I have a cannondale slice which can take a rear mounted (behind the saddle) bottle mount.
If I were trying to maximise aero efficiency, would this be the best place to mount my water bottle?
The only other option is on the seat tube. If I were to do this, would I be better with an aero bottle v’s a standard round bottle?
I think the accepted mantra is between the aerobar extensions
couple of zip ties and you’ll be away
Adam
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That’s the million dollar question…I prefer behind the seat over anything on the frame just to keep the frame lines clean. With that said if you do use a frame mount then go with the aero bottle. If you need a third bottle besides the two in the back the xlab torpedo mount between the bar extensions is a good one.
I think the accepted mantra is between the aerobar extensions
couple of zip ties and you’ll be away
Adam
I tried this and didn’t like it. Went back to NXT aero bottle between the bars and flexible tubing with a magnet at the end. Another magnet on the bar extension and that eliminates the straw sticking up.
No way to mount bottles on the seat rails?
Would a behind the seat option still add drag? I ask because the body is already covering that area right?
According to some testing, a single nearly horizontal bottle tucked in very close to the back of the saddle can in some cases actually reduce drag by a very small amount. That said, while it may be a good place to carry water, it’s not very accessible without a big aero penalty. But some of the advanced front drinking systems (i.e., Torhans aero 20 or 30) can be just as good but the water is right there, easy to drink with no aero penalty.
Generally accepted bottle positions seem to be
Between the aero bars
Behind the saddle (1 only, as seen on crowie’s bike above, 2 is typically a huge aero penalty)
On the frame. A lot of bikes have tested well with even a round bottle on the seat tube or downtube (one or the other tho if you’re bike has two, most newer aero bikes only have one for the seat tube tho).
I will use all three locations to get the number of water bottles I need.
I have spent way too much time stressing over this issue, and I’m sure that I’m not alone. I carry only one bottle, between my elbows, because I read that it is most aero. I attempted to put another under my saddle, but then I had no place to put my flat tire supplies. (I have them tucked under the saddle and taped to the rails.) I manage to get by with only one bottle by using the on-course nutrition. (For Ironmans, this meant finding out what drink was on course and buying a bunch of it a few months beforehand to use in training.)
I couldn’t stand the idea of compromising the aerodynamics of the frame by strapping a clunky bottle on them. Then I saw this:
In short, it says that the BMC time-trial bike that Cadel Evans and others rode in the Tour is probably MORE aero with a bottle on the frame, as evidenced by the fact that they put an unnecessary bottle on the frame during the prologue.
I am going to write to my bike manufacturer and see if my bike is designed to actually be more aero (or at least equally aero) with a bottle.
I’m trying out a new configuration in the last of half of the season here, and so far, I’m really diggin’ it…
I was pleasantly surprised to find that the horizontal behind-seat bottle is actually quite each to reach and use. Admittedly, it takes a few times to get used to it, but once you have those grab & replace motions down, there’s no need at all to break aero.
Reach back, grab the bottle by the indent, swing it up to mouth for a quick shot (you grab it in such a way that you are already holding it upside down for drinking, so there’s no awkward “flipping” the bottle), then just reach back, slide the bottle along the cage to the end and pop it back in. Once you have the motions down, you can easily stay in full aero the whole time.
I’m getting to point where I actually prefer using this bottle over my between-bars bottle!
For the aero bottle on the downtube, I have 2 separate flat-kit bottles that I just swap out as necessary - 1 bottle just for training with clincher spare stuff and a few more tools, and 1 bottle just for races (spare tubular, CO2, razor, and teeny mico-tool). The downtube-aero-bottle configuration provides plenty of flat-kit storage, and has the added benefit of being an aero fairing.
Cheers, Chris
My set up exactly. I use a Speed Bottle on the downtube. I have two types. One for hydration and another cut-out to store tools/tire/CO2. I always carry the speed bottle. Shorter distances, I use the BTA setup.
I’m curious to know everyone’s opinion on this question:
If you tuck 1 bottle in tightly behind and under the seat, and run a front aero bottle between the extensions, then where do you put your spare tube/tire, CO2, CO2 air chuck, and/or can of fix-a-flat???
^^
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I’m curious to know everyone’s opinion on this question:
If you tuck 1 bottle in tightly behind and under the seat, and run a front aero bottle between the extensions, then where do you put your spare tube/tire, CO2, CO2 air chuck, and/or can of fix-a-flat???
In the bottle behind the seat. With aid stations every 10 miles I never need/use more than one bottle anyway
I’m curious to know everyone’s opinion on this question:
If you tuck 1 bottle in tightly behind and under the seat, and run a front aero bottle between the extensions, then where do you put your spare tube/tire, CO2, CO2 air chuck, and/or can of fix-a-flat???
For me I am running an Torhans Aero 20 up front for water that will be replaced each aid station, then on the seat tube I have one of my calorie drinks and during IM Texas I had the other calorie drink behind my seat in the cage. I then put my flat kit in my Fuel belt bento box. The reason I carried both calorie bottles was because I did not want to deal with special needs. But I am toying around with the idea of either keeping the rear cage empty to start so I can grab extra water or Perform at aid stations if needed or put my flat kit there. Still not sure which route I want to take but that’s how I have been running my flat kit.
/insert elitist Shiv hydration bladder comment here. 
At my last race some guy lost both his bottles mounted behind the saddle. I guess he hit a pothole and they went flying. How common is this?
Me- I went with a TorHans up front and an aero bottle on the frame, because it’s at least pretty good in the aero department, and provides easy access to hydration.
but here’s what Cervelo came up with. good article.
http://cervelo.com/en_us/news-blog/article/ask-the-engineers-hydration-and-aerodynamics/2930/
Not meaning to hijack the thread, but having never done anything longer than an Olympic tri, do they have water bottles (every 10 miles as stated above) that they give to you? Are they normal bottles that you could buy at a store or in cycling bottles? Dumb question, so take your best shot and I’m good with it. 
I just don’t know and am learning. Slowwwwly.
/insert elitist Shiv hydration bladder comment here.
At my last race some guy lost both his bottles mounted behind the saddle. I guess he hit a pothole and they went flying. How common is this?
Very common… Many of the behind the saddle carriers mount the cages to upright. One good hit and they bounce right out the top.
My suggestion, and what I use in longer races is a cheap AL (gasp) Minoura bottle cage zipped tied under my seat. The reason is I can bend the cage and no amount of shaking is going to dislodge that bottle. It is not too hard to reach back and grab the bottle and put it in the cage on the aero bars. I don’t even have to break position to do it if I don’t want to.
Hey Chris,
I really like your recommendation - can you explain how you split the Chrono bottle along the bottom, did you just cut it and then tape it shut? Do you have a pic of the bottle you can share?
Thanks!
Doesn anyone have any close up images of how these single bottle set ups are secured untder the saddle? I run a Specialised Transition with the standard seat post.