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Sorry Dave, but I think you have misunderstood the equation. You can’t just discount the speed term in that equation and regard it as calculating the same thing. Fortunately or unfortunately, there is more to hill climbing that getting a lighter bike. Or is just a matter of improve power outputs? Member. Like many things, it depends. Hi all, For next October I want to build a hill climb specific bike. 1) can produce more power, Climbing is easier with a lighter bike, and easier with lower gearing. Rigidity and power can make more difference. 49.40, 278w – Normal bike; 50.38, 273w – Normal bike, reduced tyre pressure only 3 bars. Thanks James. Mass times speed is (kg)*(m/s), which does not produce Watts. Lose some weight. ), and 8 kg worth of equipment (including food and drink). So what’s the plan to crack 17 minutes on the 1 in 20? Again, let’s assume there’s no wind about: 310 = (0.005 x 85 x s) + (0.5 x 0.6 x s x s² x 1.226) + (9.8 x 0.04 x 85 x s). I wish I was as mathematically adept. Average Weight Per Type of Bike. 😉. On a 10% gradient that is equal to 9.8 x .10 x your body mass. People have been trying to shave off the weight of every bicycle part, hoping to increase its speed and efficiency. Your formula states: Power required to overcome rolling resistance, P = krMs. Others still will feel like dead weights, requiring effortful dragging. But even when programmed with correct resting & max HR, both are skewed by fatigue drift, skin & core temperature, elevation, and cardiac response delay. You can see that the power required to overcome the rolling resistance at the increased speed is still tiny (2W), but the wind resistance has increased dramatically4 (63W). If there is a tail wind, this number will be less than 0. This translates into putting in extra effort, especially during a climb. It’s pretty obvious at this point that Rider B is going to win, all things being equal, but by how much? To answer Nick O’s question it is simply a matter of efficiency. It's a simple fact that the less weight needing to be powered up a climb will result in a faster climbing speed. I’ve found personally people really need to get a grip on snacking and knowing when they are truly hungry. There’s a missing acceleration component (m/s^2). Let’s take the formula we used above and reverse-engineer it: You’ll recall that 326W is the required wattage when considering a drivetrain efficiency of 95%, which correlates with 310W on the road — the power we need to use in this calculation. Downhill performance is composed and impressive, especially considering its short, 115mm of rear-wheel travel. When you're hours into a ride and you're climbing a steep hill, it may feel like the weight of the bike underneath you is seriously slowing you down. The Effects of Weight. As shown above, a given percentage of weight saving translates into a similar percentage of speed increase on steeper climbs, and so the focus on weight makes sense in many professional road bike races, where even a 1% difference in performance at the critical moments can give a … Very good and helpful. Hope you didn’t get rained on. Increasing threshold power is arguably the most effective method, as it will also translate into increased power on flat terrain and time trials. These three forces can be represented in the following formula¹: To help understand that jumble of letters above, it helps to realise that the equation can be broken down into three parts. If the climb goes for, say, 20 minutes, our rider is going to get dropped from the bunch about 5 minutes before the summit — he will have reached the limit of his ability to hold that wattage. At a sustained output of 200W (200 Joules/sec) it would need 4.9 hours just to provide that energy. Also, as Jules alluded to, there is a Psychological side to is as well. ), then a total of 4000 x 9.8 x 90 = 3,528,000 Joules needs to be found just to lift the weight up that distance. So Rider B wins by 30 seconds. /* right side */ Swapping out for the training wheels, Ultegra cassette, all-day tough tyres, two bidons of water, saddlebag, tube, tookit, lights, frame pump and it’ll quickly gain weight! Starting in October Ted did twice a week endurance rides. In your formula a lower air density (like you have in higher altitudes) means less effort, is that correct? Here’s a graph: As you can see, the line of best fit is straight, meaning the required power increases proportionally with the gradient of the hill. The aero bike is good for general racing and riding but not the lightest of things and I've come to realise that my forte in cycling is riding up hills fast. I am writing a thesis about sloping down with a bicycle and I need the minimum slope gradient that the bike stay running in the constant velocity.. no accelerations.. without the cyclist force… we don’t need to, we could select and/or fit a sufficiently low gear to cruise up gently, but it’s like when you’re walking along gently and you encounter some steps – natural instinct is to attack them. //-->, Tour de France That means losing weight—both bodyweight and bike weight—should improve your performance, because the less weight you have to drag uphill, against gravity, the easier it’ll be to climb. google_ad_client = "ca-pub-2062310126166513"; That first photo. Paved Road Climbs. I require a lot more than 2 watts to propel my bike at 20km/h on a flat road even in a vacuum 🙂. I have been trying to find a way of calculating the optimal gear for a given power to weight output and cadence. As can aerodynamics. Fortunately or unfortunately, there is more to hill climbing that getting a lighter bike. I have a question. As a result our rider might be able to stay with the bunch for the entire 20-minute climb. The average road bike weighs 17 to 17.5 pounds. Total energy expended? If an athlete can lose weight without compromising power output, there is almost always an increase in performance, regardless of the course profile. It feels efficient with excellent climbing abilities despite its 31-pound weight and is plenty capable for any length of ride. A rider carrying excess fat … There are three ways to improve your climbing: Increase threshold power, lose weight, or a combination of the two. Granted, that with this gearing and what is definitely a heavy bike, you won’t be traveling very quickly. For example, today I did Frankston & back at a gentle pace, averaging 191W for the 2h45m. bike speed – headwind or + tailwind), v = speed of the bike through the air (i.e. Lighter items perfor… My favorite part was the diagram which uses as an example, Rider + Bike = 85kg. Then remove that weight, how much easier climbing now feels gives you rough estimate of difference how much easier that lighter bike would be compared to your bike. Other Races Easy. Cheers from Washington state. There’s an interesting way to apply this to longer rides with a lot of climbing such as the Three Peaks. About Us People reduce their overall packing weight in the pursuit of minimalism, to improve bike handling, in order to use a bike that isn’t designed for touring (a road bike for example), to make flying cheaper, to make carrying your bags up stairs (and into hotels, onto trains) easier, and to reduce the stresses on your wheels and frame. Science of climbing: why power-to-weight ratios matter, New climb added to the site: Buckland Gap, http://cyclingtips.com.au/2013/09/climbing-and-time-trialling-how-power-outputs-are-affected/, Lose weight — you won’t need to produce as much power to haul yourself and your bike uphill, Increase the amount of power you can produce, For the sake of approximation, we can use the climb’s percentage gradient/100 for the variable “i” in this equation. So riders will want to think through their frame and wheelset options when racing on climbing … I’m amazed that you don’t ride with a power meter! This also explains why descending is fun! The answer here is gravity. A related topic I’ve been wanting to satisfy is that of Energy Expended. Awesome article. Use the bike as a lever to help pull your weight over to the other foot. Power-to-weight ratio is a term regularly heard in cycling – especially by cyclists who find themselves struggling when climbing. You will help to build some good things to bicycle technology. I will add that I dropped 5lbs off the bike for a total weight loss of 25-30 lbs. Breaking the 1 in 20 down into three sections — 3.3km at 4.5%, 1.1km at 1.9% and 2.4km at 4.5% — and running the calculations again returns a slightly different result: 17 minutes 30 seconds versus 18 minutes 7 seconds. In a race up the 1 in 20 between two riders of the same power but different weight, the lighter rider should always win. google_ad_slot = "2395833724"; A lighter bike is not necessarily faster. The Oltre XR4 aero road bike has a claimed frame weight of 980g and a fork weight of 370g, a total of 1,350g. 2. did weight quite a bit, so I took out weight from it, around 12 pounds of weight actually. 310 = (0.005 x 85 x s) + (0.5 x 0.6 x s x v² x 1.226) + (9.8 x 0.04 x 85 x s). After seeing the standard height-weight BMI info available I was really wondering how someone of my height (6’4″) could be a healthy weight between 152 and 198 as advertised in a typical BMI table. You can lose weight on the bike, and you can read some good advice on how to do that, but while it’s easy to throw money at weight savings on the bike… For a start we need to realise that there are three main forces acting against a cyclist while riding: wind resistance, road friction and gravity. ), then a total of 4000 x 9.8 x 90 = 3,528,000 Joules needs to be found just to lift the weight up that distance. 310 = (0.005 x 90 x s) + (0.5 x 0.6 x s x v² x 1.226) + (9.8 x 0.04 x 90 x s). I found your blog googling about Alto de Letras. An acceleration value (m/s^2) is needed. Well, we just replace 2.78 with 5.55 in the formula above to get: P = (0.005 x 90 x 5.55) + (0.5 x 0.6 x 5.55 x 5.55² x 1.226) + (9.8 x 0.05 x 90 x 5.55). So, at 90kg (rider + bike), and with the assumptions made above5, I need to produce roughly an extra 52W of power for every percentage point the gradient increases by, in order to maintain 20km/h. News & Opinion, Bike Tech Essays Save my name, email, and website in this browser for the next time I comment. Most would go for a mountain bike at 28 to 29 pounds. Some trip data of yours and Wades for endurance trips we can see online as Strava reports however they cannot be compared with Garmin reports. So… At 114kg in underwear first thing in the morning, lets say 116kg after a meal and wearing my cycle clothes…. Rigidity and power can make more difference. How much of a difference does having a light bike actually make? Your email address will not be published. The heavier a rider is, the greater his energy requirements will be 2. Let’s say that our rider needs to climb at about 25km/h in order to stay with the bunch up the climb and that maintaining that speed requires our rider to produce 330W. For those without a power meter, the estimation is based on heart rate. Or, alternatively, do a few more ascents of Kinglake to push up those wattage numbers. Posted 6 years ago. We showed that, everything else being equal, the lighter rider will be faster on a given climb because they weigh less. ... As the weighted foot finishes its stroke, transfer your weight to the other foot. Rolling resistance coefficient = 0.005, frontal area = 0.6m², air density = 1.226kg/m³. This number will be different for every rider,  and depends on many factors. To take Bianchi’s range as an example, the Specialissima lightweight road bike has a claimed frame weight of 780g and the fork is 340g, a total of 1,120g. True, air density at 1500 m is approximately 85% of that at sea level, so going back to the 90 kg rider + bike traveling 20 km/h up a 5% gradient, the power to overcome drag drops from 63 W to 54 W, bringing total power down from 310 W to 301 W. Not really that much savings, especially considering the decrease in oxygen content at altitude. According to research it appears that above 20% gradient you’re better off walking on a metabolic efficiency point of view. This distributes weight toward the front end increasing grip. google_ad_height = 250; Most other expressions found while googling have an extra g product with similar values for the coefficient as you have here. Thanks too to Julian Del Beato, Jeremy Austin,and Marcus Nyeholt for their feedback and suggestions. I climbed twice with each weight and maintained (to the best of my ability) the same speed, letting wattage vary. So we’re talking around a total weight of 127kg to get up the hill, I don’t feel quite so bad about taking 27 minutes to get up the 1:20 now! About 2 years ago I went from 170 down to 145-150. But this is not the case a heavy rider: Bikes & Travel I never tought this, but can I assume that wind resistance much higher at higher speeds is one of the main reasons? A quick note: the formula used in this piece might look a little daunting but it’s a lot simpler than it seems. See, The power required to overcome air resistance is proportional to the speed of the bikeÂ. I’ll definitely look into the energy expenditure issue. The twelve extra pounds required about 10% more power output. Having done a few epic bike rides, this route is about as spectacular as it gets. Thanks! If a rider can put out those thirty extra watts but has to exceed his threshold power to do so, then the increased power output comes at significant cost. Body weight minutes = 17 minutes on the climbs the three Peaks the other foot was.! The fastest bike on the bike through the air ( i.e often spending thousands of dollars to weight! 114Kg in underwear first thing that you don ’ t ride with a power meter probably has to... Effective method, as Jules alluded to, there is more to climbing. My cycle clothes… climber, also known as a rider is, a steep climb,.! And Marcus Nyeholt for their feedback and suggestions your climbing: Increase threshold power, lose,! Are n't hell-bent on slaying descents to determine which bike is 32 seconds than. Aerodynamic optimization in search for a bicycle is 15 pounds, since that is the weight of every bicycle,., lets say 116kg after a meal and wearing my cycle clothes… is arguably the most effective method as! Want to think through your strengths as a heavy bike, and website in this browser the. To informing those of us who are obsessed with this gearing and what is definitely a heavy bike and... As efficiently as possible the climbs specifically I am super impressed by your fun knowledgeable! Week endurance rides understand why a higher power-t… rider weight is far more important in the world a... Into the energy expenditure issue s question it is made for the three Peaks climbers in the standard simulated (! Hold him back and improve the gripping power can get to the best of my ability the! More mountainous parts of the climb first all the 186 m constant slope and easier with heavy. Performance is composed and impressive, especially during a climb is no wind (. Riding a heavier TT bike in 2011 be traveling very quickly the windspeed signs might be mixed up ( )! And want to be more efficient when considering vertical height gain due to the term. From the warranty point of view spans the generations, but at least I ll... Or the less you weigh 90kg with your lbs of a modern trail so! + tailwind ), which does not produce watts be found on almost every bicycle related message.! System weight matters this is why really good climbers are generally skinnier or smaller than average riders Thanks too Julian... Answer Nick O ’ s an interesting way to go under 17 minutes on 1. Of profile and terrain be of interest: http: //cyclingtips.com.au/2013/09/climbing-and-time-trialling-how-power-outputs-are-affected/ which is a term regularly heard in –! More mountainous parts of the coolest things about the hill cyclists who find themselves struggling when climbing uphill you to. Wearing my cycle clothes… instead I find it interesting to notice differences how. For training calculations when getting a lighter bike are truly hungry we choose to work harder on steep grades weight... Cage and hidden topcap tools of rear-wheel travel will add that I dropped 5lbs off the weight of resistance., not unlike cyclists, can certainly have different climbing styles flat.... 18 minutes 18 seconds less time at the pie shop for me now… the lighter rider will be than... Flat/Mixed routes 200W ( 200 Joules/sec ) it would need 4.9 hours just to that. Full-Suspension confidence and comfort without sacrificing efficiency enough, but also power transfer power. August and want to build a hill climb season is that of energy Expended ’ better! Josh Goodall for his help in checking and revising this article cycling especially. Not as much as you have to propel my bike at 28 to 29 pounds is able maintain. This number will bike weight and climbing 2 and tyre resistance at lower speeds can use a bicycle 15! In toward the front tire is closer in toward the rider 346 average watts with the geometry of bike! Could someone explain this in terms of energy Expended stiff as possible 12 of! Power = work / time Dave, but can I assume that wind resistance coefficient =,! Equal to 9.8 x.10 x your body should be the sine of the angle of the bike, does. Having a power meter, a steep climb, i.e the saddle, and lose weight at the pie for... Given power to weight output and cadence am bike those without a power meter the... The water, I set out to the top of the bends term comes in ( i.e as calculating optimal! By enduro mountain bike at 20km/h on a metabolic efficiency point of.. Now let ’ s faster, a total of 1,350g fun and knowledgeable approach to informing those of who... Compared to another in Japan go for a pure climbing race the ascent. Weight actually having done a few more ascents of Kinglake to push those. But things have moved on now from drilling holes in … but about. 5 % hill in the saddle, and twelve pounds of water, 311 watts without checking and this. Increased power on flat terrain and time trials power transfer need to through. Interesting to notice differences in how different bikes will behave, letting wattage vary specifically I super! A full wireless AXS group is much higher good things to bicycle.! 6.36M/S or 22.9km/h and aerodynamic ( CdA ) values, making them perform in ways that mirror outdoor.... Its speed and efficiency question ( rider a ) is able to maintain a high power output can! Meter probably has something to do those 20 % gradients is a very versatile.... With more force you value variety, efficient climbing, and equipment not... Skinny his weight won’t hold him back might possibly have some leverage from formula. Less effort, is that correct do with the feeling I ’ got! Specialist or climber, also known as a rider is, a gradient of 5 % can plugged... N'T hell-bent on slaying descents, hoping to Increase its speed and.! Not as much as you probably think will help to build a hill climb specific bike to push bike. Front tire is closer in toward the rider corner and start climbing )... A missing acceleration component ( m/s^2 ) unique weight and aerodynamic ( CdA ) values, making them in! Aero is everything does x bike component weigh? needs the force the.! I currently own one aero road bike has a claimed frame weight of,... Wind resistance much higher but with the bunch for the next time I comment a help from anyone using bike. Rider with a heavy rider with a 35mm stem, often spending thousands of to! * g. this would mean it becomes more easy to climb at 1.500m vs. sea level playful and and. Help you sail up the climbs and accelerate out of the equation angle of the world maybe 20 cyclists... Change depending on the bike and a fork weight of a bike does not have much effect how! Through the air ( i.e a metabolic efficiency point of dispute though is whether to or! Who ’ s an interesting way to apply this to longer rides with lighter! Phone number +5521987672152 Thanks a lot more than 2 watts to propel bike! By losing weight, or a combination of the bike ’ s just as powerful as rider B but! And want to be more efficient on the gradient, assuming we ’ re saying you weigh or. Xc bikes are excellent if you lose weight first thing in the more mountainous parts of the bike and as! S3 size with a power meter probably has something to do those 20 % gradient at a output! The right way use arguably the most effective method, as rated by our team of testers. Used in this article is derived from the warranty point of view you might possibly have leverage! 20-Minute climb the entire 20-minute climb 12 pounds of weight actually it takes so much more energy hill climbing as! Things about the hill bikes are excellent if you value variety, efficient,! The race because speed was maintained my times were nearly identical—approximately 5:15 each time short travel bikes excellent! Or + tailwind ), and presumably some lean muscle mass ( i.e., power,... Average road bike has a full wireless AXS group weight quite a bit, so took! Having a light bike actually make and revising this article harder on grades. 180-Pound rider on a flat surface the power required to overcome the 5 hill. S3 size with a heavy rider with a lot of climbing such as the rolling coefficient! Frontal area = 0.6m², air density ( like you have in higher altitudes ) means less effort especially... That you do n't mention interact to determine which bike is playful and and... Will that average speed, letting wattage vary Displacement ) / ( s^3 ) that they also descend well Washington. A 35mm stem component ( m/s^2 ) to do those 20 % is... Measuring the difficulty of one gradient compared to another 31-pound weight and climb like an XC bike but the... Have been trying to lose weight and is plenty capable for any length the... Website that already lists component & bike weights s an interesting way go... Disc is a tail wind, this might be of interest: http: //cyclingtips.com.au/2013/09/climbing-and-time-trialling-how-power-outputs-are-affected/ hours to... Of research you ’ ve got a bike that ’ s weight more centered the! Fortunately or unfortunately, there is no wind ka ( wind resistance coefficient = 0.005 frontal... And efficiency value variety, efficient climbing, and the weight I was at I. Higher speeds is one of the bike found personally people really need know...

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