I am concerned that I am not expressing myself well, or you are looking for me to say something inconsistent with what i already wrote. When I said I haven’t seen any studies to back up my experience but my experience is what it is, I meant that. My experience is that 800mL/hr isn’t the limit on the bike. My experience is that 800mL/hr is a reasonable upper limit - higher than i can handle, even - when running. Ergo, my conclusion is that the limits must be different.
No it won’t. That’s the great thing about gravel: you race what you brung.
HOWEVER you will see a lot of gravel riders with aerobars but you won’t see too many with hydration on the aerobars. There are practical reasons for this but you may have those issues solved. My advice is make sure you get out there and test your setup.
Most riders carry extra water in a hydration pack.
Which is why I say: you gotta get out there and test your setup. You might think a certain amount of liquid is enough to go a certain distance. But wait until there is that heat, or that headwind, or those rollers, or you find out your bottle cages aren’t as secure as you think.
A lot of folks lose their a bottle or all bottles in the first 50 miles of a gravel race. That’s low hanging fruit. Make sure that’s not you.
You can wear a hydration pack under your jersey. I’m convinced a hydration pack under the jersey and two bottles on the frame is maybe the intersection of most reliable/most aero gravel hydration setup. But I would love to see somebody show up with a big triathlon reservoir on their aerobars. I think they’d be wearing their water but, hey, this is gravel so it’s all good.
For those that missed, the TR podcast crew touched on the hydration pack issue in the latest podcast with the Specialized Win Tunnel folks: https://youtu.be/yf6FwjoZ0tE?t=3198
Maybe the sweet spot is BTA, one large bottle on the downtube and slim hydration pack (under a skin suit if you can stand it). Additional nutrition/flat kit securely stored behind the seat.
I’m sure I’ll keep playing around with all of this leading up to August. I’ve still got a lot of time to test things out.
Now that I’ve had some more time to think about it, I do think it’s prudent to test my sweat loss. Pinning that piece of it down is a big time piece of low-hanging fruit. FWIW, I recently checked my sweat on a 2 hour endurance trainer ride (fan on the lowest setting) and it came out to 1.3L/hr
I’ve ridden a few long gravel events including DK200 and came to the conclusion that a hydration pack in a frame bag is the ideal setup for me. I skip the seatbag entirely and place all tools in the small half of the frame bag, and keep a hydration bladder in the main compartment.
I couldn’t stand the hydration pack on hot days in the South. Also, I fashioned my own quick release mechanism using two rare earth magnets, one on the back and one on the hydration hose so I can just put it back close to the right spot and it will snap into place.
I hope some day a bike manufacturer will figure out how to do integrated hydration/nutrition right on a gravel bike. I know that the Specialized has a bit of that with the Diverge.
They have it on the old and new Shiv tri bikes. Bladder in the front on one and a reservoir on the rear.
Yeah, looking at the new Shiv is what got me going on this. How wide of tires will the Shiv disc take?
Riding a long hot gravel event with a hydration pack under a skinsuit?! I’m trying to think of something less pleasant… and failing. But I would love to hear your experience if you try this. (It also seems to me that the PITA factor of refilling your pack would be so high that any aero benefit you gain would be more than offset by time losses at aid stations.)
Since the original post in this thread, I’ve measured my sweat rate several times as well as getting sweat salinity tested by Precision Hydration. Very eye opening. My sweat rate frequently gets up to 2 l/hr and I suspect it’s more during the hottest events. If I focus on it, I’ve been able to drink 1-1.2 l/hr without overdoing it. But I’m still losing a net of ~1 l/hr. Add that up over a very long day and it’s no wonder the wheels start to come off the cart, especially if I’ve been underdoing it with salt.
Bottom line, next time I do a DK or equivalent event I will absolutely use my frame bag bladder with hose run up to the stem. Plus 2-3 bottles (ST, DT, and one under DT) with varying mixes in them. I don’t love setting out with 4 liters of liquid weight on the bike, but the pain of an initially heavy bike is nothing compared to the pain of inadequate hydration on an event like this.
I think you’re onto something with the Gravel Shiv! I removed my aero bars after DK… and I really miss them lol.
Now you’ve got me wondering if I could fit 650b on the Shiv…
I guess I don’t really care if it’s uncomfortable, as long as it isn’t causing me actual pain. I’ll take the aero gains. I’m thinking a very light base layer under the pack or a ton of bodyglide.
Also, I’m not sure how it would really be that much of a PITA. Unzip the skinsuit down to the waist and take the pack off. Gravel Worlds is neutral support only so these aren’t going to be F1 pit stops.