Gravel Bikes: Why should you have this bike?
Maybe not all of us are aware of the existence of a gravel bike, what is it, for what, for whom? In this article, we will take a deeper look at gravel bikes.
The more we see, racing bikes with disc brakes, or racing bikes taken to dirt/offroad roads, chances are that what we see is not a racing bike, but a gravel bike. Have you ever cycled with a road bike, wanted to enter the rock/dirt road but were hesitating? Maybe this gravel bike is right for you.
Gravel bicycles when translated directly means bicycles for gravel roads. Gravel / gravel is a small rock, the result of the fragmentation of large rocks both geologically and artificially, with a size of 2mm to 63mm. In Indonesia, this gravel road is also known as macadam road, a road that is sometimes smoothed again with sand/soil or gravel. It’s not hard to find a road like this, and that’s where the gravel bike or gravel bike is intended.
Ordinary racing bikes are certainly not very comfortable when used on off-road types like the ones above. So that racing bicycles must be modified in some of their components to make them more comfortable and efficient on offroad roads, so that they become gravel bikes. The offroad road in question is not a road with bumpy and extreme boulders, but a rocky/dirty road that is still in the flat category. but what is the difference between a gravel bike and a hybrid bike?
Gravel bike vs Hybrid bike
Hybrid bicycle (hybrid bike) is also a bicycle that combines a racing bicycle with a mountain bike. Then, what is the difference between a hybrid bike and a gravel bike?
In appearance, hybrid bikes are more likely to look like mountain bikes (MTB), because they use straight handlebars, and some also use bicycle suspension. Gravel bikes look more like racing bikes, because they use drop handlebars (curved downwards), and most don’t use shock absorbers.
Read on below to see what makes gravel bikes different from race bikes, mountain bikes, and hybrid bikes. Racing bikes, which are cheap or expensive, use more rim brakes than disc brakes, while gravel bikes almost all use disc brakes.
Gravel Bicycle vs Cyclocross
In appearance, cyclocross bikes and gravel bikes may be the same. But there are actually a few different little details on the bike. In principle, cyclocross is maximized for cyclocross bicycle races (a special bicycle race that combines onroad and offroad), so it focuses more on speed than comfort. While gravel bikes, not for racing but more for adventure, trying new sensations, but also not forgetting the speed but also the comfort of cycling.
The geometry of a cyclocross bike is more racing, generally a cyclocross race lasts 2 hours, so the body position is maximized to spur the bike, such as a shorter chainstay and wheelbase. The geometry of gravel bikes is not as aerodynamic as racing bikes, the body position is more upright in order to get better vision on dirt roads that have more dynamic obstacles than asphalt roads. Other things, such as the width of tires on cyclocross bicycles, elite cross racers (following UCI regulations) are limited to 33 mm in width. While on modern gravel bikes, the tire clearance is at least 40mm. By using wider tires, air pressure can be reduced, so the bike feels softer.
What makes gravel bikes different
Gravel bikes also allow the use and combination of various components such as race bikes, 700C thin tires, thick 650B, or large 29″, single chainring or double chainring, some use a super light frame or some are super strong.
In the gravel bike segment, anything is possible and manufacturers use terms like adventure bikes, monster cross, all-road, road plus in their product portfolio. These terms want to define the special character of each bicycle and identify their field of application which differs from other bicycles. But all gravel bikes are designed with the same thing in mind: fast all-terrain cycling. And of course, there’s a wide range of uses for each particular bike option.
Light and fast
Wherever you go
Another interesting reason to use a gravel bike. Light dirt and offroad trails may be boring if passed by mountain bike. But with gravel bikes, hitting the road at high speed is a pleasure in itself. Except for roads that are not for vehicles, the exploration limit of this gravel bike is only your knees and guts. Even if just crossing a ditch, small river, or a short obstacle, a gravel bike can be lifted. For leading brands, they usually weigh only 7-9 kilograms (carbon, titanium, aluminum), some made of steel can reach up to 11 kilograms.
Enjoy the bike and the atmosphere
The most important and principal part of gravel bikes and other types of bikes, they are about fun and enjoyment, not just about performance. Of course everyone has a different view on this, gravel bikes are not about pushing the bike as hard as you can, sprinting and chasing all the bikes in front, gravel bikes are about the spirit of adventure, enjoying a different atmosphere in a new way. Not to do 250km on a Strava, but to enjoy and narrate your 3 hours of adventure on roads not traveled by everyone, that’s the interesting part of gravel bikes.
Category Gravel Bikes
In appearance the gravel bike looks more like a muscular racing bike, and feels somewhat similar to the XC (Cross Country) mountain bike. But the influence of the components on a gravel bike will create a bike with different specialties. There are two main categories in gravel bikes, namely:
• Backroad Gravel-bikes
This gravel bike looks very similar to a road bike, and is the most widely circulated on the market. The weight of this bicycle is usually quite light and agile, and the geometric shape of the bicycle frame takes the form of a classic or endurance racing bicycle. Most use tires measuring 700C, with a width of 40C, and tire tread without a profile. This bike is designed for more dominant areas on asphalt (tarmac), gravel, compared to dirt roads or dusty roads.
• Adventure Gravel-bikes
In the gravel adventure bike category, the influence of mountain bike style is more pronounced. By using tires with a more aggressive profile, with widths ranging from 1.9″ to 2.1″, combined with 27.5″ or 29″ wheels. This gravel bike prioritizes performance on off-road roads, from adventuring on village roads to touring on off-road roads.
Even so, this bike is much faster than a mountain bike on asphalt roads, macadam roads or ordinary dirt roads. There are some that have the added feature of a special place for the placement of bicycle bags, racks, panniers, and so on.
Gravel bike sizing system is not much different from racing bikes. If we use a racing bike with a size of 54 cm, then a suitable gravel bike is in the same size. Some gravel bikes also wear sizes XS-S-M-L-XL, or are limited to a few sizes. Cycling on both onroad and offroad roads will actually make a body position that will not stay in one place, will definitely change along the way.
So for the size of the bike, it doesn’t really matter as long as it’s not too small or too big. If the most comfortable ideal position is between two bicycle sizes, choose the bigger one if you are going to cycle more often for long/long trips, so that the body can be more relaxed, and can load things if you have a lot of luggage. But if the bike is more often used for short and fast trips, it is better to take a smaller bike size.
The adventure type gravel bike comes with a gentler head angle, and the handlebars are firmer and stronger, thus increasing confidence on hilly roads.
The gravel bike is a special bicycle because it combines the advantages of a racing bicycle with the advantages of a mountain bike, by using a combination of components and designs of both, so that we get an amphibious bicycle, effective on asphalt roads but also tough on dirt roads.
Bike frame material
Just like other bicycles, gravel bikes are also available in a wide selection of bicycle frame base materials. Even so, the use of aluminum frames is not as much as frames made of carbon or steel (steel). Titanium is also used on high-end gravel bikes.
Aluminum frames are a simple and inexpensive frame material to manufacture. Although not as strong as carbon, it has a similar level of rigidity. On a race bike, the rigidity of the aluminum frame may not be as noticeable, but on a gravel bike it will be a problem. Combined with a carbon fork, and using an aluminum alloy (alloy) will increase the performance of a gravel bike, it can be an option for a frame with a fairly cheap price.
The weight-to-strength ratio of carbon material is extraordinary, to get the same strength or even stronger than alloy material, carbon material requires less material, which makes it much lighter than alloy material with greater strength. The carbon frame molding process is also easier to customize, making complex bike designs easier to obtain. Such as making flexible shapes with different thicknesses of bicycle frames, bottom brackets that are heavier or stronger, can be well customized on carbon bicycle frame molding.
The disadvantage of carbon material is that the cracks in the frame will not be seen immediately, because carbon material cannot bend but breaks immediately, although it does require very strong pressure or slamming to break the carbon material. Repairing also requires special bicycle skills and equipment which is more expensive than straightening a bent aluminum frame.
Manufacturers or carbon frame makers must also be skilled and experienced to get a carbon frame that is truly maximal in strength.
Steel is very tough. However, the damping quality, weight, resistance, and stiffness depend on the type of tube and the combination of mixed materials. From cheap alloys, thick and sturdy CrMo tubes, to the thin and elegant Reynolds 953 or Columbus XCr. All available according to the desired price. Bikes from larger manufacturers usually have stronger, heavier tubing with thicker off-road tires.
Titanium is usually the most expensive material we can buy. Titanium bicycle frames look very sleek and offer a number of advantages that have made them so popular. Titanium is lighter than steel, just as strong and offers better damping qualities – and unlike steel, titanium is anti-rust/corrosion.
The geometry of a gravel bike makes for a more relaxed riding position and style than a race bike. The head tube is higher and the head tube angle is gentler for more relaxed steering and control, but at the same time sacrificing responsiveness compared to race bikes. The bottom bracket will usually be slightly lower than a cyclo-cross bike. Gravel bikes are also designed with a longer wheelbase, making them more stable on roads and when riding on uneven surfaces, and providing extra stability and comfort over long distances.
The angled top tube makes it easier for the bike to stand on the bike, which is useful when getting off the bike.
Gravel Bicycle Tires
The concept of tires, both tire size, material, profile and tread, on a bicycle will affect three things, namely speed, grip and comfort. There is no perfect bicycle tire that can get a perfect score for all three things, one must be sacrificed to increase the value of the other. Expensive tires may be a better value for one or two, but won’t be perfect for all three of the above.
Gravel bicycle tires are different from racing bicycle tires, although they have the same size, but the material, tread and width used are more aggressive, approaching the character of mountain bikes.
Is a classic size for racing bikes, which are also found on gravel bikes. Wheels and tires with a size of 700C are usually combined with a width of 28mm to 40mm. There are some gravel bikes as well that use wider tires on the 700C but with a special tread too. Somewhat similar to cyclocross bicycle tires, the profile tread of gravel bicycle tires does not have long and aggressive knobs, but rather a flat and square or slot pattern with wider center spacing and lugs. The 700C bicycle tire has less rolling resistance, and it is easier to accelerate on straights and corners. Generally 700C tires require an air pressure of 2.5 to 4 bar depending on the type of tire and the area to be traveled.
Often referred to as “road plus”, these tires have a slight profile with a width of between 42mm to 50mm. So far, not too many gravel bikes cursing 650B tires. These tires generally have a higher thread count (TPI), greater volume, and provide a more supple feel. Thanks to the higher volume, lower air pressure and wider contact area, the 650B tires absorb vibrations and pressure very well – thus keeping speed on rough terrain better than the narrower models. Smaller wheels / tires will also affect the speed of the bicycle, because the distance traveled on one revolution of the smaller wheel will be shorter than the larger wheel. So that at the same Cadence (number of pedal cycles per unit time), the 650B wheel distance will be shorter than the 700C wheel.
The 650B tires offer a high level of comfort on rough asphalt roads and rough trails, but lack grip on muddy forest soil or wet soil/grass, where the thinner 700C model can cut through soft soil layers. 650B tires typically require air pressure between 2 and 3 bar and are very sensitive to pressure changes, even small ones.
The ideal tire pressure on asphalt roads usually becomes excessive for rocky roads, and the optimal air pressure on rocky paths is often too low for asphalt roads. There is no other way than to adjust/change the air pressure according to the terrain, to get maximum performance in a certain area. As the development of gravel bikes continues to increase, the selection of 650B tires also continues to grow and provides a viable alternative to the 700C model. On some bikes, we can convert 700C tires to 650B or vice versa.
The size of this tire is very identical to that of a mountain bike. When used on gravel bikes, the width is usually between 1.9″ and 2.2″ and even wider. While the profile, weight, and puncture resistance of these tires are a bit poor by mountain bike standards, but with specific settings for gravel bikes they allow for a significant increase in off-road capability, at the expense of speed and rolling resistance on smooth surfaces.
Bikes with this type of tire are often designed for adventure and offer the best combination of speed, comfort and safety on unpaved terrain while remaining fast on asphalt roads.
Almost all tires and rims that we find on gravel bikes today are tubeless-ready. The advantages are numerous: stronger leak resistance, increased flexibility and better grip, and slightly lower rotational mass. Tubeless installation can also reduce rolling resistance by up to 10%. We recommend bringing a spare inner tube on offroad adventures. Depending on the type of tire and the extent of the damage, a tire patch kit can also make it easier to fix tubeless bicycle tire leaks. Since heat, oxygen and even mechanical influences can cause the sealant to dry out, it is important to regularly check the sealant level on the tubeless tires and increase it when it is lacking.
The size of the bicycle tire is usually closely related to the size of the bicycle frame. But on the tire tread, we can choose various types of tire treads that will affect the performance of the bike. Which bicycle tire tread is best for gravel bikes? The answer depends on the suitability of the cycling area and the destination we want.
Different tread patterns will affect speed, grip, strength and comfort. In general, gravel bike treads prioritize speed, both on offroad and offroad roads. So that it is more similar to the tread of a racing bicycle tire, but with more prominent studs (rubber teeth). To make the bike go faster, the center stud pattern will be tighter and the studs much lower than the side studs. Racing bicycle tires usually do not have side studs, but because gravel bikes will be used on offroad roads, the side studs will provide protection against punctures from the rock/wood from the side and provide bite when cornering on uneven roads.
We can change or choose bicycle tires to better suit our area, for example wet or muddy areas, more rocky areas, or maximizing speed, and others.
Drivetrains / gravel bike groupset
As we have seen, the use of triple chainring has been abandoned on modern bicycles. Improved capabilities of components, electrical technology and cog in smaller and larger sizes, making the drivetrain and groupset options for gravel bikes only for 2x or 1x drive systems, to produce an effective and efficient bicycle.
2x (Double Chainring)
A classic drivetrain with two chainrings at the front and a small cassette at the rear certainly makes a lot of sense for a gravel bike. For bikes that are used mostly on smooth roads, smaller gear jumps will be more useful. In this case, we can use the same derailleurs and shifters that we use on conventional racing bikes. However, it is highly recommended that a compact crank should be combined with a 32T cassette.
The Shimano Ultegra RX offers a derailleur equipped with a clutch, which can prevent the bicycle chain from detaching due to shocks on uneven roads. While SRAM currently only offers this option with their 1x drivetrain.
One of the drawbacks of the 2-speed drivetrain is the frequency of shifting gears that is more frequent and also requires more intensive maintenance, and also the shifting chainring is not always reliable on off-road roads.
1x (Single Chainring)
In the mountain bike (MTB) segment, 1x (single chainring) drivetrains have become the norm, and rightfully so. Most gravel bikes now also rely on the same standards. One of the keys to a good single chainring bicycle is having a cassette with a large gear range (500% or more), or having a sprocket size that is smaller or larger than a regular cassette. This results in cassette sizes up to 10-42 and offers the same gear ratio as a 2x drivetrain, but simplifies gearshift significantly.
Not only simple, gravel bike 1x drivetrains are also lighter, easier to install, and more durable against wear and tear. But they also have some drawbacks: the gear jump is bigger. But SRAM and Shimano have offered more speed sprockets such as the 12 speed groupset which will become the new standard including for gravel bikes.
Single chainring gravel bikes require a wide gear ratio range, in order to be able to get high speed as well as light pedaling on offroad or uphill terrain. So the use of 12 speed on a gravel bike is the best choice.
The advent of electronic groupets has opened up more responsive and precise drivetrain systems. Shimano’s Di2 for MTB and road bikes is not only made to make shifting easier, but also guarantees the accuracy and precision of bike gearing. The use of an electronic groupset is preferred on 12 speed bicycles, because the distance between the sprockets is very narrow, requiring smoother and more precise chain shifts.
Almost all gravel bikes use disc brakes with a hydraulic system, for more gripping braking power, making it more convincing for offroad areas. Wet areas, mud, sand and rain will not reduce the efficiency of disc brakes. So the choice of disc brakes on gravel bikes is non-negotiable. Modern disc brakes are not as heavy as traditional disc brakes made of heavy metal, but have used a mixture of materials that are not only lighter and stronger, but also more heat resistant.
The use of rim brake/U-brake/V-brake will feel less than optimal because the bicycle will also be used a lot in dusty, muddy and watery areas. The rim brake/U-brake/V-brake type brakes are no better than disc brakes if they are getting wet and new particles/dust/mud have been introduced between the brake pads and the bicycle rim.
Damping with fat tires, carbon frames and suspension forks is not the only solution. Bicycle technology continues to evolve, as one example that is applied to gravel bikes is the Future Shock System from Specialized (which has been used on some Diverge and Roubaix models). The Future Shock Specialized is a suspension with 20mm of travel, positioned above the head tube and moving vertically. So when the bicycle passes through a bumpy road, the bicycle will move up in the handlebar position while maintaining the bicycle’s momentum so that it will not reduce the speed of the bicycle.
The use of suspension forks on gravel bikes will indeed reduce the feeling of a racing bike when cycling on asphalt roads or smooth roads. Not all can work well for gravel bikes, considering that one of the goals of gravel bikes is speed. The addition of a suspension fork will also change the balance, handling, weight on a gravel bike, which can reduce the true principle of a gravel bike. One of the suspension forks used on gravel bikes is the FOX 32 AX. Forks on gravel bikes do not have long travel, just enough to dampen minor vibrations. The use of suspension with long travel will reduce energy efficiency, making us tired faster, because some of the energy that should be used to push the bike will be absorbed by the suspension.
Whatever system is used on a gravel bike (suspension or non-suspension), the added comfort is undeniable and will help many people to rediscover the joy of cycling, and spend more time on the bike.
Next maybe use suspension on seatpost.
It may not be very noticeable, but gravel bikes usually have more eyelets for bag mounts, racks, straps, mudguards and more. This can make it easier for us to carry a lot of goods for long journeys.
Gravel Bike Special Groupset
In 2019, SRAM, followed by Shimano, launched a special groupset for the gravel bike segment. Indicates that gravel bikes will indeed be one of the segments that will continue to grow in the future. Even though we can build or assemble our own gravel bikes, or combine components to make gravel bikes, the appearance of this special groupset for gravel bikes makes gravel bikes more lively.
SRAM eTap Red AXS
AXS is an electronic and software integration technology for SRAM bicycle components. SRAM AXS allows cyclists to view battery status, change component settings, controls, schedule maintenance, and more.
The SRAM eTap Red AXS is available with 1x or 2x drivetrain systems.
The Shimano GRX emphasizes gravelling cycling ergonomics, optimized gearing, component durability, which sets it apart from other bicycle-class groupsets and components. Actually, not only the drivetrain groupset, Shimano also has a specific wheelset for gravel. The Shimano GRX is available in 10 speeds, 11 speeds, and Di2. Di2 (Digital integrated intelligence) is an electronic smart shifting technology from Shimano.
Using a motorbike and turning a gavel bike into an electric bike seems to be the new trend in this unique style of bike.