Which is faster? I need to use one or the other for my race set up. Remove the cage from my downtube (is that the right term? the same tube my septets goes into…or remove the cage from behind my seat.
Some thoughts … it depends on the cage for behind the saddle, some are better in aero some are easier to reach, both not as easy as at the frame … and the tube where the seat post goes into is the seat tube.
Behind the seat is probably better. Google cervelo bottle placement wind tunnel, also lots of tests showing behind the saddle can actually decrease drag. Do some searching on forums for exact results.
Which is faster? I need to use one or the other for my race set up. Remove the cage from my downtube (is that the right term? the same tube my septets goes into…or remove the cage from behind my seat.
A seat tube bottle cost me 6-7 watts (at 25 mph). I did not test a behind-the seat bottle though, but 6-7 watts is A LOT.
http://chadmwilliamson.blogspot.com/2013/08/a-trip-to-a2-wind-tunnel.html
Which is faster? I need to use one or the other for my race set up. Remove the cage from my downtube (is that the right term? the same tube my septets goes into…or remove the cage from behind my seat.
A seat tube bottle cost me 6-7 watts (at 25 mph). I did not test a behind-the seat bottle though, but 6-7 watts is A LOT.
http://chadmwilliamson.blogspot.com/…-a2-wind-tunnel.html
Awesome. Thanks
And where you put it behind the saddle can make a difference as well. You could save 6-7 watts or you could save 1-2w. In which case I’d just run the seat tube bottle.
Neither. Aero bottle on down tube, 1 BTA, nothing behind. Learn to live off the course.
I’ve never found a way to mount the bottle where I could reach in aero position. I have to be sitting up. So for me, it’s useless and I suspect so far behind me that it’s aerodynamically not much better than downtube, definitely worse than aero bottle I’d suspect.
Neither. Aero bottle on down tube, 1 BTA, nothing behind. Learn to live off the course.
I’ve never found a way to mount the bottle where I could reach in aero position. I have to be sitting up. So for me, it’s useless and I suspect so far behind me that it’s aerodynamically not much better than downtube, definitely worse than aero bottle I’d suspect.
While your idea has merit to it and is better than what a lot of people do, you’re assuming that you’ll be regularly drinking from the rear bottle, and that doesn’t have to be the case. I do all my drinking from the front bottle, the rear is just for storage, not for drinking. When the front bottle is empty I just trade bottles. I do have to sit up to trade, and try to do this on a false flat where the aero penalty is reduced, but anyway it only takes me a few seconds. It’s a very simple & flexible system. On halfs (don’t currently do fulls) I carry a stainless steel down tube cage just in case I need to temporarily stow an extra bottle, but have yet to use it. (I use a stainless cage as it has the lowest frontal area of any cage I’ve seen.) I’m pretty confident that my behind the bottle setup is very aero, haven’t tested it in isolation but it was one of a number of changes that have dropped my CdA substantially. I did test a downtube conventional bottle and it added significant drag. I’m also aware of testing that indicates that while aero bottles are much better than regular bottles, they’re generally still slower than no frame bottle at all.
Now if you have a high concentrate bottle then you can’t swap, then a down tube aero bottle might make sense. But usually you don’t drink concentrated solutions that often so the penalty of reaching back isn’t as great, especially if you do it on hills.
Zip ties. Mine is a bit crooked but that actually makes it easier to reach.
There are lots of ways to do it between the rear contraptions that are sold, zip ties and some DIY home built things to mount it.
You may be surprised out how aero or not some of those aero bottles are on down tubes. In some cases you’ll have fingers left over on the 1 hand you need to count your savings aero vs round.
ymmv