Pop'n and Crack'n Noise
 

All,

I have a Cannondale Synapse with Shimono wheels. I have about 1600 miles on the bike now. I recently had my bike in the shop because of a noise that is a little unnerving. About 20 or so miles into a ride I start getting and feeling an occassional popping or click noise coming from the front of my bike.

I had the bike mechanic tighten my head assy and replace the front wheel bearings. The noise is still there. Sometimes it is so severe It feels like an electric shock to my hands. Thats the unnerving part. This past weekend, I was thinking about it and started wondering if it could be loose or misadjusted spokes, especially since it seems to come after the bike has been ridden for a while.

Thoughts?

thanks,

Stevo:(

Wow, I've never even hard of that!

Viking, any ideas?

1.) Are you sure it is coming from the front? A hollow tube bicycle transmits sounds throughout the entire frame. My bb was clicking once and I would have bet a testicle it was my seat post.
2.) Does the frequency (frequency as in how many, not Hz level) of the popping increase with speed? Is it a constant on every revolution of the tire?
3.) Does it happen on varying terrain?
4.) If you stop pedaling does it still happen?

Just because you don't notice it until higher milage does not necessarily mean one is related to the other, though they could be.
Possible problems:
Cracked frame tubing.
Cracked rim.
Cracked spacer.
Something "stuck" where it shouldn't be.
Gremlins.
Faulty crank/bottom bracket (assuming it is not actually coming from the front)
Martha Stuart.

The fact that you can "feel" it is a good thing (as far as diagnosing it goes).

the noise happens if I am peddling or not. The speed doesnt seem to make a difference although it might be louder with speed. The noise doesnt happen every revolution of the wheel or crank. There doesnt seem to be a pattern, that I can detect anyway, to when it will happen. I have checked my odometer sensor, the brake pads and all seem to be as they should.

Spokes load and unloading, try a drop of Tri-flow on each nipple:) The wheel changes shape as it rotates due to centrifugal forces and precession..... Even the strongest wheels will change a few .0001's on inch

I thought about this too. But if the change in force on the spokes were enough to cause him to feel it in his hands as though it were an electric shock, wouldn't you think the wheel would have already taken a **** already?
Though nothing can be ruled out at this moment I guess.

My Bontrager RACE front wheel does it and drives crazy at times,:eek:(not a long trip) the Tri_flow helps for a few hundred miles or more

It's hard to say with these. Yeah, aluminum tubing can transmit sounds/vibrations in weird ways that can be very confusing, especially if you can't reproduce the sound. That said, I think we can rule out the rear of your bike. Also we can probably rule out the bottom bracket and BB shell for the time being. If there is something wrong behind the pedals, you will usually notice the noise as you pedal.

For example, I just took my Lemond in to have the bottom bracket and crank warrantied, but at first I could have sworn that the clicking was coming from my head tube. The dead giveaway was that the cracking noise eventually coincided with my pedal stroke. Even so, you might want to have them tighten down your bottom bracket, especially if it is a truvativ!

One way to rule out the front wheel is to borrow a front wheel from your buddy. Go for a ride and if the problem is gone, then you know that it is your front wheel.

It might be a problem with your stem or handlebars. I'm guessing your mechanic checked over everything here, but you can't be too sure. In other words, it is one of those things you can easily rule out by greasing all of the bolts on your stem, lightly greasing the handlebar before tightening the face plate of the stem and, after everything's in place, backing off the tension on the top cap / star nut bolt. It might just be the case that the grease was washed or blown out somehow.

If the sound is still there then the question is: what is the pattern? More specifically, does it tend to make a noise when you're rolling over a bump or a crack? When you're leaning forward vs. sitting back? Does it increase in frequency when the road becomes rougher? This sort of thing might seem irregular at first. Either would suggest that something bad is going on with the head tube or even the fork.

I guess I would get out a bottle of windex and a bright light to help you inspect the downtube, top tube and head tube (especially the welds) for cracks. Even a very small crack will produce a noticable clicking noise and pinging effect in an aluminum frame.

My Cannondale cracked last year and it took me two months to find the crack even though it was unbelievably noisy. It became louder and more frequent, so it was obviously expanding, but it was only 1/4 of an inch long when I found it!!! The crack looked just like a tiny, scratch. The telltale sign was that it was irregular in shape rather then straight. If your bike is a darker color, a crack like this will be very hard to see but you will notice it as your run your fingernail over it. Finding something like this is tedious work!

It's hard to inspect a fork without taking it off the frame, but I would hope that your mechanic took a look at it for you because you can have similar issues with the carbon cracking but don't forget about the steer tube as well the connection between the carbon and steer tube.

If you've ruled out headset, stem, handlebars and front wheel, and you can't find the the problem after inspecting your frame, keep taking it back until your LBS isolates the problem and furnishes a solution. They don't have much else to do this time of year anyway.

Thanks for the advice. I will work on this and let everyone what I find. Changing out wheels will be easy as my son has the exact same bike. I will start there.

Stevo

Good luck stevo, let us know what you find.

My money's on the front wheel - I had something similar happen but it turned out I was snapping spokes (6 in one ride while hammering). Either something detensioning or a small crack in the rim.

You might be right about the crack in the rim. I've never had that happen so I don't know what sounds like.

...and the borrowing the wheel from someone should determine that pretty quickly - always a great suggestion :)

I have cracked rims and the resulting noise varies depending on where the rim is failing, if it is failing around the eyelets then it can make a popping noise as the spoke is starting to pull through the rim, if you crack the sidewall you get a ping noise from the spokes. The cracked sidewall is much more obvious though as you can feel a pulse when braking with rim brakes or you will feel a wobble in the wheel even though it may appear true when you spin it with no weight on the rim.

When my rim was cracking around the eyelets I found that if I stood and put a lot of weight on the bars while coasting I could make the frequency of the noise increase.

That makes sense.

What worries me is that the OP says he feels it in his hands like an electric shock. Is this your experience?

Most of the time, its just a clicking pop sound and then a bigger one that is felt in the handle bars. Like I said before, thats the one that scares me.

The fact that you say the frequency of the noise does not increase/decrease with your speed would lead me to think;

1)It is a either a frame, fork, stem, handlebar problem or any combination of those, which could either be something is not snug enough or someone torqued something a little too much resulting in my next thought

2)There is a slight crack/fracture in or around the parts mentioned above. Not only would I closely inspect those parts where they connect to one another, but I would also unwrap the bars and check under the tape (if you use drop bars). You should also check the steerer tube of the fork if the mech did not which means removing it from the frame.


What year is your bike? Maybe not part of your problem but a couple of 2007 Synapse models sold were recalled because of brake failure. Not sure what the brake failure was but it would be good thing to look into.

Here is a link to the recall U.S. Consumer Product Safety Commission - Synapse Recall

DBD:beer:

I have never had the electric shock sensation as a result of a wheel problem, missed that in the original post.

I could see dry bearings clicking and popping and perhaps catching once in awhile and causing a bit of a shudder the hub was serviced so that shouldn't be the cause. Perhaps the headset bearings are dry, worn out or maybe even missing a bearing or two. The original post said that the headset was tightened but not serviced. I would be inclined to pull it apart and check the lower bearings.

My bike, a Giant OCR 1, was driving me crazy with something like this, and I felt clicking and popping all the way up into the handlebars. It was in no way subtle. What solved my issue was to take out the seat post, clean and regrease it. I have to do this within 2-3 days of riding in the rain. Very odd in how much of the bike it felt like it effected. This may not be your problem, but worth trying.

So far it is the only "fluke" I have found on the bike. Before my LBS helped figure this out, I overtightened the head steam, cranks, crimped the carbon seat post it came with (btw, the aluminum doesn't feel any different).

Did you swap out the wheels? Result?

I've never been thrilled about my Bontrager crank and bottom bracket, but it turns out that they're working just fine.

I had a look at my Bontrager rear wheel and, sure enough, it's cracked at multiple eyelets. I guess my Lemond is spending another week in the shop waiting for a new wheel or wheels.

my experience with creaks is cracks....bad karma and can make for bad things to happen. I cracked a Ti frame above the BB shell on the seat tube. Was repairable but still could have been bad news. Next creak was right before the left crank fell off, crack across the area where the crank attached to the spindle on the BB. Lucky enough, was not standing on it at the time.

Hi TallSteve
This problem has occurred with a number of Shimano, Bontrager and lately Hope wheels. The crack/creak is invariably caused by the smooth end of the axle stub rubbing on the inside of the dropout(inside the cutout slot). The noise is often worst when out of the saddle and putting more pressure on the bars.
It is often accentuated if the end of the wheel axle stubs are anodised and made louder if the hollow fork blades are carbon as they act a little like a sound amplifier.
The cure is to smear a very thin layer of grease on the inside of each dropout cutout slot, not the inner or outer face. Tightening the skewer does not make improve things as there is aolways some flex in the system.
Older front wheels with threads on the ends of the axle stubs never did this.

Try this simple and effective cure, it works like magic and is verrrrry cheap.

Thanks Den for the advice. I will give it a try. I road about 60 or so miles last Sat and Sunday and didnt notice the noise. I am not sure if it was because it was cold out. Around 45 or so. I did check for cracks around the spoke ends and didnt see any. I will try your suggestion before riding Saturday.

thanks again,
Steve