TT bike mounting

[John]

The first picture is a top view close-up of the stem and aerobar extensions. The second a stock photo of the bullhorn handlebar. I know this is old-school stuff. I am not the original owner of the bike, a 2009 Cervelo P3. I am not sure how wide the mount is that comes with the aeropod. Could it fit between the aero-bar extensions and the stem? The handlebars are Easton Deltaforce with Easton Aeroforce carbon extenstion bars.

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[Velocomp]

Only 1 image was posted. Please post the other one.

[John]

Here is the stock image I mentioned. I will post other pictures of the handlebar and extensions later. Could a mount like the Newton Dual be designed for the AeroPod? Even better, a mount that used the same idea as a hose clamp but the band would be flexible enough to mold around any shape.

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[BillOsler]

How much room is there between the extensions and the stem?
Alternatively how much room is there on the round section of the base bar on the outside of the extension?
I don't have calipers to get an exact measurement but all of the mounts I checked are about 3/8" (~9.5 mm) wide.
What I ended up using on my TT bike was a K-Edge K13-420: https://k-edge.com/shop/light-and-actio ... r-mount-2/
That K-Edge mount places the Aeropod well in front of the base bar, about the same distance as the Velocomp TT mount, but the mounting method is different since the Velocomp mount attaches via the bolts on the bottom of the extension mount if the extension mount uses 2 bolts.

[trpnhntr]

I also have a Speed Concept and an (apparently useless to me) TT mount.

My plan had been:

Take my existing TT bike computer mount (I race with a Wahoo Element Bolt) which is this https://k-edge.com/shop/computer-mounts ... -tt-mount/

Buy this piece https://k-edge.com/shop/computer-mounts ... interface/

Use that for whenever I wanted to throw my Garmin and AeroPod onto the TT bike to do some Aero testing.

Because the speed concept has fully integrated aero bars I don't think the concerns about movement should be too severe and I plan to mount it at the very base of the bars so it will be level and see minimal play.

Does that seem viable?

[Velocomp]

I also have a Speed Concept and an (apparently useless to me) TT mount.

My plan had been:

Take my existing TT bike computer mount (I race with a Wahoo Element Bolt) which is this https://k-edge.com/shop/computer-mounts ... -tt-mount/

Buy this piece https://k-edge.com/shop/computer-mounts ... interface/

Use that for whenever I wanted to throw my Garmin and AeroPod onto the TT bike to do some Aero testing.

Because the speed concept has fully integrated aero bars I don't think the concerns about movement should be too severe and I plan to mount it at the very base of the bars so it will be level and see minimal play.

Does that seem viable?

We do not recommend using any mount that attaches to aero bar extensions. Aerobars flex, and that creates undesirable variation for AeroPod.

Please email technicalsupport@velocomp.com We have a solution for Speed Concept that works and that is very unobtrusive.

[trpnhntr]

I will email them.

I'm hoping to have something that isn't permanently affixed to the bike (I read above about a glue based solution) as I want to use my AeroPod to minimize my aerodynamic profile and anything unnecessary on race day is a bit counter to that mission

[evokesiron]

Thought I'd post some pics in case it helps anyone..

I ended up using the Garmin mount on the bottom of my stem (the curvature was flatter than the aerobars, and so fit better with the mount). After unclipping the AP along with the Garmin mount, the remaining piece on the stem is quite minimal. Could remove it if I cared enough, but I don't forsee that happening . And it will be nice to be able to just clip the AP back on if I want to do some testing later.







Unmounted:

[Velocomp]

This looks nice! I think you have more than one image, and the image you posted needs to be rotated...

[evokesiron]

Yeah, issues with the attachments coming through as desired (it decided to rotate the images and dropped a couple). Went with hosting site and modified my post, so take a look now..

[quantus]

Where is the sweetspot for position of Aeropod? Which distance is optimal to Tyre and Bar?

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[Velocomp]

This is a very nice setup, assuming your bolt extensions don't allow the mount to flex...

Obviously, you don't want the pitot tube directly behind your hands or your cables (your setup accomplishes both). Other than that, the purpose of the calibration ride is to customize AeroPod settings to the exact location on the bike. In that sense, there is no optimal position.

[quantus]

Ok. Then I can wait for sun to go out.
Thanks

[Guido_K]

Hey,
after reading the revised instructions for firmware 7.06 I think I need to check my setup since my AP is attached to my aerobars. However, it is rather close to the massive alloy sleeves connecting the extensions to the also rather massive base bar. So I hope this setup is still fine.

The mount itself is aluminium and attached by epoxy resin and screws into the extension.

Thank you,

Guido

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[Velocomp]

We strongly recommend against attaching AP to aerobar extensions, even when the underlying AP mount is stiff.

The reason is that most bars flex, which causes problems with AP slope readings.

Slope is a very important measurement in getting best-quality CdA readings. AP can resolve slope differences as little as 0.05%. To give you an idea of just how "sensitive" this is, here is a bike riding on a "road" with 0.0% slope--completely flat. After riding 1000 feet (right side of plot) the the elevation has changed by 0 feet:

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Now, here is the same plot, this time with a 0.1% slope--twice the difference that AP can detect. After traveling 1000 feet the elevation "climbed" is just one foot!

bike on 0.1% grade.png (100.53 KiB) Viewed 16476 times

No cyclist can physically detect a 0.1% slope difference, but AP can. AP's sensitivity is why you can't have any flex in the AP mount.

Your bars look pretty stiff, but this is just an impression...

Do a short ride, where you ride on a straight road for the first 5 minutes. While riding try to flex your bars during the first 5 minutes of the ride, as you might do when moving from hoods to TT position, or pulling on the bars in a sprint.

Post the ride file and I'll take a look...

[Guido_K]

Hey John,
sorry for the long delay, I was simply busy at work.

Please find attached the two ibike files my aeropod produced during calibration and the requested short ride afterwards.

My CdA on the basebar was about 0.19 and in the aero position 0.18. Both a little low - or I missed my profession. It is a rather calm day. Eyeballing, the wind speed looked right, perhaps also a little high.

Please let me know if I need to move my aeropod. I have to note, the only feasible alternative solution is to move it closer to the junction with the base bar reducing the leverage of any vibrations.

Thank you,

Guido

P.S.: I might have missed it, is there a way to switch the Connect IQ CdA app from miles to km?

[Velocomp]

Hey John,
sorry for the long delay, I was simply busy at work.

Please find attached the two ibike files my aeropod produced during calibration and the requested short ride afterwards.

My CdA on the basebar was about 0.19 and in the aero position 0.18. Both a little low - or I missed my profession. It is a rather calm day. Eyeballing, the wind speed looked right, perhaps also a little high.

Please let me know if I need to move my aeropod. I have to note, the only feasible alternative solution is to move it closer to the junction with the base bar reducing the leverage of any vibrations.

Thank you,

Guido

P.S.: I might have missed it, is there a way to switch the Connect IQ CdA app from miles to km?

You should upgrade to 7.06. Please email technicalsupport@velocomp.com for the FW.

What DFPM are you using? If it reads low that will force CdA down.

At this time there is not a way to change ConnectIQ to KM.

[Guido_K]

Hey John,
thank you, I got the firmware this morning and had the opportunity for a short ride this evening.

Please find the ride files attached. As advised, I tried to be rather "lively" on the bike like sprints and in/out off the aero position. Near the end of the ride is also a section of rather rough road surface, I hope that helps.

Regarding the low CdA, I think I forgot to zero my powermeter. I did it today and the CdA looks much different. My powermeter is a crank based avio powersense. I also got a powertap wheel if required.

Thank you for your help,

Guido

[Velocomp]

Your CdA is in the .265 range...very reasonable now.

It's important to have a calibrated DFPM!

[Guido_K]

I read this that we don't have any problem with flexing of the aerobars? That would be great.

Cheers,

Guido

[johnb_uk]

This looks nice! I think you have more than one image, and the image you posted needs to be rotated...

Hi this is my first post on the forum, i was just wondering what mount exactly it is you are using here?
I am mounting to giant trinity and would like to attach to the underside of the base bar just like you have here.

[Velocomp]

Please post an image of your handlebar mounts and we will try to help.

[aeropod.user]

Hello John,

What do you think about this way of mounting AP? It's very stiffly mounted to the bike, however I'm not sure if distance to bike frame (~1,5cm gap) will work fine for all its sensors.

Thank you for your answer.

Regards,
Bartosz

[Velocomp]

This looks really good!

Please do a cal ride, then a regular ride, and post the .ibr ride file here.

[aeropod.user]

Hello John,

I did today calibration ride and regular ride (incl. 12km long time trial). As you asked, I post both files here. Are they OK in your opinion?

One additional question: while setting profile in Isaac I was asked about "Device Mount Location" (Handlebar, Stem, Front Mount). What selection would you recommend for the location I showed on photos from my previous post? How big influence any wrong value in this field may have on data from AP?

Regards,
Bartosz

[Velocomp]

Don't worry about the Device Mount Location. One of the things the cal ride does is automatically figure out where the device is located.

You've got a really impressive 15 minute interval in your ride!

Based on your HR/CdA channel readings your CdA for that interval is about (58.5+180) / 1000 = .2385 That is a very reasonable value.

I've adjusted your profile to use the lower CdA value measured. Load this into your AP.

[aeropod.user]

Hello John,

thank you!

I have two additional questions.

1) First is about the difference in calculations. If I separate my TT effort (attached to this post), it gives me average HR of 58.6, what corresponds to calculation given by you for my CdA ((58.6+180) / 1000 = .2386). Actually, I used Profile 3 for this effort, so maybe I should use the second formula: 58.6x4 / 1000 = .2344. Nevertheless, if I go to to Tools->CdA Analysis, I get CdA of .246 instead. What do you think - from where comes this difference and what is more reliable calculation for this effort?

2) Second is about AP mounting. If I experiment with stack high of my pads, AP goes up or down or little more forward to its initial position used in calibration ride, is it better to repeat calibration ride? And can you give me some details on how you calculated changes to my profile, just for better understanding?

Regards,
Bartosz