stormywaters

well, something terrible happened.

my new (to me) 1983 Bianchi Super Leggera Specialissima was assaulted.

i was at the local bike shop, getting the headsets switched out on my new and old Bianchis, when the person working on my bike made a grievous error. Said person was not being careful with a certain tool, and preceeded to cave in the top of my steer tube. After much panic, the lead mechanic cut the top of the steer tube and was able to get the top of the headset thread on what was left of the steer tube.

After everything was said and done, there was probably 3mm cut off of the top. Since there was so little material available to cut in order to get the headset to thread back on, they couldn't remove the entire caved in portion. That being said, the threads at the top of the tube are flared out and up, and the once clean and factory perfect fork is now hacked. Yes, the headset tightened back up, but I don't know how confident I am in this "repair".

am I over reacting? is there nothing wrong here? the bike is full columbus tubing, and that raises the question: if I decide to have the steer tube replaced ($125 at Joe Bell and Cyclart here in town), is the steer tube made out of columbus SL tubing or just the fork blades?

little help?

lotek 

I believe that on a Bike of that quality that the steerer tube would
be columbus also.
One way to check is to look for the columbus dove on the tube.
Given the bike (super leggera) I would seriously talk with the bike
shop about splitting the cost of the replacement.

Marty

luker

wow. no, I don't think you are over-reacting. I dunno what the cash flow of the shop is; they may be strained to pay for a repair that is for something functional and not visible...

did they remove the washer between the top cup and the lock nut? If they did, you'll probably never get it to stay tight again. If not, then the loss of 3mm probably won't be terrible.

Splitting the cost of the repair is more than fair to the shop, btw. But small claims court is such a pain, and not really very effective...

unworthy1

I guess you're down in the San Diego area, but up here in Alameda (Oakland, SF Bay) Bernie Mikkelsen does a LOT of steerer replacements. Very clean work and very good price, too, alot less than $125. It might be worth giving him a call and ask him about shipping, it's not that far and he's fast, too: 510-521-9727. I had him do a Ciocc fork and was very pleased with the result, no damage to the paint/chrome.

number6

No damage to the paint or chrome? Now that is amazing, as silver brazing is even higher in temp than chrome can handle before going "blue".

Perhaps he is using tig? or splicing above the crown.

I would go to JB, as Rob Roberson is in house and does the torch work.

shiftinjon

It is possible to splice in a sleeve and a section of steerer tube. It is usually done to lengthen a steerer, which is what is needed here, so it would work fine. This bike has a chrome crown if i recall, and it would be pretty hard to match the paint to the frame exactly, so splicing would be a good idea.

T-Mar

Rule of thumb for headset nut engagement is a minimum of three full turns on good threads. If you don't have that or they had to remove the lockwasher to achieve it, then you're playing with fire.

A Columbus SL steering tube will have six spiral ridges in the bottom of the tube.

A reputable LBS would cover the full cost of replacing the steerer. If they didn't, I would take what I could get, but that is the last time that I would use them. Good luck.

(Edit: The correct number of spiral ridges is five.)

shiftinjon

A Columbus SL steerer tube is smooth walled with a butt at the crown and will not have six spiral ridges in the bottom of the tube; a Columbus SLX steerer will though.

unworthy1

Yes, he splices in any length (threaded or plain) steerer tube to the old stub and uses a reinforcing insert. It's TIG welded all around and ground smooth, checked on his lathe for straightness. Last time I had him do it, it cost less than $50 and was "invisible" after I masked the fork and painted the tube.
BTW, it raises the question for me: I always thought the diff between SL and SLX was the spiral ridges in the butt of the steerer only on SLX, but have seen examples (and own them) of SL forks with spirals...was there a transition period for the "rifling" in late SL?

T-Mar

Columbus instituted the spiral ridges/helical reinforcements on their steering tubes long before SLX and SPX made their debut. All SL & SP tubesets used them. I've got early 1970s frames, prior to the SL to SP designations, that have the ridges in the steering column. A lot of people do not notice them, because they are only about 0.2mm high. You have to look closely.

shiftinjon

I have never seen or heard of a Columbus schematic of SL or SP tubing, nor have I seen a SL or SP steerer, with rifling of any dimension. Do you have a Columbus schematic, or an actual sample from a frame pre-SLX of this? If these riflings exist as you say, they would appear on any schematics or tube diagrams.

unworthy1

I'm gonna hazard a guess here: I reckon that *some* builders opted to cut down the butt (and rifled) section of the steerer to shorten it for smaller frames (probably not a good idea, but "weight-saving") instead of leaving it and cutting from the top. So some SL (and SP, SLX, etc.) forks could show small amounts of spirals or none at all depending on the builder and the finished size of the fork.

stormywaters

well, I spoke with JB, and he gave me a $200+ estimate. the low end would be to splice a donar tube onto the existing piece through a process of machining and brazing. A full restoration would include paint and replating the chrome, obviously much more expensive.

I have yet to approach the bike shop with my concerns, but I know the person who put me in this predicament has been fired. I'm friends with everyone at the shop, so I feel a little weird broaching the subject, especially because it's going to be such a pricey fix.

I'll keep you all in touch.

T-Mar

This undoubtedly has happened, but it shouldn't. The prime reason to remove material from the butt end on small frames is not weight savings, but to ensure having at least 5cm of non-butted tube for adequate stem insertion. Even on the smallest lugged frames, this should still leave at least 3cm of butt at the fork crown end.


As stated in my previous post, I do own Columbus frames, with the helical reinforcements in the steerer tube, that go back as far as the early 1970s. In the case of the oldest frame, I am the original owner, so there is no doubt as to the vintage.

shiftinjon

I can tell by your posts you pay a great deal of attention to detail so no doubt you have carefully documented the serial numbers, year of make, etc... of these pre-SLX/P frames made from columbus tubing with steerers that have helical reinforcements. What kind of frames are these, who made them, and what year exactly were they made?


Also, I'm very interested in how you were able to detect these .2mm helical reinforcements in these frames from the early 70's.

.2mm is less than the thickness of an anodized finish on a rim.

It is virtually undetectable by human touch, let alone the human eye peering down a steerer. It makes sense that so many people would miss it. How did you manage to detect these microscopic helical reinforcements in your steerers?

avenan

https://www.os2.dhs.org/~john/catalog...mbus-tubes.pdf

Page 10. Steering column. Specifically calls out the helical reinforcements. No mention of SLX in this pre SLX catalog. (84/85 for SLX general availability)

Plenty of people on the CR mailing list who have well-dated frames with helical reinforcements. Supposedly been around as long as SL has (late 60's?)

T-Mar

Avenan, thank-you for the supporting evidence.

Shiftinjon can also check his copy of Cycling, 1971 (aka the CONI manual), page 76, where the discussion on front forks states, "certain pillars have internal helicoidal ribs standing out on the lower part whcih assure a high resistance". In this case, the pillar is the steerer and while it does not reference Columbus, they were the patent holder.

Also I'm attaching an excerpt form The Custom Bicycle, 1979, showing the cross-section of the steering tube and mentioning the ribs. Note the word "unique" in the description, implying that Columbus was the only manufacturer with this feature, at the time.

Finally, I've attached some photos from a 1974 Scapin frame showing the ribs in the steering tube. They are quite hard to illuminate, but with the proper technique the ribs can be seen and emphasized, to a degree. They can be quite easy to miss with the naked eye, especially if some corrosion has set in, unless you know they are present and are looking for them.

Hopefully, this will put the matter to rest.

luker

well. I'm reassured. at risk of thread piracy, I have a related issue. A couple of years ago I found a good quality steel fork in the junk at a local bike shop, and I took it home to cut down and rethread for a 56cm frame. The steerer tube was at least 9" long, and the bottom showed rifling like you are discussing above. I didn't look down the steerer, but just clamped it in the vice and cut it to the correct length. I then threaded the steerer, installed it in the bicycle, and found I couldn't get the stem into the steerer tube. On closer inspection, I found that the rifling at the bottom rapidly got thicker, until at a point just below where I cut it, it almost filled the steerer tube. The tube had been milled out to accommodate the insertion of the stem, and I had cut almost all of that milling off. I found another fork and used it instead; and I still have that fork waiting for the day I need to drag some other things to a machinist...I'll have it milled out then.

What kind of steerer is this? Has anyone else seen such a thing?

shiftinjon

Umm, Mr. Mar., why do you want to put the matter to rest? Actually this has been a refresher for me and I appreciate the info posted by all the positive posts. Sorry if you were offended by my not remembering this.

I'd still like to see your fork with the .2 mm rifling.

My regards to the OP for this off topic foray.

stormywaters

well, I took the fork in for restoration. The shop agreed to pay for the repair, and they gave me an awesome loaner bike while my specialissima is out of commission... a 2006 Bianchi Pista Concept.

Great job on all of the semi-off topic discussion about tube differences, I learned a lot.

T-Mar

I'm glad to hear that things are working out well for you. Kudos to the store owner and/or manager for acting responsibly. The loaner was a touch and who knows, they may even get a sale out it? But isn't that a track model? I'm sure the members would like to hear your opinion on the modern versus vintage models.

billydscout

As it appears the discussion regarding the original post is primarily complete, maybe we can continue the discussion on tubing and helical reinforcement. Is the helical reinforcment present in the SL steerer tube also present in some SL main tubes, or only in the SLX main tubes?

T-Mar

Helical reinforcement, in other than the steerer tube, is present on SLX, SPX and MSX. In SLX and SPX it is present only in one end of the seat tube, down tube and chainstays. The helically reinforced ends fit into the bottom bracket shell. The top tube is not helically reinforced on SLX or SPX. TSX extends the helical reinforcment along the entire length of the tube and includes a helically reinforced top tube. The only helical reinforcement on SL and SP is in the steerer tube. I believe there was also helically reinforced, tandem tubeset, Tandem CM.

PBR Streetgang

Not to further hijack, but I have a 1970s Bottecchia frameset with the helical reinforcement in the steerer tube. Does that mean it is either SP or SL?

I say it's a 1970s frame, but I'm not entirely sure. It has absolutely no braze ons, so it is likely not any newer than the 1970s.

stormywaters

Yeah, the shop handled my concerns extremely well. While the Pista Concept is an amazing showcase of modern technology in track design, it is not exactly to my taste, especially for road riding. There is a reason I ride vintage steel.

The Bianchi is far more aggressive than my seventies era Columbus SL Cinelli Pista. I'm not saying that the Pista Concept is at all a bad bike in anyway, it's simply amazing, but boy is that double-butted aluminum stiff! It is nice to be back on a fixie though, as I was hit by a car about a month ago and the Cinelli is awaiting re-alignment by Joe Bell.