How close is best bike split

I hace posted in the past my desire to go sub 5 on the IM bike so I chose Maryland (again) for the flat course.

BBS is telling me I need to average 200 watts to go 4:59

Are they pretty on the money? Cleary the race is far away so my numbers will be adjusted over time.

Once you have done some testing and have adjusted your cda close to what it really is in the real world, yes it’s pretty accurate.

You will also need to re-run it multiple times as you get closer to the race. The weather forecast adjusts more the closer you get to the date.

Once you have done some testing and have adjusted your cda close to what it really is in the real world, yes it’s pretty accurate.

You will also need to re-run it multiple times as you get closer to the race. The weather forecast adjusts more the closer you get to the date.

I have no real way to measure my CDA

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You don’t have to measure, you can estimate it.

Setup a race/course in BBS that you have done with your information. Then adjust CdA in BBS until you get to what your time/split was. Use that CdA for the future races. You might need to run different several prior races/courses just to make sure your CdA estimate is relatively accurate.

Another option is go ride 20-30km in full race setup and import that bike file into the BBS aero analyzer tool. That will estimate your CdA.

I can’t remember for sure but some of these features might require the paid version.

This may help…

https://www.bestbikesplit.com/case-study-aero-analyzer

Do you have a power meter? Then you can get a good idea of CdA.

http://forum.slowtwitch.com/...g_Protocol_P3536905/

Over 5 races I have found it to be dead nuts accurate. My 2 cents.

I’ve found it pretty accurate. The way I “figured” out my Cda was to plug in past races then adjust cda until I got close to the time. Then I’d add other races using that cda to see if the time was close.

It has been pretty spot on for me except for one race. But that was because I started in a late wave and was able to sling shot basically the whole ride.