# I don't understand wattage : speed ratios

I don’t get it. I am a bigger guy - for a cyclist (~190 lbs, 6’2"). am I hitting a point where I am just like a sail or something?

two days ago in perfect conditions I rode ~200 watts and was ducking into an aero position on the hoods or in the drops…I tried to hit corners sharp, etc. 26.7 km/hr

today was slightly swirly winds but otherwise similar conditions. I was on the hoods the whole time and rode at ~160 watts. like basically super super easy for me. 26 km/hr

I understand there are a lot of variables to speed but c’mon! i feel like at some point I have to pedal sooooo hard to get any extra speed. is this normal?

looking back at recent rides, even going at 270 I am only getting to like 31km/hr

(my course is rolling terrain…no major hills but not flat for long…always slightly up / down or 2 min hills here and there).

Aerodynamics play a massive role on the flatter terrain, most of that being your body position.

A bit of wind can make a large impact on how fast you are going and the watts required to maintain a specific speed.

It sounds like you are doing this on a course? If so any stops or other variables can make a very big impact on your overall average speed.

You can test by finding a specific section of road and doing several repeats of it to get a better idea of the power required for different speeds.

Something like myWindsock can also be helpful if you are keeping your power consistent and adjusting your body position to test it out.

Were you on the exact same route? Hills obviously make a big difference. I’d assume zero stops for both, any stops throw averages out the window pretty quick. Identical tire pressures and similar clothing are also important.

Once you hit around 17-18 mph, aero makes a much larger difference and the return on watts for speed diminishes crazy fast. That’s why an elite racer may finish a race averaging 270 watts and 21 mph, while another racer in the same race might average 175 watts and 18 mph.

I have a local “100k” bike route I do most every other Sunday. The route is about 45 miles out and back, so I tack on some random backtracking. Other than that, it’s nearly identical weekend to weekend (I generally wear the same thing with no stops, same tire pressure). The last two times I rode it were as follows:
1st time - 63.01 miles, 3:29, 1322’ ascent, 18 mph, 154w average power
2nd time - 62.41 miles, 3:38, 1325’ ascent, 17.1 mph, 160w average power

Now that I look at it, a .9 mph is slightly more difference than I would expect, but if I did any sections really slow and then made it more power later, etc. that would have an impact. Each ride I had less than 2 minutes non-moving time.

If you can provide more stats of each ride, that might help determine the differences.

Yeah, aerodynamics are everything when it comes to speed vs. watts on flatish courses. And the relationship between watts and speed isn’t linear, so it takes a lot more watts to gain another kmh as your speed increases.

And I wouldn’t read too much into comparing a few rides. It’s really hard to tell what the wind is doing and you may not be in the same position each time like you think you are. Little things make big differences and what feels (or looks) aero isn’t always aero.

It’s definitely something that can be worked on and you can gain a lot of speed very quickly if you are willing to put in the work. All you need is a good stretch of road and schedule some days that are reserved for testing different positions and equipment. It won’t be a perfect process, but most people don’t even do that much. Google “chung method”, it’s a method for measuring aerodynamic drag. Once you have a decent way to measure, it’s just a long and tedious trial and error process.

During covid, we were doing a lot of solo riding and several of us were trying to see how fast we could roll a solo century on a road bike. With minimal group rides, it was easy to fit in a bunch of solo testing and it was pretty cool to see speeds increase (at similar watts) by trying new positions, cloths, equipment, etc. People think that “getting aero” is just about getting low on the bike, but it’s very individual. For me, focusing on getting narrow was much more effective than getting low, but everyone is different. And I’m still not a very aero rider, but dramatically better than what I was.

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yeah same route but stops depend on traffic. i don’t have a way to log it but it didn’t seem unusually different. the only difference was a slight swirly wind. still though i would have guessed 160 to 200 would be a bigger difference in speed than say 260 to 300.

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Stops mess your average up most. Do loops with only right turns and no street lights and you’ll get an extra +1mph average or so at same effort and weather

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Stops alone make this kind of unreasonable to compare. A small difference in time spent slowing down and speeding back up can have a large impact on the average speed not to mention the different wind conditions.

Add to that different clothing, weight and any other variables.

Have you tried looking at mywindsock?

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Agree with others, the stops make a huge difference. it doesn’t take many seconds at 0mph to really bring down your average.

Try looking at specific segments within that route where you have a known wind direction and no stops to get a better comparison.

Also, don’t underestimate that a swirly wind could give you a net positive benefit if it happens that you get tailwinds on open sections and headwinds on more covered sections or something like that.

Terrain and wind are two huge factors. With rolling hills you often cannot make up the time on the downhill that you spend on the uphill. Pacing also plays a crucial role: do you pace for highest average speed or do you want to stay in Z2? If you want to maximize average speed on a long right and you picked a course with rolling terrain, you might want to increase power output on the uphill a little and not let it drop too much on the downhill. (There is the temptation to give it the beans uphill and let drop power too much on the downhill.)

However, if you aim to ride Z2, then this might not be the right way to go about it since your goal is to stay within Z2 rather than maximize your average speed.

You should not use average speeds reached on the flats as a guide stick for hilly or mountainous routes.

Here is what I would do:

• The biggest factor is aero drag, so train yourself to stay in the aero hoods position for as much as possible. This is the fastest position where you still grip your bars. (Don’t do .) Alternate between aero hoods and your drops.
• Get tight-fitting clothing, this is a huge win.
• Pace evenly, don’t let your power drop when going downhill and don’t overdo it uphill.
• Take terrain into account when you are going fast. Flat terrain favors heavier riders with high Watts (FTP in absolute terms). The more climbing you do, the more relevant your W/kg (FTP relative to your weight) becomes.

Even fairly subtble wind speed and direction differences can make a big impact.

And wind is much more varialbe than most people think. I raced sailboats for a time. Wind is never steady in direction or speed. Sailors are constatnly playing 5 degree wind shifts and gusts of a couple mph every few minutes during a race to get an advantage while at the same time on land cyclists say stuff like “slightly swirly winds.”

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Do you have auto-pause turned on? If so, turn this off and then compare the total time at zero speed (speed below 5 mph) between rides. This will give you a good estimation of the impact of traffic on your ride average speed.

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Your averages are totally ok when including stops, traffic etc. Please don‘t take any risk for this number.

I only look at average speed on segments without traffics and other obstacles. You have to find them, there is some fun in trying to best your previous PR.

Without looking it up, no significant winds: It should be easy to hit 35 km/h (I guess it takes around 200-250W?). Totally possible to do 40 km/h on longer segments and faster, up to 50 km/h, on shorter segments (~8min). But that‘s me.

Also check if your PM is calibrated.

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Every time a cyclist talks about wind I chuckle in sailboat racer.

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