bike weight and climbing

My take: 2000m climbing on a 100km ride is a big day in the saddle, and is something I very rarely do. What about if I wanted to average 20km/h (5.55m/s) up the 5% hill in the example above? More than that, any bike frame on the list above can beat the Tron up the Alpe, using any wheelset on our list of top climbing wheelsets. Thanks for posting this info. How significant is that thirty watts? 🙂, If you have a power meter then it is simple: energy expended = average power (W) * time riding * human metabolic efficiency factor (which I personally just assume is 4). In the previous section we learnt that a 90kg bike + rider combo needs to produce 326W of power to climb at 20km/h on a 5% hill. How much of a difference does having a light bike actually make? 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… Power-to-weight ratio is the maximum power output that can be produced in relation to body weight. There are three ways to improve your climbing: Increase threshold power, lose weight, or a combination of the two. Short-travel trail bikes feature about 110-130mm of rear-wheel travel. So riders will want to think through their frame and wheelset options when racing on climbing … To answer Nick O’s question it is simply a matter of efficiency. so you’re saying you weigh 90kg with your bike? Awesome article Matt! Lose some weight. Is there ever a trade-off? This number will be different for every rider,  and depends on many factors. I’m curious how much more energy hill climbing burns as opposed to flat routes. plus my bike is around 11kg including pump/spare tyres etc…. 1. Riding a mountain bike up a 20% gradient is easier because you can select a more appropriate gear and ride at a more sustainable (slower) speed and whilst still be ascending vertically at a similar rate. These bikes forgo heavy aerodynamic optimization in search for a frame that is as light and stiff as possible. Highly recommended. That … This is why really good climbers are generally skinnier or smaller than average riders. We highlight some easy steps you can take that will help you to be more efficient on the climbs. Posted: Sep 1, 2010 at 23:45 Quote: 30lbs is a decent weight for an AM bike. google_ad_height = 90; v = speed of the bike through the air (i.e. Very good and helpful. Our calculations are most accurate when climbing given accurate rider and bike weight. Component lists are updated almost daily. And what about Rider B, who’s just as powerful as rider B, but 5kg lighter? A 180-pound rider on a 20-pound bike results in an overall weight of 200 pounds. In a race up the 1 in 20 between two riders of the same power but different weight, the lighter rider should always win. Climbing was lively, It felt like my old Epic EVO with a … The Effects of Weight. A climbing specialist or climber, also known as a grimpeur, ... the cyclist must also lift the weight of his bicycle. A rider carrying excess fat can also improve climbing by losing weight. Also, as Jules alluded to, there is a Psychological side to is as well. So that is (using the 90kg example) 9.8*.1 *90 = 88.2 Watts taken just to go nowhere! Determining Ideal Bike Weight. Thanks a lot! Use the bike as a lever to help pull your weight over to the other foot. The ideal weight for a bicycle is 15 pounds, since that is the lowest amount allowed in competition. Yes that is all very well that a lighter rider can ride up hills faster than a heavy rider assuming they ( the lighter rider) have a higher power to weight ratio. Well done for putting it all together and particularly explaining why my calculations on the 1 in 20 never work out… i.e. I’ll definitely look into the energy expenditure issue. As a result our rider might be able to stay with the bunch for the entire 20-minute climb. Sorry Dave, but I think you have misunderstood the equation. That would mean it becomes more easy to climb at 1.500m vs. sea level. I have a Tomac Snyper at 30lbs and I climb some sick long climbs here in Japan. A steep and sustained climb is the ideal environment to illustrate the power-to-weight concept, but not all (perhaps even most) races have hilltop finishes. Where is the missing acceleration component (m/s^2) in the rolling resistance equation? To emphasise this point, here’s the above graph with an extra line added to represent a rider and bike with a combined weight of 85kg (i.e. You might possibly have some leverage from the warranty point of view. We can estimate that a well-maintained bike has a drivetrain efficiency of roughly 95% though, so: So, at 90kg (me + my bike), on a hill of 5% gradient, with no wind and on a decent road surface, I need to produce roughly 139W of power to travel at 10km/h. Unfortunately, one of the enemies of fast climbing is how much weight you have to propel up the climbs. So the algorithm that each company uses is certainly quite different. The Garmin Edge will produce an estimate of this parameter and Strava will also. The first thing that you should consider when getting a bike for hill climbing is the weight of the bike. Sounds simple enough, but I don’t think I could have done what you have here. If you are a bike rider capable of producing consistantly in the order of 250-300 Watts it means that most of your effort is being used just to overcome your own (and your bikes) weight! Increasing threshold power is arguably the most effective method, as it will also translate into increased power on flat terrain and time trials. 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. 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. Road bikes are not optimised for riding up 20% gradients because the gears are generally too high and they’re hard to ride at slow speeds (lower than 10km/hr). google_ad_slot = "0004268070"; Mass times speed is (kg)*(m/s), which does not produce Watts. In the standard simulated scenario (see the General Methodpage), a total weight of 85 kg is assumed. Power-to-weight ratio is a term regularly heard in cycling – especially by cyclists who find themselves struggling when climbing. If someone tried hard to minimize the weight of their bike and equipment then t… Some good long travel AM bike … I’m too tired from my bike ride up a 10 mile hill at the moment to be certain your formula could be used to get the answer to the problem I pose. Armed with a power meter, a steep climb, and twelve pounds of water, I set out to answer some questions. Having done a few epic bike rides, this route is about as spectacular as it gets. I’d like to say a huge thank you to Josh Goodall for his help in checking and revising this article. But how big is the weight penalty? But this example should make it clear that the lighter you are the better suited you are to climbing, assuming a fixed power output. If a rider keeps losing weight, and presumably some lean muscle mass (i.e., power), will he still climb faster? Awesome article. Stuff We Like, Rider Histories Get to Climbing Weight. And how long will that average speed take Rider B to finish the climb? Cannondale SuperSix EVO Hi-Mod Disc Dura-Ace Di2: £9,000 / $11,500 / €10,499 / … Let’s assume the rider in question (Rider A) is able to hold 326W for 20 minutes. Now imagine if the same rider, with the same functional threshold, managed to lose 5kg. Thank you very much. I think you may have missed a factor of g in the rolling resistance term. 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. And because that part of the equation factors in the rider’s weight — as discussed above — the lower the weight, the lower the required power to climb at a certain speed. Climbing Hills on a Road Bike. Bikes are becoming increasingly specialized as manufacturers make specific bikes for every kind of profile and terrain. News & Opinion, Bike Tech Essays As the weight came off climbing ability really increased. There’s an interesting way to apply this to longer rides with a lot of climbing such as the Three Peaks. It’s pretty obvious at this point that Rider B is going to win, all things being equal, but by how much? The giMs part of the equation. If an athlete can lose weight without compromising power output, there is almost always an increase in performance, regardless of the course profile. As can aerodynamics. If there is a tail wind, this number will be less than 0. You can ride this uphill at 10mph. On a flat surface the power to overcome gravity is zero. Here are five DC bikes that I like. Before heading up my local (and much shorter) Alpe d’Huez, I weighed the total mass (me, bike, and clothing) I would be carrying up the hill both with and without the extra bottles. I found your blog googling about Alto de Letras. This means it’s possible to express the effect of weight on climbing, with a fair degree of accuracy, by dividing one weight with another using the following formula: Let’s take a typical, relatively sprightly bike of 25lbs / 12kg as a demonstrator. But it will happen in the more mountainous parts of the world. 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. Posted 6 years ago. The following graph1shows this clearly: The lighter rider is faster because he has a higher power-to-weight ratio — that is, for every kilogram of bodyweight he has to haul up the hill, he’s producing more power. I really like your analysis of power and climbing. For example, today I did Frankston & back at a gentle pace, averaging 191W for the 2h45m. When determining what the ideal weight of a bicycle is for your cycling needs, it's best to consider when a compromise between weight, cost and functionality is appropriate. So, why isn't there a website that already lists component & bike weights? To understand why a higher power-t… 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 … BMX Bikes i find this stuff really interesting. He might be able to push 330W for 15 minutes, for example, but as the wattage increases, the length of time he’s able to maintain that wattage for decreases. can be found on almost every bicycle related message board. Or, alternatively, do a few more ascents of Kinglake to push up those wattage numbers. So we know that if a 70kg rider and an 80kg rider are producing the same amount of power the lighter rider will climb faster. Specifically I am doing the Haute route Alps in August and want to be able to ride as efficiently as possible over successive days. Your email address will not be published. Like many things, it depends. For example, I wish I’d ridden a heavier TT bike in 2011. I’d suggest 0.5 would be a fairly strong tailwind! I’ve gone through and calculated the required wattage for the whole number gradients from 0% (a flat road) to 20% (ouch), assuming that I want to maintain a speed of 20km/h on each of those grades. That is, a gradient of 5% can be plugged in as 0.05. Food You will help to build some good things to bicycle technology. 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. So, how does the required power change depending on the gradient, assuming we’re talking about a constant speed? The fastest setups available (Specialized Tarmac Pro or Cannondale EVO with Lightweight Meilenstein wheels) turn in a time ~17 seconds faster than the Tron bike over our ~49-minute test.. 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. This issue of power-to-weight ratios deserves an article (or several) of its own, but we can see from the above that there are three main ways you can improve your climbing speed: If you’d like to have a play around with some numbers yourself, without having to worry about formulas, variables and coefficients, I’d highly recommend the Bike Calculator website and the excellent and free Bike Calculator app for iDevices. There are three ways to improve your climbing: Increase threshold power, lose weight, or a combination of the two. Thanks for posting this info. This is that same amount of power needed to lift 90kg at a speed of 10cm/second no matter what the method of propulsion (crane, bike on hill, running up stairs, etc). For this calculation we’ll also need the average gradient of the 1 in 20 which is more or less 4% (not 5% as the climb’s name would suggest). (6.8/22.9) x 60 = 17.8 minutes = 17 minutes 48 seconds. For a 5% grade, each meter of road requires lifting the body weight … 😉. Nice article, mate. Rigidity and power can make more difference. 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. I am super impressed by your fun and knowledgeable approach to informing those of us who are obsessed with this kind of stuff. I will add that I dropped 5lbs off the bike for a total weight loss of 25-30 lbs.