Stem use and stem cutting question
 

I want to raise the handlebars on one of my smaller bikes and I have this Nitto Technomic Deluxe stem that I inserted last night, only to find that it will not go far enough into the steerer tube to reach the insertion line. It has a 3 inch insertion length with a total rise of 7-1/2 inches (4-1/2 inches above the insertion line) and there is literally 1/8 of an inch (see picture) showing to the insertion line. With such a small amount showing could I use this stem or is that a definite no-no and a disaster waiting to happen?

If I cut an inch or so off the bottom of the stem which would probably be closer to the height I am wanting anyway, what are the ground rules for calculating a new insertion line? Could I just maintain the original ratio (3 to 4-1/2) with whatever length was left after cutting to maximize the rise or must I just insert the stem as far as it will go and be done with it? Thanks for any input!

http://farm4.static.flickr.com/3240/...a762dcdf6b.jpg

Personally, I don't think 1/8" is going to matter too much. It is a long stem though and you might find that it creaks when you are standing on the pedals, rocking the bike back and forth, going up a hill.

You say that you may be able to cut an inch or so off the bottom of the stem to give you the height you really would like to achieve. I cannot see anything wrong with that as it would reduce the 'turning moment' and the insertion length would remain the same (approx. 3"). Make sure you are able to do this and still retain the clamping action, and, can the bolt accomodate the shortening of the stem?

Have you investigated what is stopping the stem from going further down the steerer tube?

The reason the stem stops in the steerer tube is due to the double butting of steel inside the steerer tube toward the bottom of the head tube which narrows the tube. The bike is a 51 c-c and I was surprised it took as much of the stem as it did. Take a look at the bottom of this link from Sheldon Brown...

http://www.sheldonbrown.com/handsup.html

What do you mean... "reduce the turning moment"?

Nothing to worry about then. The steerer can't take a longer insertion length anyway.

The turning moment is a physics term. The further your hand (on the bar) is from the headset / steerer the greater the pressure you can exert on the steerer tube. A longer stem will allow you to place more pressure on the steerer tube.

Think about it... if it's already bottoming out, you aren't going to get any more insertion if you cut it down, will you? You will still have the same limited head tube length. The min insertion mark will then be down into the headset, but you will still have the same length of stem in there anyway, so there will really be no change except to how high your handlebars are. It would just be wasted time and effort.

Your problem is that you are using a wedge type stem in a short head tube. Some of that insertion length is taken up by the wedge itself. It doesn't usually matter, but it can if your frame is small and is butted in a way that prevents the stem from going all the way in (ie. it bottoms out too early). What you need is to get a more classic stem that has a cone instead of a wedge. That should fit fine.

Of course, you wouldn't get your bars as high as you can with the Technomic, but those very high stems look and ride goofy anyway -- only useful for refusenicks who just won't accept that a classic road bike position is the best way to ride both efficiently and comfortably in the long run, unless maybe you're a Copenhagen Girl in high heels.

I know the insertion length cannot be altered. The purpose is not to get more insertion into the head tube. As an example, let's say I cut 1/2 inch off the stem. The object is to use the insertion I have available (just under 3 inches) and change the total length of the stem (reducing the exposed length from 4-1/2 inches to 4 inches) which would make the inserted amount acceptable in terms of the minimum insertion normally required for a 7 inch stem rather than a 7-1/2 inch stem. It's a safety and stability issue. At the same time, I've raised my handlebars to a more desireable position (about 1 to 1-1/2 inches higher) than with a standard stem.


The real problem is the bike is a little too small for me which requires that I raise the seat post to get proper saddle height, thus necessitating the rise in the handlebars to accomodate my preferred riding posture which is to have the handlebars 1 to 2 inches below the saddle.

- Got any photos of Copenhagen girls in high heels?

CPSIrwin, I agree with Gary that the small "violation" of the insertion limit is not an issue, especially if you are not a harsh user. I've used several Technomic Deluxes inserted that same way, and with zero creaking noises or slippages. I wouldn't worry about the exposed vertical length.

I'm a little confused, and didn't really get any less confused in the later posts. You want to raise your handlebars to sit right relative to your saddle. Because of your small bike frame, you can't raise this stem. Inserting the stem is impossible due to the internal butting or spiral (for a Columbus steer tube), so the stem is now where it can be. The rise of around 11 cm is correct for a Nitto Tech Deluxe, and you are stuck with that rise for that stem and that frame. I have similarly small frames (52 and 53 cm) and believe me, you're stuck.

The comment about steering moment or turning moment is not relevant to the vertical extension, assuming normal handlebar forces and a reasonably rigid quill. With a Nitto you can be assured of that, they're really well-made. The turning moment is significant in the other element of the stem, the extension. This is the length of the part that goes forward connecting the handlebar clamp to the top of the quill. Its length is called the "extension" of the stem. It's basically center to center, in centimeters.

Regarding one of the other comments, I don't think any stems with cone wedges and the kind of quill length you need are made, or perhaps ever were made.

You CAN raise your handlebars. You need either a Technomic stem (more about this later) with the same extension as you now have, or a different design of stem. The Tech Deluxe, the Technomic, and most "road" stems have a 73 degree angle between the extension and the quill. You can get stems that have a different angle, all the way up to 90 degrees (right angle). The trick with these is to do the math and determine what combinations of quill length, extension, and angle will raise your handlebars to where you want them with the correct effective extension.

Back to the Technomic: the overall length of the Tech Deluxe quill is 18 cm, with 11 cm above the insertion line. For the Technomic its a LOT taller, 22 cm overall and 17 cm above the insertion line. The insertion area is the same as for the Tech Deluxe, so it also cannot be adjusted once installed. If you need to go 6 cm higher than the Tech Deluxe will allow, then the Technomic is what you need.

This will function, but I have tried it, and I think it looks really ugly, what I call the giraffe effect.

I think my need for a Tech Deluxe implies I am riding frames that are too small, and I want to try a French fit with a 54 or 55 cm c-c frame. This should allow me to use a standard short road stem. If you need a Technomic to fit your handlebars, I think you have a greatly undersized frame, and you just might not be able to be happy on a vintage frame with a horizontal top tube - you might have to to the dark (sloped top tube) side.

Road Fan

Let me clarify. First of all, I am not using the Technomic Deluxe presently. I am using a conventional stem that is providing about 2-1/2 inches of rise. I wanted to change to the Technomic Deluxe for a little more rise and I was concerned about the max line showing when I inserted it as far as possible into the steerer tube. The Technomic Deluxe, when inserted to the insertion line, will provide 4-1/2 inches of rise. Actually that is a little more than I need, and since I can't reduce the rise by inserting the stem any further into the steerer tube, I am going to have the stem cut and sanded to provide about 4 inches of rise. I am satisfied that I'll get sufficient insertion (just under 3 inches) for the slightly shorter stem and have the height I want in relation to the saddle.

With the stem inserted as far as it will go, measure from the top of the locknut to a point just above the max insertion line and cut that much off of the stem with a hacksaw. You don't have to match the wedge angle exactly, just eyeball it. If you cut the stem extemely short, you'll run out of threads on the stem bolt and you'll have to find a shorter one. That's all there is to it. I've done it more than once to Nitto dirtdrop stems.

I'm not following you on your instructions. I intend to remove the wedge and bolt and cut 1/2 to 3/4 inch off the bottom with the angle parallel to the existing angle and sand it smooth. If I insert it as far as it will comfortably go, I should have a 3-3/4 to 4 inch rise. I will check the bolt length before I proceed to make sure the the threads extend far enough up to tighten the clamp with the shortened length.

I cut a Cinelli stem to use a slanted lock nut. I used a Dremel tool with the thin cutting blades. It took several. It can be done and you just need patience. A bench grinder helps a lot. Your bolt may end up being too long. (precisely why I had to change bolts on the Cinelli)
Two questions:

1) Are you just trying to get it in to the insertion line to be safe?

2) How much farther down does it need to go to fit you?

If 1) is yes, I'd cut off about 1/2 inch.
If 2) is less than 2", cut what you need to for the fit. If it's more than 2", I'd think about it more.

It sounds like you need to cut 1/2 to 3/4 inch. Have at it. Been there, done that. Take your time, and it will be cool.

1) Yes, I am just trying to get to the insertion line to be safe.

2) If I could insert it about 3/4 to 1 inch more, it would work perfectly without cutting.

Since the stem is hitting against something at the bottom of your steerer (probably the brake bolt), you'll never get more insertion. By the way, I have never seen a butted steerer.

Because the Technomic has so much rise beyond the steerer, the leverage on its connection are greater. It therefor needs to extend further into the steerer, which explains why you're seeing the minimum insertion line. By cutting the stem down, say, an inch, you will lower the height and reduce the leverage. In a sense you'll be converting it to a "semi-" Technomic having more rise than a normal stem but less than an uncut Technomic. I would recommend cutting at least enough to bury the minimum insertion line.

You might have to extend the threading on the quill binder bolt.

A safer, less invasive work-around would involve purchasing a quill converter and a threadless riser stem. There'd be no cutting and machining and no question about getting a strong interface between your handlebar and steerer.

From Sheldon Brown:

Too Low! Danger!
Note: Steerers are butted at the bottom, so the hole in the steerer is constant-diameter until near the bottom, then the walls taper inward in the butted section.
It is vitally important that the stem extender (or stem) is not inserted so far that the wedge is installed where the steerer is narrowing, or it could come loose unpredictably.

When this happens, only the edge/corner of the quill or wedge contacts the steerer, and it is trying to "grab" a slanted surface.

This is sometimes a problem on smaller frames if you try to insert the stem or a stem riser too far down into the steerer.

http://farm4.static.flickr.com/3083/...632a9b38_m.jpg


Exactly!

Agreed!

You'll have to pry my cold dead hands form the handlebars before you can make that kind of modification on my mid 80's Merckx Corsa Extra!

I'm still not totally clear on what it is you're trying to accomplish, but if what you want is to cut the quill down a bit, that's not a problem at all. Just do it. I've done that with no problem, and with only a hacksaw and nothing to clamp it down with but my hands. You can easily even it out with a file afterwards if you need to, although if you can, some means of clamping down the stem and controlling the angle of the cut would be easier. Me, I just used the wedge itself as a guide to make a mark on the quill.

As long as you end up being able to put 2 and half inches of stem into the tube, you should be fine. I disagree with others that having more quill sticking up out of the tube in relation to the shorter length in the tube is going to affect safety. It won't if you have those 2 and half inches in there. That's all you need. Less, and you're on your own. That 2 and half inches I'm talking about includes right down to the very bottom point of the quill.

By the way, on a classic style bike, a slightly cut down Technomic Deluxe that isn't sticking a mile up from the head tube looks absolutely terrific. It has that classic drop down nose that many of us love. I have some 3TTT Synthesis stems for my custom-made lugged frame, but I actually prefer the Technomic on it just for the looks. I took about an inch off the quill because it was bottoming out too early. It was actually the guys at Rivendell who suggested cutting it. They probably don't get too many calls about a Technomic being too long :-)

Thanks for the correction. I'll have to spend more time looking into the steerers of fine old steel bikes.

And in my opinion, a Technomic is just as much a travesty as a converter with a riser stem. If you can't slam your stem, get yourself a fitness bike! ;)