Sheldon's advice on danger of quill stem/butted steerer...?

[drissa]

I had my eye on a 225mm long Technomic quill stem for an old racer. I'm concerned about being too hunched forward and I'd like plenty of adjustment upwards if needed. But this article worried me a little. Is there a way to know where the butting starts and how far a quill can safely be inserted? Any thoughts? Thanks.

 

[sittingbull]

I would have thought that if the expander/wedge was tightened just sufficiently to allow the stem to move within the top section of the steerer with minimal clearance then it should be possible to feel where the butting starts as the stem is inserted further.

Having read the article a little further I find the comment on failure of stems with the handlebar bolt behind the handlebar more alarming, I just hope the example shown was of lower quality than the norm

 

[Gravity Aided]

As illustrated, a bit above the crown, where I've found any such butting. Your minimum insert line should guide you. This seems mainly a problem with situations where the stem is fitted low, It sounds like yours will be higher in the steer tube.Conversely, you could take a small wooden dowel, feel for the curve of any butting, and then mark that depth on the dowel and transfer to the steerer tube. Failure example looks more like a failure of design and metallurgy than anything else, perhaps a bad casting or forging, as well as bad design.

 

[hoski]

I would have thought that if the expander/wedge was tightened just sufficiently to allow the stem to move within the top section of the steerer with minimal clearance then it should be possible to feel where the butting starts as the stem is inserted further.

Having read the article a little further I find the comment on failure of stems with the handlebar bolt behind the handlebar more alarming, I just hope the example shown was of lower quality than the norm

Mmm... I remember reading that and then looking at my stem...

So far, so good not dead.

 

[sittingbull]

Mmm... I remember reading that and then looking at my stem...

Ditto........I've just bought another used previously tested one too.

 

[drissa]

Thanks, yes I thought I might just use the stem itself to feel for where the butting starts. My concern is that 225mm might be excessively long and if I decide to have a lower/more usual handlebar height, I'll run out of space inside the steering tube.

 

[HovR]

Mmm... I remember reading that and then looking at my stem...

So far, so good not dead.

Note that not all "clamp bolt behind the handle bar" style stems are made as inferior as that design, which appears to be particularly bad. Yours probably looks something like this, which is a very different design. In fact, I've never seen another stem similar to the one on Sheldon's page, probably for very good reason.

Either way, if your older stem has made it this far (most likely 30 or so years since it was cast, if not more), you can probably stop worrying about design and manufacturing flaws. It's still worth inspecting it for fatigue/cracks etc when you do your standard bike clean/maintenance, however.

 

[Gravity Aided]

Thanks, yes I thought I might just use the stem itself to feel for where the butting starts. My concern is that 225mm might be excessively long and if I decide to have a lower/more usual handlebar height, I'll run out of space inside the steering tube.

You certainly don't want your expander bolt system coming out of the bottom of your steerer tube, either. I always kept shorter steerer tubes around in case I needed a lower handlebar height. I never have yet. I did start getting bigger frames, though, as I ran across them.

 

[Deleted member 1258]

I would have thought that if the expander/wedge was tightened just sufficiently to allow the stem to move within the top section of the steerer with minimal clearance then it should be possible to feel where the butting starts as the stem is inserted further.

Having read the article a little further I find the comment on failure of stems with the handlebar bolt behind the handlebar more alarming, I just hope the example shown was of lower quality than the norm

In years of using quill stems in the past I only ever had one failure and that was a stripped thread, the result of screwing a hardened Allen screw into a light alloy stem, if I remember correctly failures were very rare.

 

[mickle]

Sheldon don't half talk some sh!t sometimes.

 

[Gravity Aided]

http://www.bikexprt.com/witness/product/stems.htm

 

[Deleted member 1258]

Sheldon don't half talk some sh!t sometimes.

There's some good stuff on his website but he doesn't get it right all the time.

 

[Deleted member 1258]

http://www.bikexprt.com/witness/product/stems.htm

The Modolo stem shown as failed was a very common design in Britain, I did many thousands of miles on stems of that design, the stem I had fail was one of those, if I remember correctly most of those stems had a steel insert in the top for the allan screw to screw into, the one that failed had no insert, the allan screw screwed directly into the alloy stem, I applied the brakes the bolt pulled out and the handle bars rotated in the stem, fortunately I wasn't going fast and managed to miss everything and get it stopped.
To go back to the OP's question my own experience with quill stems was that I never had a stem inserted that far that I had to worry about the butting, my usual problem was not getting it that far out that the max extension line was showing.