Bicycle Mechanics - Wheel imperfection?

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View Full Version : Wheel imperfection?


bagel007
06-18-09, 04:10 PM
The last time I was in my LBS (where I bought my bike) I showed the mechanic one thing that looked to me suspicious: When I lift the rear wheel in the air (by holding the saddle in one hand) and pedal with the other hand so the wheel turns fast, the wheel is "pulsating" -- pulling up and down. It's not very strong, but quite noticeable. The mechanic told that it's nothing, just "wheel imperfection".

I'm not sure he's right. I also hear clicking noise when riding the bike and it seems coming from the rear wheel. When they put the bike on workstand in the shop, no noise. The mechanic and even the shop owner took the bike for ride around the block and as they came back told me that they cannot hear any unusual sounds or noises.

Now I'm pretty sure about the clicking noise. It's not always there, but once I shift to 4th or 5th rear gear (while on the middle chainring in the front), the clicking noise is very obvious.

It's quite a new bike (I bought it less than 4 months ago). Maybe it's just matter of greasing the BB or the rear hub. Or it's related to what the mechanic called "wheel imperfection"? Not sure what to do about it.

Oh, I've attached an old audio tape-recorder with packaging tape to the seat tube and recorded the noise. Yes, you can hear the click-click noise very clearly in the recording.

Any advice?

Thanks in advance!


Torchy McFlux
06-18-09, 04:24 PM
Chains make clicking noises. It's sometimes more pronounced on newer bikes. A derailleur that is sightly out of adjustment or has a cable that's binding a little can make it worse. However, it's not a problem.
The imbalance of the rear wheel is very normal. There's naturally a heavy spot on the rim where the seam is. It's unnoticable while riding and nothing to worry about.
You're not a bike-ochondriac, are you?

sooprvylyn
06-18-09, 06:02 PM
if you are noticing a clicking in a particular gear look down at your front derailleur cage and see where the chain is in relation to the sides. Chances are you simply need to trim your front derailleur a little to get the chain centered in the cage.
when you are in gear 1 (smallest front gear and largest back gear you will notice that the chain is fairly straight or slightly angled in towards the rear wheel. As you go up in gears(from the largest rear to the smallest rear) you will see that the chain angle moves away from the wheel. This is also reflected to a smaller degree up on the front gear through the derailleur cage and results in chain rub on the cage when the angle gets high enough. In larger rear setups this is exagerated even more(8-10 speed rear cassettes). Your front shifter(if indexed) should have a "halfway" point in shifting that does not go up 1 full gear, this is called trim and will tweak the cage in the direction of the chain angle and eliminate this rub. If you have friction shifters you can manually tweak the shifter for this trim. I bet this will solve the noice problem.

Also cheap tires often have imperfections. To see whether you have a tire issue or a wheel issue turn the bike upside down and spin the back wheel. Use a pencil held against the frame with the point at the top of the rim as it spins, this will give you a fixed point to focus on. If the rim moves up and down it is a wheel problem and your wheel needs trueing(not likely on a new bike). If it is just the tire then you have an imperfect tire. The wheel is not what is making the clicking noise, guarunteed.


Mondoman
06-18-09, 08:31 PM
T - I think the OP is describing an out-of-round condition (as s addressed), not an imbalanced wheel.

b - on a new bike, the wheel itself should not be significantly out-of-round; if it is, the shop can easily fix it on a truing stand. However, after 4 months, the bike really isn't "new" anymore. Most shops in the US include at least a free "tune-up" of the bike after you have been riding it for a few months, to make sure everything is still tight, adjust the cables if they have stretched a bit, and so forth.

bagel007
06-18-09, 08:31 PM
if you are noticing a clicking in a particular gear look down at your front derailleur cage and see where the chain is in relation to the sides. Chances are you simply need to trim your front derailleur a little to get the chain centered in the cage.

The chain is not touching any part of the derailleur cage when it happens. I've looked numerous times down at the front derailleur when the clicking started and the chain had enough clearance on both sides.

Also, the clicking happens only when I ride the bike, not when it's on workstand or the bike is upside-down.

It seems to me that the clicking sound is originates in the wheel hub, but I'm not sure about it.

How difficult is it for a mechanic to open the rear wheel hub and add a bit of grease to see if that solves the problem???

Mondoman
06-18-09, 08:39 PM
b - I assume you are talking about the front derailleur. The rear derailleur is another possibility. If the rear wheel hub were the source, it would happen in all gears, so I'd look elsewhere.

How fast is the clicking? Does it match your pedaling rpm? Wheel rpm? Neither? Does it happen only while you are pedaling, or also when you are coasting? If you apply either brake a bit while it is happening, does it stop? Does it happen if you pedal backwards? Can you get it to happen when in the 1st or 3rd front gears?

If possible, try to get a friend to ride the bike and get a second opinion of where the noise is coming from. Also have them ride right by you so you can listen for the noise location from the side of the bike.

bagel007
06-18-09, 08:39 PM
T - I think the OP is describing an out-of-round condition (as s addressed), not an imbalanced wheel.

I'm not sure what is "out-of-round condition". But yes, it's like the wheel is not pefectly round. When spinning, the centrifugal force makes it pulsating. So, if you're looking from the top, the wheel is symetric, it doesn't move from side to side. But if you hold the rear side of the bike in the air (like by a saddle) and the wheel is spinning, you can feel the up-and-down pul.

Mondoman
06-18-09, 08:44 PM
b - OK, now I'm confused. Is this something you *feel* or something you *see*? If the former, then Torchy was right and I apologize to him, and you don't need to worry about it. If the latter, then either the wheel or the tire is not quite perfectly round, and when you turn it fast, you will see its outline moving up and down.

bagel007
06-18-09, 08:45 PM
How fast is the clicking? Does it match your pedaling rpm? Wheel rpm? Neither? Does it happen only while you are pedaling, or also when you are coasting? If you apply either brake a bit while it is happening, does it stop? Does it happen if you pedal backwards?

It happens only when pedaling. It's faster then the pedaling -- several times per one crank revolution. Haven't tried to apply brake while pedaling. And no, it happens only when pedaling in the forward direction.

bagel007
06-18-09, 08:58 PM
b - OK, now I'm confused. Is this something you *feel* or something you *see*? If the former, then Torchy was right and I apologize to him, and you don't need to worry about it. If the latter, then either the wheel or the tire is not quite perfectly round, and when you turn it fast, you will see its outline moving up and down.

It's something (the pulsating) that I feel in the hand holding the saddle.

I'm not so much worried about the "wheel imperfection". What worries me is the clicking sound. As I said, both the shop mechanic and the shop owner took the bike for a ride around the block and claimed there is no clicking sound and the bike is in perfect condition, gears shift as should, etc. I agree with them on the latter, but not on the clicking sound. I've listened to my audio-recording I made with an old tape-recorder attached to the seat tube. And yes, the clicking sound is there.

(BTW, I was amazed how strong is postal packaging tape...the tape-recorder stayed put during the ride...)

rm -rf
06-18-09, 09:01 PM
Most bike wheels are heavier at the seam. So, on a repair stand, cranking the pedals to make the back wheel spin, the bike bounces up and down due to the out of balance wheel. But--you never feel it when riding. The only time I've even barely felt the pulsing was a 30 mph downhill on a newly paved, extremely smooth road. So: it's normal.

On the clicking: shift to the rear cog that has the noise and listen for the clicking. Now stop without shifting, and get off the bike. From the back, check how the chain fits on the cog. If the rear derailleur is slightly off adjustment, the chain may be touching either the bigger cog or the smaller cog next to the cog that the chain is on. That slight rubbing can cause a clicking type of sound, too. The chain is centered on the cogs by slightly turning the barrel adjuster on the cable housing. See Park Tool's repair guides (http://www.parktool.com/repair/readhowto.asp?id=64) for a step-by-step process to adjust it.

bagel007
06-18-09, 09:43 PM
On the clicking: shift to the rear cog that has the noise and listen for the clicking. Now stop without shifting, and get off the bike. From the back, check how the chain fits on the cog. If the rear derailleur is slightly off adjustment, the chain may be touching either the bigger cog or the smaller cog next to the cog that the chain is on. That slight rubbing can cause a clicking type of sound, too. The chain is centered on the cogs by slightly turning the barrel adjuster on the cable housing. See Park Tool's repair guides (http://www.parktool.com/repair/readhowto.asp?id=64) for a step-by-step process to adjust it.

Thanks! I'll try that.

But, if that's the case (the chain rubbing the smaller or the bigger cog next to the one it's on) -- why the clicking happens only when I ride? Shouldn't be the clicking also there when the bike is on a workstand??

rm -rf
06-19-09, 06:32 AM
Thanks! I'll try that.

But, if that's the case (the chain rubbing the smaller or the bigger cog next to the one it's on) -- why the clicking happens only when I ride? Shouldn't be the clicking also there when the bike is on a workstand??

Yeah, that's a good point.

Clicking can also come from a slightly loose crankarm, if you have something like an FSA crank with the two bolts on the left crank. I would get a click at the same point in the pedal stroke.

bagel007
06-19-09, 08:23 AM
Clicking can also come from a slightly loose crankarm, if you have something like an FSA crank with the two bolts on the left crank. I would get a click at the same point in the pedal stroke.

The last time I was in the shop (a couple of weeks ago) the mechanic said that the pedal was loose and he has tightened it up.

But after all his work I took the bike for a ride around the block and the clicking was still there, without any change in intensity or pitch. The same click-click-click sound. I came back to the shop telling him that. Then he took the bike for a ride. He said nothing, no clicking sound. Then the owner intervened and took the bike for a ride. The same streets, exactly the same path. One particular street has not so much traffic, so before their rides I told them exactly where to pay attention. Once again, the owner came back telling me that he couldn't hear any clicking.

I think I'll go back to the shop with my audio-tape recording and play it in front of them to show them what I hear when pedaling. I know it sounds a bit un-ortodox -- but do I have a choice? It's very-very pronounced sound. I could go to a different shop, but then ... well, I bought the bike in THAT shop and if (by any chance) someone will tinker with the bike and make it worse, the original shop could rightly say that NOW I have a problem because someone was "playing" with the bike. It's a nice shop with nice people and I even have their promise to take care of the bike maintenance for the full year since the purchase. So, I don't want part with them.

Shouldn't they open the hub to see if the bearings have enough grease? Maybe that's the problem. How difficult is it to open the hub? Is it worth trying?

Hydrated
06-19-09, 08:48 AM
I would almost bet that your rear wheel wasn't built and stressed properly.


You have two symptoms:

Wheel out of round.
Clicking from the rear wheel when the wheel is under under driving stress (when you're pedaling).

Both of these point to a wheel with one or more spokes that are either much tighter than the others or much looser than the others in the wheel. As the wheel rotates, the spokes load and unload as their orientation to the ground changes. When you pedal, the spokes in the rear wheel have the added torsion from the drivetrain twisting things and driving the bike forward. Viola! Click click click click...

My first step would be to pull the rear wheel and rework it. Take the tire off and loosen all of the spokes and start the stressing and truing process all over again. I'd bet that your mechanic doesn't want to do that for you because he doesn't know how. It amazes me at how many shop mechanics don't know how to build a wheel.

Those machine built wheels that come stock on most bikes can really suck.

AEO
06-19-09, 09:04 AM
spoke torsion, spokes will wind up when under tension and tightened further. they can be stress relieved by the sheldon method.

when the wheel is built it, it's not 100% perfectly balanced all around and there will be a bit extra or less weight at one point or another. usually the seam or valve hole because of the extra reinforcing material.

Booger1
06-19-09, 09:23 AM
I think it's the spokes making noise since it only does it under load..Check the spokes where they cross each other.Pull them apart a little a little and see if you have a flat spot on them.Under load,the spokes are flexing and clicking against each other.I think the spokes want more tension.

tatfiend
06-19-09, 10:05 AM
If the clicking is happening only when pedalling in certain gears and multiple times per pedal revolution then the problem is not likely to be the bottom bracket, rear hub itself or loose spokes IMO. You mentioned the noise while in the middle chainring and in 4th or 5th casette cog. How about while on the other chainrings or in other rear cog positions? Does it vary in sound level based on pedalling hard versus easily?

The difference is chain moving versus not moving which to me indicates a chain adjustment related problem. Not doing it on the stand can be caused by the difference in chain tension under riding versus low load conditions. I have had to occasionally tweak index shifting adjustment to get clean shifts or eliminate noise under riding conditions even though it worked fine on the stand.

BTW almost all current bottom brackets are sealed cartridge type and there is no greasing provision. It should not be failing in only 4 months on a decent quality bike.

Personally I would try minor adjustment changes on the rear derailleur to see if that has any effect. Mark the adjustment barrel so you can return it to the original setting if no change in noise is noted and change the adjustment 1/8 to 1/4 turn each way and note any change in sound.

Trying to remotely diagnose bike problems via sound descriptions is extremely difficult as you are finding out. Better learn at least basic maintenance yourself or the LBS will be all too familiar. Taking your recording in may help though.

Mondoman
06-19-09, 10:41 AM
I agree that bringing in the recording is a good idea. At least the shop will be able to hear the specific noise you are worried about and maybe even listen for that specifically on a test ride.

joejack951
06-19-09, 10:58 AM
The answer to the "pulsating" wheel is right in the picture of the recorder set up posted by bagel007. Remove that relatively useless reflector on your wheel and 99% of that pulsation will be gone. The rest is the wheel seam, the valve stem, or cheap tire casing.

bagel007
06-19-09, 01:02 PM
OK, this is a part of my recording. This is exactly the type of clicking sound I hear when pedaling.

http://www.youtube.com/watch?v=NK7V5dTnUoA

Dan Burkhart
06-19-09, 01:54 PM
Take 2 of these. The noise will go away.
http://i42.tinypic.com/1tkl0i.jpg

JanMM
06-19-09, 09:42 PM
OK, this is a part of my recording. This is exactly the type of clicking sound I hear when pedaling.

http://www.youtube.com/watch?v=NK7V5dTnUoA

I hear clicking! Sorry, can't tell exactly what it might be. It's not coming from the rear derailer, is it? Maybe the little plastic pulleys? Just a guess.

rm -rf
06-20-09, 06:07 AM
How many times per pedal revolution? Is it repeated at the same place in each pedal revolution, or not?

And you never hear it when coasting, is that right?

There have been riders on BF that found their shoe or laces were hitting the bike on each pedal stroke. Or the end of the front derailleur cable was hitting their shoe.

Can you make the sound stop by shifting gears?

Or is the sound repeated per wheel revolution, whenever you are moving?

See tatfiend's post above--it does sound like chain/drivetrain adjustments.


If you are concerned about the bearings, just lift the bike and spin the wheel with your hand. Does it coast down slowly or stop quickly?
It's not spokes. They make a sharp pinging sound, and wouldn't be a regular, repeated sound anyway.

Greenfieldja
06-20-09, 11:34 AM
Check for the following:

1. is the end of your front derailleur cable is hitting something like your shoe or the frame upon each pedal stroke.

2. is there is something striking the plastic disk between your gears and the spokes on your rear wheel.

-j

bagel007
06-20-09, 11:36 AM
How many times per pedal revolution? Is it repeated at the same place in each pedal revolution, or not?

And you never hear it when coasting, is that right?

There have been riders on BF that found their shoe or laces were hitting the bike on each pedal stroke. Or the end of the front derailleur cable was hitting their shoe.

Can you make the sound stop by shifting gears?

Or is the sound repeated per wheel revolution, whenever you are moving?

See tatfiend's post above--it does sound like chain/drivetrain adjustments.


If you are concerned about the bearings, just lift the bike and spin the wheel with your hand. Does it coast down slowly or stop quickly?
It's not spokes. They make a sharp pinging sound, and wouldn't be a regular, repeated sound anyway.

More than one time per pedal revolution.

I never hear it when coasting. Never.

I usually stick even my shoe laces into the sneakers, so neither the shoes/sneaker, nor the laces are touching any part of the bike.

No, I cannot stop the sound by shifting gears. I'm in the fifth gear and it's clicking. I shift to the sixth gear, it's clicking. I shift back to the fifth gear and it's clicking. I'm climbing, it's clicking. I'm pedaling on flat terrain, it's clicking.

I lift the bike and whatever I do with the pedals, no clicking. That's the point. In the bike shop they put the bike on the workstand and tried everything. I was close to the bike and I couldn't notice any clicking. So, the clicking is only when I ride the bike, pedaling, not cruising.

I cannot tell if it's once per wheel revolution -- I cannot count wheel revolutions when riding.

Dan Burkhart
06-20-09, 11:47 AM
It is possible the sound is comming from another source altogether. Have you tried getting out of the saddle while pedalling?
I've seen this numerous times where someone goes just about bonkers trying to pinpoint a drive train noise, only to discover it was the saddle that was the culprit.

Wordbiker
06-20-09, 11:54 AM
Considering that bike quality levels vary from mass-produced $50 Xmart specials to $30,000+ one-off wonder bikes...how perfect do you expect it to be?

Yes, rims can be manufactured out of perfect round.
Yes, tires can be manufactured out of perfect round.
Yes, rim seams can be wider than the rest of the rim causing a click with rim brakes.

Just putting out there that there are imperfections in everything made by humans or human design. The problem may not be with the pea, but with the princess.

bagel007
06-20-09, 12:31 PM
I think I'll return to the bike shop, play in front of the mechanic or the owner (even better) my audio-recording of the clicking sound, ask them to replace the rear wheel (by a wheel from other Cypress -- I guess all Giant Cypress models, regardless of their size -- small, medium, large -- have interchangeable wheels) AND ride the bike around the block. If I won't be able to notice any clicking sound, I'll be more than happy.

As a matter fact, since I purchased the bike from them, I was in the shop at least 3 times telling them about the clicking noise.

Oh, maybe I'll buy from them some fenders that I need in any case -- I don't commute, but I ride in rain and what bothers me more than the rain from the skies, is the wet and dirty stream of s***t the tires throw on my legs and back. If they'll install them for free -- that will make both of us happy. (Before buying the bike they told me that they would install bike rack for free if I buy it from them...)

I don't know what's the partnership between bicycle shops and Giant. But I believe that Giant will accept faulty wheel from the shop and replace it by a new one.

Not sure about that whole idea, but certainly owners of bike shops will have some experience or opinion on how it works or might work in my case.

bagel007
06-20-09, 12:54 PM
It is possible the sound is comming from another source altogether. Have you tried getting out of the saddle while pedalling?
I've seen this numerous times where someone goes just about bonkers trying to pinpoint a drive train noise, only to discover it was the saddle that was the culprit.

Yes, I have tried to pedal with my butt in the air. And that didn't stop the clicking sound.

I must add, that the clicking sound sometimes goes away and sometimes it's so strong, that I almost could swear I feel it in my hands as the sound rattles the bike a bit.

Sdlong92
06-20-09, 01:37 PM
Maybe it's your pace-maker? Click, click click.

I have to ask, have you checked how long the excess cable is on the RD? If you're shifting into 5th/6th gear is it possible that the excess cable is hitting the spokes? That would explain why it doesn't click on smaller cogs since the RD is further away, and the excess cable by virtue of that.

bagel007
06-20-09, 02:10 PM
I have to ask, have you checked how long the excess cable is on the RD? If you're shifting into 5th/6th gear is it possible that the excess cable is hitting the spokes? That would explain why it does click on smaller cogs since the RD is further away, and the excess cable by virtue of that.

If it's that, why is not showing up when the bike is on a workstand?

It must be something that is related to the load or stress under which is the bike when I'm riding it. And I weight with all the gear about 175 lb.

Sdlong92
06-20-09, 02:41 PM
If it's that, why is not showing up when the bike is on a workstand?

It must be something that is related to the load or stress under which is the bike when I'm riding it. And I weight with all the gear about 175 lb.

Spoke DO bow under load, however miniscule. It may be enough for one more to contact in the 5th/6th cog.

rm -rf
06-20-09, 07:49 PM
More than one time per pedal revolution.

I never hear it when coasting. Never.

I usually stick even my shoe laces into the sneakers, so neither the shoes/sneaker, nor the laces are touching any part of the bike.

No, I cannot stop the sound by shifting gears. I'm in the fifth gear and it's clicking. I shift to the sixth gear, it's clicking. I shift back to the fifth gear and it's clicking. I'm climbing, it's clicking. I'm pedaling on flat terrain, it's clicking.

I lift the bike and whatever I do with the pedals, no clicking. That's the point. In the bike shop they put the bike on the workstand and tried everything. I was close to the bike and I couldn't notice any clicking. So, the clicking is only when I ride the bike, pedaling, not cruising.

I cannot tell if it's once per wheel revolution -- I cannot count wheel revolutions when riding.

So, it's not a bad spot on the chain-you would hear it once every two or three pedal revolutions.

I like the "try a different rear wheel" idea. If the sound goes away, it could be bad bearings or freewheel after all. If it stays, it's the cranks, bottom bracket, frame, pedals, or derailleurs.

Since it does stop when not pedaling, the once per wheel question isn't important. (At slower speeds, you could see the valve in the front wheel to match it to wheel rotations.)

Will it stop if you pedal just with your right leg and the left unclipped?

rs1101
06-20-09, 10:08 PM
usually weird clicking noise like you describe are the r d-rail being cocked off at a funny angle.

bagel007
06-21-09, 11:18 AM
Will it stop if you pedal just with your right leg and the left unclipped?

No. It doesn't matter which leg I use to pedal. When it's clicking, it's clicking. Changing the leg with which I step on the pedal doesn't have any effect.