Jump to content
Sign in to follow this  
fishboy

Getting aero and pacing for TristanP

Recommended Posts

Thanks for sharing the photos Tristan!

 

Some quick Q's;

Elbows much closer together. How does this effect your breathing?

 

Elbows much lower due to forearm angle, side effect is head is much lower. How does this effect your visibility?

 

Seat angle must be close to 90% in the current shot, does this load up your quads or do your glutes still work ok at this angle?

 

Thanks again!

No problem...

 

Any change in position takes a while to adjust to, and I have been adapting to this one for a while now. It is not at a point where I am confident of being not only comfortable for 180k, but more comfortable than my previous position.

 

Visibility? Why do you need to see where you are going??? Its not actually that bad, I watch the road about 3 or 4 meters in front of me, and look up to make sure that there are not issues every now and then. To be honest, if you knew me you would understand that vision is not a high priority. I am almost legally blind without glasses on and I dont race with contacts or glasses, so being able to see much further in front of the bike wouldnt help anyway ;-)

 

I have always ridden a tri bike steep like this. It is something that some people are able to do and others are not. It works for me. It does load up the quads a little more than is you were more slack with the seat angle, but as I said, it works for me.

 

On a side note, if I was racing a 1/2 rather than a full, I would more than likely go a little more Landis on the front. This is faster, but its not comfortable for a long distance. Its something that I tested at Shep half and rode a 2:11 but would not be able to hold the position for as long as needed for a full.

Share this post


Link to post
Share on other sites
I ride steep, like really steep... It is an Adamo, and I dont know what the seat angle figure would be with a normal saddle, but it would be well over 80 degrees

The Lilo likes to go steep as well :lol:

 

In fact, having had a recent bike fit check by Parkside, he confirmed to me that I am the current steep seat angle Parkside bike fit title holder.

 

Interested in what your seat angle is when you get a chance to measure it (I'll just need to confer with Parkside to find out exactly where on the seat he measures the seat angle from).

 

TGL

Share this post


Link to post
Share on other sites
My IMWA CdA was 0.31. Looks like im ratsh!t,

Thought this might make you feel better Rattie.

 

Did the Kurnell TT this morning. Decided to get as slippery as I could given that it is only 16 km and I don't need to run off the bike.

 

Lowered my bars to the lowest possible level. Moved my aero bar elbow pads as close together as possible. Bought a skinsuit

 

Used my P3 with aero helmet. Only non aero thing I used was my training wheels rather than my race wheels.

 

Power Calculator tells me that my CdA was 0.3367 :lol:

 

TGL

Share this post


Link to post
Share on other sites

Are you sure you got all the right settings? Sounds kinda high if you beat TU5, musta been putting out about 650 watts for 16km.

Share this post


Link to post
Share on other sites
Are you sure you got all the right settings? Sounds kinda high if you beat TU5, musta been putting out about 650 watts for 16km.

More than happy to be corrected on the settings.

 

I kinda used the default ones except I put in 40kph for av speed (because that was my average speed) and 316W for my av power (which is what my Garmin told me was my av power).

 

Put in 90% humidity (happy to accept that it was 100% given that it was raining). Don't think that I changed any of the other settings re smoothness of road etc. Maybe the road is not super smooth but it is pretty smooth. I guess the only other thing is that there is two turn around points so it is not a point to point course (not sure if this matters but anyway, thought that I would throw this in).

 

Happy to stand corrected re the settings (or anything else for that matter). Very interested in being as slippery as possible and although I didn't have shoe covers or race wheels, I was otherwise in my most super slippery position :lol:

 

TGL

Share this post


Link to post
Share on other sites

Sorry Fishboy - forgot to mention that it was also a very windy ride. The course changes compass direction a lot so the yaw angle is constantly changing and wind velocity is also constantly changing as it was quite gusty.

 

TGL

Share this post


Link to post
Share on other sites

if it is really windy it throws things off.... that does represent your drag for those horrible conditions, but if it was calm or light winds you'd probably be a lot more aero.

Share this post


Link to post
Share on other sites

if it is really windy it throws things off.... that does represent your drag for those horrible conditions, but if it was calm or light winds you'd probably be a lot more aero.

Share this post


Link to post
Share on other sites

if it is really windy it throws things off.... that does represent your drag for those horrible conditions, but if it was calm or light winds you'd probably be a lot more aero.

Share this post


Link to post
Share on other sites

if it is really windy it throws things off.... that does represent your drag for those horrible conditions, but if it was calm or light winds you'd probably be a lot more aero.

Share this post


Link to post
Share on other sites

Were you doing the testing using a motorbike? Seen someone motorpacing a few times between Black Rock and Mordiallic ...

Share this post


Link to post
Share on other sites
if it is really windy it throws things off.... that does represent your drag for those horrible conditions, but if it was calm or light winds you'd probably be a lot more aero.

Thanks Fishboy - was hoping that this was the case.

 

Will see how the power calculator goes when I use it to analyse data taken in better conditions. Thanks again for sharing it - much appreciated.

 

TGL

Edited by The Glycogen Lilo

Share this post


Link to post
Share on other sites

this is the stuff i put into the calculator

 

You submitted the following information:

Mass: 90 kg

Air density: 1.199

Speed: 10 m/s

Slope: 0

CdA: 0.3131

Crr: 0.004

Power: 223 watts

 

My hands have changed position slightly since these pics. As TGL said maybe its about weight and size.

Lastlap3.jpg

Bike3.jpg

1stlap2.jpg

Share this post


Link to post
Share on other sites

I would have thought that my huge aerofoil shaped honker and large overbite would have been somewhat advantageous!

Share this post


Link to post
Share on other sites
Were you doing the testing using a motorbike? Seen someone motorpacing a few times between Black Rock and Mordiallic ...

 

Er... no. Motorpacing behind a bike will give you a very low drag number as the motor bike is doing most of the "work" to move air out of your way. Carnegie velodrome is our location of usual testing.

Share this post


Link to post
Share on other sites
this is the stuff i put into the calculator

 

 

 

My hands have changed position slightly since these pics. As TGL said maybe its about weight and size.

Lastlap3.jpg

Bike3.jpg

1stlap2.jpg

 

RD, you've got a pretty typical triathlete position... plus big shouders and noggin ... By eyeball I'd say 0.280-0.285 ... if you take a small chunk of data at constant speed/watts (eg. 2 min) in this position and run through the calculator, what comes out? A full IM will have a higher CdA as you spend time climbing, out of the saddle for rests/stretching/drinks etc, whereas holding this aero position is probably the figure above.

 

Some suggestions, bearing in mind: a. I am not a bike fit guru - these are aero purely suggestions, and may hamper your bike fit/function. b. Don't change anything too close to IM, you need time to adapt and c. If you do change things, and it goes wrong, please remember I warned you that this could happen.

 

- Forearm angle: Looks like about 125 deg angle between forearm and upper arm. It may be more comfortable, and more aero, if you tip your forearms up to around 15 deg, reducing this forearm-upper arm angle. It will also help deflect air away from your chest/hip area. Your aerobars might not allow this as you have to rotate the bars up, and keep the base bar flat.

 

- Elbow width: Wide is comfortable. But not aero. If you can, try narrowing the elbow pad width a bit. Again, your bars may make this difficult.

 

- Head: There is a lot of lid up there in the breeze, and the Spuik suits that style with the underside of the lid fitting nicely onto your back. If you can lower your neck and rotate your head up (turtling) you will be more aero, but less comfortable. You may need a different helmet with a shorter tail as a Spuik won't work as well if you do it. This will possibly reduce your frontal area by quite a bit and give you a good drag reduction. It may also be too uncomfortable to ride for a full IM, so use caution. Looking down to relax your neck muscles can help, but you have to be very careful you don't prang into anything... this gets more critical as you get tired!

Share this post


Link to post
Share on other sites

Looking at before and after pics and something I have often thought about as I push into the wind, is positioning of the hands at the end of the aero bars.

 

Maybe a dumb question, but if you hold your hands with fingertips together rather than as a kinda fist, is there any difference in aero? Does the 'fairing' created by your hands push air out and around? Or is this just wishful thinking

Share this post


Link to post
Share on other sites
RD, you've got a pretty typical triathlete position... plus big shouders and noggin ... By eyeball I'd say 0.280-0.285 ... if you take a small chunk of data at constant speed/watts (eg. 2 min) in this position and run through the calculator, what comes out? A full IM will have a higher CdA as you spend time climbing, out of the saddle for rests/stretching/drinks etc, whereas holding this aero position is probably the figure above.

 

Some suggestions, bearing in mind: a. I am not a bike fit guru - these are aero purely suggestions, and may hamper your bike fit/function. b. Don't change anything too close to IM, you need time to adapt and c. If you do change things, and it goes wrong, please remember I warned you that this could happen.

 

- Forearm angle: Looks like about 125 deg angle between forearm and upper arm. It may be more comfortable, and more aero, if you tip your forearms up to around 15 deg, reducing this forearm-upper arm angle. It will also help deflect air away from your chest/hip area. Your aerobars might not allow this as you have to rotate the bars up, and keep the base bar flat.

 

- Elbow width: Wide is comfortable. But not aero. If you can, try narrowing the elbow pad width a bit. Again, your bars may make this difficult.

 

- Head: There is a lot of lid up there in the breeze, and the Spuik suits that style with the underside of the lid fitting nicely onto your back. If you can lower your neck and rotate your head up (turtling) you will be more aero, but less comfortable. You may need a different helmet with a shorter tail as a Spuik won't work as well if you do it. This will possibly reduce your frontal area by quite a bit and give you a good drag reduction. It may also be too uncomfortable to ride for a full IM, so use caution. Looking down to relax your neck muscles can help, but you have to be very careful you don't prang into anything... this gets more critical as you get tired!

 

 

Thanks Fishy,

 

I have rotated the bars up since those pics and it feels pretty good. Ill see how things go at Port.

 

Softy, I often ride with hands in the prayer position, psychologically it works wonders although im sure The Hot Pants Guru isnt listening to my murmers about the constant head winds.

Share this post


Link to post
Share on other sites
Looking at before and after pics and something I have often thought about as I push into the wind, is positioning of the hands at the end of the aero bars.

 

Maybe a dumb question, but if you hold your hands with fingertips together rather than as a kinda fist, is there any difference in aero? Does the 'fairing' created by your hands push air out and around? Or is this just wishful thinking

 

It depends... really small changes in hand position can make a significant difference. Ask Dalai...

Share this post


Link to post
Share on other sites
Thanks Fishy,

 

I have rotated the bars up since those pics and it feels pretty good. Ill see how things go at Port.

 

Softy, I often ride with hands in the prayer position, psychologically it works wonders although im sure The Hot Pants Guru isnt listening to my murmers about the constant head winds.

 

Have you got a short run bit of power/speed data (~2min constant speed/watts flat course low wind) to calculate a rough CdA?

Share this post


Link to post
Share on other sites
Have you got a short run bit of power/speed data (~2min constant speed/watts flat course low wind) to calculate a rough CdA?

 

This is the best fit (flat i could find from that day in busso

 

You submitted the following information:

Mass: 90 kg

Air density: 1.199

Speed: 10.83 m/s

Slope: 0

CdA: 0.2284

Crr: 0.004

Power: 212.2 watts

Share this post


Link to post
Share on other sites
This is the best fit (flat i could find from that day in busso

There you go - you are now in the "super good" category!!

 

Reckon that all you need to do now is get an all over body wax, polish up the helmet and you will move into the "slippery like a fish" category :lol:

 

TGL

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×