What is a Gravel Bike Part 4: Frame Material
WHICH GRAVEL BIKE FRAME MATERIAL TO CHOOSE?
We’ve talked about where gravel bikes fall in the wide range of bicycle options (What is a Gravel Bike Pt 1 and Pt 2) as well as an explainer on geometry … so now we are looking at what our bikes are made of. Both the geometry/fit of the bike and material are equally important … and there seems that there is as many options of material as there are types of bike. Current trend is carbon frames, which is incredibly clever stuff but there are also titanium, aluminum, steel frames … even wood gets a look in on the more ‘unique’ frames. Each of them have their advantages and disadvantages and quite often we will see mixes of materials on the one bike – most commonly a metal frame with a carbon fork.
- Steel – The OG: Years ago, steel was really your only option and it came in a wide variety of tube types that would use different tube diameters and thicknesses to provide a variety of ride feels. Steel never went away and recently, especially in the trekking/bikepacking world, it has seen a resurgence.
- A steel bike is going to be a lot heavier than any of the other materials but it will also be near bullet proof. You can load a steel bike up to the gunwhales with racks, bags and accessories and it will still ask for more. Steel bikes will also tend to be cheaper when comparing equivalent bikes in manufacturer’s ranges though that doesn’t mean all steel bikes are cheap – especially when you get into the beautifully lugged and painted examples from bespoke and custom frame builders.
- Aluminium (or aluminum if you prefer) – Steel’s Successor: Stepping up a price level, aluminium has been around in the bike industry since the ’70s and ’80s and offers the strength of steel but much lighter. Aluminimum tubing is an alloy and like steel, will come in a variety of tube shapes and diameters in order to tune the feel of the ride.
Aluminium frames are relatively easy to manufacture so are often seen as the gateway to performance cycling – lightweight but strong. However, they aren’t quite as bulletproof as steel and many riders will tell you that an aluminium frame is inherently stiffer than steel … which can be a bonus (super snappy handling) and a liability (harsh ride on particularly rough terrain).
- Carbon – The Upstart: Carbon is the current Wonder Kid of the cycling when it comes to performance and media hype. Carbon … or more correctly Carbon Fibre Reinforced Polymer … bikes are made of layers of resin impreganted carbon fibre sheets built up in layers to create a super light and tough bike frame. There are many ways that a carbon bike frame can be manufactured from simple CFRP tubes glued to carbon (or other material) lugs/joints through to the handlaid, monocoque frames that are essentially a one piece frame. Because it is built up in layers of fiber sheets, each manufacturer can control (through thickness, direction and cross-laying) the way each component will behave.
So you can have a bike that is very compian up and down (to make for a smoother ride) while being resistant to sideways forces (making it handle like a racecar). As it is a much more complex material to work with, carbon frames will likely be much more expensive than aluminium or steel however as manufacturing techniques improve, the relative prices are dropping.
- Titanium – The Pinnacle: Ahh titanium, the stealth ruler of the cycling frame roost. It’s light, strong, corrosion resistant, longer lasting and so beautiful to look at and ride. Titanium is an expensive amterial to start with and, for the very reasons it is so good as a frame material, it is difficult to shape and bend. Recent developments in 3D printing and CAD processing are making inroads into some of the more complex parts but it is still a much rarer material to see. However, the ride, responsiveness and (most improtantly) strength to weight ratio make this one of the most desirable frames to own. We quite often categorise these beauties as our ‘forever bikes’ – they’re a big investment but will likely last a lifetime.
So, how do you choose which material is right for you? Well, that’s going to come down to a number of key factors:
- Budget: Unless you are building up a bespoke bike, you are likely to be buying a complete bike, not just a frame. However the frame is at the core of your ride and everything else hangs off it so the trick is to look for how much bike can you get for the money and then you will usually be trading off frame material with components. It’s probably worth keeping in mind that the frame will likely be around for a long time and all the components get replaced or upgraded. Also keep in mind that higher quality frames in the same material may be worth the investment but get the lower level componentry so you can upgrade that later.
- Purpose: Are you a performance oriented weekend blaster? Maybe you are a multi-day gravel tourer lugging a small house worth of gear? Or, are you possibly someone who wants a mix between both these worlds so needs veratility to ride to work and the shops during the week, do the occasional weekend cruise and then load up all the gear for a few nights bike-packing through the Darling Downs? Each material is going to lend itself better to different uses so unless you can afford to separate bike for each purpose (the good old n+1 rule) then you will need to think about primary purpose and lead with that.
- Longevity: This is from the perspective of both how much riding you are going to do as well as how long you intend to keep the bike. A long distance tourer that is going to take a pounding, having more bolt points than you can point a spoke at while expected to carry a fair load will benefit from a solid steel frame. Whereas, a weekend blaster that gets ridden often on a mix of bitumen, smooth gravel and the occasional bit of single-track but not carrying the same type of load will likely be better served with aluminium or carbon.
A few examples to make it clearer:
- You wish to acquire a Gravel bike to discover the sport? Choose a Gravel bike with an aluminum or steel frame for a more affordable ride. You can always upgrade the components later but steel and aluminium are the entry into the sport.
- You have been riding road bikes for a few years and you want to discover the pleasure of riding on trails? Opt for a carbon frame. The rigidity of carbon will give you the same sensations as a road bike when climbing and a well designed carbon gravel bike will also provide compliance and performance through the rougher stuff.
- You’ve decided it’s time to treat yourself and invest in the longer term, durable and oh-so-silky forever bike that has multi-purpose capability then titanium might be the choice for you. You will likely be leaning to a more bespoke or custom experience where you define more of the componentry and build specs but, hey, this is it … isn’t it? 🙂
So, this is perhaps the most important part of your considerations and once you’ve researched all of that it’s time to pick your components – drivetrain, tyres, bars, wheels, saddle, seatpost … OK, that’s for another post.
Happy cycling
More information
Check out some of these sites for more information on how to compare the different materials:
- https://www.bikeexchange.com.au/blog/bike-frame-materials-explained
- https://www.rei.com/learn/expert-advice/bike-frame-materials.html
- https://bmcr.com.au/articles/best-bicycle-frame-material/
- https://www.bikeradar.com/advice/buyers-guides/bike-frame-materials
