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*"So as you can imagine I had to make some assumptions. The best number I can find for drag coefficient for a good racing motorcycle with rider fully tucked is .6 I could find no numbers for when the rider comes out of the tuck and is intentionally aerobraking with his body, so I just used an intermediate number between a race bike and a touring bike on which you sit upright. I used .75 could be higher or lower based on rider/bike combo.*

I know the GP guys' bikes are insanely light, but I just shaved a few pounds off an S1000rr with rider ( since the velocity is the the dominant term at high speeds anyway). Assumed 600 lbs total bike/rider weight.

I also had to guess on the cross-sectional area of bike/rider when they’re out of the tuck and I decided to use .75 square meters just using a rough guess based on a frontal photo of a GP rider on braking and average height of motorcycles, etc.

I also assumed sea level for air density.

At 210 mph, just wind resistance would be generating .51 G’s

at 200 mph it would be .466 Gs

at 180 mph it would be .375 Gs

at 160 mph it would be .299 Gs

at 140 mph it would be .228 Gs

at 120 mph it would be .168 Gs

at 100 mph it would be .117 Gs

at 80 mph it would be .076 Gs

Notice that it falls off quickly as speed decreases (the drag force is proportional to the velocity squared so halving the speed cuts the force to 1/4 it’s original value).

So the big takeaway from this and it definitely makes your point is that a 180 mph turn has 3.5 times as much braking force being applied by the wind before you even grab the brake lever as a 100mph corner. And the GP guys have 10 times the braking force from aerodrag on the front straight as they might have on a slower 60 mph turn. It’s definitely something that has to be taken into account.

For the starting at 180 mph I’ll be going X speed after 1 second, I can try to get you a more comprehensive answer to that another time, but fortunately you’re asking for a short time interval, so even though the drag force is changing with time, I’ll assume it is constant over that 1 second. My rough estimate is that in 1 second you will have slowed down to around 170 mph. Assuming a -.375 Gs and a starting velocity of 180 mph (80 meters per second), after 1 second you’ll have slowed down by about 3.7 meters per second. 76.4 meters per second comes out to around 170 mph. 10 mph in 1 second is pretty significant."I know the GP guys' bikes are insanely light, but I just shaved a few pounds off an S1000rr with rider ( since the velocity is the the dominant term at high speeds anyway). Assumed 600 lbs total bike/rider weight.

I also had to guess on the cross-sectional area of bike/rider when they’re out of the tuck and I decided to use .75 square meters just using a rough guess based on a frontal photo of a GP rider on braking and average height of motorcycles, etc.

I also assumed sea level for air density.

At 210 mph, just wind resistance would be generating .51 G’s

at 200 mph it would be .466 Gs

at 180 mph it would be .375 Gs

at 160 mph it would be .299 Gs

at 140 mph it would be .228 Gs

at 120 mph it would be .168 Gs

at 100 mph it would be .117 Gs

at 80 mph it would be .076 Gs

Notice that it falls off quickly as speed decreases (the drag force is proportional to the velocity squared so halving the speed cuts the force to 1/4 it’s original value).

So the big takeaway from this and it definitely makes your point is that a 180 mph turn has 3.5 times as much braking force being applied by the wind before you even grab the brake lever as a 100mph corner. And the GP guys have 10 times the braking force from aerodrag on the front straight as they might have on a slower 60 mph turn. It’s definitely something that has to be taken into account.

For the starting at 180 mph I’ll be going X speed after 1 second, I can try to get you a more comprehensive answer to that another time, but fortunately you’re asking for a short time interval, so even though the drag force is changing with time, I’ll assume it is constant over that 1 second. My rough estimate is that in 1 second you will have slowed down to around 170 mph. Assuming a -.375 Gs and a starting velocity of 180 mph (80 meters per second), after 1 second you’ll have slowed down by about 3.7 meters per second. 76.4 meters per second comes out to around 170 mph. 10 mph in 1 second is pretty significant."