Getting the right gearing for you gravel bike is essential if you want to enjoy your off-road adventures.
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00:00There has been a trend in off-road riding in recent years, and that is a reduction in
00:04the number of chainrings on your bike and an increase in the size of the cassette.
00:09In this video, we're going to let you in on the five key things you need to know about
00:13gearing before choosing your gravel bike.
00:24To calculate the number of gears your bike have, you need to take the number of sprockets
00:28on your cassette and times it by the number of chainrings, which should mean that a two-by
00:33setup is instantly the winner.
00:35Yes, well, that's technically true that it does have more gears, but it's actually the
00:39ratio of the gears and the range of the gears that has the biggest impact on how it rides,
00:44and that will be a little bit different for on and off-road riding too.
00:48By range, we mean the spread in your gears, and the bigger your range, the smaller your
00:54smallest gear can be, and the bigger your biggest gear can be.
00:59For example, with a two-by setup, say with Shimano's GRX system, that can have a 48-tooth
01:05largest ring on the front and a 31-tooth smallest ring on the front, and it compare that with
01:10a 34-tooth cassette on the back.
01:13Those two chainrings on the front have a massive 17-tooth jump between them.
01:18That is huge.
01:19Now, this is similar to SRAM's AXS system, which can use a 43 and a 30-tooth chainring
01:24on the front, and pair that with the lowest gear of a 36-tooth sprocket.
01:28Now, these massive ranges of gears are particularly beneficial if you're planning on using your
01:33bike on both the tarmac, so a bit of road riding, but also if you plan to be winching
01:38yourself up off-road climbs laden with heavy bikepacking bags.
01:42Now, that's not to say that you can't get a really good range with one-by.
01:45Typically, on the front chainring, you might run something like a 38, 40, or 42-tooth chainring,
01:52and then on the back, you can get something like a 10- or 11-tooth to 42-tooth.
01:56However, increasingly popular is a mullet setup, so business at the front and party
02:01at the back, where you have typically a gravel-specific chainring setup, and then mountain biking
02:08specific equipment at the back in terms of your cassette and your rear mech.
02:12So, that could be anything up to a huge 10-to 50-tooth cassette, which is phenomenal for
02:18winching up the really steep stuff.
02:20Now, if you are running a cassette that large on the back with a one-by setup on the front,
02:25you are more likely to notice the jumps between the gears when you shift, and this can affect
02:30your cadence.
02:31Now, cadence is how comfortable it feels to pedal, so how quickly your legs are spinning
02:35and how easy it feels to move the bike along the trail.
02:38So, with a bigger cassette, all of the shifting is put at the rear, which this is offset if
02:44you use a two-by chainring because the bigger jump is at the front.
02:48So, that 17-tooth jump I spoke about, this allows you to then have much tighter spacing
02:53on the rear cassette, so you can have nice incremental gear changes of much smaller number
02:58of tees.
02:59Now, this is particularly useful if you live somewhere which isn't particularly hilly,
03:03or if it is hilly, there is a consistent gradient, so you don't need to be dunking loads of gears
03:08because you can just make nice little minute changes on the rear cassette, and it can be
03:12much more comfortable on your legs.
03:14However, if you're riding off-road and you have a one-by setup, you're less likely to
03:18notice these bigger shifts in the gearing because you tend to be going a lot slower,
03:22for example, if you're doing a technical climb.
03:30Now, what I really love about a one-by system is the simplicity of it.
03:33It's simply one lever to shift up and one lever to shift down.
03:37So, if you're guilty of cross-chaining when on the road with a double like me, it's really,
03:43really easy because you don't have to worry about making sure that you're in the middle
03:46of the cassette when you change the chainring, and if you're riding off-road, it's just one
03:50less thing to think about, and makes it super easy and simple.
04:00Now, among the many other benefits of one-by, it's also a bit lighter.
04:04You don't need a second chainring, a front mech, and all the other gubbins that comes
04:07with that.
04:08It's about 250 grams lighter.
04:09Yeah, but how can it be that light when you're also running that much bigger cassette?
04:13Ah, yeah, well, it's more aero.
04:15Says who?
04:16You're covered in mud and you've got your bike bags on.
04:18That's hardly aerodynamic.
04:19Okay, well, I just like how it looks.
04:22Yeah, fair enough.
04:24I do think it actually looks nicer than a double chainring.
04:32Now, lastly comes my favourite point, which is about reliability, especially if you're
04:36heading out into an area such as this, where you're quite remote from a good bike shop
04:41or some help.
04:42And that's because you don't have a front mech on the one-by system, it's just one less
04:45thing to go wrong.
04:46Now, there is a minor argument to make here that a two-by system is less wearing on the
04:53parts of your drivetrain.
04:54So, your chain is going to wear less because it's got a more efficient line, and your cassette
04:58is going to wear less as a result of that.
05:00But I will admit, it's a minor argument when you're riding off-road and you're riding in
05:05the rain and just really muddy trails, it's not going to make that much difference.
05:12So, there you go, the points for both one-by and two-by systems.
05:18Really depends on use case, but obviously go for a two-by setup.
05:21Absolutely one-by.
05:22Well, it looks like we're not going to come to a conclusion together, so why don't you
05:27let us know in the comment section below what you think.
05:29And in the meantime, don't forget to like and subscribe to the Cycling Weekly YouTube
05:33channel, and we'll see you again soon.