Modern mountain bikes are incredibly capable off-road. Should this be owed to the geometry advancements or better components? Let’s take a look.
A couple of years ago Enduro MTB Magazine did a group test of 10 enduro bikes raced by the likes of Jack Moir, Richie Rude, and other world class athletes. They noted that a lot of the pro riders were opting for bikes that were around 10-20mm shorter in reach than the current trends would suggest them to be riding. Despite this, the bikes were still very composed in rough terrain and they owed this to their high quality suspension. This raises the question: Which is more important, geometry or suspension?
The evolution of mountain bike design
The last decade or so of mountain biking has seen brilliant advancements in the way bikes are designed. But not only that, the components that form part of the whole mountain bike system have evolved as well. The result of these advancements is that mountain bikes are now more stable and capable off-road than they have ever been.
A lot of people attribute this to the geometry changes that mountain bike frames have undergone; namely longer reach, longer wheelbases, slacker head angles, and (more recently) longer chainstays. We must note alongside this that brakes have gotten more powerful, dropper seatposts have become mainstream and increased in typical travel, tires have gotten bigger and offer more grip, wheels are stronger, handlebars wider and so on.
Suspension technology? Well that has also had huge advancements. We are riding bikes now with highly effective suspension systems that offer more travel, on average, to what was ridden previously. The latest mountain bike suspension systems pedal very efficiently even without a lockout and are able to isolate trail chatter and big hits superbly, reliably generating traction in tricky conditions.
So let’s break things down a bit so we can contrast what geometry brings to the party with what suspension has to offer. These are what, I would say, are the two most significant contributors to a bike’s off-road capabilities.
What good geometry does for you.
The way I see it, good geometry (in terms of what it has to offer in regard to making a bike feel capable off-road) offers your body a stable platform with which to interact with the bike. It does this by naturally putting you in a central position between the wheels and having you sit nice and low in the bike. This type of platform inspires confidence on the bike in rough terrain and is largely why modern cross country bikes are so much more capable than their ancestors even though their suspension travel has only changed by a cm or 2 (if at all in some cases).
The particular geometry factors contributing to this are a long reach (ideally paired with an appropriately matched chainstay length) and a low BB height. I will note that wider handlebars also contribute to this stable platform. You can see the chart below for a reference of the terms.
So even if you have a short travel bike and get into some sticky situations on a technical descent, if your bike has up-to-date geometry you should find that you still feel balanced on top of the bike and able to give positive inputs to control it. With a shorter reach and higher BB you are more likely to feel unstable as the bike bucks and jerks around underneath you. Now, let’s get into suspension.
What good suspension does for you
The suspension on your bike serves two main purposes. The first is to maximise traction by keeping the tires in contact with the ground. The second is to keep the bike stable and dampen impacts between the ground and the rider. World class suspension is only going to be useful if you’ve taken the time to set it up for your riding weight and style, if you’re not sure about that process you can follow our simple suspension setup guide here.
In terms of what suspension does in relation to geometry, good suspension will keep your bike stable underneath you and easier to control. Take the previous example, you are descending and enter into a rough and rowdy section of trail. If you have generous travel on your bike’s suspension (say 140mm+ as most trail bikes would commonly have now) the bike will be more settled and less likely to buck you all over the place. You won’t necessarily “need” that wide, long, and low geometry platform to feel in control. Make sense?
Good suspension keeps your bike settled underneath you, allowing you to make the inputs that you need unflustered by the trail feedback. This becomes more and more noticeable the faster that you ride.
So then. Which is more important?
While this is subjective and will vary depending on the rider preference, I would argue in favour of suspension, for my purposes at least. With a good suspension setup on your bike and a fair amount of travel, you can feel confident going fast on technical terrain because the bike isn’t wanting to throw you off. There always comes a limit though and that is where a stable platform for your body (provided by good geometry) steps in.
The ideal, of course, is to have both a good suspension setup and an optimal geometry working in unison; the suspension keeping your bike stable underneath you while the geometry offers a solid interface through which you give inputs to the bike.
As for the drawbacks of too much of either? The longer, lower, and wider you go with geometry the more cumbersome the bike becomes. This is why those enduro pros referenced at the beginning of the article tend to opt for bikes with a shorter reach, this makes them more responsive to steering and other inputs. Too much suspension? Well you lose your connection to the trail which isn’t that fun if you like to get some feedback when riding. When pumping for speed you may also not find you can generate much acceleration as your energy is lost in the travel. I think I’d personally rather be ‘over biked’ with suspension than geometry though.
One takeaway that I think is fair from this discussion is that for less experienced or skilled riders, good geometry is going to have a greater positive impact on your technical riding. This is largely due to the speed factor that makes the benefits of greater suspension more apparent. If you aren’t intent on finding maximum speed, opt for geometry. If you want to hit gnarly trails at mach 10, go for long travel and good quality suspension. Or, as with most modern trail bikes, go for both!
Hopefully this little geek-out session gave you some food for thought or clarified up some concepts around geometry and suspension in your mind. If there are any other topics that you’d like us to discuss, let us know on our social media and we’ll be sure to dive right in!