I thank everyone for the comments, positive or not, but all I really asked for is if anyone has tried this and what their experience was- not opinions on why this might be stupid. I already know stupid!

Unterhausen- I dd read the report (twice) and the conclusion didn't really answer my question. There was no evidence on how much the stress, before failure, the steerer tube endure above the support (crown race- bearing seat to to head tube.) I suspect there isn't much stress in this area.

And, for those who didn't think there's much weight savings, it is 150g. Yeah, not much, but when you get a complete bike down to the 15# range, grams count!

John D. Thompson- I would totally agree with your comment ("There are sensible places to try to save weight, and then there are stupid places to try to save weight.
Steer tubes are heavy for a reason. Save your weight somewhere else.")... but here it does not really apply.

I didn't ask where to save weight. My mission is to save weight on a budget. I'm building wheelsets that are as light as I can get them without breaking the bank, which is the first, and best place to save weight. So we go from there. By careful shopping one can get a really light crankset without raping the wallet. Build a frame that weighs less than 3 pounds. An oz. here- oz. there... blah, blah, blah.

So... Instead of a "light" CF fork, I want to build a steel fork to get to the target weight. That's why I asked if anyone had tried it and succeeded, or not. My goal is to build a minus 15# bike for under $1000. I'm only a few grams away. FWIW- a builder a few miles south of me is building 12# road/race bikes. I can't justify the parts costs. I need to keep the costs down.

Thats's why I asked the question in the first place. I'm gonna built it and if it works, maybe I'll get some testing done. (Yeah right!)

Maybe more important... A couple posters thought that this should be reported to the moderators. Why? Really?

all of the bending moment around the lower headset bearing is carried in the steerer inside the head tube. The lower headset bearing will not take up moment, that's what the upper headset bearing does. This stress is not insignificant, and steerers do have a history of breaking, including the one in the test.

It was one poster. Since I'm a moderator, and Siu Blue Wind is a site administrator, it's obvious we know about your posts and would do something about it if we thought it was a problem.

I still don't get where you see the 150 g. I did some quick calculations. A 2.3-1.55 butted 25.4 steerer, 250 mm long weights about 258 g with the entire butting (65-30-155 profile). If you trim the butting to the minimum for silver brazing, say to a 35-30-185 profile, it should weight 246 g. A straight gauge 0.049 tube will weight 184 g. So you can save 62 g at most. A 0.065 tube will weight 240 g and so on...

I would think the place to save weight is the crown. I remember seeing weight weenie builds from back in the day that used flat fork blades in a "unicrown" configuration. You would probably need to do some internal bracing of the blades to keep them from flexing too much. Of course, getting tire clearance might drive you to 1 1/8" steerer, but as has been pointed out above, those are actually lighter. The lightweight steerers are stronger than 4130 too.

If you did want to take some weight off the steerer, you could consider putting it in a 4 jaw chuck and only taking material off of the front of the steerer because that is in compression, which it should handle better. The transition between sections needs to be done smoothly however.

Hey guys- I really appreciate all the input, even if it didn't answer the question directly. Personally I still consider this a viable option to obtain my goals, and one which I will explore. Safe? Maybe not, but I haven't been presented with any evidence to the contrary. You never know until it's been tested, and apparantly it hasn't been in the exact case I'm suggesting.

To whomever suggested that the weight savings were not what I mentioned, that was the difference I got from actually comparisons of tubes supplied.

I may not have mentioned this before, but I don't take safety lightly. I'll take a risk now and then, but I will err on the cautious side. I'll test and experiment until the cows come home. If it works out in my favor- Whoo hoo! You don't live to be this old without putting some thought into the risks.

I would not continue this discussion if I weren't seeking answers. The "nay-sayers" don't bother me. I realize this is the internet and expect the "input." What does bother me however is the folks that said I should be "reported" to the mods? Just because I asked some question that some might consider ridiculous and unsafe practices? Thanks Unterhausen for your perspective on this subject.

Over the holidays I visited an old friend who is an engineer and an employee of one the major (bicycle) component manufacturers (can't mention the name at this point.) She oversees the department which does destructive/durability testing of prototypes and random testing of new-in market products.

I mentioned my "little" experiment. I'm totally serious about doing a steel fork that (in my mind) is better than a carbon fork. I've been given the specifics on fixturing for the testing. The cost is way less than I'd expect. Just not sure if SOP (seat of pants) testing wouldn't serve me better.

I'll let you know- RD

Thanks! If you don't kill yourself, we'll all learn something, perhaps!

Hey sorry to second-guess you again, but I have a 1" butted steerer, 320 mm, and a piece of 1x0.049" tubing, 555 mm. They weigh 320 g and 410 g respectively. That corresponds to my numbers within 1-2 g so I stand by them.

No problem- Maybe it's my scale (or my eyes) but my numbers are 319g at 250mm for supplied (butted) steerer tubes vs. 170g for .049 wall tube, both 1" od.

I'm not arguing any info, but hoped someone has tried and tested what I'm proposing.

Just out of curoisity I am gonna do some testing. I'm building a fixture to support the steerer tube exactly as it's supported in the head tube (headset bearings included). Primarily I'm interested on comparing steerer tubes, but other results may be enlightening too. I really want to know what the loads are on the steerer and where failure is, and which materials produce what results. Trying to figure out actual loads under most riding conditions is way beyond my scope of this test, but that's not what I'm after. I'm thinking the deflection anywhere between the supports(top and bottom HT bearings) and load is really quite small. We'll see.

I've seen all the fork failures (steeel, aluminum, carbon/AL and carbon) but they have all failed in the blades... never the crown or steerer. Then you have frame distortion from crashes. Oh yeah- wheels collapse too. So, the question remains- How much lighter can I make the steerer tube and have it not be the weak link?

steerer tube failures are rare, but george hincapie's at paris-roubaix a few years back is the most famous instance.

Not sure about your numbers. You'll find plenty of references quoting 0.498 lbs/ft for 1x0.049" tubing, i.e. 185 g for 250 mm. It's easy enough to compute yourself. This is what I did, and the numbers matched the pieces I have in hand. I'd double check the weights & lengths and/or measure the walls, perhaps your steerer is thicker?

Anyway. Good luck with the testing, but I maintain that there is only about 60 g to save. Btw you can have stuff fatigue-tested for a about $100 + shipping.

I've been riding bikes for 50 years, but I'm pretty new to this forum. It's great!

If you really want to lose 150 grammes, take a pee before getting on your bike.

Let the frame tube manufacturer worry about testing to destruction. Life's too short as it is.

Why spend even one second on any bike if you even suspect the forks might snap off?

Bonkers!

So, R, are you still doing this? What's happening?

reddog3 you show the patience of Job. i haven't met too many forum members who could have weathered such a storm of mighty insults with the poise and maturity that i wish i shared with you...

i have little to say about fork building, but i imagine ferrous metal materials strengths and weaknesses became well known soon after their use on bikes. and soon standards for safety regarding their weight ensued, driven by expectations of profit on one side and liability on the other.

manufacturers often have to build to a specification suitable for a large range of potential customers that exhibit a wide range of physical attributes. focusing on a smaller subset, in this case the OP, of those potential customers offers manufacturers, and especially the custom builder, opportunities to safely modify those standards. so, given the above, i see nothing wrong in asking the question posed here.

As a moderator, I'm somewhat sensitive about insults and I don't really see any here. Some strongly worded warnings, yes. Going to shut this one down. I think we have covered most of the bases on this one, if reddog has further results, it's appropriate to start a new thread.