So i'm fairly new to this forum, started lurking a few weeks ago before making an account and i would like to bring up a subject that always comes up, whether it be here, cycling videos on youtube, LBS websites and the likes. This is, as the title suggests, the question of speed differences between road bikes and mountain bikes. It seems that no matter how much it's avoided, the topic will eventually arise, and it only ever seems to rest in a way that always baffles me. For this reason, i'd like us to take a moment and think about the ACTUAL differences between road and mountain bikes, and how they relate to speed.
Firstly, I wish to address the notion that whenever comparing the two, the person involved on either bike is, for some reason, never good enough. What i mean is, people will always jump to the conclusion that it's not your bike that makes you faster, it's you. Well excuse my brief language but no ****, Sherlock. Yes, practise makes proficiency. Everyone vested in any hobby knows this. However, thats not the topic being questioned. I'm sick of seeing people respond to this, saying that it doesn't matter which you ride on, as long as you're riding. This is pure bs. I'm much faster on my 70's Huffy road bike then i am on my '13 29er, and i have numbers to back it up. On my 29er, my
PR on a segment i frequent was 2:04. Days after getting my road bike, and my first time doing that segment with it, i got it to 1:53. Clearly, the bike being used matters.
Next, i would like to discuss what makes a road bike definitely faster than a mountain bike. Now i'm no expert, far from it. I'm a novice cyclist with less than 2k miles under my belt who only recently found out what the word peloton means. Despite this, however, it seems to me that the
#1 thing that sets apart a mountain bike and road bike in terms of speed, is geometry. Mtb's are all laid back and relaxed, while road bikes are aggressive and straight forward, literally. Geometrically, the difference between a Specialized Demo and a Specialized Shiv is monumental. It's not just about being aero. In my experience, being in a more aggressive geometry has allowed me to put a huge difference of power down. On my 29er, i would be struggling on 2-5 sitting up right, but if i clung to the forks, i'd be zipping by on 3-7 with 80+ cadence no problem. The difference in ability was astounding and all i had to do was change my geometry.
Lastly, i'd like to talk about marginal gains. I'm no Team Sky advocate, but i'll be damned if their view on marginal gains isn't spot on. This idea that speed is solely dependent on the rider is constantly proven nonsense day in and out by people around the world when they try different things on their bike. It may be a new position, it may be lighter wheels or perhaps clipless pedals. People are always trying to upgrade their ride because they realize that many little things make a big difference. A ten dollar road bike from a garage sale shaved 11 seconds off a
PR on my favorite segment over my $200 mtb. Why? Geometry and the ability to effectively put more power down is one, but it's also marginal gains. A much lighter frame to push, much less rolling resistance, slightly more aero bike and available position. These small, marginal gains allowed for a big difference in results. Those 11 seconds might not seem like much over a 1 mile sprint, but taking advantage of those gains could lead to even more over a greater distance, leading to better speed. Thats the whole point here: going faster.
I realise that i've ranted a lot so far, so i'm going to put this into simple formulaic sense. X=rider at 145lbs Y= Strava segment, Z= 25<x lb 29er hardtail, Q= ~20lb crappy old road bike. So then:
X+Y+Z= 2:03
X+Y+Q= 1:53
This example is hardly scientific, but accurate. The mere change is bike adds gains. And when the question is achieving greater speeds, why is it that people always feel the need to fight gains? When Contador wins the TDF on a mountain bike, then we can say the bike doesn't matter. Until then, road bikes are faster than mountain bikes on the road, hence the ****ing classification.
TL;DR: A lot of little gains lead to big gains and if you think differently, you're not thinking right.
P.S I see one person saying it's the rider not the ride, and i will burn down an orphanage.