Measuring drinking out of a hydration pack

Looking for advice as to how to be sure I’m drinking enough out of my hydration pack for MTB. For example: I did a 3h ride today and figured out what I wanted for calories and had that prepped between gels and my drink mix in my pack. Gels are easy, but when I got done with my ride, I had about 1/3 of the fluid left when I ‘should’ have finished it. This seems to be a recurring theme…On the road I find it much easier as finishing a bottle an hr or whatever is much easier to judge. Anyone got good techniques to be sure you are drinking enough?

Hydro pressure pad that converts weight to ounces and sends via ANT+/BT to a Connect IQ app on my Garmin, but only works when you are in the drops :wink:

I’ve had the same issue while hiking.

haha I’ll buy that. Needs to be Wahoo compatible though…

I don’t think they’re made any more but you want a Camelbak Flow meter

1 Like

Assuming sip size remains roughly same, you can calculate your drinking interval if you know ride duration and amount of fluids. Of course, required amount of fluids change with temperature and is highly personal. But with some experience it can be precise enough.

For example, during spring/autumn period with 10-15℃, I need 2x 750ml bottles for 150km flat course, sipping every 5km. During summer with ~20-25℃, it takes 3x 750ml. I keep interval same, just taking slightly bigger sips.

In hilly area, time-based interval is probably more appropriate :thinking:

Someone gave me this advice who used it in preparation for the 24hour world MTB Champs… Jump on the indoor trainer with your hydration pack full and a measuring cup.

Get your heart rate in to your typical event Heart Rate Zone.

Take a mouth full of fluid from the pack, typically like you would in an event.

Do not swallow the fluid, instead spit it into the measuring cup.

Now record how many mls of fluid you can take in per mouthful consumption.

Once you know your mouths volume during elevated heart rate you can now work out how often you need to drink from the pack per every 10 minutes of so…


Yeah, been there plenty of times. If you combine pack and bottle it kinda helps. Finish pack first and have a 1 liter bottle on the bike. Then you know when the pack empties you still have the bottle remaining. My experience is that typically you can never drink enough from the pack, so always be drinking. Then you have the reassurance of still having a bottle remaining, in the unlikely event you drink from the pack too fast.

1 Like

I think practice perhaps is the simplest solution. I generally know how much I intake in an hour. It’s pretty regular and my body subconsciously seems to keep me on that regimen. I then measure how many hours I’ll be riding and fill my hydration pack accordingly. I try to drink as frequently as I would with bottles and it seems to work out pretty closely if I listen to my body and you have perhaps the practice that confirms for you that your pace is correct.