Drinks bottles aren’t great for aerodynamics. Phil Graves tells you how to reduce drag and still stay hydrated during a race.
We all want to go faster in races and that’s why we train so hard in all weather, and spend a fortune on aero frames and deep-section wheels, but a lot of us forget the simple things.
Everyone needs to refuel during a race, and the longer you race the more important this becomes. Walking into transition on the morning of a race, you see bikes with water bottles slapped on them with no regard to how this might affect aerodynamics and speed. I know a lot of people want to take as little fluid with them as possible – who wants a bottle behind the saddle, two on the frame and an aero bottle between the handlebars? It destroys the handling characteristics of the bike you’ve spent a fortune on, and those full water bottles will add 3-4kg – adding about 50 per cent to the weight of your bike.
There are so many options out there, and all have their pros and cons; it’s difficult to know where to start. What’s going to be the easiest drinks system to use? What’s the most aerodynamic? It’s a minefield, so let’s go back to basics and examine the best options to keep you hydrated and get you to the finish line as quickly as possible. I’ve also taken into account some recent research by bike manufacturer Cervélo to add some quantifiable drag figures to my own experience. Drag is given in grammes; power expert Dr Andy Coggan’s rule of thumb is that 50g drag = about 0.5secs/km at 30mph.
Normal bike bottle, behind saddle
Drag Cost: 0g
This set-up is great if you want to also carry a spare tubular tyre or inner tube with you . Research shows that there is no real aerodynamic disadvantage to this positioning as long as you keep the bottles as close together as possible. Access may be an issue: you will need really long arms and a short torso to be able to reach the bottles easily – or at least have practised it over and over again. The best time to use this set-up is for a hot race, where you can keep a spare bottle behind your saddle and then transfer it to somewhere else on your bike so you can drink from it more easily.
Aero bottle on down-tube
Drag Cost: Approx 17g
If you want to move from regular to aero bottles, you can save up to 30g of drag. In certain circumstances they can even act like a disc wheel, creating a small aerodynamic advantage in certain wind conditions. They cost from £15 up to about £45 for a cage and bottle, so they won’t break the bank. The major disadvantage with the set-up comes during a longer race when you need to double up on drinks, as once your aero bottle is empty you can’t replace it on the fly. My advice would be to use the aero bottle to store your gels for the race and use another drinks system for your fluids.
Normal bike bottle between tri-bars
Drag Cost: 0g
This has become popular with the pros lately for one major reason – it is the most aerodynamic place you can put a drinks bottle on your frame. In fact, it’s more aerodynamic to have a bottle there than nothing at all because it fills in the turbulent area behind the riders’ hands, creating less drag. It’s no more expensive than putting a bottle on your frame, as all you need is a few cable ties to attach it to your frame, and you’re ready. Your drinks bottle is always to hand, and its position is a good reminder to keep hydrated. The only possible limiting factor is that you might not be able to fit it between your arms.
Aero bottle with straw
Drag Cost: Depends on the size of the straw and width of your head tube
They are easy to refill and have a great big straw sticking out the top. The one major advantage with them is that your fluid is right in front of you, so if you don’t have to reach underneath or behind you to drink. They are also a little more aerodynamic than having a regular bottle on the frame. A standard aero drinks bottle set-up costs less than £20, so this is definitely the next stage if you want to try to squeeze a few extra seconds out of your bike set-up. This is definitely the easiest way to hydrate on the bike.
Standard bike bottles
Drag Cost: 45g (on down tube)
We all train with bottles on our frame, so we all know where the fluids are going to be come race day. We’ve practised getting our bottle out of the cage, having a drink and putting it back thousands of times before, so in terms of practicality and price this is a winner. Unless you don’t have a bottle cage on your bike there isn’t really going to be any monetary outlay on this option, either. These bottle types add 40-50g of drag when placed on your down tube which isn’t ideal, but you can probably live with it.
In terms of access and extra weight, it seems that the best set-up for many people will be a regular drinks bottle zip-tied between your aerobars. The most important thing, though, is that you are comfortable and practised with the drinks system you end up using. For example, if you have never tried having a bottle behind your seat then don’t just put one on for a race and hope everything works out. It’s always better to have practised your nutrition – don’t try something new come race day. If you do struggle taking in enough fluids in on race day, the aero bottle hung from your aero bars is probably your best bet, as you can drink from the straw without having to move from your tuck. The key points of race hydration to remember is you must practise drinking when on the bike and find a method that is comfortable and that will work for you.
This article was originally published in Triathlon Plus magazine. Save time and money by having every issue delivered to your door or digital device by subscribing to the print edition or buying digitally through Zinio or Apple Newsstand.
You’ll find loads more triathlon training advice in triradar.com’s Training Zone section.