The Philosophy of the Aluminum Bicycle Frame

A hardtail mountain bike.

(Photo credit: Wikipedia)

When I started in the bicycle industry, at a small bike shop, in 1996, aluminum was still and “exotic” frame material. Aluminum bikes were still coming in at around the $1000 price point. My first LBS bicycle, a Trek 7000 mountain bike, was aluminum. $1100 was paid for that, and it was the entry level aluminum mountain bike.

Fast forward to 2014 and you can get an aluminum mountain bike at Target for just about $200. Granted, it is no where near the level of the Trek 7000 I bought all those years ago, but it shows that the process of making aluminum into bicycle frames has gotten a lot less expensive.

After the break, we’ll dive into this do it all metal.

You’ve heard me mention ride quality before when I was talking about steel. Although aluminum is soft, especially when you’re bashing the crap out of soda cans and baseball bats, it is quite rigid in tube form, ideal for soda cans or baseball bats. This rigidity made for a better performing machine in terms of energy lost due to frame flex. Of course, this is hotly debated to this day, and technological advances in other materials make this argument even more heated. But back in the day, aluminum gave riders a lighter, more responsive frame. The downside to all this is that every road or off road imperfection was transmitted through the frame to the rider. Some tube manipulation was used to minimize this, but until hydro-forming was introduced, the tube shapes were rather normal; circular, oval, or square, depending on what the manufacturer wanted out of a particular tube set.

Hydro-forming, which uses hydraulic fluid and bladders (stop chuckling) to form aluminum into more complex tube shapes helped make aluminum what it is today. A good all around material that is light, and now a bit more comfortable than its ancestors. Just walk into a bicycle shop and you will see that the majority of bicycles are made from aluminum. Let’s list the pros and cons.

  • Lightweight. This goes without saying. Dollar for dollar, aluminum is the lighter metal. I say dollar for dollar because the more money you spend, the closer steel gets in weight.

  • Corrosion Resistant. Yes, resistant. Aluminum actually oxidizes. That white powdery substance you see on aluminum is its equivalent to rust. It gets worse in areas where the roads are salted and you ride in it. Look at aluminum rims that have seen year round commuter duty and you’ll get the picture.

  • Everywhere. I list this as a pro cautiously. This is because though the selection of bikes is plentiful, that selection also extends into department store bicycles, which I don’t recommend to anyone who is seriously taking up cycling.

  • Responsive. The stiffer frame enables stronger riders to put more energy into moving forward as opposed to making the frame flex. Again, this becomes a narrow margin based on how many dollars you spend.

  • There are no cons! That’s a joke.

  • Dents. Aluminum dents rather easily, when compared to steel. It doesn’t hurt anything except the resale value of the bicycle.

  • Fatigue Life. This is the favorite argument of aluminum haters. It is true that aluminum has a shorter fatigue life than steel. Remember this: Bicycle companies regularly test frames to failure in a cycle that would outlive everyone. Everyone except professional riders. Barely. I’m not going to say that aluminum never fails, there is a very small percentage that do, but when you consider the amount of bicycles manufactured at any one time, those are pretty good odds in your favor.

  • Stiff Ride. Though many companies have made huge advances in making frames more comfortable, aluminum is still going to be a stiffer ride when compared to steel. It’s nothing that anyone can’t get used to, but if your old bones complain, get ready for some constant nagging.

So there you have it. Just remember, the pros and cons aren’t meant to be all inclusive, but more educational so that when you walk into your LBS shopping for a bicycle, you won’t be overwhelmed by the sales person’s technobabble. Next up is carbon fiber!


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