Coast downs in addition to a cal ride?
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ScottChapman
- Posts: 186
- Joined: Thu Sep 18, 2008 9:42 pm
Coast downs in addition to a cal ride?
If I have already done a cal ride, would coast downs help get a more accurate profile? If so, what additional work is done with a coast down (what aspects of the profile would be improved)?
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lorduintah
- Posts: 642
- Joined: Fri Jan 11, 2008 9:37 am
- Location: Plymouth, MN
Re: Coast downs in addition to a cal ride?
The cal ride is applied to the wind scaling and tilt. The other power components that are refined with coast downs include CdA, friction and Crr as you are measuring the rate of deceleration based on you normal riding position - hoods, bars, drops or other. The more CDs you do the better chance that these values will be determined correctly for your typical road surface (another factor that can influence your ride.)
Tom
Tom
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ScottChapman
- Posts: 186
- Joined: Thu Sep 18, 2008 9:42 pm
Re: Coast downs in addition to a cal ride?
OK. I have attached my cal ride with 8 coast downs. The surface was pretty smooth, byt the Crr seems pretty low.
SHould I take the Adjusted Crr or fix it to 0.0055?
SHould I take the Adjusted Crr or fix it to 0.0055?
- Attachments
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- 100925_cal_data.ibcd4m
- Cal ride (with coast downs)
- (376.59 KiB) Downloaded 333 times
Re: Coast downs in addition to a cal ride?
Can you post a ride file from a solo ride on a calm day?
If you did the coastdowns on a smooth road, but used the fixed crr of .0055 then it will make your aero numbers too low. he fixed crr has solved some issued, but created others.
Honestly, the best and easiest way to get a good accurate profile is to run through the fast start menu using the estimated aero and then do a longer (2+ miles out, and then back). With the coastdowns, if you don't have something right beforehand then you can get really bad data. With the estimated aero you'll always be a within a certain range.
You can also fine tune using the estimated aero. Enter the coast down screen and start coasting. Judging by the wattage being shown (this will show a positive or negative wattage) you can then adjust your weight on the estimated aero screen.
For example, if you are 5'8" and 160 pounds. then you go to the coast screen and as you're coasting it says you are at +25 watts. Then you can go back into the estimate aero and adjust your weight to 155 pounds and see how that looks.
If you did the coastdowns on a smooth road, but used the fixed crr of .0055 then it will make your aero numbers too low. he fixed crr has solved some issued, but created others.
Honestly, the best and easiest way to get a good accurate profile is to run through the fast start menu using the estimated aero and then do a longer (2+ miles out, and then back). With the coastdowns, if you don't have something right beforehand then you can get really bad data. With the estimated aero you'll always be a within a certain range.
You can also fine tune using the estimated aero. Enter the coast down screen and start coasting. Judging by the wattage being shown (this will show a positive or negative wattage) you can then adjust your weight on the estimated aero screen.
For example, if you are 5'8" and 160 pounds. then you go to the coast screen and as you're coasting it says you are at +25 watts. Then you can go back into the estimate aero and adjust your weight to 155 pounds and see how that looks.
Boyd Johnson
http://www.boydcycling.com - high performance carbon wheels and accessories
http://www.boydcycling.com - high performance carbon wheels and accessories
Re: Coast downs in addition to a cal ride?
If only it were that easy in real lifecoachboyd wrote:Then you can go back into the estimate aero and adjust your weight to 155 pounds and see how that looks.
-- Ken