub and cleaning & lubricating as per recommended for this type of freehub.

 

[mclydeg]

My bike is new low miles and I ride very laid back stuff. No changes to the stock setup.

 

[brizi2003]

My bike is new low miles and I ride very laid back stuff. No changes to the stock setup.

In that case take it back to the dealer.

 

[salko]

Does any1 have a spare gopro or similar camera and try to catch this clunk on a video? I noticed this clunk quite often when I am on steep climb, in higher gear and usually in Turbo mode ...

 

[Glen]

Was frustrated with this happening badly. Always starting off or when under load. 11 tooth gear mostly. It was 80 % adjustment of derailleur end point with 20% derailleur alignment. Now gone completely.
Ps tried to video it to find issue but couldn't.

 

[salko]

Yesterday I have taken my bike to LBS to 1st service (have about 350km on the clock), told them about occasional clunk when under load, they say they will look into it ... today went to pickup the bike, they said they ckecked and made some corrections to derailleur and it should be fine now ... afternoon I went to a short ride, and well before first steeper climb I shifted to 2nd gear, put in turbo mode, double checked I was in 2nd gear and soon after starting to climb a *CLUNK* again, now I looked down and I was still in 2nd gear ... I'm now quite convinced clunks are comming from freewheel ...

 

[DS.]

My bike is doing the same thing and it’s a new motor didn’t do it with the old motor feel like something moves or slips and it’s not the chain or cassett

 

[salko]

Just been at LBS, told them it is still clunking, now they said this is completly normal for e-bike, "It's very powerful motor you know!". I don't buy this sh*t!
I will try to find a way to catch it on a video ... this just can't be normal ...