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Much of bicycle design is driven by the needs of racing cyclists--even though the vast majority of cyclists are not racers. Racing styles and positions are not necessarily suited to the needs of the touring cyclist.
Newer road bikes tend to have longer top tubes and to be sized smaller than was common a few years back. This is good for the racer who is looking for the fastest, most aerodynamic position, or for the weekend athlete out for a brisk high-intensity workout, but is less good for the long distance rider who is likely to spend more time in the saddle.
Racers aim for the holy grail of the "flat back." The racers' high-intensity, high-gear pedaling style allows the reaction forces from their leg work to hold their upper body in position, even when leaning very far forward. Indeed, in a hard sprint, the rider is actually pulling upward on the bars! This intense riding style, however, is not sustainable for long hours in the saddle.
A touring cyclist rides longer, but with less intense pedaling effort. A long-distance rider is not seeking speed, but endurance, and will generally tend to avoid extreme effort, so as to not waste physical resources. Thus, the touring cyclist is likely to seek a more upright posture. As cyclists age, their position preferences also are likely to change.
Similarly, a casual recreational cyclist, or beginner cyclist is not likely to be comfortable with a low handlebar position.
Achieving a comfortable position will often involve substituting a different handlebar stem, to move the handlebars higher up or closer to the saddle, or both.
Most "road" bikes use threaded forks, and take a stem that slips inside of the fork's steering column. The stem will have a long bolt running down through the vertical part, connecting to a wedge at the bottom. Tightening the bolt pulls up the wedge, and the wedge jams against the inside of the steerer, securing the stem to the steering column.
Loosening up the bolt, usually with a 6 mm Allen wrench, may free up the wedge and allow you to move the stem in the steerer. Sometimes, loosening the bolt won't loosen the wedge, so you may need to unscrew the bolt a few turns and then give it a tap on top with a block of wood or a soft mallet.
Older stems used a conical "expander" nut, with a split quill (shaft) that would expand against the inside of the steerer, but the principle is the same.
Once the stem is loose in the steerer, you can raise or lower it, and rotate it from side to side. If you decide to raise it, it is important that you don't overdo it. If you raise the stem too high, so that there's not sufficient length remaining inside the steerer, you might find the whole handlebar assembly disconnecting from the bike--your life will pass before your eyes and down you'll go! Most stems have a "minimum insertion" mark that shows how high it may safely be set. If you can see this mark, the stem is too high. If your stem doesn't have such a mark, a good rule of thumb is that there should be at least 2 inches/50 mm of stem inside the fork.
If your bike currently has the stem lower than you'd like, don't get your hopes up too high that you can just raise it--most bikes already have the stem set to the max when they leave the shop. If your bars are too low, chances are you'll need to buy a new stem.
If your bike has a "threadless" fork/headset , options for stem adjustment are usually even more sparse. There may be some spacer washers above or below the clamp-on "threadless" stem that could be re-arranged, but, generally, again, the stem is probably already as high up as it will go, with the spacers underneath it.
Threadless forks are generally supplied with very long steerers, intended to be cut to appropriate length for various different bike frame sizes. If you are buying a new fork, or a new frame, you can leave the steerer full length even if you ride a smaller frame. This will let you get the stem nice and high without needing any extra accessories.
On some of my own bikes, I've gone this route, and have used a separate clamp to secure the headset, rather than using the stem for that purpose. A 1 1/8 steerer is 28.6 mm. Pinch-bolt type collars are readily available in this diameter, some of them intended for seat tube use.
Using the separate collar allows you to mount the stem anywhere on the extended steerer, without any need for spacer washers, and without any need to re-adjust the headset every time you raise or lower the stem.
This system also eliminates the star nut. To adjust the headset, I loosen the pinch bolt in the collar, and also the pinch bolt(s) in the stem. I put the stem as far down on the steerer as it will go, sitting right on top of the collar. Leaning with as much weight as possible on top of the handlebars, I twist the bars back and forth, also wiggle them front/back to get all of the slack out of the headset. I then let go of one side of the handlebar while holding my weight on the other side, and tighten the pinch bolt in the collar to hold the headset in adjustment. Once the collar is tight, the stem may be raised to any convenient height and secured with its own pinch bolt(s.)
I do not recommend this approach for carbon fiber steerers, nor for 1" steeerers, but I've had very good results with it on metal 1 1/8" steerers.
If you wish to change your stem, in addition to height and reach, you need to consider compatibility with your bicycle's fork and handlebars.
If your bike has a traditional threaded fork/headset, your stem will be sized to fit inside of the steerer. This sometimes causes confusion because the nominal size is based on the outside diameter of the steerer, but the diameter of the stem is 1/8" smaller to fit _inside_ the steerer. Thus, a normal 1 inch fork requires a stem of 7/8" (22.2 mm) diameter, while a 1 1/8" fork requires a stem 1 inch in diameter. Thus, depending on how you look at it, either of these stem sizes might be referred to as "1 inch."
If your bike uses a threadless headset, there's less confusion, because the stem fits the outside of the steerer, just like the headset.
|BMX/ O.P.C. bikes||.833"
|26.4 mm||32.7 mm||24||Used mainly on bicycles with one-piece cranks, also some early mountain bikes.|
|French 25 mm||22 mm||26.5 mm,
|Obsolete. French steerers usually have a flat filed on the back, rather than a grooved keyway as with other threaded systems.|
|1" ISO Standard
|7/8"(22.2 mm)||26.4 mm||30.2 mm||24||This is the standard 1" size.|
|1" Italian (25.4 mm)||7/8"(22.2 mm)||26.5 mm,|
|30.2 mm||24||Obsolete. Threads are cut at 55 degrees, but ISO or J.I.S. headsets can be used.|
|7/8"(22.2 mm)||27.0 mm||30.0 mm||24||Older or lower-quality bicycles from Asia|
|7/8"(22.2 mm)||26.4 mm||30.2 mm||26||Proprietary size used on Raleighs made in Nottingham, England|
|22 mm||26.7 mm||30.8 mm||25.4
|Higher quality Austrian bikes use English/ISO|
|French Tandem 28 mm||22 mm||25.4
|Obsolete and rare.|
|1 1/8" (28.6 mm)||1" (25.4 mm)||30.0 mm||34.0 mm||26||"Oversized" (This size is more often used for threadless systems.)|
|1 1/4" (31.8 mm)||1 1/8" (28.6 mm)||33.0 mm||37.0 mm||26||Mainly used on tandems|
|BMX/||26.4 mm||32.7 mm||Used mainly on bicycles with one-piece cranks.|
|1" ISO Standard (25.4 mm)||26.4 mm||30.2 mm||This is the standard 1" size.|
|1 1/8" (28.6 mm)||30.0 mm||34.0 mm||Most newer mountain bikes use this size.|
|1 1/4" (31.8 mm)||33.0 mm||37.0 mm||Mainly used on tandems|
|1.5" (38.1 mm)||39.8 mm||49.6 mm||Proposed OnePointFive standard for downhill and freeride applications.|
In the past there was a wild proliferation of handlebar diameters and stems to match. Different countries and different companies would each have their own set of "standards." This anarchic situation is gradually being rationalized, to the point that there are now only three sizes left, the international ISO standard size (1" or 25.4 mm) and the Italian national size , nominally 26 mm.
|22.2 mm||7/8"||22.2 mm||7/8"||Steel bars. Mainly BMX, older Mountain bike bars.|
|23.8 mm||15/16"||22.2 mm||7/8"||Obsolete British size for steel handlebars, common on older 3-speeds.
This size was also used for older British steel drop bars.
|25 mm||23.5 mm||Obsolete French size.|
|25.4 mm||1"||22.2 mm||7/8"||Standard I.S.O. size, used on the vast majority of newer bicycles with upright handlebars.
This size was formerly common for steel drop bars.
|25.4 mm||1"||23.8 mm||15/16"||Standard I.S.O. size, used on most bicycles with drop handlebars.
Also used on older British aluminium upright handlebars.
|25.8 mm||23.8 mm||15/16"||Unofficial in-between size used by some Italian handlebar makers for handlebars designed to be usable in either ISO (25.4) or Italian (26.0) size stems.|
|26.0 mm||23.8 mm||15/16"||Italian standard for drop bars, other bars made to fit Italian stems and some high-end aftermarket drop bars.
This is sometimes incorrectly called "road" size.
|26.4 mm||23.8 mm||15/16"||Older Cinelli and Cinelli copies. Cinelli changed over to 26.0 mm in 1998.|
|27 mm||23.8 mm||15/16"||Titan (obsolete).|
|31.8 mm||1 1/4"||23.8 mm||15/16"||Road oversized.|
Some people in the industry make a false distinction, referring to the ISO size as "mountain bike" size, and the Italian size as the "road" size.
The vast majority of bikes made in the last 10-15 years use the ISO 1" size, whatever sort of handlebars they use. High end aftermarket drop bars are commonly Italian (26 mm) size, but most drop bars supplied on built-up bikes were ISO (1") through the 1990s.
Many Italian bars are actually closer to 25.8 than the nominal 26 mm size.
Most current-model drop bar bikes use the 26 mm or 25.8 mm size, or the new "oversized" 31.8 dimension.
If you're shopping for a stem, and are not sure the handlebar size you need, don't guess; measure, or get somebody to measure for you with a proper caliper. If the bars are too skinny for the stem, it is possible, but inelegant to shim the bar with thin metal stock. If in doubt, however, don't take chances, especially with aluminum stems. If you force an aluminum stem to bend to a shape it wasn't made to fit, it may fatigue and crack. If it is going to break, it will break when you are pulling or pushing extra hard on it, and down you'll go. Stem failures are among the most dangerous parts failures there are, and almost always lead to nasty crashes.
Many of the newer bikes are coming with "pop-top" stems. This type of stem has a removeable front section held on by two bolts, rather than the usual single bolt. In addition to being light and strong, this type of stem can be interchanged much more easily than traditional one-bolt stems, because you don't need to remove handlebar tape/grips nor brake/shift levers to change the stem.
Stems are measured in ways that are often confusing, and measurement systems will sometimes vary from one manufacturer to another.
"Rise" refers to the angle of the "extension" part of the stem. This may be referenced either to the steering axis, or to an imaginary perpendicular to the steering axis. Thus, a stem with the extension perpendicular to the quill might be referred to either as a 90 degree stem, or as a 0 degree stem! A traditional "7" shaped road stem might be referred to as a 73 degree stem, or as having a 17 degree negative rise! Caveat emptor!
Many of the newer "comfort bikes " come with pivoting stems with adjustable rise. These are good for the casual pootler who just wants to sit up as straight as possible, but are not always the best choice for a more committed cyclist. As these stems go up, the bars also move back, and this may move the bars back so far as to disturb the weight distribution and steering geometry. That doesn't matter to the occasional bike-path cruiser, but may be a significant issue to the touring cyclist, especially with a loaded bike.
The "reach" is the distance from the centerline of the steering axis to the center of the handlebar clamp area, but the issue is the angle this measurement is taken from.
Traditional "road" stems shaped like the number "7" have a reach measured along the horizontal axis. Newer type stems that have different "rise" angles most often measure the reach along the axis of the rise, which leads to confusion...a 120 mm "7" shaped stem raised to place the handleabars at the same height as a nominal 120 mm stem with 135 degree (45 degree) rise will actually place the handlebars substantially farther forward.
Height is an important variable, not usually specified in any clear way. In the case of "7" shaped stems, if height is specified, it is usually the overall length of the vertical part from top to bottom.
Stems are available in a wide range of rise, reach and height.
If you want to raise your bars and your stem is already at the maximum, one option is to replace the stem. Another is to use a "stem extender" a stepped tubular device that mounts between the stem and the steerer. These are readily available for both threaded and threadless headsets, 1" and 1 1/8"sizes.
An extender for use with expander/wedge type stems is narrow at the bottom to fit into the steerer, and has its own wedge to secure it. The wedge bolt is deeply recessed so you'll need either a long Allen wrench or, sometimes, a 13 mm socket wrench with an extension to reach it. The original stem fits into the wider top half of the extender. Thus, the bottom of the stem winds up about 1/2" (1 cm) above the top of the steerer, so an extender of this type will raise the stem about 2 1/2 inches (6 cm) above the normal "max" level. This may be overkill for you.
Extenders for use with a clamp-on stem and threadless headset are similar, only they have the wide part at the bottom, narrow at the top. The bottom section will have a binder bolt to clamp it onto the threadless steerer, and there will be a deeply recessed bolt in the middle, to connect to the star nut. The original stem clamps on to the narrower upper section of this type of steerer.
Note that the installation of a stem extender (or tall stem) may be complicated by the need to replace some or all of the brake and shift cables, if the original ones are not long enough to reach the bars in their new, higher position.
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.
Illustration by Nicholas Flower
An earlier version of this article appeared in Adventure Cyclist magazine.
|Articles by Sheldon Brown and others|