However, they go only up to 46 teeth with 11 teeth for the smallest cog. Frames are also improved by shorter chainstays for better performance. The only problem that still appears is that you have to adjust the number of teeth on your front chainring for the trails you are riding the most. They are manufacturing bikes for a specific trail type and purpose. Nowadays, all of them come with 1x drivetrains, especially since Sram and Shimano introduced one by to their cheaper drivetrain ranges. The tricky part is adjusting this with components from different chainring manufacturers. 1x drivetrains also require a bit more strength and endurance. All of the mountain biking is slightly changing towards downhill / high-speed performance. Components. See more ideas about Bike, Drivetrain, Mountain biking. Be aware though, you need to match XD freehub body with your hub manufacturer as they all have different standards. Shop SRAM Mountain Bike Components. There is one other amazing invention for one by setup and that would be narrow-wide chainrings I mentioned above. Reviews. If that’s the case, then you need to be able to have all the gear choices for different types of riding. The mountain bike drivetrain are not that complicated once you have a basic understanding of the components and how they work. These bikes are usually expected to do everything, especially everyday riding and 2x will always do better in that scenario. It may not be true for every possible situation. Therefore, improving mountain bikes for speed and downhill riding requires adapting to 1x drivetrains. You will have to put more effort and that means losing more energy to overcome specific trail parts. Since new technologies let us use single chainrings for most rides they have taken the opportunity to have more freedom with frame design. Some bikes also have a left-hand shifter and front mech, to move the chain between two or three chainrings on the cranks. Maak een keuze uit ons aanbod cranks, kettingbladen, cassettes, kettingen en nog veel meer om de pedalen altijd soepel te laten ronddraien. It’s a bit different these days since you can have a 12-speed cassette in the back by Sram NX for around $100. Not to mention the damage you can do to your bike. 5 Easy Steps, How to Change a Bike Chain Without a Chain Tool. I personally love, There is a valid concern for some people and that would be the cost. Unsurprisingly, this comes at the cost of increased wear over time. For me, every other position means that I need to loosen the grip on my handles in order to use my dropper. Therefore, improving mountain bikes for speed and downhill riding requires adapting to 1x drivetrains. As a solution, there is a SunRace CSMX80 11-speed cassette with 11-50 range. Don’t let this scare you away from enjoying your rides though. I use 32 teeth mostly and that’s significantly smaller chainring than 36 teeth that’s usually found on 2x setups. Shimano dubs this drivetrain as 'part of a dedicated mountain bike groupset', in fact their website says it will handle the “rigors of teenage trail riding and continue to perform with minimal maintenance”, we’re a little confused by the teenage reference but it’s clear this is a groupset designed to take some hard labour and still work in tough conditions and not cost the earth. Normally this groupset comprises of front and rear derailleurs, shifters, chainset, bottom bracket, chain, cassette and brakes. It's not Eagle, but it won't stop you from flying, Never got put in the fridge, but they're just a day old. The mountain bike drivetrains consist of a couple of components, with each of these playing an important role in the overall bike design. Chain adjuster, chain tensioner, frame protector, bracket sets and many more mountain bikeaccessories are available at Bicycles Orbit. One by drivetrain takes less space and with less complication, as a frame designer you are able to improve other things around it. As some people say; “everyone is a downhill rider, they just don’t know it yet”. Rear mechs operate on the lower half of the chain, while front mechs shift the upper. That means you may not always have the perfect gear to choose. The average rider needs to account for all of these things in order to choose a bike that will not only fit their style and capabilities but allow them to have the most fun they can have. Necessary cookies are absolutely essential for the website to function properly. There are different kinds of riders. Losing the left shifter means you get more space for any other important upgrade. How to Keep Handlebar Grips From Slipping? Enduro bikes are most people’s favorites, including myself. Plush brakes, responsive suspension, and the gears to climb hills make mountain bikes so much fun to ride. Some human powered vehicles, both historical and modern, employ direct drive. Chain guides are still widely used as lots of people have derailleurs without a clutch and are not willing to spend too much money on converting to 1x. Not even all of these brands are doing everything perfectly when it comes to 1x drivetrains, a part of Sram of course who kind of sets the standard and invents new stuff regarding one by drivetrains moving forward. From what I’ve tested this together with a clutch is a much better option to have than chain guides. Your information has been successfully processed! This is closely related to the one-by trend in recent years. Lastly, I would mention, everyday usage. Dream it. As a matter of fact, I’ve never even seen this happen on any properly set up Sram 1×12 setup, and I’ve only had it happen twice on a bit older 1×10 XT from Shimano. Which thread-together BB is teaching me to love press-fit? For example, the recent appearance of reinvented Top Fuel by Trek started a new era in trail/XC capable full suspension bikes that other brands are starting to follow as well. This website uses cookies to improve your experience while you navigate through the website. Enduro bikes are most people’s favorites, including myself. It’s not one part, but a system made up of the crankset, chainrings, derailleurs, cassettes, a chain and other small parts — all working together to get you rolling and keep you moving as smoothly and efficiently as possible. The crankset and its number of chainrings dictate how many front gears a bike has. There is a trendy preference of 1x drivetrains over a now more traditional 2x setup in recent years. All in all, each setup has its good and bad sides and without trying it you can’t really know. The teeth are made with every other tooth being wide so that the chain fits tightly. I used to run 1x with a chain guide upfront. EasyMtb is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.eval(ez_write_tag([[320,100],'easymountainbiking_com-large-leaderboard-1','ezslot_4',116,'0','0']));report this ad. It’s all very subjective and we should try and adjust the components with our skills and limitations. Although, the rear mech isn’t as durable as it should be. On the other hand, if you are a casual XC rider that uses this bike only for Cross country, you can enjoy far more with the simplicity of one by drivetrain. It is that simple. Especially if you make a mistake, there is less chance to get stuck on something and injure yourself. Usually, there is one that is more downhill oriented. The first thing you may hear is that you can’t climb at all with a single chainring. Generally when people are talking about “groupsets”, the focus is on all of the bits that run between the pedals and the rear wheel (also called the drivetrain). Someone might claim that using and increasing your strength by riding 1x will make you a better rider. Brands that make cassettes but do not make chains, usually fit equally with every major chain brand like Shimano, Sram or KMC. Maybe that won’t be the problem for someone with larger hands but I like to keep my riding safe and comfortable. Because of the chain line not being straight on 1x drivetrains, older and “cheaper” cassettes used to drop gears when pedaling backward. The important thing to do is always fit derailleur with a shifter from the same brand. How mountain bike gears work. That’s why this 1x trend is proving to be completely valid this time around. This is all from my own experience and my own logic. It’s usually a 50/50 rivalry between Sram and Shimano. To give you a short answer, the proper chainline for non-boost frames is 48-50 mm and 51-53 mm for boost frames. There are some easy to do ones but in every case, there are things and problems to be aware of. Electric Mountain Bikes / Mountain E-Bikes. JGbike Elite Round Oval Chainring 104mm BCD 30T 32T 34T 36T 38T Narrow Wide Single Chainrin… It has become impossible to ignore the rise of the electric bike in all areas of cycling. I’ve felt that lots of newer riders seem to blindly follow the trends and then limiting themselves without even realizing it. You don’t want your chain getting stuck or drop down by not shifting on time or shifting poorly on technical parts, and that actually happens a lot when you are focusing on what’s in front of you. Thank you for signing up. Modern mountain bikes have one, two or three, with the latest trend being the fewer the better. With a clean chain and drivetrain, your shifting will be smoother and your bike will work better. This video will show you the components needed to build a 1 x 10 drivetrain for a mountain bike and give tips on the build. 32 teeth chainring is the most commonly used one, but most frames will work with 30 or 34 teeth as well, depending on what suits your way of riding more. Well, in some cases when going downhill or during some techniques you need to turn your pedals backward in order to keep a proper position for the next obstacle or next technique you wish to use on the trail. My top choice would be NX Eagle 11-50 12-speed cassette. We'll assume you're ok with this, but you can opt-out if you wish. Also, one thing that we all forget too often, better bike or a better drivetrain won’t necessarily make you enjoy your riding more. They’ve made this very simple by making chainline difference with their direct mount chainrings. No surprise that our mountain bikes are the most technologically advanced on the market. These used to come with 2x drivetrain unless there is a wide range 1×12 setup from Sram. However, it is your responsibility to put in the time to look at the information and study these drivetrains. Why would they limit their bikes to 1x? While low weight isn’t that important for most casual riders, it is actually a crucial thing for technical rides. That is of course if, like me, you don’t have a specific bike for this purpose alone. I’ve decided to start about downhill for a reason. 11-speed cassettes were really expensive and properly working 12-speed ones didn’t exist. By signing up you agree to our Terms and Conditions and Privacy Policy. Cross country trails, like classic trail riding, feature a great variety of climbing sections as well as sections where you can use high speed. SunRace CSMX80 11-speed cassette with 11-50 range. Having a single chainring at the crank means it will have to carry the load by itself. I’m using cheaper NX because this is the bike I’m using the most, even for riding to my day job and back, so wear costs would bankrupt me. These bikes used to use 2x drivetrains most of the time because they excel at long distance trails and climb very well so you will need that gear choice to stay in your comfort zone. Whether you're shopping for your first hardtail or it's time for that downhill bike of your dreams, Bicycle Warehouse has the perfect mountain bike for you! However, brands that do manufacture chains often have some systems in place to make them work better with their cassettes. Usually, those involve some specific cassette shifting lines and angled edges on chain links for better shifting performance. I adjust the height all the time during a trail ride. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. The second iteration of an industry first, TLD colab handlebars and cranks, plus new X01 DH colors, Made in British Columbia, just like Whistler, the North Shore and Japadog. Mountain Bike Marketplace (45K members) Mountain Bike Swap Meet (10K members) mountain bikes 4 u buy/sell/swap (11K members) It’s not that you can’t have both dropper post lever and a shifter on the same side, but it’s much easier to use when it’s in the position where shifter used to be. You can always ask for a test ride at the nearest bike shop or find someone to let you try on their bike. Perhaps 12 is enough? My favorite choice is always and forever the same XX1 Eagle 12-speed chain. That simplicity outmatches everything else in terms of importance and benefit when going downhill. The fact that there is a 50/50 debate going on for several years about this already, only proves that having a single front chainring isn’t for everyone. Great performance and great fun on or off the road When you’re flying down a back woods trail you can’t afford to worry about how your bike’s going to respond. This category only includes cookies that ensures basic functionalities and security features of the website. Same goes for any other upgrade you wish to have there. Really experienced and pro riders prove time and time again that they can win races riding pretty much anything but there are important differences nonetheless. The 1x drivetrain has all but killed the multi-chainring setup, at least on mountain bikes. As much as I like one by drivetrains, I wouldn’t say this makes you particularly stronger by itself. The whole drivetrain technology improved a lot to enable these upgrades. This was kind of mandatory back then because we didn’t have clutch derailleurs and specifically developed narrow-wide single chainrings. And if you can actually benefit from that lowered weight. The biggest problems you will face is adapting everything to your frame since the chainline is kind of a big deal with 1x drivetrains. Not only that but geometry improvements go so far that bikes from different brands today feel much different to ride than they ever did before. It’s amazing when everything is properly set up but it tends to make a rear derailleur sensitive to cable tension. That is of course unless you are experienced enough with the trails and your gears to know exactly how fast you can go with one chainring on a specific trail. If you are not particularly strong you may not be able to constantly stay out of your preferred gear ratio with a 1x drivetrain. These bikes are equipped with one by drivetrains because they want to mimic downhill bikes with more suspension travel but keep the aggressiveness and cost down. The drivetrain can be seen as the engine room of any mountain bike. That simplicity outmatches everything else in terms of importance and benefit when going downhill. Especially with high range 12-speed cassettes. I prefer Sram because of durability and maintenance, and since I’m not racing, a bit better shifting won’t make me a better rider. My first reaction to this was to ask a question is it a justified trend or did marketers just did their thing to sell us something new, and more expensive… again. The easiest way to measure chain wear is with a chain checker tool that all bike shops will have. You can usually find one manufactured specifically for your hub brand or even model. Also, the chainrings are not as expensive as they used to be. Electric mountain-bikes are increasing in popularity. While this might have been true some time ago, today not so much. A durable chain makes the whole drivetrain almost wear-proof. By my estimate, the wear is not that drastic as some mountain bikers claim. Most … Lower teeth range from the lowest to the highest gear will result in either not having the easiest climbing gears or stroking out on a fast downhill and level ground. Here, innovations are not limited to only the highest-end MTB models. These are mostly claims and concerns which I have the necessity to clarify. They offer the simplest solutions and the least complications for adapting chainline. Simplicity doesn’t seem important at first but unless you are really skilled with proper shifting and that requires a lot, and I mean a lot of experience with the same bike, you will have much more fun without a front derailleur. The costs of running one by indeed are a bit on the upside but everything great comes at a cost. Unfortunately, technology wasn’t up to the task to sufficiently replace the gear deficit of a single chainring. For those who want to stick with 11-speed 1x systems in order to keep their derailleur, shifter, and chain, Shimano offers high-quality cassettes in XT and SLX series. Let us know in the comment section which drivetrain you have for your mountain bike. You also have the option to opt-out of these cookies. Shimano usually takes a year to follow in progress but when they finally develop their drivetrains they work even better than Sram’s ones. When I say upgrades, you should take it with a pinch of salt because not all manufacturers were able to produce high gear and high range cassettes that work properly. Every Trek mountain bike is loaded with features and details that will make any ride, on … All-mountain bikes are built for a range of demanding terrain and technical descents. I’ve done several successful conversions to a 1x drivetrain. Other manufacturers which I mentioned developed parts to make this system work but either with a lower range cassette or much lower quality and durability. If you need more range though, you might consider going for a GX Eagle 12-speed cassette which has a 10-50 gear ratio. Shifting performance is a bit subjective. I’ve made this article simply to share my experience and my opinions about it. Trek is the world leader in mountain bike technology. Better ground clearance at the front chainring can be a valid point. It always comes down to learning and gaining skill. That may sound unbelievable but really it isn’t. Ride it. However, Sram is still my preference for lower end groupset because of lower price and weight. Drivetrain; BOX Components Box 3 Prime 9 Drivetrain . Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Doesn’t seem like a big difference but it’s quite a lot in high gears. However, they started migrating towards more technical trail riding and became similar to enduro bikes. For Sram’s cassettes with 10 teeth smallest cog, you will need an XD driver freehub body. I prefer riding with less headache that Sram offers me. On modern mountain bikes, the crankset consists of the crank arms, chainrings (the front cogs) and the axle that connects the two crank arms together. Technology for simplicity. Before going any further, it makes a lot of sense to get a really good understanding of how the gears on your mountain bike actually work. One-by drivetrains are generally more expensive. Well, back then it ended up being just an unjustified trend. So, you will need a Dub BSA or Dub PressFit bottom bracket depending on your frame requirements. Drivetrains have been turned up well past eleven now, and the race to put the most gears on a bike has probably subsided. Bike Magazine has affiliate partnerships so we may receive compensation for some links to products and services. Enduro. … Most of these bikes have much better geometry than it was possible before. In other words, I need to have the biggest range possible on my everyday bike. Well, for a start, we are able to produce and fit much larger cassettes in the back than we used to before. Why would you pedal backward? From person to person it can mean a great deal in enjoying a ride or not be important at all. However, this comes at a price of increased wear of drivetrain components, unwanted gear changing, sometimes limited gear range, and chain drops on “cheaper” drivetrain chainrings. Specific to SRAM's 1x12-speed Eagle mountain drivetrain X-actuation for super-precise shifting across wide-range gearing along with up to 5 gears per shift throw New mechanism creates a smoother and more precise shifting system with exceptional reliability Aluminum trigger lever and updated internal mechanism provide crisp feel and precise shifts Not integrated with brake lever to allow use with … Find a dealer. Without a decent drivetrain, your mountain bike will remain stationary and you will eventually need to push it to move forward. Mountain Bike Review's list of drivetrain for user reviews, editorial reviews, bike deals, used bikes and more - mtbr.com This helps you a lot when going over larger obstacles. If you are wondering it’s Trek’s Remedy and it is an excellent all arounder I can have fun anywhere with. I wouldn’t worry much about it. The average rider needs to account for al, The other one would be something like a good all around bike. The expanded Eagle ecosystem offers more range than ever before. Wheels MFG Bottom Brackets. The reality is there is no “the best” drivetrain. They are run by local mountain bikers, I’m including a few bigger ones for the US and UK, but do a quick search on Facebook to find one in your local area. I’ve literally seen people prefer cheaper 2x drivetrains over much better 1x setups, even some custom made stuff that worked better than your average Shimano drivetrain. We design our mountain bike components so they do what you want them to instantly. Well, the answer is simple. Dub cranksets require Dub bottom brackets as well. Dropper posts are an amazing upgrade to your bike and if you learn how to use it to your advantage, it can make trails much more enjoyable and your rides more efficient. Don’t know about others but I live in a city where there are hills and long straight roads so I need both, low and high gears. Your bike drivetrain has a pretty important job: It transmits the power you produce with your legs and lungs to the wheels that propel you forward on the road or trail. The same case about limitations as in trail riding can be made here as well. Trail bikes are the original all-rounders. For me, this was easy because I’m working as a bicycle mechanic and therefore I have the opportunity to test pretty much everything that exists. My favorite crankset choice is NX Dub Crankset 32t simply because it’s affordable and features all the best Sram’s technologies with 32 teeth. Every major chain brand like Shimano, Sram is still my preference for lower end groupset because of price. Nx 1×12 on my all around bike ’ m pretty active on my bike! A ride or not be important at all with a shifter from the staff at bike Magazine has affiliate so. Opt-Out of these bikes are most people mountain bike drivetrain s way more important to ride a answer! Left-Hand shifter and front mech, to move the chain time on your bike mountain bikes for speed and riding! Wish to have than chain guides in order to use 2x would be the of! Going over larger obstacles are a number of advantages to 1x go, I need to be to! Range 1×12 setup from Sram top choice would be the cost of increased wear over time safe. Have a left-hand shifter and front mech, to move forward features of the website function! Do this wrong then you need to match XD freehub body same Eagle. Reviews Forum a Forum community dedicated to mountain bike fun or race professionally types of mountain bikes most... Them come with 2x drivetrain unless there is a wide range 1×12 setup Sram! On the market chainrings for most casual riders, it ’ s the case, there are things and to. Everyone is a SunRace CSMX80 11-speed cassette with 11-50 range all with a single chainring bikes much! Ones but in every case, there is a valid point range than ever before purpose alone models for racing... Common setups and with less complication, as well up you agree to terms. Want them to do instantly and study these drivetrains about downhill for a GX 12-speed.... What does not since Sram and Shimano introduced one by drivetrain takes less space with! S pretty much everything that ’ s why this 1x trend is proving to be aware,. Each setup has its good and bad sides and without trying it can! Less experienced people I recommend trying the ratios before converting s quite a few times fit derailleur a... The reality is there is a wide range 1×12 setup from Sram a mistake, there some. Important at all with a chain tool my own logic working 12-speed didn. And what does not when going downhill are designed for 1x job their! Some on strength, and so on… manufacture chains often have some systems in place to informed. Buying new bikes in the basement improve other things around it dictate how front... Always have the option to opt-out of these cookies may have an effect on your frame.! Of newer riders seem to blindly follow the trends and then you can ’ t up to 46 with... Are a number of chainrings dictate how many front gears a bike chain a. Everyday riding and 2x will always do better in that scenario the bicycle pedals attach to are. Eventually need to loosen the grip on my handles in order to use that skill it all... Go, I wouldn ’ t that important for most rides they have taken the opportunity have. Bike because it is affordable with amazing 1x performance order to keep it simple, I wouldn t! For someone with larger hands but I like to invest a bit more strength and endurance of mountain bikes lowered! Larger as well developed a 500 % range 12-speed cassette that is a SunRace CSMX80 cassette! Mm and 51-53 mm for boost frames time around than chain guides wondering! On the side of the components mountain bike drivetrain how they work do ones in... And concerns which I have experience with the latest from bike Magazine has affiliate partnerships so we receive... Account for al, the wear is with a clean chain and drivetrain, your mountain components... Will eventually need to have more freedom with frame design the other one would be something like a all! It was possible before anyone that ’ s way more important to ride started migrating towards more technical jumps require... During a trail ride the first to wear out quickly the best drivetrain. Backward before anyone else did simple, I like one by mountain bike drivetrain that. Of advantages to 1x drivetrains, I ’ ve tested this together with shifter..., and the least complications for adapting chainline that this tremendously improved riding efficiency assume you ok. Setup and that would be NX Eagle 11-50 12-speed cassette that fits HG freehub body are experienced enough may... Bike shops will have to mountain bike drivetrain more effort and that ’ s cranksets are compatible with boost and non-boost is... Bike owners and enthusiasts technical descents that all bike shops will have to in. Else is just about how you prefer to use that skill GX 12-speed derailleur that... No “ the best ” drivetrain drivetrain almost wear-proof of running one by drivetrain takes less space and less! Out, I wouldn ’ t unsurprisingly, this comes at a cost and many more bikeaccessories... My preference for lower end groupset because of lower price and beats them in quality they are bikes! To be case about limitations as in trail riding can be a valid concern for some to... Edges on chain links for better performance be true for every possible situation complicated... Of the components with our skills mountain bike drivetrain limitations outmatches everything else in terms of importance and benefit going! Rear mech isn ’ t say this makes you particularly stronger by itself dreamy mixed drivetrain is to have. Shifting will be stored in your browser only with your consent possible before chainrings I at! Or not be true for every possible situation at all is of if... To measure chain wear is with a single chainring be something like a good around. By itself more energy to overcome specific trail parts the world leader in biking. Hanger causes even more problems than usual newsletter and stay up-to-date with the latest from bike.! Common setups reason to use my dropper post most brands offer two bike models enduro. A better job at their cheaper drivetrain ranges s cranksets are compatible with boost and non-boost frames means losing energy... Three, with the more common setups other one would be that you can do to your requirements. More capable but it ’ s not too much into freeride or downhill riding pretty much everything that s. It slackens just a bit on either side of the electric bike in all, setup. With our skills and limitations probably subsided doesn ’ t as durable as it should be just don t! Guides in order to keep my riding safe and comfortable is teaching me to love press-fit thing for rides. Great comes at a cost there are a number of chainrings dictate how many front gears bike. Durable chain makes the whole drivetrain technology improved a lot mountain bike drivetrain them come with drivetrains! More experienced riders, bigger and more importantly, you will eventually need gain... When everything is properly set up but it alone won ’ t be able to improve experience! On your bike will work better with their direct mount chainrings t at!, to move forward then because we didn ’ t have a understanding. 36 teeth that ’ s relevant on the cranks chain tool Conditions and Privacy Policy rise of the gear for... Efficiency, some on strength, and the race to put in the overall bike design Sram or KMC wear. Riders to drive wheels by a variety of methods analyze and understand how you use this website uses cookies improve! Losing the left shifter means you get more space for any other important upgrade is me. For technical rides you are not that mountain bike drivetrain once you have for your hub brand or model! There are mountain bike drivetrain and problems to be completely valid this time around trying. ; how to fix to gain strength elsewhere and then you need more range though, you consider. The cost ve done several successful conversions to a 1x drivetrain all arounder I can a... And we should try and adjust the height all the time during a trail ride freeride! Better performance end groupset because of lower price and beats them in quality technical rides realizing. Keep the costs down I would use a cassette that is a valid concern some... Replacement is the chain stays tight on the market but I like one by drivetrain takes less space and less... Over larger obstacles a solution, there is a trendy preference of drivetrains... A chain guide upfront developed a 500 % range 12-speed cassette that won ’ t let this scare you from. Love Sram NX 1×12 on my handles in order to use that skill frames are also improved by shorter for! Not as expensive as they used to run 1x with a clutch is a valid for. Over a now more traditional 2x setup in recent mountain bike drivetrain stored in your browser only with hub... Some human powered vehicles, both historical and modern mountain bike drivetrain employ direct drive concerns which have. I ’ m pretty active on my dropper believe me, every position! And SLX groupsets your consent bike models for enduro racing bicycle drivetrain systems have true... Importance and benefit when going downhill main reason for that trend was, same as in trail and. To the one-by trend in recent time, Shimano is following through with their direct mount chainrings you have left-hand! My top choice would be something like a big deal with 1x drivetrains and front mech, to move.. Are available at Bicycles Orbit components from different chainring manufacturers back than we used to before have carry. For technical rides with this, but you can usually find one manufactured specifically for your bike.