Fun fact of the day: The world's first bikes were built in 1817 out of wood.
To say we've come a long way would be the cycling understatement of the century (including the late 19th Century once people realized lumber "boneshakers" were less than adequate). Today's frames are obviously far more comfortable and durable than their predecessors, ranging from steel and aluminum to space-age carbon fiber and titanium.
It may be tempting to shop for one of these newer, high-end bikes in pursuit of that elusive Parent of the Year award, but let's pump the brakes first. Before you go splurging on something that would survive atmospheric re-entry, take a few minutes to read on and learn more about the underlying pros and cons of each material. You may find that you don't need to skip a mortgage payment just to buy your kids wheels they'll love and match their needs perfectly.
Steel Bike Frames
STEEL. It just exudes strength and confidence, doesn't it? After all, last time we checked, Clark Kent's alter ego was the "Man of Steel," not the "Man of Titanium Carbide." Steel is one of the most common bike-frame materials on the market. Never mind that it was the only bike-frame material on the market for decades, there's a reason it's so popular. In fact, there are several reasons, but they all need to be weighed against steel's downsides. Let's examine.
Steel Bike Frame Pros
Bikes using steel—specifically chromoly rather than its cheaper high-tensile counterpart used in low-end department store bikes—are quite strong. And their strength-to-weight ratio can be adjusted during the manufacturing process through what's known as "butting." Whereas straight gauge tubes have uniform thickness, single-, double-, or triple-butted tubes do not. Their welded ends are thicker than their centers, reinforcing or lightening them as necessary. The result is a muscular piece of equipment.
It also leads to a smooth ride. Steel's springy quality mitigates the roughness of bumpy roads, making long rides more comfortable for your hands and legs. This also makes it easier to find a nice climbing rhythm when pedaling through hilly areas.
Hand in hand with strength is steel's durability. You can knock these guys around and they'll keep coming back for more. Combine this with the inexpensive price tag relative to some other materials and easier repairs over the long haul and you can get some great value out of steel-framed bikes.
Steel Bike Frame Cons
Before you get carried away with the grunting and chest beating over steel's affordable strength and toughness, keep in mind that these traits come with a non-monetary cost: weight. Compared to other materials, steel is heavy. This might not be an issue for burly grownups, but for less physically-developed tykes it may come into play. And it's certainly a factor for any sort of competitive racing.
The other thing to keep in mind is corrosion. Wet or wintry climates in particular could rust steel frames more quickly than drier ones. This is not to say you can't clean and take care of your bike, but you do typically need to pay more attention to regular maintenance with this option.
Aluminum Bike Frames
Aluminum—or "aluminium" for our British buddies—has overtaken steel as the most common frame material on the roads and trails today. Its popularity is due to both its specific metallic properties and frugal price point. That said, shelf-life may be an issue for aluminum bikes (think Coke can versus steel drum). We'll look at both sides of the coin.
Aluminum Bike Frame Pros
Aluminum is associated with two primary characteristics: light and stiff. This is great if you're looking for a fast ride, but too light and you risk strength. That's why the aluminum in bikes is alloyed with other metals. This keeps the weight and density of the material down while stiffening the overall frame. Like steel, aluminum tubes can be butted to optimize strength.
Unsurprisingly, these features are preferred by many racers. Road bikers of all ages enjoy the improved performance over steel options. Mountain biking fans also appreciate what aluminum can do out on single track. Its ability to be formed into different shapes feeds nicely into full-suspension MTBs, and the strength-to-weight ratio makes it easier to take on steep slopes.
Unlike their more advanced carbon fiber and titanium cousins, aluminum bikes are pretty easy to manufacture. Cutting down on the time and expertise necessary to build bikes also happily cuts down on their cost. This is great if you're not looking to tackle the Alps any time soon.
Aluminum Bike Frame Cons
In biking, as in life, there's no free lunch. If you're looking for light and inexpensive, you're facing a tradeoff somewhere. In this case, it's durability. Aluminum simply fatigues more quickly than other materials. This is true with both long-term wear and tear as well as individual wrecks or accidents. Since it's extremely difficult to manipulate aluminum back into its original shape, even seemingly small dings and dents can challenge your nearest mechanic.
Aluminum has also gained a bit of a reputation for harsh ride quality. It's all relative, but other materials like steel tend to do a better job in cutting down on vibration transfer to the rider over bumpy surfaces. That said, newer aluminum technologies have done a nice job in turning this corner.
Carbon Fiber Bike Frames
If we take a brief detour from the metal family, we run straight into carbon fiber. Without going all engineer on you, carbon fibers are thinner than strands of hair. Once woven into hundreds of layered sheets, resin is added to glue everything together. This gives you a reinforced, inflexible composite material that's great for things like, say, bikes. How great? You be the judge.
Carbon Fiber Bike Frame Pros
Of our four options, carbon fiber is the lightest and stiffest (even more than aluminum). Because of its slight flex followed by progressive tightening, this is the preferred material for many sprinters and climbers. In fact, every Tour de France winner in the last 20 years has sported a carbon fiber bike. From the pro peloton to top-tier triathlons, this is the stuff you're going to find the serious racers piloting.
Much of this has to do with the versatility carbon fiber offers during the manufacturing process. Designers aren't limited by tube shape, meaning they can tailor the structure in all kinds of ways. Carbon can be layered in different angles and directions to produce various degrees of strength and stiffness-to-weight ratios. It also allows bike makers to maximize aerodynamics, an obvious plus when you're talking about high-speed competition.
Carbon Fiber Bike Frame Cons
From a construction standpoint, this guy's chief downfall is durability. When it was first introduced on bikes, carbon composites were somewhat mediocre, and inconsistencies in manufacturing methods resulted in frame cracks and failures. But, bicycle brands learned from their mistakes, and these early issues have been virtually eliminated.
Of course, nothing's perfect. Because of its rigidity, carbon fiber can still be compromised under excessive stress. Unfortunately, this kind of damage isn't always clearly visible. A carbon fiber bike with weakened structural integrity is fragile, so it must be carefully inspected after any sort of collision to avoid the dangers of complete failure while in motion.
By the way, this is not our attempt to freak you out, parents! Carbon fiber is an excellent choice for bikes. Just be careful about what you're buying since not all frames are created equal (to the point that many brands even use different names for their own carbon fiber terminology). Quality is based on things like how the raw material is heated and layered and what resin is used to make the composite product. Consequently, performance ranges widely between cheap and expensive bikes. Prices do, too, but luckily these have been dropping steadily for higher-end models.
Titanium Bike Frames
If steel frames are the Incredible Hulk of the bike world, titanium frames are the Superman: lighter and stronger (we can debate each hero's bench press in another post, Marvel fans, but right now just go with the analogy). Of course, Superman comes with a super premium, which makes titanium one of the rarer frame materials on the circuit. Let's go ahead and profile one of the biggest rock stars on the periodic table.
Titanium Bike Frame Pros
Like we said, very light and ridiculously strong. Similar to aluminum, bike titanium is actually an alloy that includes a dash of other metals such as aluminum (go figure) and vanadium. This not only gives the frame strength, it also makes for one smooth trip. Titanium frames are renowned for their bump-absorption over splotchy terrain.
At least when it comes to the frame, titanium bikes are practically indestructible (but please don't test this out at home). Not only do they hold up extraordinarily well against wear and tear, but their anti-corrosive properties help brush off water, road salt, and other elements that wreak havoc on alternative materials.
Because titanium bikes last so long if well cared for, most brands offer lifetime warranties against manufacturing defects. If nothing else, this is certainly a nice way to justify the up-front investment.
Titanium Bike Frame Cons
Okay, let's plow through this quickly because there aren't many. And they're all concentrated around the cash register. Why? Raw titanium is expensive. Construction is labor intensive. Significant expertise is needed. Availability is typically limited to boutique or custom shops. Repair is challenging.
See where we're going with this? Be prepared to shell out for a titanium body.
What This Means for Your Kids' Frames
If you're looking for a formula for finding the best frame for your little one, sorry, we can't help. We would love to, it just doesn't exist. Riding style, size, climate, experience, budget, and other individual considerations all play into a decision like this.
On the other hand, we can break down the previous 1,600 words into a more manageable set of quick-reference guidelines to support your search.
- Steel: Strong and smooth. Buy steel if you're looking for durability and don't mind the extra weight. These are great for casual and touring cyclists once they get a little older.
- Aluminum: Light and inexpensive. Buy aluminum if weight is an issue or if your kid is becoming more involved in a specialized sport that requires stronger performance than steel.
- Carbon Fiber: Stiff and ultralight. Buy carbon fiber if you've become a regular parent on the competitive racing scene and you can stomach the higher price tag.
- Titanium: Powerful and durable. Quite simply, buy titanium if your child is a serious cycler and you want it to be the last one you purchase for a while. Or ever.
Good luck on the bike hunt! And remember, young rider styles, tastes, and sizes can all change over time. If Jenny and Johnny decide to ditch their aluminum MTBs for carbon fiber roadies, keep your eyes peeled for ways to recycle your unused bikes so the next generation can enjoy them!