How much drag do you think a set of clip on aerobars adds on a road or gravel bike when you aren’t using them?
Basically, if you are riding in your drops on a bike without aerobars vs riding the drops on a bike with clipons, what would be the difference in cda or equivalent watts
I doubt that there would be an accurate universal answer to this question.
Because the design of a clip on aerobar’s clamps, the extensions, the armrest supports, the actual armrests, the angle at which the bars are mounted, etc. would all affect the total drag of the set up. And designs of all of those elements vary hugely among different aerobar brands/models. I imagine that some clip-ons would be almost invisible aerodynamically, while others might generate readily measurable drag. (But such aerobars might not be equally comfortable to use either.)
That said, with some caveats, probably the easiest dinner-napkin approximation of the added drag of a set of clip-on aerobars would be how much (or how little) frontal area they would add to an existing drop bar bike.
This is just a basic math problem of integrating the work over time in the aero position + integrating while in the drops with a clip on just sitting there doing nothing versus integral over time of just riding drops with no clip on hardware.
So the answer is going to be, “it depend on the course and time in the aero positon”.
I can’t answer for a gravel bike, but my gut feel is that for any course that involves riding and generating power in an aerodynamic position the set up with clips ons will win. Unless this is a hill climb up Alpe d’Huez, I can’t really see too many scenarios where the clip on options becomes worse. I would guess if you just spent 5% of the time in the aero, it would more than offset 95% of the time that the hardware is creating drag versus never being aero and only standard roady drop position.
Disclaimer: Assumption is this is a solo event and you’re not drafting in a pack
That said, with some caveats, probably the easiest dinner-napkin approximation of the added drag of a set of clip-on aerobars would be how much (or how little) frontal area they would add to an existing drop bar bike.
Which would basically be zero since they’re typically entirely in front of your body.
So the answer is going to be, “it depend on the course and time in the aero positon”.
I can’t answer for a gravel bike, but my gut feel is that for any course that involves riding and generating power in an aerodynamic position the set up with clips ons will win. Unless this is a hill climb up Alpe d’Huez, I can’t really see too many scenarios where the clip on options becomes worse.
The other situation would be a technical descent where you would want to be in the drops rather than on aerobars for better control.
It’s not quite zero. The bars kind of disappear, but the armrests don’t. I’m also concerned with higher yaw angles.
I’m specifically talking about a gravel race I have coming up. I usually use aerobars, and they’ve been pretty clutch in some of my results. They seem especially helpful in crosswind sections when the pace gets high and riders gutter one another to try to cause splits.
In the race I’m training for, I did the course yesterday and it was a lot sketchier than normal. Lots of ruts, deep gravel, and some slippery mud. Plus, it’s almost all rolling hills with slow enough climbs that I wouldn’t be in aero, and sketchy enough descents that I still wouldn’t be in aero. I’d estimate that out of the 100 or so miles, I probably did about 20-25 miles in aerobars.
So, is 20% of the time worth the added weight and drag for the other 80%. Especially knowing that just a single crosswind section could make or break my day if I have them.
What kind/model/brand of bars do you plan to use?
https://www.dropbox.com/s/mo5kl1mv9uj54g2/Screen%20Shot%202020-02-24%20at%209.13.44%20AM.png?dl=1
They are 3T aerobars.
This is totally a guess.
If you use them for even 20% of your event, I think the aero advantage you gain would far outweigh the very small amount of added drag (if any) when you are not using them. Those aerobars are pretty minimal (although your left extension and armrest–left from the rider’s perspective–seems to be listing out to the side a bit … ).
Thanks for the info.
Zipp says about a 6.5 watt saving between their SL Aero drop bar and a traditional round bar. Maybe that’s not with a rider on board. If the difference between an aero profile bar and round bar is that big, I would have guessed that a set of clipons would be a much bigger penalty than the profile of a set of handlebars.
About 10 of the miles will be asphalt, so resting forearms on my tops is a possibility there. That’s not really a possibility on most of the gravel sections, which as I mentioned above are dicier than normal.
Looks like I’ll probably keep them on. I doubt I’ll be sorry if I make that decision, but if I don’t put them on I think I will regret it mid race, even if In reality they don’t cause much of a net benefit based on how little I’ll use them.