I couldn’t find the data I was looking for in the search and would be interested in new or old data on the topic of rear vs. front hydration. I usually race with a rear hydration in LD races, but I am re-thinking the process now. If you look at pro hydration strategies in Kona many are riding front hydration. Some athletes are even riding front and rear. Can anyone point me to wind tunnel data or general opinions?
If you dont’ mind looking like a total dork, the Neverreach works for me. 64oz lasts an entire HIM and more than half of the IM bike. It can be topped off on the fly. (I use water bottles and InfiniT concentrate to top off.)
Wind tunnel says No Bottles for less drag. Now, stop at every aid station, drink and gently leave the bottle on the floor and don’t forget to thank your volunteers.
I use a front since it is so much easier to drink from and refill on the fly. I don’t even bring an extra bottle but I start out with a water/gatorade mix and then just alternate between water and gatorade at each aid station to top it up. I have rear mounted cages on my bike and carry extra bottles there when training but they sit empty on race day.
Like Allan, I use a front mounted system and refill as required and for training have a BTS system. On race day, the only thing that is in the BTS racks is an old bottle with my flat kit.
Shane
There is fairly conclusive wind tunnel data that a front-mounted system (like Aerodrink or Jetstream) is the most aero - in fact it actually improves aerodynamics believe it or not. I don’t remember where the study was posted (may have been on Slowtwitch?) but there was also a piece on the Tri-Talk podcast about it a while ago.
I don’t have time to search for the links, sorry. Anyone else see/hear this?
Depending on your body shape, a camelbak would be most aero. You can take it on the run too 
With out getting into the specifics of a brand by brand of frame, discussion, a front Profile bottle is generally a good choice. The length of the straw will matter and it should be as short as is useable. Having those dual straws or a very long front straw can cause more drag than a good front wheel can save. Rear systems can be measurebly faster than no rear systems but the shape of the top of the water bottle is usually the main deciding factor. For systems that ride the bottles up higher above the back, flat top bottles are very important. For systems that carry the bottle very low, rounded top bottles are the answer. Having all you “stuff” strapped to the rear system is a completely bad plan. The on going frame question/ answer is … I would use a bottle on the seat tube most any time and not fear the results, downtubes bottles are not always the best choice. Camelbaks that are completely filled up are not very good aero wise. We use camelbaks for 40k TT’s but only put in a few ounces of fluid. Putting a Camelbak bladder in the hollow tail section of the TT helmet works very well.
Not to steal the thread but I’m curious why no one ever talks or tests rear bottles with a hose up to the front. I did this in a HIM last year and it worked great, I never had to get out of the aero position which in my thinking saves more time than any other option (aid stations, reaching back, etc.). For the HIM I used a PD up front for water only and refilled twice. I ran the hose from one water bottle (900 calories) and attached it to the PD straw. I am planning to do the same thing for my IM this year but will have two full bottles on the back with two hoses to the front. I don’t think I will need to get out of aero at all except for maybe grabbing a water bottle to refill the PD.
BTW, if you think this is a great idea I happen to know someone already has a patent on it. I guest don’t think they have marketed it well and personally I found it easy to make on my own…
Pic worth a thousand words:
With out getting into the specifics of a brand by brand of frame, discussion, a front Profile bottle is generally a good choice. The length of the straw will matter and it should be as short as is useable. Having those dual straws or a very long front straw can cause more drag than a good front wheel can save. Rear systems can be measurebly faster than no rear systems but the shape of the top of the water bottle is usually the main deciding factor. For systems that ride the bottles up higher above the back, flat top bottles are very important. For systems that carry the bottle very low, rounded top bottles are the answer. Having all you “stuff” strapped to the rear system is a completely bad plan. The on going frame question/ answer is … I would use a bottle on the seat tube most any time and not fear the results, downtubes bottles are not always the best choice. Camelbaks that are completely filled up are not very good aero wise. We use camelbaks for 40k TT’s but only put in a few ounces of fluid. Putting a Camelbak bladder in the hollow tail section of the TT helmet works very well.
any consensus on Arundel/Bontrager aero bottles John? work or no, where to put them, etc ?
I would second sib1’s question about the Bontrager aero bottle while extending it to the worth of doubling up on the Bontrager bottles such as Chris Leito does, thus having one bottle as almost a continuous fairing for the other. Good bad or too much side surface area?
I finished a week of testing riders two weeks ago and we had run some of these test. Here are some numbers to look at. These are the average drag in Grams for a sweep of “0” - “20” degrees.
- 5’9" male @175lbs - Trek TTX w/ Trek aero bottle on seat tube. 3072gr.
-
Trek TTX w/ No bottles 3059gr. ** 20 gr. is nothing that will show up in the real world.
Cervelo P3 No rider - Round Rocket Science bottle on Down tube - 1024gr.
P3 No rider - Trek aero bottle on down tube - 1079gr.
P3 No rider - No frame bottles - rear Hygro tail - 1198gr. Not having a rider probably was not a fair test for the rear setup.
I finished a week of testing riders two weeks ago and we had run some of these test. Here are some numbers to look at. These are the average drag in Grams for a sweep of “0” - “20” degrees.
- 5’9" male @175lbs - Trek TTX w/ Trek aero bottle on seat tube. 3072gr.
- Trek TTX w/ No bottles 3059gr. ** 20 gr. is nothing that will show up in the real world.
Cervelo P3 No rider - Round Rocket Science bottle on Down tube - 1024gr.
P3 No rider - Trek aero bottle on down tube - 1079gr.
P3 No rider - No frame bottles - rear Hygro tail - 1198gr. Not having a rider probably was not a fair test for the rear setup.
did you have a baseline figure for P3 No Rider No Bottles?
What about with the XWing systems? Is there any data on those systems?
No
.
I also have a front mounted hydration and rear. I love both of them for different reasons
I would use a bottle on the seat tube most any time and not fear the results, downtubes bottles are not always the best choice. Camelbaks that are completely filled up are not very good aero wise. We use camelbaks for 40k TT’s but only put in a few ounces of fluid. Putting a Camelbak bladder in the hollow tail section of the TT helmet works very well.
So in general terms, would using my camelbak, tucked as far up under my aero helmet as possible under my skinsuit, be the best hydration solution for a long (50 mile) TT? Would I be better off fitting a down tube round bottle to my P3, or investing in an aero bottle, profile front system, or some rear mounted setup?
I’m somewhat less than happy about the idea of mounting an aero drink system to my Hed bars though.
Any opinion as to how low or high the Profile front bottle should be mounted?
Low as possible (in front of the head tube) or as high as possible (closing the gap between the arms and blocking the chest area)?
The higher position would result in a much shorter straw.
Thanks.
David K
I’m ashamed to say that I have not given that much thought. That’s what I love about racing, anytime you think you’ve done a good job of testing, someone ask a pretty simple question that means you have to go do more testing. This question caused me to drag out the 'ol sketch pad and do some rethinking about how to mount a front bottle, I am positive that the long straw is very bad so I suppose we have to work out a relationship between headtube length and bottle height, this will be fun. I do a lot of work on hand/forearm to chest area airflow and the relationship of the upper arm length. If I ever take the time to learn how to post pictures on here, I have some very cool photo’s that show interesting air patterns. A lot of racers have rounded shoulders and relatively long upper arms so in that case, having the bottle higher would make perfect sense to me. For shorter racers 5’5" and down, probably having the bottle lower would be better. It will be about 2 months before I go back to the tunnel so I will definently work on this then. I went and posted some airflow pictures on my Blog which will help show this. Maybe next week I’ll sit down and figure how to put pictures on here or maybe Jordan Rappstar can school me on it.
Thanks. I look forward to new info some day.
While it is being considered:
In addition to how high or low - Should the Profile front bottle be back towards the headtube or forward behind/between the hands?
Would a rounded or shaped top cap be a benefit with a Profile front bottle? Flat? Some other shape?
Personal fit questions based on picture:
I am tall 6’3, with long arms/torso and shorter legs (34 inch inseam jeans). I think I have broad shoulders. I can get down where my head is not too far away from the bottle - the straw pokes at me.
Please see Pic.
http://www.brightroom.com/view_user_photo.asp?EVENTID=23180&ID=38136633&FROM=photos&BIB=746
My aerobars are lower and a little more forward this year. The pic does not show how I usually hold my head. I am usually looking more downwards and in line with my shoulders and chest.
Any suggestions would be welcome and greatly appreciated.
David K