I got tired of maintaining the MTB drivetrain over a decade ago. How ridiculous is the idea of a derailleur? If you were riding a motorcycle or off road vehicle on trail would you hang the transmission off the back bumper? It's just dumb. I'm convinced replacing these fragile, vulnerable pieces of crap are a major source of revenue for the MTB industry but that might be another conversation.
Once I abandon the pinky-toe of the MTB drivetrain I began to develop more as a trail rider. Conservation of momentum became the key component in how I attacked a trail. Learning to keep up on my one speed started me down a path that not only increased my level of enjoyment for riding aesthetically, but it taught me many lessons and increased my technical ablility as a Mountain Biker in general, and I think it's worth thinking about no matter what kind of bike you ride.
In what is the most obvious situation, climbing, I was forced to climb faster then riders with intact multi-gear drivetrains, at first anyway. The tactic of standing and hammering away from a geared group only works for so long....like an hour. If I was to hang on the longer rides, I couldn't afford to be climbing 50% faster then everyone. By definition I was doing more work and while this would improve my fitness, there reaches a point where everyone on the ride is fit, and so outworking them on the climbs was going to limit me as compared to them.
What a rider has working for them climbing out of the saddle is their entire body in engaged. The opposing forces of pushing down on the pedal, while pulling up on the handlebar as the hips (where the real power is generates) move forward to drive the foot down is significant. In addition, body mass helps to push that crank arm down. As soon as you sit, you isolate the legs, can't generate nearly as much power, and need more torque to push you up hill, and so a lighter gear is required. The point to make there is climbing a one speed is less about having more strength then a geared MTB rider might think. While riding a SS will make your entire body work, and change your build for more power and less endurance, that's not the real key to hanging tough on long rides. What you lose with a bigger gear and slower cadence is the bio-mechanical rotational inertia. Spinning your legs at high reps give you stability, just like when your wheels turn fast. So when you slow your cadence you become less stable. Balance becomes the key ingredient. Once you develop great balance while standing up on your bike, you can climb slower and slower. Ultimately, if I can climb at the same speed as someone with my same mass, I am doing the same amount of work. As long as I am not spazzing out trying to keep my balance, I am not having to work harder to climb the same hill. Of course, it is inevitable that you will fight it a bit and so the best you can hope for is to approach that ideal and you will be required to work slightly harder then your geared friends, but it's less about gearing and more about balance. Developing this fine-tuned sense of balance with enhance your entire game. Low speed tech sections where you stall, track-stand, hop once or twice, then pedal away, or a lunge over some slick surface on a short punchy climb that brings you to a momentary stand-still, only to hold, then pedal away, or even feeling confident on a rock spine or log ride will all seem like a piece of pie after a while. That will be developed while climbing at a slow cadence on a single speed.
Rolling along on trail presents different challenges when in a mixed group. It's true that sometimes you're on a trail where folks just hit a big ring and drop you. That is unavoidable. In New England that is not very frequent. On the more technical single track, you will be forced to corner faster to keep up. Ironically, cornering faster means better braking technique. A rolling tire has a better friction coefficient than a tire that is attempting to brake. It becomes imperative to brake before you start cornering and exit the turn at maximum speed. The key here is picking your head up and looking through the turn. It feels odd, particularly on sharp turns because you end up turning your head and you lose sight of your front wheel even in your peripheral vision. Proper cornering at speed is crucial because it doesn't take long to spin out of gear and so grabbing too much brake mid turn, then pedaling hard after exiting is not always an option. Conserving that momentum by cornering faster and cleaner then your geared-out crew is another skill you will develop. Once you dial in how to brake and corner on a free rolling tire your game will be that much more polished and you will start dropping people on twisty trail no matter what bike you're on.
Pumping. Once you exceed you ability to pedal faster, which happens quickly, you need to stay as fast-rolling as possible. Pumping everything is the key. Every tiny feature you ride over required your tires to move up, then down. As the rider you have two options. Be heavy, or be light. The idea of pumping is to unweight the bike as the tires roll up the front side of the feature, then be as heavy as possible on the backside, or downhill side of the feature. On a pump track the feature are very regular shapes. Rollers, and whoops. On a Single Speed Hard Tail the trail become a pump track. Every rise or root has a front side and back side. While geared riders, particularly those on dualies, can ride passively, letting the bike eat chatter and absorb terrain then pedal to make up for the lost kinetic energy, we don't have that option once at speed. We have to unweight and then pump, avoiding the slowing affects of having our tires essentially roll uphill, lifting our mass up against gravity for a fraction of a second, and maximizing the affect of having our tires roll downhill for a fraction of a second by weighting, being as heavy as possible, at that moment. Sometimes there is only room for a back-wheel to fit in a compression and then a quick manual wheelie through a trough or hole in the trail will maximize your "squirt" down trail. Sometime the rough terrain extends too far down trail to remain un-weighted for the entire section. You may just have to take it, stay very loose on the bike and try not to flat. Or maybe not. Maybe you just jump it.
Jumping. Being in the air is fun. It's smooth, and if you land on the backside of a feature smooth enough, it's fast and can send you hauling ass. Get good at jumping, and you will get really fast. Putting the back tire down with precision is the way to maximize the physics at work here. If there is a long root bed, and you boost off the first root, and place your rear tire down on the backside of the last root, and don't pinch-flat, you can get incredible squirt. Eventually this technique will lead you to nose-manuals where you front wheel will track the features of a trail ever-so-lightly, and your back tire will hover a few inches off the tread waiting for that perfect pocket to stomp and send you flying with a whizz of your free wheel. The precision wheel placement while rolling at speed will greatly improve your general ability to hit clean lines and interpret the trail in a new way allowing for maximum conservation of kinetic energy.
While riding a Single Speed Hard Tail will force your hand in learning these lessons, it's can be done on any bike, though deep suspension will absorb a lot of the pumping energy and make it more difficult to pedal standing and limit the lift you can get off of small features. Hope this gives some food for thought about pedaling less, braking more affectively, and progressing as a rider, 'cause personal progression is what it's all about.
$.02
Once I abandon the pinky-toe of the MTB drivetrain I began to develop more as a trail rider. Conservation of momentum became the key component in how I attacked a trail. Learning to keep up on my one speed started me down a path that not only increased my level of enjoyment for riding aesthetically, but it taught me many lessons and increased my technical ablility as a Mountain Biker in general, and I think it's worth thinking about no matter what kind of bike you ride.
In what is the most obvious situation, climbing, I was forced to climb faster then riders with intact multi-gear drivetrains, at first anyway. The tactic of standing and hammering away from a geared group only works for so long....like an hour. If I was to hang on the longer rides, I couldn't afford to be climbing 50% faster then everyone. By definition I was doing more work and while this would improve my fitness, there reaches a point where everyone on the ride is fit, and so outworking them on the climbs was going to limit me as compared to them.
What a rider has working for them climbing out of the saddle is their entire body in engaged. The opposing forces of pushing down on the pedal, while pulling up on the handlebar as the hips (where the real power is generates) move forward to drive the foot down is significant. In addition, body mass helps to push that crank arm down. As soon as you sit, you isolate the legs, can't generate nearly as much power, and need more torque to push you up hill, and so a lighter gear is required. The point to make there is climbing a one speed is less about having more strength then a geared MTB rider might think. While riding a SS will make your entire body work, and change your build for more power and less endurance, that's not the real key to hanging tough on long rides. What you lose with a bigger gear and slower cadence is the bio-mechanical rotational inertia. Spinning your legs at high reps give you stability, just like when your wheels turn fast. So when you slow your cadence you become less stable. Balance becomes the key ingredient. Once you develop great balance while standing up on your bike, you can climb slower and slower. Ultimately, if I can climb at the same speed as someone with my same mass, I am doing the same amount of work. As long as I am not spazzing out trying to keep my balance, I am not having to work harder to climb the same hill. Of course, it is inevitable that you will fight it a bit and so the best you can hope for is to approach that ideal and you will be required to work slightly harder then your geared friends, but it's less about gearing and more about balance. Developing this fine-tuned sense of balance with enhance your entire game. Low speed tech sections where you stall, track-stand, hop once or twice, then pedal away, or a lunge over some slick surface on a short punchy climb that brings you to a momentary stand-still, only to hold, then pedal away, or even feeling confident on a rock spine or log ride will all seem like a piece of pie after a while. That will be developed while climbing at a slow cadence on a single speed.
Rolling along on trail presents different challenges when in a mixed group. It's true that sometimes you're on a trail where folks just hit a big ring and drop you. That is unavoidable. In New England that is not very frequent. On the more technical single track, you will be forced to corner faster to keep up. Ironically, cornering faster means better braking technique. A rolling tire has a better friction coefficient than a tire that is attempting to brake. It becomes imperative to brake before you start cornering and exit the turn at maximum speed. The key here is picking your head up and looking through the turn. It feels odd, particularly on sharp turns because you end up turning your head and you lose sight of your front wheel even in your peripheral vision. Proper cornering at speed is crucial because it doesn't take long to spin out of gear and so grabbing too much brake mid turn, then pedaling hard after exiting is not always an option. Conserving that momentum by cornering faster and cleaner then your geared-out crew is another skill you will develop. Once you dial in how to brake and corner on a free rolling tire your game will be that much more polished and you will start dropping people on twisty trail no matter what bike you're on.
Pumping. Once you exceed you ability to pedal faster, which happens quickly, you need to stay as fast-rolling as possible. Pumping everything is the key. Every tiny feature you ride over required your tires to move up, then down. As the rider you have two options. Be heavy, or be light. The idea of pumping is to unweight the bike as the tires roll up the front side of the feature, then be as heavy as possible on the backside, or downhill side of the feature. On a pump track the feature are very regular shapes. Rollers, and whoops. On a Single Speed Hard Tail the trail become a pump track. Every rise or root has a front side and back side. While geared riders, particularly those on dualies, can ride passively, letting the bike eat chatter and absorb terrain then pedal to make up for the lost kinetic energy, we don't have that option once at speed. We have to unweight and then pump, avoiding the slowing affects of having our tires essentially roll uphill, lifting our mass up against gravity for a fraction of a second, and maximizing the affect of having our tires roll downhill for a fraction of a second by weighting, being as heavy as possible, at that moment. Sometimes there is only room for a back-wheel to fit in a compression and then a quick manual wheelie through a trough or hole in the trail will maximize your "squirt" down trail. Sometime the rough terrain extends too far down trail to remain un-weighted for the entire section. You may just have to take it, stay very loose on the bike and try not to flat. Or maybe not. Maybe you just jump it.
Jumping. Being in the air is fun. It's smooth, and if you land on the backside of a feature smooth enough, it's fast and can send you hauling ass. Get good at jumping, and you will get really fast. Putting the back tire down with precision is the way to maximize the physics at work here. If there is a long root bed, and you boost off the first root, and place your rear tire down on the backside of the last root, and don't pinch-flat, you can get incredible squirt. Eventually this technique will lead you to nose-manuals where you front wheel will track the features of a trail ever-so-lightly, and your back tire will hover a few inches off the tread waiting for that perfect pocket to stomp and send you flying with a whizz of your free wheel. The precision wheel placement while rolling at speed will greatly improve your general ability to hit clean lines and interpret the trail in a new way allowing for maximum conservation of kinetic energy.
While riding a Single Speed Hard Tail will force your hand in learning these lessons, it's can be done on any bike, though deep suspension will absorb a lot of the pumping energy and make it more difficult to pedal standing and limit the lift you can get off of small features. Hope this gives some food for thought about pedaling less, braking more affectively, and progressing as a rider, 'cause personal progression is what it's all about.
$.02