Good TT Loops

ppereira
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Re: Good TT Loops

Post by ppereira » Mon Jan 27, 2020 3:23 pm

this is a long drive for anyone (except for me when I'm down there anyway) but the Buzzards Bay Tri course in Westport is one I do when I'm visiting my parents, it's about the only place where I've been able to do steady power intervals outside of the trainer, and if you like wine or beer and you're down on a Saturday you can hit up Westport Rivers and Buzzards Bay Brewing on the loop lol

https://www.strava.com/segments/16056154?filter=overall

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KTeves
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Re: Good TT Loops

Post by KTeves » Tue Jan 28, 2020 10:44 am

Thanks Phil! Looks like a TT route I want to try. I'll have to remember to bring my bike with me when I visit the fam. in the area.

Funny that looking at the elevation profile you'd almost think there are some pretty good hills in there, but the whole course has only about 100 feet of elevation.
KT

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remad
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Re: Good TT Loops

Post by remad » Fri Jun 05, 2020 9:52 am

hjron wrote:
Thu Jan 23, 2020 12:57 pm
After a dismal TT at GMSR, I used the Aerolab Chung Analysis feature in Golden Cheetah to find the best aero position. It took a while to work out the process so I could repeat reliably. But once I got it down, I found the feature was sensitive enough to estimate/measure CdA differences due to the various positions I tried.

Fitwerx has a pretty good guide for Aerolab here: https://fitwerx.com/ask-fitwerx-article ... available/

It's recommended to use a short loop so you can run your trials on the same day in the same weather conditions. Then just repeat the same number of runs after tweaking whatever test variables you want (like helmet A vs B). I found a nicely paved loop with all right-hand turns in my neighborhood that had minimal traffic.
The article doesn't mention it, but wouldn't this require a speed sensor? GPS doesn't seem reliable enough to catch small differences in CDA on a short loop like this.

hjron
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Re: Good TT Loops

Post by hjron » Fri Jun 05, 2020 3:06 pm

Correct - you should use a speed sensor! And don't touch the brakes =)

Let me know any questions about GC setup, I may be able to save you some time

I'm thinking about getting one of these to take the testing to the next level: https://notio.ai/

Maybe rent it out to others on the team so I can recoup some of the cost. Interested?

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remad
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Re: Good TT Loops

Post by remad » Fri Jun 05, 2020 3:26 pm

I might be interested, going to attempt a few rounds of the Aerolab Chung Analysis first. How much do you think you would charge? It is pricey, but it might end up saving you more time than other expensive upgrades (like a wheelset).

I've actually done a couple of test runs of the Aerolab Chung Analysis and it does take some getting used to. If I assume that the numbers are right, then my CdA on my TT bike is around 0.0031 right now which seems high for a TT bike, so hopefully with some fine tuning I can get that down.

I put off aero testing because the races that I wanted to use the TT bike in got cancelled, but thinking about giving it a real go tonight with different wheelsets to see if results are repeatable.

hjron
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Re: Good TT Loops

Post by hjron » Fri Jun 05, 2020 3:57 pm

Pricey yes, but I was also running that very same watts_saved/dollar rationalization in my mind... I'll let you know once (if?) I get the device.

Do you mean CdA of 0.310 for your TT bike? Your bike is a couple of orders of magnitude lower than what I've seen for CdA range so maybe you have to tweak some params? There's a good setup guide if you google "floataero golden cheetah"

The relative number is probably most important though. I was able to get my road bike from 0.3804 to 0.3154 just by optimizing my position.

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remad
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Re: Good TT Loops

Post by remad » Fri Jun 05, 2020 4:03 pm

Yes, 0.31, was confusing a couple of things due to multi tasking lol. I would be really fast at .0031. If my tests go well tonight I will post an updated number. But some people can get their CdA in the range of .2, maybe they are shorter people?

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pace21
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Re: Good TT Loops

Post by pace21 » Sat Jun 06, 2020 7:12 pm

Height giveth and height taketh away

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tsavage
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Re: Good TT Loops

Post by tsavage » Sun Jun 14, 2020 7:11 pm

"When I see an adult on a bicycle, I do not despair for the future of the human race." - H.G. Wells

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