steerer-tube extensions -- undue paranoia? (steel)

[wallymann]

one struggle many cyclist have is the misfortune of having a steel steerer-tube cut too short, leaving inadequate length for a desired headset or insufficient rise for a desired handlebar height.

having a few forks thusly afflicted, i searched google and found some examples of very complicated sleeved-extensions (groovy cycleworks is one). in the end i found an experienced builder that simply cuts off the steerer about mid-length and butt-welds longer sections of steerer in place. he's done this for many-many years with nary a problem.

while doing my searches, i found alot of chatter about how risky a welded on extension would be...and i just want to open it up for discussion.

thinking about it more, i think such paranoia is unfounded -- as long as the welder is experienced and does a proper job, why would a butt-weld in the middle of a steerer tube be inherently risky above any other TIG welded joint in a modern steel frame?

while the center section of a steerer does flex, the steerer is solidly supported at both ends by the headset. in comparison, i can think of oodles of unicrown forks where the top of each fork-leg is simply welded onto the side of the steerer tube -- such an attachment is exposed to just as much stress (arguably more, due to the leverage of a fork-leg on the crown-steerer interface) than the center section of a steerer.

anyway, just want to get some discussion going...am i missing something?

[mktng]

couldnt the steerer be replaced on a steel fork?

[tv_vt]

One practical thing that comes to mind is sliding on/off a lower base plate. The weld joint would have to be perfectly smooth on the outside to get the base plate on or off.

Does the builder you mentioned ever use an inner sleeve to join the top and bottom sections?

[David Kirk]

I personally would never let a friend or loved one ride a steerer that had been extended with a butt weld. No way. While the chance of failure (if the welder is really good) is small the results of that failure can be very bad.

There is a better way....if I had to make a steerer longer I'd slip a sleeve into the steerer so that it went in at least 2 diameters (call it 2"+) and then slide the new extension onto said sleeve the same amount. So you'd have a roughly 4" long internal sleeve that is slipped 2" into the lower steerer and 2" into the upper steerer. I would sliver braze this all together. The chance of failure is very, very low and if it does fail it will likely creak and wobble a long time before it lets go. A butt weld will not do this.

All that said....life is short and there's already enough things trying to kill us without adding to the list. Make a lamp out of the fork that is too short and replace it.

dave

[charliedid]

Not a chance :-)

[ultraman6970]

My diseased master builder in my country always did the weirdest fixes and never had a problem but with steering tubes he always replaced the whole thing in steel forks. Specially when the affected fork had a engraved crown lug.

I asked him why do not just cut and sleeve an extension and he told me that was quicker just to replace the steering tube, heat the lug, remove the old one and put the new one in, just 1 hour of work tops. He said that sleeve the tube in steel fork was doable but why when sure a steering tube from an longer broken fork was moving around the shop, the did not trash any broken bike because at some point they may need a tube in specific and source them was hard, like for example a SLX flat seat stay tube.

With carbon is different because you can sleeve that w/o much of a problem, and that can be done pretty much at home.

If your fork is steel you can get a new tube at nova cycles w/o that much of a problem. If you sleeve you add more weight just to start, simpler and quicker to just replace the whole steering tube.

[speedevil]

Replacing the steerer on a steel fork can be done safely and has been done many times. It will probably destroy any paint or chrome on the fork crown unless measures are taken to protect it. It's much more likely that chrome can be saved than paint, but if you're going to this extent to save the fork, a repaint is probably going to happen anyway.

Silver brazing a sleeve inside the existing steerer and then brazing an extension over the sleeve is a good solution as well, but is at least as much work if not more than replacing the steerer. There's less chance of damaging chrome or paint, but more brazing is required to secure the sleeve.

I would be wary of a butt-welded steerer extension, but I would not be concerned about a sleeved extension, properly prepped and welded. Replacing the steerer is the best option.

Neither choice is a first choice, but once the steerer is cut your options decrease dramatically.

[wallymann]

couldnt the steerer be replaced on a steel fork?

it can, but i've heard that the heat required makes it impractical in practice.

Does the builder you mentioned ever use an inner sleeve to join the top and bottom sections?

that's what groovy does, but my guy does a simple butt-weld, no monkey business on the ID. i believe he bevels both sides of the butt to ensure full weld penetration.

[wallymann]

couldnt the steerer be replaced on a steel fork?

it can, but i've heard that the heat required makes it impractical in practice.

Does the builder you mentioned ever use an inner sleeve to join the top and bottom sections?

that's what groovy does, but my guy does a simple butt-weld, no monkey business on the ID. i believe he bevels both faces ofthe butt to ensure full weld penetration.

I personally would never let a friend or loved one ride a steerer that had been extended with a butt weld. No way. While the chance of failure (if the welder is really good) is small the results of that failure can be very bad.

why is a butt-welded steerer more "risky" than these conglomerations of fork-crown welds? i just dont see it.

http://www.beardmanbicycles.com/images/unicrown_segmented_forks.jpg

[ultraman6970]

If the guy knows what he is doing is a mere thing of heat the base of the fork and pull the tube out. Clean really well... braze the other tube back in place. Pretty much same heat for both.

As for the sleeve probably the heat needed is less because the tubes are thinner, you get the right temp quicker but you have more chances for the tubes to warp if the dude doesnt handle the torch like the gods because the silver (if silver is used) needs to flow exactly where you want it to flow. Sleeves are tricky just because of that, and Ive seen my fair share of sleeves in frames (top tubes and seat tubes), easier to get a frame straight than a steering tube anyways.




it can, but i've heard that the heat required makes it impractical in practice.
.

[speedevil]

why is a butt-welded steerer more "risky" than these conglomerations of fork-crown welds? i just dont see it.

I don't see it either. Replacing a steerer tube is fairly straightforward, but the heat required will probably require a repaint.

[David Kirk]

FWIW - replacing the steerer on a lugged crown fork is always theoretically possible but in practice it doesn't always go that well.

First and most obviously whatever finish the fork has (paint or chrome) will be toast and it will need to be redone. Less obvious is that pulling the steerer can lead to the crown failing. Lots of these forks were built in mass-production factory conditions and it should come as little shock that the utmost care was not always taken when the fork was originally built. It could be that the steerer was a very tight fit into the crown and that it was literally pounded into place before brazing and/or that the whole thing was heated up to a shockingly high temperature during assembly line brazing. I've seen enough video from factories where they proudly show off the bright red glow of the upper 1/2 of the blades all the way up to mid-steerer. Not good.

So sometimes, if the fork was built with skill and care in the first place, the finish of the crown can be removed and the steerer/crown can be gently heated and slipped out nice and clean and life is good. At other times one will heat the assembly and the crown will crack when trying to slip the steerer out. It's very common.

It depends as much on how the fork was put together in the first place as it does on the builder removing the steerer years later. It's not a sure bet....not even close.

dave

[bicycletricycle]

I think a brazed sleeve would be a better option as described above.

On the other hand, I think a properly done butt weld should be fine. It does add one more point of failure to the system and that failure can be really painful so I think the paranoia is relatively reasonable.

If the bike is threadless or you don't mind it being threadless I have considered cutting the steerer short and then just using a long threadless adapter. The adapter would be the contact point for the top bearing of the headset and then have spacers and a stem clamped onto it just like normal. Only some means for pre loading the bearings is required but a few relatively simple options exist for this.


I imagine many people might think this is insanity but I contend that the load the adapter normally sees above the headset is higher than the load it sees below it.

[David Kirk]

.......


why is a butt-welded steerer more "risky" than these conglomerations of fork-crown welds? i just dont see it.

http://www.beardmanbicycles.com/images/unicrown_segmented_forks.jpg

The big stresses are at the steering of course as there is only one steerer while there are two blades. The forks pictured have the blades welded to the sides of the steerer and the steerer itself is one continuous tube from bottom to top. This puts the steerer into a bending load and it deals well with this and it puts the welds of the blades to the steerer into a shear load....again....just fine.

A butt weld on the steerer is a much different animal. You are putting the weld (and adjacent head affect zone) into both bending and tension and this is not a great way to go with a weld. The weld is not as strong at the base tube and you so you have this effective perforated line around the steerer and you are bending it and pulling on it....and if it fails there's nothing to catch it. So when it fails it's likely to do so suddenly and without much warning.

I don't like my face (such as it is) and my teeth hitting the pavement so, knowing what I know, I strongly recommend against a steerer butt weld.

My 2 cents.


dave

[weisan]

Wally pal, I totally understand and share your pain. :p

That's why I was willing to put myself through the extensive behavioral modifications same place as Jason Bourne personally overseen by Dr. Albert Hirsch. He asked me repeatedly to "fully commit to the program" which I did eventually and assured me that "after we are done, you will no longer be afraid of wearing stems that look like these:

https://www.universalcycles.com/images/products/medium/38815.jpg

https://i.ebayimg.com/images/g/u-YAAOSwTA9X4U5Y/s-l300.jpg

https://captainoverpacker.files.wordpress.com/2015/05/stems.jpg

[FlashUNC]

Hard pass. Just find the right fork or get a new one made.

[wallymann]

Wally pal, I totally understand and share your pain. :p

weisan, bud...my issues are really just getting a threaded fork with a 150mm steerer to fit onto a frame with a 180mm HT length, not much rise needed -- i generally run my bars pretty close to slammed!

[d_douglas]

Very few road bikes ever look good with a stem that has rise. Zero degree rise stems can look pretty awesome in many cases.

The highrise ones MUST be a last resort - that Trek hurts my eyes!

FYI, I'm no framebuilder, but I would just buy a new fork, unless this 150mm fork is incredibly special.

[Kontact]

it can, but i've heard that the heat required makes it impractical in practice.



that's what groovy does, but my guy does a simple butt-weld, no monkey business on the ID. i believe he bevels both faces ofthe butt to ensure full weld penetration.



why is a butt-welded steerer more "risky" than these conglomerations of fork-crown welds? i just dont see it.

http://www.beardmanbicycles.com/images/unicrown_segmented_forks.jpg

The problem, as I see it, is that it is like doing a butt weld on your down tube and then grinding away the fillet. There's no extra material, and now you've replaced the cold worked tube with cast material at the same thickness.

Why does that sound okay to you? Would you ride a fork with a cast steerer tube the same thickness as a cold worked tube? Because that's what you'd be doing.

[cadence90]

The cost of the time (just Dave Kirk's alone) spent on this thread so far has already surpassed the cost of a new fork.

Ergo, retire the old fork and replace with a new fork.
.

[CSTRider]

The cost of the time (just Dave Kirk's alone) spent on this thread so far has already surpassed the cost of a new fork.

Ergo, retire the old fork and replace with a new fork.
.

Ditto on the "cost avoidance" of replacing one tooth with an implant (to say nothing of concussion, plastic surgery etc.) ... just ain't worth it.

[hokoman]

http://www.elephantbikes.com/blog/

Glen modified his Ruby steerer.

[Kontact]

http://www.elephantbikes.com/blog/

Glen modified his Ruby steerer.

But that's a 1.125 steerer over the top of a 1". It's now the strongest steerer on earth.

[cadence90]

http://www.elephantbikes.com/blog/

Glen modified his Ruby steerer.
Well, good for Glen.
Roebling built a bridge, too.
Neither thing is really very near the op's question.

But that's a 1.125 steerer over the top of a 1". It's now the strongest steerer on earth.

No kidding...must be a monster.
.

[hokoman]

But that's a 1.125 steerer over the top of a 1". It's now the strongest steerer on earth.

oops! I have been skimming articles while I am on hold for GE customer service. 48 minutes and counting....

[weisan]

wally pal, tell me the truth, does any of the responses so far catch you by surprise?

I am speaking to my pal wally.

[Kontact]

wally pal, tell me the truth, does any of the responses so far catch you by surprise?

I am speaking to my pal wally.

Do you both clamp your bikes by the top tube?

[wallymann]

wally pal, tell me the truth, does any of the responses so far catch you by surprise?

not really. i'm still skeptical. the anecdotal feedback is interesting, but i would really like to see an FEA of a fork steerer showing the magnitude and location of stresses a steerer-tube actually experiences.

maybe i should have had my guy use "friction-stir" welding instead of TIG! ;-)

in any case, i may epoxy a CF inner reinforcement tube on the inside of my butt-welded extended steerer tubes, to mitigate the risk of catastropic failure.

[cadence90]

not really. i'm still skeptical. the anecdotal feedback is interesting, but i would really like to see an FEA of a fork steerer showing the magnitude and location of stresses a steerer-tube actually experiences.

maybe i should have had my guy use "friction-stir" welding instead of TIG! ;-)

in any case, i may epoxy a CF inner reinforcement tube on the inside of my butt-welded extended steerer tubes, to mitigate the risk of catastropic failure.

You want some FEA?

Here's all the FEA you really need:

https://thumbs.gfycat.com/RectangularWeightyAstarte-size_restricted.gif

:)
.

[Louis]

I don't think anyone really needs a FEM to know that all else being the same, a sleeved joint is going to be better then an butt joint. (unless you use beer-can material for the sleeve).

[pbarry]

The silver brazing method works. Have seen it done. Not a big deal for someone who knows how to use a torch and a lathe.

I personally would never let a friend or loved one ride a steerer that had been extended with a butt weld. No way. While the chance of failure (if the welder is really good) is small the results of that failure can be very bad.

There is a better way....if I had to make a steerer longer I'd slip a sleeve into the steerer so that it went in at least 2 diameters (call it 2"+) and then slide the new extension onto said sleeve the same amount. So you'd have a roughly 4" long internal sleeve that is slipped 2" into the lower steerer and 2" into the upper steerer. I would sliver braze this all together. The chance of failure is very, very low and if it does fail it will likely creak and wobble a long time before it lets go. A butt weld will not do this.

All that said....life is short and there's already enough things trying to kill us without adding to the list. Make a lamp out of the fork that is too short and replace it.

dave

[weisan]

not really. i'm still skeptical. the anecdotal feedback is interesting, but i would really like to see an FEA of a fork steerer showing the magnitude and location of stresses a steerer-tube actually experiences.

maybe i should have had my guy use "friction-stir" welding instead of TIG! ;-)

in any case, i may epoxy a CF inner reinforcement tube on the inside of my butt-welded extended steerer tubes, to mitigate the risk of catastropic failure.

Thanks for your honest feedback, I appreciate it.

[wallymann]

I don't think anyone really needs a FEM to know that all else being the same, a sleeved joint is going to be better then an butt joint. (unless you use beer-can material for the sleeve).

yeah, no doubt -- belt and suspenders and all. but is the sleeve joint necessary given the real stresses experienced?

[Louis]

yeah, no doubt -- belt and suspenders and all. but is the sleeve joint necessary given the real stresses experienced?

I think your dentist would say "Yes."

[cadence90]

yeah, no doubt -- belt and suspenders and all. but is the sleeve joint necessary given the real stresses experienced?

Would you butt-epoxy a cut carbon-fiber steerer tube? I think (hope) not.

Honestly, I don't see much difference, given the potential risks, between butt-gluing carbon-fiber or butt-welding steel.

But, I'm in the "just get a new fork" camp regardless, sleeve, no sleeve.
.

[pbarry]

yeah, no doubt -- belt and suspenders and all. but is the sleeve joint necessary given the real stresses experienced?

How many frames have you built? Just asking.. ;)

[unterhausen]

the truth is, steerers can bend like crazy under some road conditions. Bunny hops, for example. Steerers break, that's a known thing. So a butt weld in the middle probably isn't the best idea. A good welder can get away with it, probably.

[Kontact]

not really. i'm still skeptical. the anecdotal feedback is interesting, but i would really like to see an FEA of a fork steerer showing the magnitude and location of stresses a steerer-tube actually experiences.

maybe i should have had my guy use "friction-stir" welding instead of TIG! ;-)

in any case, i may epoxy a CF inner reinforcement tube on the inside of my butt-welded extended steerer tubes, to mitigate the risk of catastropic failure.

The main force of concern on the steerer are bending forces, which are constantly present because the steerer isn't vertical.

And I'm sure you've heard that weld a good weld is stronger than the metal it is joining, but that's only because a normal weld has a bead that fillets the two pieces together with overlapping material. But on a steerer you can't have much of a bead. Instead you have cut a deep V into the cold worked, directional grained tubing and replaced it with cast metal, which means that even if the weld is perfect, the center of the tube is now 20% weaker and has 27% less fatigue strength.

I don't know how much CF or fiberglass you'd have to stuff inside there, because it isn't going to do much to increase the stiffness of the outer diameter of the steel tube, though it might hold it together if the weld cracks.

[wallymann]

How many frames have you built? Just asking.. ;)

as am i, mate! zero, but i did stay at a holiday inn. ;-)

I don't know how much CF or fiberglass you'd have to stuff inside there, because it isn't going to do much to increase the stiffness of the outer diameter of the steel tube, though it might hold it together if the weld cracks.

thats my thinking, insurance against a catastrophic failure.

[fogrider]

in any case, i may epoxy a CF inner reinforcement tube on the inside of my butt-welded extended steerer tubes, to mitigate the risk of catastropic failure.

is this what you were thinking? https://www.homedepot.com/p/FiberFix-1-88-in-x-20-yds-10X-Black-Tape-857101004495/303437546

its all about risk management. I think you should have 10 tubes butt welded together and then load tested to failure. average out the loads and use a safety factor of 3.

[paredown]

I personally would never let a friend or loved one ride a steerer that had been extended with a butt weld. No way. While the chance of failure (if the welder is really good) is small the results of that failure can be very bad.

There is a better way....if I had to make a steerer longer I'd slip a sleeve into the steerer so that it went in at least 2 diameters (call it 2"+) and then slide the new extension onto said sleeve the same amount. So you'd have a roughly 4" long internal sleeve that is slipped 2" into the lower steerer and 2" into the upper steerer. I would sliver braze this all together. The chance of failure is very, very low and if it does fail it will likely creak and wobble a long time before it lets go. A butt weld will not do this.

All that said....life is short and there's already enough things trying to kill us without adding to the list. Make a lamp out of the fork that is too short and replace it.

dave

Sounds like this is the method. I'm curious about the sequencing.

Would you braze the sleeve into the fork first, and then move to the extension? (This would be my inclination...)

I can see doing it this way for a fork with nice chrome--peeps are getting a lot of money for Precisas in decent shape...

[unterhausen]

I feel like the best way is just to braze it all at once. Heat control will be essential. Good news is you can see both ends of the sleeve, so you can tell that the silver flowed through.

[jrsbike]

As it happened I was trolling the internet yesterday seeking information about tube extensions. Glad I found this thread although I think I now have too much information to make a rational judgement.

[dddd]

A couple of things to consider.

First is that some steerers are made with much lower-grade metal (steel) than the premium one that Wally is trying to save. And unlike other parts of a good frame, the steerer of a fine bike has the same wall thickness as on the low-grade bike's steerer.

Another thing to consider will be how far up the steerer from the lower bearing and from where the butt ends that a butt weld can be made. The bending loads are reduced along the steerer in the upward direction, so a big reduction in stress level at the weld should be possible. This assumes that the maximum quill depth is known and that the effective steerer length (between bearings) and the butt length will be measured.

I think that the builders who have done butt welds on steerers likely gave consideration to both of these issues, and so were thus comfortable that a margin of safety was being well preserved.

So actually there is a bit of calculation involved to determine if the butt weld done on a particular fork (and at a particular location) would be the point of first failure as stress on the steerer (generated by forces applied at the front axle) was increased until something yielded or failed.
The builder will of course have to know (using metallurgical knowledge) what the decrease of strength at the weld joint will be for the steerer material in question, which I don't think is beyond the capability of a good builder.

[Kontact]

A couple of things to consider.

First is that some steerers are made with much lower-grade metal (steel) than the premium one that Wally is trying to save. And unlike other parts of a good frame, the steerer of a fine bike has the same wall thickness as on the low-grade bike's steerer.

Another thing to consider will be how far up the steerer from the lower bearing and from where the butt ends that a butt weld can be made. The bending loads are reduced along the steerer in the upward direction, so a big reduction in stress level at the weld should be possible. This assumes that the maximum quill depth is known and that the effective steerer length (between bearings) and the butt length will be measured.

I think that the builders who have done butt welds on steerers likely gave consideration to both of these issues, and so were thus comfortable that a margin of safety was being well preserved.

So actually there is a bit of calculation involved to determine if the butt weld done on a particular fork (and at a particular location) would be the point of first failure as stress on the steerer (generated by forces applied at the front axle) was increased until something yielded or failed.
The builder will of course have to know (using metallurgical knowledge) what the decrease of strength at the weld joint will be for the steerer material in question, which I don't think is beyond the capability of a good builder.

Whatever grade of steel a steerer is made of, it isn't cast. A weld is cast.

The bending forces aren't concentrated at the lower bearing. The steerer is being flexed between its upper and lower bearing, which act as fulcrums.


You're giving the people who have done this kind of work too much credit for understanding the forces involved. No part of a bicycle is made with flat ground butt welds - everything is built with an overlapping flange or fillet.

[cadence90]

We're talking here about a 1" diameter steel steerer; of indeterminate spec, age, and wear; post-original re-worked butt-welded and then ground.

The wall thickness of a 1" steel steerer is 2.3mm max - 1.5mm min.
Subtract some material for the chamfers, grinding, and what is that...1.8mm max - 1.0mm min?

This is a 1" diameter steerer with 1.5mm wall thickness, on my screen.

[].....................[] <--- 1.5mm wall thickness
<<<25.4mm>>>

Sorry, but there is no way that I'm trusting a retro-fabbed butt-welded steerer with ~1.0mm of surface, even if the God of Welds hisownself did the work.
.

[dddd]

You're making it sound like the weld has to be ground flush on both sides of the material, but it doesn't need to be flush at all. A sleeve to back up the weld can be below the lowest quill insertion, and the OD need only clear the larger ID of the crown race.


Kontact, I already know all about how the bending stress peaks at the lower bearing, and I already mentioned how that stress regresses along the steerer in the upward direction.
There are a couple of mathematical correction factors as I said, having to do with the materials involved and the reduced stress level at the weld location.

The weld strength is still important, the weld material strength versus cold-worked tube, but all kinds of auto, bikes and airplanes are made by joining high-strength chrome-moly steels with welds, whose known strength is trusted absolutely and whose application is made using trusted and well-documented practices of welding.

If you would trust a frame builder to make you a welded frame, then you should be able to trust that builder to do any repairs or alterations to it as well. It isn't like just going to a local welding shop!

[cadence90]

Yes, and since it certainly isn't at all a matter of "just going to a local welding shop!", what I'm saying is that the time, cost, and headache involved in finding and contracting a competent and willing "builder to do any repairs or alterations" on an older fork of indeterminate spec, age, issues, etc., is likely really not worth it compared to simply selling the old fork as it is and buying a proper new fork, for which I'm sure many more willing and competent builders exist if a NOS or mint suitable original cannot be found.

The theoretical is all well and good, but we don't ride our bicycles in the theoretical.
.

[Kontact]

You're making it sound like the weld has to be ground flush on both sides of the material, but it doesn't need to be flush at all. A sleeve to back up the weld can be below the lowest quill insertion, and the OD need only clear the larger ID of the crown race.

The crown race is 1mm larger in diameter, which means the maximum additional material would be less than .5mm. A regular weld fillet joining two tubes is several millimeters thick in the center.

Kontact, I already know all about how the bending stress peaks at the lower bearing, and I already mentioned how that stress regresses along the steerer in the upward direction.

That isn't what I pointed out. Take a stick and lay it across two pipes representing the upper and lower headset bearings, now press down on the ends of the stick. Between the pipes, the stick will bow up. The weld is in the center of that bow, like rot in the middle of the stick.



The weld strength is still important, the weld material strength versus cold-worked tube, but all kinds of auto, bikes and airplanes are made by joining high-strength chrome-moly steels with welds, whose known strength is trusted absolutely and whose application is made using trusted and well-documented practices of welding.

Welds that are noticeably thicker than the base material. Show me a bike make with just fusion welds and no filler material at the joints. Those fillets at the welds more than double the tube wall thickness. Adding less than .5mm does not.

If you would trust a frame builder to make you a welded frame, then you should be able to trust that builder to do any repairs or alterations to it as well. It isn't like just going to a local welding shop!

I trust a frame builder to use time tested methods to build a frame - like welds with filler material to form fillets. Butt welding is not one of those methods. Frame builders are welcome to come up with new methods, and the frame builder on this thread says that he thinks this method is unsafe.

So if someone would like to create and use such a method, they either need to be able to demonstrate their engineering prowess by going back to the books, or they need to destructively demonstrate that their technique produces a joint that is as strong as the weakest steerer tube commonly used.

[wallymann]

...a competent builder willing to do the sleeve-reinforced extension w/ silver solder?

kirk declined. maybe kontact? anyone else?

[Doug Fattic]

...a competent builder willing to do the sleeve-reinforced extension w/ silver solder? kirk declined. maybe kontact? anyone else?It might depend on how fast you expect the repair to be done. The closest experienced frame builder to you is probably Matt Assenmacher in Swartz Creek MI. He went to learn at Bob Jackson's in Leeds a couple of years before I went to Ellis Briggs in Shipley West Yorkshire back in the 70's. He is busy working in his bicycle shop in the summer so I don't know how quick he could get to it.

I'm heading to Ukraine in a week to continue our charity bicycle project. While I'm there I am also going to be teaching a German and Israeli the fundamentals of how to build a bicycle frame. I won't have any time to take on such a project until mid/late July. I've done this kind of sleeve repair on forks before. Sometimes it is preferable to keep the original paint/maybe chrome for historic or sentimental reasons. I'm on the other side of the state from you in Niles. If you stop by I can show you my personal frame that I used internal sleeves to repair the top tube (it fell off the top of my car). It has a Hellenic style of seat stay attachment so I couldn't replace the entire tube at the lugs.

There are a number of young frame builders in the midwest (most of whom I have taught in one of my frame building classes) that might be willing to do this job too. Again it depends on how fast you want the job done and how many years of experience you hope your frame builder has before giving him the job.

[wallymann]

The closest experienced frame builder to you is probably Matt Assenmacher in Swartz Creek MI.

I know matt...he did some paint work for me many years ago ...and we recently messaged about some cold-setting I need done...so I'll ask about this, too! If that doesn't work out, I'll give u a holla!

[dddd]

"The crown race is 1mm larger in diameter, which means the maximum additional material would be less than .5mm. A regular weld fillet joining two tubes is several millimeters thick in the center".


Are you referring to something that anyone actually said? I said nothing about a "regular weld fillet".

Another poster commented on the joint thickness being effectively thinner than the tube wall, which needn't be the case here.



"That isn't what I pointed out. Take a stick and lay it across two pipes representing the upper and lower headset bearings, now press down on the ends of the stick. Between the pipes, the stick will bow up. The weld is in the center of that bow, like rot in the middle of the stick."


You're not understanding the conditions that exist in a steerer's stress profile at all. There is of course no application of force at the center, and it's the lower end of the steerer sees the peak of loading. And you're not listening or understanding what I have mentioned twice already, about the bending stress regressing at increasing heights above the lower bearing, so the strength at the weld doesn't need to be as strong as along the entire steerer, only strong enough at the particular location of the weld.



"Welds that are noticeably thicker than the base material. Show me a bike make with just fusion welds and no filler material at the joints. Those fillets at the welds more than double the tube wall thickness. Adding less than .5mm does not."


MILLIONS of Schwinns were made with "butt" welds about an inch behind the head tube that were ground perfectly smooth. This was perfectly appropriate, since they understood welding principles and basic stress analysis and applied that knowledge to the known dimensions and material properties of their cold-rolled tubing and of the weld itself.



"I trust a frame builder to use time tested methods to build a frame - like welds with filler material to form fillets. Butt welding is not one of those methods. Frame builders are welcome to come up with new methods, and the frame builder on this thread says that he thinks this method is unsafe
So if someone would like to create and use such a method, they either need to be able to demonstrate their engineering prowess by going back to the books, or they need to destructively demonstrate that their technique produces a joint that is as strong as the weakest steerer tube commonly used."

Says who? There are many frame builders who come up with methods that are their own, the customer doesn't usually interrogate the builder with fabrication details that they would not understand. The builder's name/reputation represents their design, testing and quality-control standards; you either trust them with these things or you don't.
If you are the customer it is up to you to ask the right questions to satisfy any doubts that you might have, that is if you are up to the level of understanding the quantitative aspects of anticipated stress related to material properties. Few customers would be able to make informed decisions about such things anywhere near to the builder's ability to do so, so again it is the trust you have in a particular builder that counts here.

And before you imply that I am recommending any particular fabrication method here, read again and see whether that is the case.
Wally is a taller rider so there will likely be some span of the steerer above the butt and below the stem quill, along which the stress level will vary. That would give a builder some additional range of stress level to work with where any method of joining might or might not be appropriate. If you were a builder then you would be the one to decide what was best for any particular application, based in large part on your knowledge, experience and expertise that is unique to you.


(Sorry for having to include my replies in the tinted quotation box above.)

[Kontact]

(Sorry for having to include my replies in the tinted quotation box above.)

You know, I do read what you write, it just doesn't make any sense.


So I'll say the following free and clear of any quotes, so you aren't confused by previous information:


Welds can be stronger than the material being welded, but only because a normal weld adds material. So while the weld metal is weaker than the metal being joined, there is more of the weld material. But if you can't add much extra material because of the crown race, then your welded joint is weaker than the two tubes it is joining.


Steerer tubes flex. We know this because bicycle designers are constantly talking about steerer tube flex and designing larger diameter tubes to deal with it. Tom Kellogg once said Ti forks are no good because the steerer tubes are too flexible for good control. They flex because of the forces on the blades and the forces on the handlebars. When you push down on the handlebars, you flex the top of the threadless steerer forward. Because the upper headset bearing is a fulcrum and acts as ball joint, the steerer under the upper bearing flexes toward the rear. The wheel also tries to flex the steerer, using the lower bearing also as a ball joint. Between the upper and lower bearings, the external upper and lower forces are flexing the steerer. Like breaking a handful of uncooked spaghetti, a steerer with a flaw (weld) in the middle will break in the middle if the handlebar pushes down while the fork blades flex up - which is what happens every time you ride over a bump.


Old Schwinns are made of heavy pipe and were designed by engineers and then tested. Welded steerers were not designed by anyone with any specific design expertise and are not tested. There's no comparison.


Frame builders come up with new methods, and if they buck convention sufficiently, they test those new methods. Unreinforced butt joints are what a 10 year old would come up with - it isn't an alternative to some other practiced method, it is like a fusion joint without the follow-on fillet to give it the strength blobs of liquid steel don't have. It isn't a new method, it is half a method without the important second half - a reinforcing fillet.

And everyone, save you, gets that. Why don't you get that? Is it because you think you can get something for nothing with metal joinery, or that you truly don't understand that steerers flex all along their length like any unsupported span?



You could make such a joint okay - by putting a third bearing halfway between the upper and lower headset so the steerer couldn't flex mid-span. But that would be stupid, since using an internal sleeve is so much simpler than re-engineering the steering system.


If you really need me to, I can draw this stuff out. But since everyone else gets it, why not take some time and pretend that it is possible Dave Kirk and everyone else is seeing something you've missed.

[rustychisel]

C'mon, four pages. Are you guys still trying to piss on each other?

[Kontact]

C'mon, four pages. Are you guys still trying to piss on each other?

It isn't about pissing on anyone. This is a safety issue, and if someone doesn't understand why there's a risk, it's reasonable to hash it out for all the people that might eventually read this.

[weisan]

It isn't about pissing on anyone. This is a safety issue, and if someone doesn't understand why there's a risk, it's reasonable to hash it out for all the people that might eventually read this.

I agree and support this spirit wholeheartedly, always learn something from people more knowledgeable and lengthy in-depth conversations like this, even though a lot of it is over my head. Just ask one small favor or perhaps one tiny bit of feedback, and that is, try to refrain from sneaking in at the last minute or end the post with any snarky remark as they add little to no value, in fact, sometimes it negates the overall message/content, or impedes receptivity...which I always thought, is a shame...because up until that point, the content or information was REALLY good. Just take a look at the posts from 11.4 or David Kirk which are often packed full of wisdom and knowledge...see how they do it and do it well. Even when they poked fun at me a couple of times, I always knew they were only joking and meant well from the inside.

The funny thing about knowledge is, they are like the mountains. There's always a "higher peak". We think we know a lot. there's always someone who knows more...or know something we don't, so there's the opportunity to learn from them. I know six languages and a bunch of other things not related to this thread at all but there's no reason to brag about them or bring them into this conversation. But one day, we will be talking about something else on a different thread, then perhaps I can add value there.

Perhaps, it's more than just a cliche, the true measure of our self is not just the people we agree with but how we respond to those we disagree or different from us.

[Kontact]

Just ask one small favor or perhaps one tiny bit of feedback, and that is, try to refrain from sneaking in at the last minute or end the post with any snarky remark as they add absolutely no value, in fact, sometimes it negates the overall message/content, or impedes receptivity...which I always thought, is a shame...because up until that point, the content or information was REALLY good.



I appreciate the sentiment, but given some of your public posts disparaging other members, I'm not sure if you are the one to deliver it.

None of this stuff is personal for me, but some people really bring out the knives when you disagree with them. dddd has called me a troll on this an other forums, so I don't feel the need to be be particularly gentle with him, even if I'm not going to insult him.

[weisan]

That's too bad.
I was hoping for a different response. Maybe I was hoping too much.
Moving on.

[Kontact]

That's too bad.
I was hoping for a different response. Maybe I was hoping too much.
Moving on.

Like I said, a different poster would likely have received a different response. Consider that next time you lash out at Oldepotato.

[AngryScientist]

There has been a lot of good information in this thread, including commentary from some industry experts. I'm going to close this for now, as it appears that the OP got his answer and is pursuing a repair. Feel free to open a new thread if there is more technical matter to discuss, but this thread appears to have run a bit off course.

thanks for all who chimed in, it was an interesting read.