Adjustable stems. You probably either love them or hate them. If you're a gram-counter riding a sub-20-pound bike you probably wouldn't be caught dead with an adjustable stem. However, if you're searching for the perfect stem height before committing to purchasing a particular stem, an adjustable model will help you determine the best angle before you plunk down your hard-earned cash. Likewise, folks who do a lot of touring may like using adjustable stems because they allow them to modify their riding position throughout the course of a tour. One day you might want a lower position whereas the next day you might want to ride a little more upright. Having a stem that adjusts to multiple angles can allow you to achieve various riding positions with just a few turns of a hex key.
I'd never used an adjustable stem until one came already installed on my 2006 Scattante road bike. That bike frame is long gone, but I kept all the components, including the stem which has served me well in determining my optimal riding position on several other bikes. Over the course of a couple years I've had the occasion to buy a few different models of adjustable stems. Some of those stems I've tried are very good, and some are very bad. Very, VERY, BAD!
The Zoom Quick Comfort adjustable stem retails most places for about $30, give or take a couple bucks. Available as a 1" quill stem this would seem to be the perfect compliment to an older bike in need of a new riding position. I chose this stem originally to give a better riding position to a mountain bike that was converted into an Xtracycle. I wouldn't wish this piece of junk on my worst enemy. All adjustable stems make a point to state they are not to be used for any type of heavy duty or extreme riding. I get it, no dirt jumps or riding downhill dual slalom at 50 mph. Makes sense. The major problem with this stem is it uses two separate pieces with teeth that engage a central piece of the stem. The two pieces engage with the the rotating, angle-changing bit of the stem if you will. Even at sedate bike commuter speeds on flat paved roads, this stem failed to deliver a problem free ride.
The inherent problem with this stem is that the two pieces that hold the stem at a specific angle are held in place only with a single bolt. The single bolt in itself is not the major problem, as pretty much all other major adjustable stem manufacturers use some variation of a single bolt to hold the angle. The problem is that the two toothed wedge pieces only engaged the pivoting section with two to three teeth each. It seems secure until you actually start pedaling a bike with one of these installed. No matter how much I tightened the stem down, I still felt the entire stem flexing up and down at the pivot. Once I disassembled the stem I saw what was causing the problem.
You can see the result of this flawed design. Because it only engages on a couple teeth per wedge, galling occurs at the interface between the teeth of the wedge and the pivoting section of the stem. You can never get this stem tight enough to prevent the joint moving and thus galling the teeth. I'm sure at some point if I continued using this stem, I'd be riding along and as I pulled on the bar while climbing a hill the stem would end up ripping loose to pivot freely. I immediately removed this stem and set it aside to be kept solely for illustrative purchases. This stem at this price point is utterly worthless and I would not recommend this to anyone.
If you're in need of an adjustable stem to use with a 1" quill stem frame, I'd recommend a quill stem adapter instead.
Quill stem adapters come in several different lengths and are available for use with both 1" and 1 1/8" threaded headsets. You can find various models of these adapters for anywhere from $7 to $20. You simply install the adapter and choose the 1 1/8" threadless stem of your choice, adjustable or otherwise.
Your second choice of adjustable stem is not quite as bad as the Zoom offering, but is still somewhat suspect. Kalloy makes some fairly decent mid-priced components. Their adjustable stem however, leaves a lot to be desired.
This stem retails most places for about $20. In design it is marginally better than the Zoom stem, primarily because it consists of two toothed wheels that clamp on either side of a pivoting center section. The toothed wheels are slightly better than the Zoom stem simply because there are more teeth engaged on both sides with the center section.
The toothed wheels that clamp on either side of the pivoting center section are thin in cross section and you can see that the teeth themselves are very shallow. I never installed this particular stem. Disassembling it after receiving it, I realized that this particular design was little better than the Zoom stem. There is certainly more surface area for the clamping force, but the single bolt holding everything together is both smaller than the one used in the Zoom stem and I feel that the teeth are simply too shallow to provide a secure clamping force. This one has gone into the spares box where it will likely donate its screws to more worthy attachments.
And so we return to that adjustable stem that came installed on my Scattante so many years ago. Bike shops often include these adjustable stems as a means of fitting inexpensive bikes to a variety of different body types and riding positions. For the reasons mentioned at the beginning of this article, adjustable stems can serve multiple purposes, and if you're going to invest in one, the Ritchey adjustable stem is well worth the money.
With the Ritchey adjustable stem, we take a major leap forward in terms of quality and subsequently price. The Ritchey stem is available anywhere from $40 to $50. This stem comes only in 1 1/8" threadless attachment style with two different clamp diameters, 31.8mm and 25.4mm. Both clamps sizes come in three different lengths, 80mm, 100mm, and 120mm all with the capability of rising as high as 45 degrees. What makes the Ritchey so much better than the stem designs from Kalloy and Zoom? It's all in how the pivoting section is designed.
The stem is composed of two major parts. The main part of the stem consists of the bar clamp and the extension of the stem proper, while the bit that clamps to the steerer tube is two separate parts joined by a stout central bolt that tightens the two sections around the pivoting area. What is different in the Ritchey stem is that you can't actually pivot the stem to change the angle. The entire stem must be disassembled, the angle chosen and then the whole thing must be bolted back together.
A close look reveals that the adjustable bit is a combination male/female set of 36 teeth. The tolerance of fit on these two toothed sections is so tight that it takes a few seconds of wiggling, and often muttered curses to get the toothed section to come apart so the angle can be adjusted. I've found over nearly 7000 miles that my original 120mm Ritchey stem has never creaked, never loosened, or otherwise given me cause to think it would give way and abruptly change angles on me at some inopportune moment. At some point, I finally purchased a solid stem at the appropriate angle for use on my daily commuter bike, and retired the Ritchey adjustable stem to my spares box to be used on future bike builds as necessary. I have since purchased an 80mm version for use with my latest bike build as I could not find any solid stems sporting a 45 degree angle with such a short length. I'm confident that my latest Ritchey adjustable stem will serve me well for thousands of miles to come.