Pop Pop Pop When Pedaling

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Buster1

Wore out three sets of tires already!
Oct 23, 2011
856
Las Vegas
Has anyone ever experienced that? My '41 Westfield makes a pop pop pop sound when pedaling hard. It's quiet when pedaling lightly.

Yesterday I replaced the pedals from another bike, thinking the pedal bearings were acting up. That wasn't it, she still did it.

So I removed the chain (cleaned and re-lubed it) and disassembled the bottom bracket. Everything looked great in there. Re-assembled it all and adjusted the pre-load a tad lighter/looser, as well as the final BB nut. The final nut over the cover plates and it's tightness seemed to have some impact on how smoothly she pedals.

Anyway, my test ride was MUCH smoother after all this. Is this a common issue? Was my pervious pre-load just too tight?

Thank you.
 

Obi-Wan Schwinnobi

Riding a '38 Autocycle Deluxe
Feb 5, 2013
6,590
41
San Diego
I find on the skip tooth that if the rear cog is shark finned it will cause a grinding popping sound sensation whilst pedaling underload.
 

pedal4416

I live for the CABE
Nov 28, 2008
1,893
37
Bryan, TX, USA
Is it a morrow rear hub? I've noticed if they make a popping noise it means they are assembled wrong.
 

redline1968

Riding a '38 Autocycle Deluxe
Oct 16, 2008
5,585
Seattle, United States
It's the bearings in the hub. they are too tight. If you lift the wheel and spin them they should spin freely without wobble for more than 2 or 3 revolutions. Front, rear and the crank hangar also. Grease them and adjust them to spin easily.
 

Buster1

Wore out three sets of tires already!
Oct 23, 2011
856
Las Vegas
Thanks for helping me try to diagnose this guys. I appreciate it. Though it does appear that I have just about every possible part of the drivetrain listed above as the culprit! :confused:;)

Let me see if I can answer a few of the questions above.

- The Chainring is not original. The Chain and Cog/Hub ARE original. (even has the wider Westfield chain)
- The chain is in excellent condition, all rollers turn easily and there are zero binds or issues with the chain (that I can note)
- I will examine for rear shark-finned cog, but I believe it is okay.
- Thank you for the links!
- It's a ND model D hub, hand turning it and such provides a very smooth action. Turns easily and seems to be 'normal.'

I do feel like it was the BB being too tight. Now with the looser/lighter pre-load almost all of the popping is gone, but I need to give her a better ride test to see.

IMG_4549-1.jpg

IMG_4540-1.jpg
 

bricycle

I'm the Wiz, and nobody beats me!
Nov 18, 2009
23,392
Chicago area west
That looks like one of those "repop" chainwheels. Maybe they were made wrong?
 
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bricycle

I'm the Wiz, and nobody beats me!
Nov 18, 2009
23,392
Chicago area west
Pop Pop Pop When Pedaling

...sometimes I hear that sound too, but is usually while riding through a bad neighborhood, so maybe I'm being shot at???
 
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Reactions: pedal_junky

Buster1

Wore out three sets of tires already!
Oct 23, 2011
856
Las Vegas
The chainring is AN original part. I had it chromed during restoration. It does have a slight wobble to it...very slight.

I will also add, that I don't feel anything through the pedals when pedaling hard. If I did, I would think chain or rear hub, but I don't feel anything. No chugging or skipping. Just noise, under load.

Thanks and keep the ideas coming guys!

IMG_4539-1.jpg
 
Last edited:

Wheeled Relics

Cruisin' on my Bluebird
Apr 16, 2013
3,561
Naalehu, HI, United States
www.facebook.com
Is it a pop pop pop or a clack clack clack? "When pedaling hard..."

Are you sure its not your knees? J/k

Check for sharking on the chainrings if no sharking replace the chain and see if it persists, if it goes away its chain stretch causing the chain to climb, the pop is it dropping back into the grooves. If there is sharking on either sprocket same thing, chain climb when pedaling hard. My .02c
 

rustjunkie

Moderator
Staff member
Jul 11, 2012
13,694
Monrovia, CA 91016
www.rustjunkies.com
It sounds like worn drivetrain component(s) to me. From my experience when "new" parts are mixed with old problems can arise that weren't noticed before. The chain, chain ring, and cog wear together, and they do wear out. W/O being able to see your parts, my guess would be that a worn chain is the culprit. Sounds to me like the chain is "stretched" to the point that it is not meshing properly with the teeth on either the cog, new chain ring (more likely), or both, and it's popping when under load. I've ridden many bikes with worn(out) drive trains, and the problem of skipping or popping was not always evident until (greater) pressure was applied to the pedals. I've seen bikes ridden in for flat repairs that have cog teeth that are badly hooked and barely there. The owners never put considerable pressure on the pedals for the problem to manifest, or if they did they backed off so it went away. Wear gets to a point where the solution is to replace chain, cog, and chain ring.
Try pulling the chain away from the chain ring at ~ the 3 o'clock mark. It should not come away from the ring much at all. I've seen them so worn that I could put my finger in between the chain and ring, but the bike rode reasonably okay, because all the parts knew each other well.
You could also remove the chain, count the links, and measure the length. A NOS 56 link 1" x 1/4" chain like what is on your bike measures 55 3/4" end to end w/o the master link.
Is the chain ring made for the 1/4" chain?
I'll bet you a Mexican Coke that chain wear coupled with "new" chain ring is the culprit. We'll settle up on the next Monrovia ride :)
 
Last edited:

Wheeled Relics

Cruisin' on my Bluebird
Apr 16, 2013
3,561
Naalehu, HI, United States
www.facebook.com
I find on the skip tooth that if the rear cog is shark finned it will cause a grinding popping sound sensation whilst pedaling underload.
Obi wan I thought same, esp what he described about it lessening under more tension, description sounds like a shark finned cog or chain stretch (worn rollers). Checking the pitch of the teeth, and if they look ok replacing the chain to further troubleshoot.
 

Buster1

Wore out three sets of tires already!
Oct 23, 2011
856
Las Vegas
Awesome guys! I think you may be right. The chain IS OG and 74 years old. I will measure it and check link spacing and report back. It's not a skip-tooth, but is the wider style chain the Westfield used on their bikes during that era.

It is more of a pop pop...NOT a clack clack or metallic sound.
 

tanksalot

Wore out three sets of tires already!
Nov 22, 2011
945
Hingham, United States
Thank you for cleaning my bike so well.:) i.d. just go through the bike one part at a time with the chain on tight ( If it tries to ride off then you narrowed the issue down to gears or chain. Then remove the chain & spin the hubs sprocket ect & see if they feel right ..Good luck it a great looking bike.
birdthanksgivingNDgame017.jpg

Thanks for helping me try to diagnose this guys. I appreciate it. Though it does appear that I have just about every possible part of the drivetrain listed above as the culprit! :confused:;)

Let me see if I can answer a few of the questions above.

- The Chainring is not original. The Chain and Cog/Hub ARE original. (even has the wider Westfield chain)
- The chain is in excellent condition, all rollers turn easily and there are zero binds or issues with the chain (that I can note)
- I will examine for rear shark-finned cog, but I believe it is okay.
- Thank you for the links!
- It's a ND model D hub, hand turning it and such provides a very smooth action. Turns easily and seems to be 'normal.'

I do feel like it was the BB being too tight. Now with the looser/lighter pre-load almost all of the popping is gone, but I need to give her a better ride test to see.

IMG_4549-1.jpg

IMG_4540-1.jpg
 
Last edited:

bikejunk

Wore out three sets of tires already!
Nov 1, 2014
752
57
passaic NJ
if your chain has no slack it could cause this noise ,as it will bind on a re-chromes ring till it wears in . nice bike
 

old hotrod

I live for the CABE
Jan 10, 2008
1,932
So Cal
www.flickr.com
Is the rear sprocket the wider 3/16 width for the wide 1/2" pitch chain? Is the chain in line? Did you replace the bottom bracket bearings? What about the small outer bearing in the rear sprocket?
 
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