Stems

How to choose a BMX stem: The influence that a stem has over the geometry of a bike is often overlooked. Many people purchase new stems primarily on the aesthetic look, rather than sizing. Understanding the different variations in stems and how they will affect your bike will put you one step closer to the perfect setup.

Stem Types

Frontload Stems – On frontload stems, the front plate is removed to install the bars, and horizontal bolts clamp the bars in the stem.

Topload Stems – On topload stems, the top plate is removed to install the bars, and vertical (or near vertical) bolts usually clamp the bars in the stem. Due to the positioning of the clamp area, most topload stems position the bars slightly higher then frontload stems.

Materials

The majority of stems are machined from 6061 and 7075 aluminum. These two versions of aluminum are used due to their high strength and low weight. 7075 aluminum has a higher weight yield strength, but it is more prone to corrosion than 6061 aluminum.

Features

There are numerous sizes, clamping styles, and colors available, which means there are several factors to consider when choosing a new stem.

Stem Reach – A stem’s reach is measured from the center of the steerer tube (where the fork attaches to the stem), to the center of the handlebar clamping area. The greater the reach of a stem, the further your bars will be from the front end of your frame, essentially adding length to your bike. While the reach of a stem is usually personal preference, adding a stem with a slightly longer reach can be a good way to make a shorter frame feel less cramped.

Clamping Systems – Some stems do not rely entirely on the use of bolts to tighten forks and bars, but instead use internal wedges and hinge systems that tighten in multiple directions. Fewer bolts means more clamping surface area, and often results in a smaller, sleeker design.

Machining – The machining of a stem reduces weight by removing material in the areas that encounter the least stress. Machining can also give a stem a unique appearance that makes it stand out.

Hollow Bolts – Some companies are producing stems that use hollow bolts as an additional way to reduce weight. This weight reduction is achieved by removing the material out of the center of the bolt. Note that this can compromise strength to a degree.

How Much To Spend

When purchasing a stem you should be looking to spend between $40 and $90. Less expensive stems will use simple designs with less machining, which results in more weight. Mid-range stems between $50-$70 will be machined and come in more size and color options. The most expensive $60-$90 range stems will use the highest quality materials, feature extensive machining, and commonly have unique clamping designs. In terms of mechanical function, stems are quite simple, which means even the lower priced stems can work quite well. When planning a stem upgrade, consider the weight savings and gains from improved design as an investment into your bike.

Things To Look For

The first thing to keep in mind when choosing a new stem is the position of your bars. If you prefer to ride your bars higher, a topload stem will be the ideal choice due to its higher clamping area. The same level of importance should be placed on choosing the reach of a stem. Riding a longer stem will create more leverage over the front end of your bike, by increasing the distance between the centerline of your bars and your fork. At the same time, a longer distance can cause a bike to feel sluggish when spinning and turning, which may be an issue for some riders. If a quick and responsive setup is important, a shorter stem reach will be the better choice.

The amount of machining in a stem depends entirely on aesthetic appeal. Just because a stem has a lot of holes in it doesn’t make it weaker. Material can be removed in unneeded areas to reduce weight without weakening the stem.

Product Reviews

Before buying, be sure to do your research and read product reviews. Reviews are a great way to find out specifics about a particular model, user impressions, and things to watch out for. After you’ve purchased a product and had enough time to thoroughly test it, we encourage you to leave a review for other people to see when they are researching bikes and parts on the web.

We hope you’ve found this information to be helpful. If you have a question that isn’t answered in this guide, our BMX forums are a great place to get advice from knowledgeable riders. Your local bike shop is also a great resource.

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