How Much Slower Is A Gravel Bike?

The gravel bike, the one bike to do it all, and they are brilliant, but the question we all want to know the answer to is that if you ride a gravel bike, how much slower is it than a road bike? Crucially, will you be able to keep up with your mates who might be riding road bikes? How much harder are you making cycling? Today, I will answer that question. I have here an Orbea Terra gravel bike and an Orbea Orca road bike, which despite the decals on the forks, I have not stolen from the Lotto Destiny World Tour team. We're going to see firstly just how fast a gravel bike is compared to a road bike when ridden at the same power outputs on tarmac, but then we're going to see what happens if you swap out the wheels to give a gravel bike a road setup. Can we simply and quickly make a gravel bike as fast as a road bike? Swapping out wheels is very easy and relatively inexpensive, certainly compared to buying a new bike, but then even if it does become as fast, is that the only consideration? Is that what it's all about? Philosophy with GCN coming up soon. Let's dive in. The test is not rocket science, but I have the equipment, the bikes, and the time to do it. Basically, I'm going to do three runs on each setup at different intensities. This current one is a chilled intensity, 150 watts, gravel bike territory. Then I'm going to step up to 300 watts, see whether that additional velocity you get, actually you end up seeing more of a distance. Distance? See if you can end up seeing more of a difference. Then finally, someone has asked me to do 400 watts. I don't know what that's going to show other than my limitations, but anyway, we'll give it a go. This one's nice at least. Whose idea was this? Ow, it hurts, it hurts. Right, before I swap from gravel bike to road bike, let's quickly start to unpick some of the differences between the bikes that might help explain the results later on. The major one, of course, is the tires, but I'll come on to that in a bit. In terms of the actual frames and setup, road bikes can, of course, designed to be aerodynamic, certainly more expensive ones, but that can be quite significant, but then also not significant at the same time. It depends on your perspective. For a racer or someone who wants to go as fast as possible, it does make a measurable difference. For most of us though, that difference doesn't really matter. A far more importance to your efficiency is you and your position on the bike. Gravel bikes tend to make you a bit more upright for comfort and control, but that makes you less efficient at faster speeds. Effectively, you yourself are less aerodynamic. However, on these two bikes, that difference could be corrected really easily and relatively inexpensively simply by swapping these handlebars and this stem from this bike on to this bike. What is more significant between the two is the weight difference. Now, the Orca I've got here is ridiculously light. This Terra is pretty blooming light as well, but gravel bikes tend to have a little bit more material in them so they can be more robust, dealing with rough off-road tracks and general abuse and rock strikes and the like. That requires more material. In these two bikes, the difference is about 1.3 kilos. In percentage terms, that's not a great deal, not if we look at the bikes on their own, but if you include my weight as well, so we get a system weight. In this case, I don't think that's going to influence the results at all, although it would if I were to ride up an alp. My position on this bike is different to the one on the gravel bike. It's a little bit longer, but otherwise, when you just sat like this cruising along at 150 watts, it's a bit smoother on this beautiful tarmac. No vibrations coming from the nobbles on the tires, but still feels good. Now, the final test. I mentioned earlier that tires were the most significant difference between the two bikes. I think we will find out, but as you can see, I've just swapped the wheels from the Orca onto the Terra gravel bike. Now, road tires, of course, are designed to roll smoothly and efficiently on tarmac. They do not need to bite into mud and dust. They do not need tread, effectively, tread which slows you down. And the carcass of the tire also can be built differently because it doesn't need to withstand sharp rocks and the like. So that too, therefore, makes you faster. So I would imagine this is a significant difference. And one, it's been very quick to make because I have a second set of wheels. Now, I appreciate not everyone can afford that, but if you can, then it definitely makes life easier. Feels very smooth, feels very nice. Sat in the saddle going in a straight line, you cannot tell anything whatsoever. Oh, other than the fact that I'm not doing 150 watts. Come on then, here we go. Not in terms of the speed, really, but this now feels as smooth as a road bike. So it's interesting to know whether or not it's fast like a road bike. Okay, here we go. 400 watts, last one. It's a bit of blooming show something. Before we dive into the results though, I do want to talk about something that is even more important than speed because there is such a thing, right? If speed were the most important thing or going further for less effort because it's all tied together, we would be riding very different bikes than the ones we're on now. Now, yes, of course, budget is a factor because aerodynamic bikes do not come cheap, but all of us, I think, could afford clip-on time trial bars that would make us more aerodynamic. We could go further and faster for less effort, but very few of us choose to use them because performance is not the most important factor. And if we were to take aerodynamics to its logical conclusion, we would all be riding fully fed recumbents and even fewer of us choose to ride those. Although we do all know someone who takes it a little bit far. You maybe need a bit more speed. No, typically cycling is not about performance. Yes, we all want to make it easier on ourselves, but really, it's about emotion. It's about fun. It's about feeling. And I can't ever escape the fact that one of the joys of a road bike is that it's been tuned to be really, really good at one specific thing. It's like a poor man's sports car. Maybe not poor man these days, but compared to a Ferrari, it's still a sweet deal. What I mean, though, is that irrespective of the difference between these two bikes, they feel different. And that's not down to tires. That's down to the geometry of the bikes. The Orca is 52 millimeters shorter from front wheel to back wheel compared to the gravel bike, which makes it turn faster. Now, crucially, this isn't something you only feel when cornering. In order to balance on a bike, you're actually constantly turning it. So the difference is something you can feel all the time, but it's at its most apparent when climbing out of the saddle. You probably think I'm weird for putting so much emphasis on this, but it is really, really important because whilst agility and responsiveness of a bike doesn't actually make it faster, that agility and responsiveness just makes it feel more precise and sharper and it makes you feel like a climbing god, no matter what your power-to-weight ratio is. Now, more agile isn't better. Absolutely not. There is an art to bike design, but it's why for people who are used to riding a road bike, riding a gravel bike on the road, even with road tires on, just doesn't feel quite as good. Like, these differences are fairly nuanced, granted, and really, it's only completely apparent when you're riding out of the saddle, because certainly cornering and descending on a gravel bike on the road feel brilliant in a different way, but those moments of riding out of the saddle, they kind of add up. And so it's why, irrespective of the results I'm about to give you, for a dyed-in-the-wool road rider, getting on a gravel bike on the road just is going to feel slower. But it is results time now. You have waited patiently through GCN Does Philosophy. So, let's go for it. The gravel bike was, on average, two kilometers per hour slower than the road bike. Now, that difference was a little bit less at 150 watts, a little bit more at 400 watts, but there's your result. Now, in terms of that question about whether a gravel bike will make it harder to keep up with your mates, yes, I think clearly it will. But it's not a hugely significant difference. I guess it depends on your perspective. But to put it another way, if you were to tackle a 100-kilometer charity bike ride on a gravel bike, then you would probably find that it would take about, I don't know, 20 to 30 minutes longer than it would do on a road bike. However, what about the wheel swap? Well, the results here are slightly less clear, frustratingly. This experiment is, of course, open to errors, but we can still see that the gravel bike is definitely faster as a result, by about one to one and a half K an hour. Still not quite as fast as a road bike. It's obviously not all about the tires, but as we suggested earlier, your body position is important too. Now, again, as we said earlier, that's something you could correct if you wanted to change the handlebars and the stem, but then there's part of me that thinks, well, if you're going to make your gravel bike set up like a road bike, both in terms of position and also tires and wheels, is it still a gravel bike? I don't know. Let's stay away from philosophy again, shall we? Nevertheless, it's good to know that that option is there. Now, as for all that talk about feel earlier on, I'm sure there are many of you out there thinking that I'm even more pretentious than I usually am, but for others of you, I wonder whether perhaps that will resonate. I'd be super interested to hear your thoughts down in the comment section. Firstly, have the results surprised you? Is that more or less of a difference than you're expecting? What about when we flipped out the wheels? Then, would you be happy with that difference in feel? Get involved in the comment section down below. As I said, I'd be super interested to hear your thoughts. Please as well give the video a like if you've enjoyed it, and we'll see you on the next one.