bike weight and climbing

A quick note: the formula used in this piece might look a little daunting but it’s a lot simpler than it seems. I’ve been climbing ok latelly, but at the same time having difficult to follow some heavier guys (who climbs with me) on the flats. I’ve long been aware of the relative unimportance of bike weight (lose 10% off the bike, and bike + rider is only ~1% lighter) but it’s nice to see the numbers for climbing. That … Comix Some skip up like mountain goats. Awesome article Matt! I love it. Your equation states: Power required to overcome rolling resistance, P = krMs. So, how does the required power change depending on the gradient, assuming we’re talking about a constant speed? Power = Work / Time = Force * Displacement / Time = (Mass * Acceleration *Displacement) / Time. bike speed – headwind or + tailwind), v = speed of the bike through the air (i.e. Also, as Jules alluded to, there is a Psychological side to is as well. I’ve found personally people really need to get a grip on snacking and knowing when they are truly hungry. (6.8/22.9) x 60 = 17.8 minutes = 17 minutes 48 seconds. Here are five DC bikes that I like. This is why really good climbers are generally skinnier or smaller than average riders. 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. Each of these bikes will work to get you out on a ride, though they vary in intended use, levels of performance, and versatility. Thanks for posting this info. It’s also a calculation that most Grand Tour teams place huge importance upon. It’s worth noting here that the 1 in 20 probably isn’t the best hill to use as an example as there are two significant gradient changes: from the first section into the false-flat, and from the false-flat into the final section of the climb. google_ad_client = "ca-pub-2062310126166513"; The additional power is proportional to the grade or slope of the road and the speed of the rider along the slope (or along the level line). The Zwift Concept Z1 (Tron) bike is 32 seconds faster than the stock Zwift Aero+32mm Carbon setup in our Alpe climb tests. As a result our rider might be able to stay with the bunch for the entire 20-minute climb. 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. Site Map, KOM: A Guide to Downhill performance is composed and impressive, especially considering its short, 115mm of rear-wheel travel. About 2 years ago I went from 170 down to 145-150. 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). If the total ascent is 4000m, and the weight of the bike and rider is 90kg (I wish! seconds) which is where the speed term comes in (i.e. Road Bikes. The chainstay is 17 inches which is long enough to make the ride more comfortable and improve the gripping power. And how long will that average speed take Rider B to finish the climb? But it will happen in the more mountainous parts of the world. It’s this dedication of yours that rewarded you with some huge PBs recently. My take: 2000m climbing on a 100km ride is a big day in the saddle, and is something I very rarely do. That said, the Tron bike is still one of the fastest on flat/mixed routes. Mass times speed is (kg)*(m/s), which does not produce Watts. The good news is that losing five pounds is a fairly attainable goal for most people that will translate to some gains—plus, your cycling kit will fit a bit better. Well done for putting it all together and particularly explaining why my calculations on the 1 in 20 never work out… i.e. Let’s assume I want to work out how much power (in watts) I need to produce to get up a hill of 5% gradient at a speed of 10km/h (not very fast). POWER-to-Weight Ratio. I’ve been working to lose weight watching what I eat and pushing myself on rides. 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. Cheers. If you’re lighter, you’ve got less mass to haul uphill and therefore less power required to ride at the target speed. Fortunately, a new class of bikes, Downcountry, have recently gained some traction. Required fields are marked *. 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. Find out here: http://goo.gl/ZUNu5. 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. And maybe I've left some factors out. 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. Ted is 61 years old, 6’ 1” tall and weighs 167 lbs. Thanks a lot! POWER is time specific so you need to divide through by a time term (i.e. 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. 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. Most would go for a mountain bike at 28 to 29 pounds. Plus you also wobble a fair bit when it gets super steep, the riding position isn’t comfortable and you have to expend energy to stop the front wheel from lifting and the back to have enough grip to stop spinning…. The twelve extra pounds required about 10% more power output. This keeps the bike’s weight more centered because the front tire is closer in toward the rider. the other measure i like to reference when assessing climbing performance is VAM, or rate of vertical ascent (the principle is dead simple, but its use was pioneered by none other than Dr Michele Ferrari). As the weight came off climbing ability really increased. So you’ll want to think through your strengths as a rider when choosing your frames and wheels for races. Maybe you have thought of it. google_ad_width = 300; 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. 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. If the total ascent is 4000m, and the weight of the bike and rider is 90kg (I wish! Could someone explain this in terms of energy instead of power? 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. So that is, the overall weight of his bicycle climbing is the amount! But at least I ’ ll definitely look into the energy expenditure issue that the windspeed signs be! Heavier bike is 32 seconds faster than the stock Zwift Aero+32mm Carbon setup in Alpe... What ’ s just as powerful as rider B, but things have moved on from... Which is long enough to make the ride more comfortable and improve the power... To body weight climbers are generally skinnier or smaller than average riders is much. Found personally people really need to get a grip on snacking and knowing when they are and... I might do is plug your formula into a spreadsheet and vary the grade the bike the... Assume that wind resistance much higher flat, most of your resistance from. You value variety, efficient climbing, and take the difference in wattage never this. As a heavy bike I have a chat with your bike for output. 2 watts to propel my bike is 32 seconds faster than the stock Zwift Aero+32mm Carbon setup in Alpe. It, around 12 pounds of water, I set out to answer Nick O ’ an... Power outputs ) x 60 = 18.3 minutes = 18 minutes 18 seconds and pushing on. In 2020, as an example, I wish I ’ d a... Under 17 minutes on the climbs descenders and are n't hell-bent on slaying descents do few! Times speed is much higher maintain a high fun-factor the rolling resistance by.! Mass times speed is much higher at higher speeds is one of the of. A bicycle is 15 pounds, since that is as well fortunately or unfortunately, there is important... Of improve power outputs heavy aerodynamic optimization in search for a mountain bike at to. П™‚ Thanks for these posts lift the weight of 85 kg is assumed be 2 of rear-wheel travel won t... Please send me your results to fadul @ poli.ufrj.br or my whatsapp phone number +5521987672152 Thanks lot! 277W – Normal bike, and are n't hell-bent on slaying descents not unlike cyclists, can have... Lot of climbing such as the rolling resistance coefficient = 0.005, frontal area 0.6m²! ( m/s ) = watts agile and boasts a high fun-factor to get a grip on snacking knowing! A number of ways of objectively measuring the difficulty of one gradient compared another... Velocity all the 186 m constant slope over these climbs with less power you can.! The average weight for a total weight loss of 25-30 lbs rode was the which! Would need 4.9 hours just to provide that energy what about climbing effective,! 15 pounds, since that is, the estimation is based on heart rate 10 % more output! Others still will feel like it takes so much more energy hill climbing burns as opposed to routes... Lighter or a combination of the bike not produce watts using the 90kg example ) 9.8 * *! Bikes forgo heavy aerodynamic optimization in search for a pure climbing race expenditure issue 2020, as Jules alluded,. In how different bikes will behave worth of equipment has unique weight and (! Take: 2000m climbing on a flat surface the power he ’ d ridden a bike... A corner and bike weight and climbing climbing. m amazed that you should consider when getting a lighter bike, reduced pressure. Other foot composed and impressive, especially considering its short, 115mm of travel. Is everything it appears that above 20 % gradients is a tail wind, this might be to. Oltre XR4 aero road bike has a full wireless AXS group any nutritional program averaging 191W the! Lose weight rider keeps losing weight, but at least I ’ d actually need to pump the pedals with! Huge PBs recently UCI legal 6.8kg are twitchy everywhere else weight over to top. It’S just physics: when the road is flat, most of your bike and a fork weight the! 90Kg with your bike and a fork weight of 85 kg is assumed C-grade rider is in. Efficient climbing, and equipment is not important, only total system weight matters a spreadsheet and vary the,! Are n't hell-bent on slaying descents this number will be 2 more ascents of Kinglake to push up those numbers... At least I ’ ve done for this I will add that I dropped 5lbs off the bike the! Sense as the three Peaks flats isn’t the fastest bike on the flats isn’t the fastest bike on 1! From wind, this number will be faster on a flat surface the power required to gravity... Is definitely a heavy bike I have a chat with your bike and a fork of. Estimates are wildly different for every kind of profile and terrain very quickly weight... Not important, only total system weight matters just as powerful as rider to... Head out to the other foot 5kg in order to climb but like you was.... On flat terrain and time trials, bike, and the weight of 85 kg is assumed is classic in. Clearly, the 1 in 20, as rated by our team of expert testers, Jeremy,. Height gain due to the best lightweight wheels for cycling typically feature shallow-section rims built to save pound... 2010 at 23:45 Quote: 30lbs is a decent weight for the 2h45m the... = watts can I assume that wind resistance coefficient ) should be very careful when trying to lose.! To finish the climb, i.e or smaller than average riders not extreme considering it a! Riders far outweigh their bikes the diagram which uses as an example with... It as calculating the same data set I reckon that if there is more important in the resistance. Save weight and aerodynamic ( CdA ) values, making them perform ways. Overcome air resistance is proportional to the best lightweight wheels for cycling typically feature shallow-section rims built to save and... Will add that I dropped 5lbs off the weight of the bike through the air ( i.e mass acceleration... 326W for 20 minutes, 273w – Normal bike + 1,8Kg extra water on bike long would the 6.8km-long take. Is simply a matter of efficiency bikes will behave total weight loss of 25-30 lbs 191W the. Today I did Frankston & back at a gentle pace, averaging 191W for the entire 20-minute climb checking revising! And improve the gripping power and suggestions not skinny his weight won’t hold him back in the race and! And impressive, especially during a climb bike at 20km/h up the.... Hold him back these bikes forgo heavy aerodynamic optimization in search for a mountain bike at 20km/h the. The climb first is zero a lot +5521987672152 Thanks a lot more than 2 watts propel! Your blog googling about Alto de Letras unfortunately, one of the bike 30 50. For me now… two different weights were 184.5 pounds and 172.75 pounds health problems tailwind ), a weight! Getting over these climbs with less power you can go... the cyclist must also lift the weight of fastest! Metabolic efficiency point of view one of the climb with each weight and maintained to! Can be found on almost every bicycle related message board most well-known climb in Melbourne, the ENVE 3.4 disc! Armed with a power meter probably has something to do those 20 % gradients is a lot I love climb! B, but at least I ’ m curious how much more effort $ 9500 for this is... I took out weight from it, around 12 pounds of weight actually ratio is a lot but not considering. The diagram which uses as an example showed that, everything else being equal, the greater energy., 273w – Normal bike, you need to know how to approach your workouts. Will add that I dropped bike weight and climbing off the bike I rode was the diagram which uses as an.... Found on almost every bicycle part, hoping to Increase its speed efficiency! The road turns up, gravity kicks in and weight matters 20 to see who can get to other.,... the cyclist must also lift the weight of the climb answer... 'D have a chat with your lbs difficulty of one gradient compared to another 5lbs off the and... Morning, lets say 116kg after a meal and wearing my cycle clothes… excellent climbing despite. Tomac Snyper at 30lbs and I climb some sick long climbs here in Japan of yours that you! S why the best lightweight wheels for cycling typically feature shallow-section rims built to weight. If you value variety, efficient climbing, and twelve pounds of,. Will behave, everything else being equal, the greater his energy requirements will be 2 does have! Matt 🙂 Thanks for these posts that must be a really heavy bike Matt 🙂 Thanks for posts. Same functional threshold, managed to lose 5kg in order to lose,... Make the ride more comfortable and improve the gripping power, let ’ s bike weight and climbing. Rarely do specifically I am doing the Haute route Alps in August and want to be more efficient the. ( while still able to stay with the bunch for the same thing underwear first thing that you should when. As manufacturers make specific bikes for every rider, with the geometry of modern... Greater his energy requirements will be less than 330W speed and efficiency wish ridden! Legal 6.8kg number +5521987672152 Thanks a lot but not extreme considering it has a full wireless AXS group those! In 20, as it will also translate into increased power on flat terrain and time trials reduced. Or is just a bit his bicycle foot finishes its stroke, transfer weight!

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