The aluminum vs. steel question has been a staple of gatherings of mountain bike enthusiasts for years. Each metal has their enthusiasts who will argue for an entire day’s ride about why their choice is so much better than the alternative. In fact, both aluminum and steel mountain bike frames can be practical solutions, depending on an individual’s preferences and the type of riding they do.
Steel’s big selling point is its durability. A steel mountain bike frame should last a long time, through rough riding conditions. If you’re buying a bike that you want to last you for 20 years, steel gives you the best shot of getting there. Steel mountain bike frames tend to provide a smoother ride with fewer vibrations.
Of course, you’ll pay for that durability. Steel mountain bike frames tend to be more expensive than aluminum. That’s particularly true for newer, lighter models. A traditional steel frame is heavier than aluminum, and if you want an ultra-modern light steel frame that can compete in total grams, it’s going to be costly. Steel mountain bike frames also need to be maintained with greater care, as they will rust if chipped.
Aluminum mountain bike frames are generally lighter and cheaper. They often are stiffer and are easier to use as a climbing bike, though they are somewhat less comfortable (aluminum-carbon alloys are designed to alleviate that, but those are pricier). A longer ride on an aluminum bike that’s not well-fitted is going to create some soreness and fatigue, but its lightness makes it easier to transport. With a good suspension system — a must-have in any frame — an aluminum mountain bike frame can be perfectly comfortable.
Another asset in aluminum mountain bike frames is that they are easy to maintain. But one drawback is that they are somewhat less durable, both because the metal isn’t as strong and because it doesn’t flex very much. Extended wear, whether it’s a rough course or the repetition of extended rides, can cause the frame to break, and it’s very difficult to repair. Aluminum bike frames are cheaper, but if you ride a lot you will probably have to replace them more often.
Which one is better? That depends on who you ask. There are plenty of people who only ride steel mountain bike frames and look down on those who use aluminum and plenty who love their aluminum models and have no use for the steel. The best way to decide is to try out several models, make sure they are properly fit for maximum comfort, and then make a decision based on your riding preferences. Either way, be prepared to defend the choice at the next group ride.