though

Hello all,

I bought a Scott Sub 20 this May. It had a ticking noise coming from headtube area. Last week I once again dismantled the headtube to re-grease and check it again before sending my bike to my dealer. I took the fork out completely this time and I noticed that ticking noise is coming when I hold the fork from the base and play with the steerer tube (trying to move it back and forth).

After further inspection, there were no welding defects, or cracks or anything. I noticed steerer tube is welded to the fork from its bottom end (so that end is rigidly connected) but there is a small play probably due to a clearance at the top of the fork where the steerer tube is coming out of the fork (place where the cone rests). Please refer to the nicely drawn figure down here.

So I think steerer tube is moving with respect to top of the fork and by doing so it is also moving the cone with itself. And bottom face of the cone is rubbing against top face of fork and this is making the noise.

I sent the fork back to my dealer for them to inspect and see what they can do about it.

My question is, is this kind of thing can be considered normal? Or is this a faulty fork? Could I just remove the cone, apply some grease to the bottom of it and put it back? Would that solve my problem. Is the play (clearance) in that area normal? Can the clearance cause fatigue at the lower weldment? What should my dealer do in this situation? Should I expect a replacement fork?

And btw, ticking noise at first was rare, like whenever I go into bumps it would tick once. After some time it ticked more. Like a couple of ticks as I go over rough surfaces. Lately it was ticking even on very smooth roads. Just my movements on the bike were enough to make it tick. And on rough surfaces it was very bad. It was almost like a continious ticking noise.

Thank you all for reading.

RookieRoadie

Sounds like the most likely explanation is a slightly mis-adjusted headset bearing, likely a little loose. This would certainly fit with:
If it was loose, it would wear faster than it should, so the play would be exaggerated and the noise would increase as time went by, especially when going over bumps. I'm not saying it's impossible for there to be a small amount of play as you said, but it seems unlikely that it would cause the symptoms you described. Either way, good idea to get it checked

FBinNY 

Here's where you have to remove and inspect the fork. If the crown race is loose you'll have the symptoms described, and that can easily be spotted (the race is loose and falls off), and corrected by a variety of methods.

OTOH, if the steerer is actually loose in the crown, this is a rare defect, but it's the most dangerous type of defect it's possible to have on a bike, and the fork cannot be ridden under any circumstances.

I'm not someone who generally post's ".... or you'll die" which is an exaggeration 90% of the time, but a loose steerer/crown joint really is something that can kill or maim.

though

I don't think it is due to headset bearing adjustment. I've tried it several times with tihgt settings and loose settings and normal settings. Doesn't effect the noise. Noise is always there. As I said, I removed the fork from the bike and as I push and pull on the steerer tube, it makes the noise. So it has nothing to do with the bearings.

mmmdonuts

What FBinNY said!

FBinNY 

You seem to have confirmed that the fork is toast. Call the maker and see if it qualifies as a warranty situation, but do not under any circumstances reinstall this fork. Or if you do, please leave a note for any heirs that I at least told you not to ride on it.

I'm not kidding or exaggerating the risk, take a moment to consider what would happen of this steerer ever works loose enough for the crown to fall off the bottom end.

though

Crown race is not loose. It is tightly fitted. Steerer is not "completely" loose in the crown (in this case lover part of the fork cause there is no sperate crown in this fork). Bottom end is fixed with the weldment but upper end of the fork is bigger than the steerer tube so there is some play there. Please refer to the figure (very exaggerated) below. This play is very little. You cannot see it with eye. But it is there, I can feel it. I am guessing that, since there is clearance at the upper end of the fork, crown race bottom is rubbing against fork and that is making the noise.

FBinNY 

I see the pictures. It's possible that a flare or weld at the bottom is keeping it on for now, but any play between the steerer and crown is an indicator of a serious, and potentially very dangerous condition. Forks are assempled with steerer either press fitted with a flare or weld at the bottom for retention, or slip fitted and brazed into a solid assembly.

If this continues to loosen, it could crack in an unseen area letting the crown fall off, or simply loosen enough so that while the crown doesn't fall of, it free spins and you lose steering. The second is better, but not a whole bunch so.

I take a risk assessment approach to many bike issues, and am usually the one who says ride it, even though it may break. But my formula is based on a mix of likelihood of failure, and consequences of failure. So for example if you had a cracked seatstay, I say ride it because the worst likely scenario, is it snaps, and the rear wheel twists to one side and no longer spins. Not fun, but you get to walk home. OTOH on a fork, the consequences are so sever that even if the chance of failure is fairly low, it's still too high. Your fork has already passed the low risk zone. It's in the process of failing already, and on borrowed time.

You have the totally unacceptable combination of a high chance of failure and a high chance of severe consequences when/if it does. Not only are you playing Russian Roulette if you ride this fork, you're doing it with more than one bullet in the cylinder.

That's it. I've met my moral obligation by warning you in the clearest language I could, after this you're 100% on your own.

though

Okay, this was the piece of information I was looking for. Thanks a lot for your explanations.

Thanks for the warning as well. I already sent the fork to my dealer and do not intend to ride it. I rode it about 800 km till now with the noise though. It wasn't a pleasant ride, it sounded like something's gonna snap anytime.

Cipyz

How did you solve the problem??

I have the same problem and the bike is pretty new. Please send me a private message, thanks!

FBinNY 

The OP here had a very rare -- almost 1 in a 1,000,000 problem, so odds are his solution -- replace the fork -- isn't right for you. The most common cause of your problem, especially on a new bicycle, is a loose headset.

Confirm it by applying the front brake and pushing the bike forward and back. You should see or feel movement between the fork and frame at the lower headset bearing. 99% of the time, a simple headset adjustment solves it. 1% of the time, the crown bearing is loose on the fork, which is more involved, but easily fixed. 1/1000% of the time it's what the OP had.

BTW- if the bike is relatively new, and still under adjustment warranty, let the dealer take care of this for you, and maybe show you how it's done for future reference. Otherwise there are plenty of tutorials on how to adjust a headset.

See here for advice about diagnosing based on someone else's problem.

Cipyz

First of all, I have to specify that my bike is 3 years old, but ridden a few times. It is in excellent condition. As a reference, the tires are like new.

1. I have checked, install, lubed again the headset.
2. I have installed again the crown race and it is very very tighten.
3. The first 2 steps had no effect on the problem.
4. I have removed the fork and checked it. In some angles, if I tap or hit the steering tube, that noise appears. The fork is full aluminium and is very light, like 600 g.
I am 100% sure that the noise comes from the joining point between the fork tube and the bottom part.
There is NO RISK of breaking because the tube is welded underneath.

FBinNY 

OK, first of all, I'm not a fan of that design.

It uses the weld to make up for sloppy tolerances. Normally the steerer is an interference fit to the crown and/or brazed. Besides the click, the gap is a place for rust to form an attack the steerer at a critical point. You might quiet it by filling the gap with grease or a heavy oil. If you want grease, dissolve it in mineral spirits or naphtha and apply as a thin liquid, so it wicks in. You'll need multiple applications to build up the fill, so this is a slow process.

Note neither oil nor grease will actually solve the problem, but they'll muffle the noise, and keep water out.

The right repair is to use an anaerobic adhesive (locktite). You need a wicking grade made to fill gaps. To prepare the fork you'll need to force mineral spirits down there to flush out any oils, then allow to dry. Best do a number of flush and dry cycles until you're convinced it's really clean and dry. Then wick the adhesive in. When it dries, it swells to solidly fill the gap.

Cipyz

Thank your for your fast answer.

Today, after taking those photos, I used some SUPERGLUE just to fill that space.
Super glue is very thin and it runs in there. I thought that using oil will increase a future play of the steerer.

After applying Super Glue and let it cure, I have assembled the whole system again and the pops and ticking noise decreased by 70%. I hardly feel the noise while riding.
But, I would like to do a better job.

I have 2 options:

1. use a better glue, like Loctite as you said, but I already have some SuperGlue inside and I don't know how to eliminate it. Also Loctite is much thicker and the gap is very small.
2. weld that gap circular line using a MIG-MAG welder but it takes time finding a good shop and someone well prepared to do the job.

Cipyz

Another option would be to buy a new Scott fork.
But brands like Scott, Trek etc, do not sell individual parts like frames, forks. What happens with a customer if he will actually break the fork? Would he throw away the whole bike?

FBinNY 

Bike companies stopped selling original replacement forks decades ago. Mostly because it was a PIA stocking all the colors and lengths. Back then you'd buy a generic chrome plated or black fork as a replacement.

These days the fork isn't so much a part of the frame as it used to be. Forks are components in their own right, and so there's no call for original parts. If you're not comfortable with this fork, you replace it with a generic fork with the same basic dimensions.

dabac

You can't weld there. The seam would mess with the fit of the grown race. You'd have to have the seam machined back to almost nothingness before the fork would be able to take a crown race again. Besides, I'd be right worried about the loss of strength due to the weld at the most critical part of the fork.
Apart from replacing the fork, your only remaining option is to keep dribbling glue in there.

though

Here is how I solved my problem.

I got 3 replacement forks from my dealer and they all had the same problem. I suspect one of them was my original fork that they sent me as a replacement. One was quiet for one week before it started ticking.

The last one I got was quiet for about 1 month before it started to make the noise. But I was fed up at the moment and didn't send the fork back. I just continued using it. After a couple of months the noise dissappeared by itself.

On an unrelated note, this last winter I noticed I had been running with no grease in the headset bearings. I guess I was dismantling the fork so often and greasing it that it was keeping the races greased. When I was fed up and stopped dismantling the fork and greasing, races was left with no grease. Bottom cone race was damaged and I installed a new headset with cartridge bearings. It is all good now and I don't have to worry about greasing it. Original loose bearing desing doesn't do well to prevent dirt and water reaching the bottom cone race.

So my advice is give it some time and just continue using it. See what happens.

Edit: I have to add that the last fork I received never made so much noise as my original fork. That is how I was able to bear with it.

Sixty Fiver

I am not a fan of this design either and it seems it causes issues... it may be safe but if it was done right there would be no clicking in the steering and extra steps would not be needed to address that.

Consider that the clicking is probably be caused by very small amounts of flex in the steerer which is not press fitted / brazed and flex equals fatigue and fatigue will eventually lead to failure.

Sloppy tolerances just aren't acceptable.

FBinNY 

This is a poor design, but could work if executed well. However, not only do they choose a poor design, that ignores 100 years of experience making forks, but they have little or no quality control, or simply don't care.

Holding tolerance on the fit is incredibly easy, so failing to do so is an indicator of a non-caring attitude on the part of the maker. That a bicycle company would spec this fork, and continue to do so, despite complaints (if they still us it), shows that whoever chose the fork, either didn't understand bicycles well, or also didn't care, and simply went with the lowest bidder.

Based on this fork, and this fork alone, I wouldn't buy this company's bicycles, and if I were a dealer wouldn't sell them either. Even Walmart bikes do better.

reddog3

If there's any play between the steerer and crown- eventually it will fail. When? You never know. Do not let my kids ride your bike! Fix it right. Get a good fork.

though

I think there might be some misunderstanding. There is no actual play in my case. But if you hold the fork under your arm and pull on the tube, you would hear the noise. You have to actually try to bend the tube to make it tick. The play results from elastic bending of the tube. It is not loose in there. You wouldn't be able to see the movement with your eyes. It may not be a tight fit but clearance is maybe in the order of microns, not even a mm.

Sixty Fiver

A micron is 0.000039 inch.

Interference fits tend to be in the .1 to .15 range... things like seatposts work this way.

though

I meant smaller than a mm. Maybe a couple of hundered microns, not 1 micron.

Cipyz

USER "though" you are right. This is my case too. I can't move the steerer with my hands, but if I tap it or hit it, I will hear a pop or a thick.

I don't agree with the idea that SCOTT is a bad brand. The bike is exceptional. The geometry, specs, alfine transmission everything works very nice.

The fork is the only bad spot. If you look at my pictures above, you'll see that the steerer is welded underneath. Due to full aluminum construction, which is a very flexible and soft material, it tends to "work" by itself.

I will fill again that thinny circular gap with a better adhesive and I will keep it like this. In my opinion it can't break. The flexibility of the material causes those thicks.

On the other hand, I have contacted a Scott dealer and they can provide a new fork same color for $100.
If USER "though" complained that new forks have the same problems, buying a new fork is NOT the best solution.

I will try to find a new fork from a MERIDA S-PRESSO.


It looks the same.

My final thoughts are: The design and material are the causes of the problem. No matter how many forks I will change, all will create someday this problem.
Also, I could not find any pictures or complaints about a cracked or broken scott sub fork on the internet.

What do you think?