Commuting, Racing, touring, mountain biking, road riding or just riding along... Non of these things have been able to avoid the great frame material debate. But what do they really mean? What are the real differences? Has this changed over time? Whelp, lets see if we can make more sense out of all this stuff...
Its one of the oldest frame materials out there, besides wood but that's a whole other blog post in itself. Due to its age it has had the most "tinkering" done as a material, starting out as your basic pulled from the ground steel it has undergone huge changes by the names of Reynolds, True Temper, Columbus, Ritchey and many others. They took this basic steel and added things to harden it, lighten it and stiffen it. In the beginning of the 1900s a frame could weigh upwards of ten pounds, now they can get down to just shy of 3.
Lets start stereotyping! Cause that's what happens when you talk in generals about a frame material. To start off we are going to talk about compliance... this can mean 2 different things, the feel from road vibrations (roads are made up of little rocks that will cause a vibration when riding) and impact (how it rides over larger cracks). This is really important actually, a bike can be incredibly smooth over vibrations but not flex enough to relive the rider of larger impacts. We will also talk about "stiffness" of the bikes. This simply refers to how well it deals with the rider's weight.
With that said, steel tends to be one of the most impact smooth rides AND takes care of vibrations better than most other materials. It also gives a little bit with the rider's weight, the stiffness does tend to be a little behind that of the other materials. This can be a good thing! It is also where "the feel of steel" comes from. It will give a little as you push on the cranks but pop back into alignment very quickly. This give can actually work to your advantage. Think of dancing of a cement floor (no give, super stiff) compared to a wood floor (more give and flex)... which one would you wanna polka on?
Steel has a great reputation in this department... It should! You can expect a frame to last as long as you want it too, its reparable, can be realigned (most of the time) and takes a lot to mess it up. This can vary though... If you have a super light steel frame don't expect it to be around for life, its how this works, it will have less material and be slightly more prone to dents, cracks and bending (sometimes depending on the mix it can be overly rigid and simply crack). It its a super heavy basic steel bike, usually older, it can be bent very easily. I can spread a frame on many 80s road bikes by hand to fit a wider rear hub into it. This means if you hop off a curb or take it off road you may end up with some issues. These are by no means an issue that you need to worry about with most manufacturers. Expect to ride your steel bike for decades. It can, however, rust. Its rare and most of the time its just a bit of surface rust (like on a steel bridge).
This has become the most common frame material that exists but please remember... this used to be exotic and amazing. Starting its life in Italy and Japan (B-Stone Radac and Alan) way back in the 80s the first bikes were some of the smoothest and most flexible bikes made. They were also not welded together but threaded into a lug. Its some crazy stuff! Then along came a man, a smart man, a man who went to MIT and loved bikes... He studied tube diameter and the differences it could make. Basically he made em fat with thin wall thicknesses. This changed how they rode and how light they could be. All through the 90s aluminum was used as the high-end race material. This gave it a pretty bad rap though... with manufacturers trying to make it as light as possible they had a lot of them brake. With the introduction of carbon and the ease of manufacturing aluminum it changed to the main stream in the late 90s. It is now one of the most reliable materials (manufactures have added at least a pound of material since the days of the 90s race bikes) and used by almost every company out there on bikes ranging from basic department store to several thousand dollar full suspension mountain bikes.
Aluminum tends to be one of the stiffest materials out there. This also means that its compliance is a little less than most. You will feel the road a tad more and feel the larger impacts to a higher degree. Out of the saddle climbing on an aluminum frame feels sturdy and fast. Many manufacturers are manipulating this material with shapes and wall thicknesses to achieve a ride quality that can actually be quite smooth and responsive. Giant is regarded as one of the leading aluminum frame manufactures because of this. It is why they have had so many awards for their aluminum road bikes.
Unfortunately aluminum is one of the only materials that can not be fixed if broken. It is also very difficult to straighten a frame that has been bent. The nice thing is it has become durable enough that this is no longer an issue. Aluminum does not rust at all but it does rot. It takes a long time but we have seen this on a few frames. By rot I mean it slowly deteriorates when exposed to extreme weather and toxins.
Carbon started its life with bikes in the 80s. Its most notable frame is the one used by Greg Lemond in the 1990 tour de France. Carbon did not go totally main stream till the late 90s. The biggest factor for this was price but also trust. Many of the earlier frames didn't have the longest life span. It was harder to produce with consistent results and so consumers took a while to trust the durability of carbon, especially when you are going to put so much money on the line. Since the 90s carbons reputation has slowly changed to being more durable. As production has gone up costs have gone down. Now, almost any bike over 2K is carbon.
Carbon has some of the most interesting ride qualities out there. You can usually "feel" the lighter weight of it and the stiffness of it can be even better than Aluminum. Its vibration damping characteristics can often make it even smoother than steel. One of the few downsides is that a carbon frame tends to be a little more impact feel than steel, many times it is very similar to aluminum. This just means that it takes up most of the road vibrations but you will feel it when you go over a larger crack in the road. Not really a big deal unless you ride on an older road.
It has been argued that carbon never wears out. This means that out of all the materials out there carbon is the least likely to change ride quality over time. The downside is because of its construction its a tad more likely to form a crack somewhere in its structure. This is why it took so long for carbon to catch on. These days its not as much of an issue but can still pop up from time to time. The plus side is it can be repaired! A talented frame manufacture like Appleman can take your cracked unusable frame into something almost better than new. Unlike steel, it can be repaired without injury to as much of the paint. He has repaired a BMC carbon frame for me and it looks amazing! With no repaint needed! On another positive note, carbon does not rust or rot. I keep saying it would make a spectacular winter bike!
Titanium Started showing its head around the bike industry in the mid 80s (this is getting a little repetitive). First with road then mtn. It spread like wildfire in the 90s due to its light weight, great ride and major durability. It had a slump in sales in the late 90s and early 00s due to the improvement in carbon and titanium's high price. We have seen an improvement in sales in the last 4-5 years. There are many reasons for this and most are simply speculation. I feel its because you can buy a titanium bike and actually grow old with it. You really don't need to worry about durability, weight, corrosion or ride change... it just goes.
Its amazing! It should be... its expensive and super durable. It will be as compliant if not more than steel in both vibration damping and impacts. It can also be almost as stiff as an aluminum or carbon frame (manufacturers usually don't bother making it as stiff as it can be). It really is a dream material... It will just cost you.
Just ride the thing! The only issue I have seen for durability is from the major manufacturer of it in the mid 90s. They made frames for many other companies as well. I have seen a few cracked welds but that is all... and that is totally repairable. For the most part you will see less problems with titanium than any other material out there AND you can leave it unpainted so you don't even have paint to get scratched.