Whats your speed into a 25mph headwind?

Gotta wonder what your pace speed is into that kinda wind. Was out for an afternoon 50mile ride this aft when the wind decided to pick up outta no where, bad thing was I had the Cosmic Carbone SLs on... BAD NEWS!!! I had my head down in 53X19 and couldn't crack 30kmh, mostly down at the 26-28kmh area for a good 20 km of fun . The best was turning around and spinning a 53X14 at 50kmh for the majority of time.

 

A bit hard to say. Would depend on whether I was by myself, whether the terrain was flat etc. I would struggle to stay above 30kmh...and like you, would just try to look forward to turning around and hammering with a tailwind.

 

Gee that's a 40kph headwind and you reckon you can maintain 30kph! (What's with measuring the wind speed in mph and then talking in kph and km's for your ride?) That is equivalent drag factor to riding at 70kph. Is your name Hercules? I'd guess 20 to 25 would be about as much as i could maintain and even then it would be a real struggle.

 

I was riding in 23 mph winds (so sayeth the Weather Channel), with 28 mph gusts (5 mph greater is a gust?) yesterday. The intention wasn't to go out too hard, just do tempo and EM. On the flatter ground, it was 15mph without spiking the HR above LT. Uphill and into the wind - about 11mph (hill that i normally can do at 13 or so). Unfortunately, there never really seemed to be much of a tailwind yesterday - every which way I turned I was getting blown - either back, or to the side - never forward!

 

i would say by myself it is around 11-12.

 

I could never ride in 25mph headwind with the cranks on 53X19. I'd be down on 39X29.
Well I rode in that crap today in NYC, I'd say I was going around 11 or 12

 

Criminy, you'd have to be turning close to 115 rpm to maintain 12 mph in 39x29T!! Quite a workout.

 

did a 42 mile ride with a buddy last week into a 25mph headwind for half the time, trading pulls every 3 minutes we were able to keep an 18mph average into the wind but this was our hard day


we get this type of wind all the time here which i really don't like, i'd much rather attack a mountain than deal with that kind of wind all the time

 

The max I hit was around 30 I was mostly in the 26-28 area grunting it out... 50 gusting 70kmh tomorrow... think I'll opt for the computrainer tomorrow....

 

riding at 30kph with a 40kph headwind does NOT equal a drag factor of 70kph.
this may seem like it makes sense but it is not the case. if it were, you would go 80kph with a 40kph tailwind, while pushing a normal 40kph effort. that would never happen.
don't ask me for the specifics, i am not a scientist

too bad it ain't the case because that would mean I could hit 100kph with a 30kph tailwind, in a sprint. that would kick a$$

 

The drag resistance or force would be equal to riding at 70 kph, but you're correct that the power you need to produce is much lower. The reason is that power required to maintain speed is equal to force x velocity. So, even with the same aero drag force pushing against you, riding 30 kph in a 40 kph headwind vs 70 kph in calm air only takes 3/7th (42%) of the power.

Another way to think about it is to look at the gears required to go 70 kph vs 30. To match the same aero drag force, at the same cadence, you've got to push a gear that's 7/3 (2.33 times) bigger, meaning you push the pedals 2.33 times harder.

 

oh yeah I was going around 115 rpm, at least it felt like that from training on the cycling machines. I always try to maintain above 100 rpm. Is that bad? Should I slow down the rpm in the wind? I dunno, I used to pedal slower at higher gears but that killed my knees.

 

during my tempo ride today, I was at 35mph with a 20mph tailwind, while pushing 350watts. totally kicked a$$, cars were creeping by me, even though most people go 50mph on that road.

going to other direction I was at 18mph with the same power. THAT sucked.

 

In fact, it’s very difficult to know what the actual wind speed when you are riding is. The speed you obtained form the weather station is different to what you have when you are riding a bike. Because 1) you almost always get some kind of shelter on the road; 2) the wind direction plays a huge part as well.


So, in the velomanct’s example (from scientific point of view):

To maintain 35 mph @ 350W you actually need only 13 mph tailwind, which blows exactly to your back.

To double check the accuracy of calculations I put your 18 mph with 13 mph of exact headwind and this gives roughly the same power, depends on you position.

If the wind speed was really 25mph, then by putting 300W your speed should be 11-12 mph.

But if you have the tailwind of 25mph you can go up to 16mph on the flat without even pedaling. By putting 300w it gives 42-43mph.