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.
00:09So in this video we're going to let you in on the five key things you need to know about gearing
00:13before choosing your gravel bike.
00:24So to 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 setup
00:33is instantly the winner.
00:35Yeah well that's technically true that it does have more gears but it's actually the ratio of the gears
00:40and the range of the gears that has the biggest impact on how it rides and that will be a little
00:44bit different for on and off-road riding too.
00:47So by range we mean the spread in your gears and the bigger your range the smaller your smallest
00:55gear can be and the bigger your biggest gear can be. So for example with a two-by setup say with
01:01Shimano's GRX system that can have a 48 tooth largest ring on the front and a 31 tooth smallest
01:08ring on the front and it can pair that with a 34 tooth cassette on the back. Now those two chainrings
01:14on the front have a massive 17 tooth jump between them that is huge. Now this is similar to SRAM's
01:20AXS system which can use a 43 and a 30 tooth chainring on the front and pair that with the
01:25lowest gear of a 36 tooth sprocket. Now these massive ranges of gears are particularly beneficial
01:32if you're planning on using your bike on both the tarmac so a bit of road riding but also if you plan
01:37to be winching yourself up off-road climbs laden with heavy bike packing bags. Now that's not to say
01:43that you can't get a really good range with one by typically on the front chainring you might run
01:48something like a 38 40 or 42 tooth chainring and then on the back you can get something like a 10
01:54or 11 to 42. However increasingly popular is a mullet setup so business at the front and party at the back
02:02where you have typically a gravel specific chainring setup and then mountain biking specific equipment
02:09at the back in terms of your cassette and your rear mech so that could be anything up to a huge 10 to
02:1550 tooth cassette which is phenomenal for winching up the really steep stuff. Now if you are running a
02:21cassette that large on the back with a one by setup on the front you are more likely to notice the jumps
02:27between the gears when you shift and this can affect your cadence. Now cadence is how comfortable
02:32it feels to pedal so how quickly your legs are spinning and how how easy it feels to move the bike along the
02:38trail. So with a bigger cassette all of the shifting is put at the rear which this is offset if you use
02:44a two by chainring because the bigger jump is at the front remember that 17 tooth jump I spoke about
02:50this allows you to then have much tighter spacing on the rear cassette so you can have nice incremental
02:56gear changes of much smaller number of teeth. Now this is particularly useful if you live somewhere which
03:01isn't particularly hilly or if it is hilly they're of a consistent gradient so you don't need to be
03:07dunking loads of gears because you can just make nice little minute changes on the rear cassette and
03:12it can be much more comfortable on your legs. However if you're riding off-road and you have a one by setup
03:17you're less likely to notice these bigger shifts in the gearing because you tend to be going a lot
03:21slower for example if you're doing a technical climb. Now what I really love about a one by system is
03:32the simplicity of it it's simply one lever to shift up and one lever to shift down so if you're guilty
03:38of cross-chaining when on the road with a double like me it's really really easy because you don't
03:44have to worry about making sure that you're in the middle of the cassette when you change the chainring
03:48and if you're riding off-road it's just one less thing to think about and makes it super easy and simple.
03:53Now among the many other benefits of one by it's also a bit lighter you don't need a second chainring
04:05or front mech and all the other gubbins that comes with that it'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. Says who you're covered in mud and you've got your bike bags on
04:18that's hardly aerodynamic. Okay well I just like how it looks. Yeah fair enough I do think it
04:24actually looks nicer than a double chainring. Now lastly comes my favourite point which is about
04:34reliability especially if you're heading out into an area such as this where you're quite remote from
04:40a good bike shop or some help and that's because you don't have a front mech on the one by system it's
04:44just one less thing to go wrong. Now there is a minor argument to make here that a two by system
04:51is less wearing on the parts of your drivetrain so your chain is going to wear less because it's got
04:55a more efficient line and your cassette is going to wear less as a result of that but I will admit
05:02it's a minor argument when you're riding off-road and you're riding in the rain and just really muddy
05:07trails it's not going to make that much difference.
05:10So there you go the points for both one by and two by systems really depends on use case but
05:19obviously go for a two by setup. Absolutely one by. Well it looks like we're not going to come
05:25to a conclusion together so why don't you let us know in the comments section below what you think
05:29and in the meantime don't forget to like and subscribe to the Cycling Weekly YouTube channel
05:34and we'll see you again soon.