Folks,
My head mechanic has fwd'd me the following collection of posts from one of the top bike mechanics/ authors in the country (Jobst is the author of "The Bicycle Wheel" considered the bible of everything you ever wanted to know about bike wheels). Apparently my advice doesn't apply to any aluminum parts (seatposts/ stems).
Reading thru these posts is very enlightening and should be required reading if you're a mechanic or shop estimator dealing with customers.
Tim
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: stem stuck... please help! Date: 3 Sep 1998 15:46:27 GMT
Jim Robin writes:
My Bianchi's handlebar stem is stuck inside the fork steerer tube. The stem is a standard aluminum quill-type (TTT Synthesis). I loosened the quill hex bolt and sprayed WD-40 in hopes of freeing it up, but no luck.
If you have loosened the bolt and driven the expander cone out of engagement with the bottom of the stem, the stem should be rotatable with moderate force. If this is not the case, then you have a corroded frozen stem. Many forks have been damaged by twisting the bars forcefully in an attempt to free the stem. Don't do it. A skilled mechanic can drill out the stem until it is a thin shell, then with a grinder. break through one side of the shell to extract the stem. Because aluminum expands with corrosion, you cannot loosen a frozen stem by force.
Get it removed by a competent shop. Frame builders do this regularly.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Frozen Stem Date: 7 Nov 1998 20:22:20 GMT
Tom Gargulak writes:
My aluminum handlebar stem is frozen into my steel frame due to corrosion. We tried penetrating oil and force. Any tips or a FAQ?
The advice to: "Twist, twist, twist. It will eventually break free." Is not good. THe result of this method is often fork failure unless you use a 2x4 through the crown of the fork, and then success is rare.
There are no solvents for the aluminum oxide that has expanded with more force than you can imagine. Steel tube swimming pool railings often expand by 1/8 inch from aluminum plugs in the ends that leaked.
The best solution is to saw off the stem, drill out to as close to the steer tube as possible and use a Dremel tool to grind it through on one side. The local frame builder has a collection of these shells in a heap.
The cause of these failures is that the stem is only anchored at the bottom and works from side to side in use at the top, where a meniscus of sweat or sweat loaded rain water waits to enter. Even the rubber seals in some head bearing lock nuts are usually not good enough to block intrusion. I have a stem with an extension protruding above the lock nut with a clamp on it. By this method the stem is held top and bottom and a fill of grease on installation does the trick as it does on seat posts. It's the motion that kills the stem.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.misc Subject: Re: stuck seatpost dilema Date: 11 Jan 2000 15:52:27 GMT
Doug VanGoethem writes:
I have a 10 year old steel frame bike that I still use for commuting and such. I was going to let someone else ride it and found the seatpost was firmly stuck. It's not a surprise when I think about it because it has to have been at least 3 years since I moved it last and who knows if I had any grease on it then.
[...]
So what's the deal? Is this just the worst stuck seatpost in history?
Your tale of woe is not unusual and the advice you found in earlier writings is mostly malarkey, invented by readers who are hypothesizing or who had seat posts that were basically a tight fit but not corroded in place. When aluminum (seatpost or bar stem) oxidizes from water intrusion, it has both galvanic activity and a captive electrolyte (water) source. Aluminum oxide formed is porous and hard and takes up about twice the volume of the metal from which it is made. This is a press fit with molecular interlocking that cannot be separated by force and cannot be dissolved by chemical action in any reasonable time without immersion in a hot bath. Even that is doubtful because the area of attack is small and depth great.
The practical way for removing such corroded parts is to saw them off and bore them out, first with a drill if wall thickness is too great (bar stem), and then with a Dremel tool.
For prevention of this effect, make sure the seat post is sealed with stiff grease or paint. Bar stems are always vulnerable if they are not double clamped because they pump water by a varying gap when you wrench on the bars. Road bikes traditionally have an expander that arrests the bottom of the stem while the top is free to move laterally in the upper end of the steer tube. Only stems clamped at the upper end can be effectively sealed.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.misc Subject: Re: stuck seatpost dilema Date: 12 Jan 2000 02:09:06 GMT
Mike Jacoubowsky writes:
Your tale of woe is not unusual and the advice you found in earlier writings is mostly malarkey, invented by readers who are hypothesizing or who had seat posts that were basically a tight fit but not corroded in place...
I don't know if you're just trying to be contrary or mean or whatever, but not all of the advice in the other posts was "malarkey" (of course, you did say "mostly"...). You are correct in your technical assessment of what causes the problem, but you are incorrect to *assume* that the problem has progressed to the point where the methods suggested wouldn't work.
Ice water, LPS-4, WD-40 or vinegar are all theoretical methods. I have seen these attempted by people who believed in them without success. After the aluminum part was removed by drill and grind, the interface showed no sign of penetration in spite of laborious applications of said elixirs. On the other hand, I have seen forks ruined by twisting on handlebars in an attempt to remove a frozen stem. This is the more common result when a stem has corroded.
Have I seen a stuck stem which I could *not* remove using the means I described? Absolutely. Probably three of them in 20+ years. Have I successfully removed a great many others that people had given up on? Yes!
As I said, the ones that came out were not a result of mystical fluids but rather brute force. I didn't notice what method you claim worked for you. I also have removed stuck parts, but it wasn't with liquid nitrogen, ice or WD-40. These methods are holding out false hope for people who are not going to get served any better than by trying force up to a safe limit and then grinding the part out.
I don't know if you're just trying to be contrary or mean or whatever, but not all of the advice in the other posts was...
I think holding out false hopes is far more unkind than to tell the reader the truth.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: stuck seatpost dilema Date: 11 Jan 2000 19:03:21 GMT
Matt O'Toole writes:
What about headsets with O-ring seals around the top to prevent water from seeping between the stem and steerer? Do they not work?
They haven't for me even with plenty of grease. My steer tube extends through the top nut with a stainless steel clamp. This no longer pumps and doesn't corrode, but then I'm using a steel stem now. The decapitated aluminum ones are hanging on the wall.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 27 Apr 2001 16:51:59 GMT
Tim McNamara writes:
In a roundabout way I am asking whether steel stems are less likely to get stuck in the steerer than alloy stems because of the galvanic corrosion issue? In which case I lucked out...
As I mentioned, steel stems do not get stuck and that is why that stem attachment was accepted in its day. The onset of aluminum stems caused the frozen stem syndrome. Creaking stem has always been a problem and the top clamp was devised to get rid of that.
Let's not get the cause and effect sequences mixed.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 27 Apr 2001 18:11:39 GMT
Jon Isaacs writes:
That was before they thought of the O-ring Band-Aid that did no good. Pumping from side to side, the O-ring reduced water intrusion only slightly over no O-ring.
I cannot say whether or not the O-ring seals are properly designed in the head set in question, however it is certainly possible to design an O-ring seal which will work under such conditions.
At the risk of being excessively repetitive, O-rings don't work well in lateral displacement, a mode in which they pump. Shimano and Campagnolo lock nuts with O-rings did not prevent water intrusion although their existence should make it obvious that there is a problem, something manufacturers don't mention. See, for instance, introduction of Campagnolo's "differential" brake. What a sham.
However, I suggest that if someone is really concerned with this problem, a gator made with carefully applied Scotch 33 tape or better yet an old inner tube and some zip ties would make a sufficient seal.
That might be a clumsy temporary fix but the design of this interface is basically flawed and the advent of aluminum stems brought it to it's knees for those of us who ride a lot.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 24 Apr 2001 01:15:59 GMT
Mike Latondresse writes:
I won't say I have commuted to work by bike for 10+ years in Vancouver BC where it sometimes rains in the winter and have never had a stuck stem. I repeat that a minimum of preventive eminence is all that it takes so negligence, not shit, is the issue. Of your 8 points in support of this over-the-horizon advantage, number 1 seems to be mainly a problem dogging you and some of your friends and not the common experience of this group, and the other 7 are somewhat dubious to me as a rider. For example who cares about a Road/MTB/tandem standard, road riders?
Oh! So what do you propose one should do, take the stem out every couple of weeks in the winter and minister to it? I can assure you that I lost a stem on a trip in the alps in less than three weeks, climbing in the rain often. When I came home, the stem was solid. I had installed it with grease before the trip.
I don't understand what you and those of your ilk get out of defending poor designs on bicycles other than that you have a religious belief that if the bicycle gods made it it must be right. Therefore, anyone who has problems is a sinner to be roundly chastised.
There's more to bicycling than commuting in the rain. It might just be that your experience is so narrow that you cannot visualize any other form of use. That would be the kinder assessment of your accusations. If that is not the case then you are guilty of greater social faux pas, namely righteous pomposity.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 25 Apr 2001 17:42:31 GMT
Jay Beattie writes:
Everybody knows that stem-stick can happen, but after only three weeks for Jobst's and one week for Johan? I wonder whether there is some other environmental factor at play, such as salt or something else that speeds corrosion.
Hold it! I thought this thread was about riding bicycles, riding that for active bicyclists involves enough sweat to cover the front of the bicycle with salt crystals. Maybe some riders never ride harder than what their mascara will sustain without running, but for those who still have a little youth, that doesn't work. I know of one local rider who was saved by titanium because everything else turned to rust and aluminum oxide under his nose.
Ordinary rain certainly isn't the kiss of death because I ride in the rain on an every-other-day basis during the winter and spring, do little maintenance (shame on me) and rarely get significant sticking.
The rain serves to wash the salt into the places where it can do some "good". Climbing hills in the rain can do both.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 25 Apr 2001 17:30:22 GMT
Lincoln Dickerson writes:
I am not sure where to interject this idea into this thread but this seems as good a place as any. The O-ring idea gave me a thought and maybe it is not mechanically sound either but here goes.
Would it be possible to use a boot like on a CV-Joint? So that the clamp would keep the water from traveling down the stem and causing it to get inside.
This of course would not be necessary for everyone because many people don't have any problem but for those that do would it work?
This ignores the basic problem, which is, that this is a mechanically flawed joint. Forget about the water intrusion. Stems break off and creak because they are attached only at the bottom end, being free to fret and gnaw at the top of the steer tube. I have cracked off stems and had ones with wear grooves at the steer tube exit. This is not a new problem but with the advent of the aluminum stem it got more evident.
In the days of yore, track bicycles had an expander at the bottom and a clamped steer tube at the top so the stems wouldn't yaw in the steer tube. I have such a clamp on my fork and it does the job. No water will go in there just as no water goes down my seat tube because it is not a dynamic joint anymore. A little grease on installation takes care of it.
Maybe we could figure out which stem and frame combinations have the most trouble. Or those with a particular riding style or environmental or terrain issue.
What do you think?
I am not sure this would be any better looking than a threadless stem but maybe it would save a lot of effort and stems.
Threadless stems are made in different sizes and can be made as neat and clean as any. They probably won't look like a 1980's Cinelli stem but that is purely fashion. I prefer function.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 26 Apr 2001 01:07:37 GMT
Richard Ney writes:
In the days of yore, track bicycles had an expander at the bottom and a clamped steer tube at the top so the stems wouldn't yaw in the steer tube. I have such a clamp on my fork and it does the job.
Are you saying that you have clamped a short section of steerer tube around the stem above the headset?
Yes.
I'm unclear about what you've done here.
You described it.
No water will go in there just as no water goes down my seat tube because it [the stem] is no longer a dynamic joint.
How is the seat-tube/seat-post not a dynamic joint anymore? What did you do?
The seat post is static. It is the stem that becomes static with a top clamp. If you look at the interface, you will find a nice meniscus of dust encrusted grease with no witness crack from motion in contrast to a typical quill stem, or pedal for that matter that always fret and pump. We've been through the pedal being a dynamic joint recently. That's why we have a left hand thread on the left pedal and why cranks break predominately there. It is a dynamic joint.
Seat posts are static joints on most bicycle because they have a good clamp and contact diameter, as is noticeable when installing the post in the frame. Stems visibly move when handlebar forces are applied.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 26 Apr 2001 15:49:43 GMT
Richard Ney writes:
In the days of yore, track bicycles had an expander at the bottom and a clamped steer tube at the top so the stems wouldn't yaw in the steer tube. I have such a clamp on my fork and it does the job.
Are you saying that you have clamped a short section of steerer tube around the stem above the headset?
Yes.
I'm unclear about what you've done here.
You described it.
How do you actually secure the steerer section to the stem? What sort of clamp are you using?
An unthreaded and split length of steer tube extends beyond the conventional head bearing lock nut and a stainless steel clamp locks it. It is so inconspicuous that no one notices it.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 26 Apr 2001 20:56:18 GMT
Dave vt? writes:
An unthreaded and split length of steer tube extends beyond the conventional head bearing lock nut and a stainless steel clamp locks it.
Just sketch yourself a picture of what I just described. It can't be that difficult. The extension is smaller in diameter than the thread.
You are right, it's not difficult. Your last sentence confirmed my suspicions.
I can imagine that the cost of machining this steerer must be much higher than the standard steerer; that's probably why it's not in widespread use. It's an answer to a question that is not asked very often.
We found it easier to turn the thread off than to make a clamp with threads. It costs nothing extra when the bicycle is being made. The same lathe operation that cuts the thread also turns the extended end. The whole frame is unavailable on the market, however, Cinelli track frames came standard with this design. This is not my invention.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 26 Apr 2001 21:06:53 GMT
Scott Hendricks writes:
The reason folks are having a hard time imagining what you describe, Jobst, is that many newer headset these days have lock nuts that CANNOT be screwed down past the end of the steerer tube. I have a bike w/ a sealed Ultegra headset, and the lock nut bottoms out on the end of the steerer, and has a seal that is supposed to contact the stem quill.
So? You chuck it in the lathe and cut a clearance bore so the thread can pass through. This is a custom operation so don't restrict yourself to off the shelf thinking.
Older headsets had lock nuts that could easily be screwed down beyond the end of the steerer.
That was before they thought of the O-ring Band-Aid that did no good. Pumping from side to side, the O-ring reduced water intrusion only slightly over no O-ring.
Jobst Brandt jbrandt@hpl.hp.com
From: jbrandt@hpl.hp.com (Jobst Brandt) Newsgroups: rec.bicycles.tech Subject: Re: Threaded vs. threadless Date: 26 Apr 2001 15:54:43 GMT
Robin Hubert writes:
Threadless stems are made in different sizes and can be made as neat and clean as any. They probably won't look like a 1980's Cinelli stem but that is purely fashion. I prefer function.
So, the question begs, Mr. Brandt, do you use a threadless system?
I think you can deduce the answer from what I have written. My solution is older than the threadless headset.
Jobst Brandt jbrandt@hpl.hp.com
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