Is mounting computer on stem more aero than out in front?

Discuss light weight issues concerning road bikes & parts.
CrankAddictsRich
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by CrankAddictsRich

kgt wrote:So Cervelo's claim is scientificaly proved BS. Good.


yes and no... I'm not an aero expert, but I do a fair bit of TT racing, so I pay attention to the aero tests and from what I gather, anything out front, in the wind, in clean air, has a pretty dramatic effect, while stuff toward the back of the bike doesn't seem to be as important because the air is already seeing a lot of turbulence. Here's how I analyze their claim.... let's assume a standard baseline bike, a general, all-around climbing bike, maybe an R5 with a standard round bar. Then, Cervelo designs the S5 with their handlebar/stem combo and that set up improves the aero over the baseline by 3%, putting the Garmin on stem (because an out front doesn't quite work) doesn't negate that 3%, maybe it only knocks it down to 1.5%. So the bar stem combo still puts you ahead in the aero game even if you do have to mount the Garmin on stem.

mortirolo wrote:Specialized used 17 degree stem in test, I think.


Yes, the bike being used is Cam Piper's personal bike and it appears as if he's using a -17* Zipp Service Course SL. Specialized has stated in numerous materials and aero reports that a -17* stem is the most aero because it puts the entire length of the stem behind the faceplate, shielding it from the wind.... its because of this, that they came up with the rider handlebars for the Venge Vias, allowing for riders to keep the same fitment with a -17* as they would with maybe a -12* or -6* stem and standard bars.
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by Weenie


Shrike
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by Shrike

@ryanw what about taking this ENVE mount and mounting it to the bottom two faceplate bolts. Seems there's decent clearance under the Cervelo bar..

Edit: nvm! Wouldn't be long enough on second thoughts. Need something similar, but longer..

ryanw
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by ryanw

Shrike wrote:@ryanw what about taking this ENVE mount and mounting it to the bottom two faceplate bolts. Seems there's decent clearance under the Cervelo bar..

Edit: nvm! Wouldn't be long enough on second thoughts. Need something similar, but longer..


I'm pretty certain you could mount it on the top stem bolts and it would be fine?
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Shrike
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by Shrike

Hmm.. not sure. Maybe work. But would still be sticking up in the air, not really level with the bars which is what i'm gunning for ultimately if spending 40quid on a bit of plastic/metal :P

sharkman
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by sharkman

Does anyone take cervelo statements serious? Soon they will claim that they apply crap paintjobs since loosing paint will result is a lighter and faster bike. Recently see more than a few not too old high end bikes that had large areas without any paint due to bad prepwork

kode54
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by kode54

Stolichnaya wrote:Not sure about the aerodynamics, but out front is easier to read when going fast and arguably safer; that counts for something.


yeah...and testing in wind tunnel doesn't matter where its located.
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Fixie82
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by Fixie82

There is a decent looking out front mount specifically for the Cervelo Aero Bars made by Rec-Mount. Could be a good option as you can add light and camera mounts underneath as well. Plenty of accessories options.

Image

ryanw
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by ryanw

That looks hideous IMHO.... Think swapping out for an Enve cockpit is the tidiest solution.
'16 Cervelo S5 - 6900g
'17 Focus Mares Force 1
'15 Scott Addict Team - 6850g Sold
'17 Cervelo R3D DA - 7580g - Sold
'16 Cannondale CAAD12 DA Disc - 7560g - RIP

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mortirolo
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by mortirolo

CrankAddictsRich wrote:
kgt wrote:So Cervelo's claim is scientificaly proved BS. Good.


yes and no... I'm not an aero expert, but I do a fair bit of TT racing, so I pay attention to the aero tests and from what I gather, anything out front, in the wind, in clean air, has a pretty dramatic effect, while stuff toward the back of the bike doesn't seem to be as important because the air is already seeing a lot of turbulence. Here's how I analyze their claim.... let's assume a standard baseline bike, a general, all-around climbing bike, maybe an R5 with a standard round bar. Then, Cervelo designs the S5 with their handlebar/stem combo and that set up improves the aero over the baseline by 3%, putting the Garmin on stem (because an out front doesn't quite work) doesn't negate that 3%, maybe it only knocks it down to 1.5%. So the bar stem combo still puts you ahead in the aero game even if you do have to mount the Garmin on stem.

mortirolo wrote:Specialized used 17 degree stem in test, I think.


Yes, the bike being used is Cam Piper's personal bike and it appears as if he's using a -17* Zipp Service Course SL. Specialized has stated in numerous materials and aero reports that a -17* stem is the most aero because it puts the entire length of the stem behind the faceplate, shielding it from the wind.... its because of this, that they came up with the rider handlebars for the Venge Vias, allowing for riders to keep the same fitment with a -17* as they would with maybe a -12* or -6* stem and standard bars.


More than 90% stem is 6*, I think, so the specialized test is just barely relevant. They made a test for almost nothing.
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Tqubed
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by Tqubed

You could always throw the Garmin in your bib pockets and use the Garmin Varia vision to display the content as a heads up display. Might be more Aero...


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Johnny Rad
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by Johnny Rad

Stolichnaya wrote:Not sure about the aerodynamics, but out front is easier to read when going fast and arguably safer; that counts for something.


So much truth here. I'm not going back to stem-mounted computers.

1415chris
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by 1415chris

Barfly just added Cervelo mount to their shop.

hambini
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by hambini

I don't think there will be much in it. Out in front would have a higher overall Cd but the cross sectional area would be smaller.

On top, the Cd would be lower but a slightly larger cross sectional area.

CrankAddictsRich
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by CrankAddictsRich

1415chris wrote:Barfly just added Cervelo mount to their shop.


here's the link.

http://www.barflybike.com/shop/bar-fly-4-cervelo-mount-includes-gopro-and-light-mounts/

Looks pretty good to me.
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by Weenie


CrankAddictsRich
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by CrankAddictsRich

ryanw wrote:That looks hideous IMHO.... Think swapping out for an Enve cockpit is the tidiest solution.


I think the Fizik Stem and Barfly/Fizik mount look better than the Enve set up and there are a lot of complaints about the enve mount losing computers.

http://www.crankaddicts.cc/fizik-cyrano-stem-barfly-2-0-direct-stem-mount/

Image

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