I am going to get a hydration pak, and am curious about what size people recommend. It seems to me that the 100 oz bladders would add significant weight. I was thinking to get a 50 oz size - which should be good for a couple of hours, and I have take another bottle on the bike frame. However, someone suggested either a 70 or 100 oz. I could fill them less than full for shorter rides, but for the 3 centuries and one double century I plan to ride this summer, I'm wondering if I don't need the larger one.

I would be happy for the any suggestions from those more experienced.

Most of the Camelbaks for cycling are 2L / 70oz, which should be good for several hours.

It's pretty easy to refill a Camelbak while you're on the road, so I don't think you need to go bigger than that.

FYI throw in a bunch of ice cubes, and the water will stay cooler much longer than insulated bottles.

do you ride in areas where there is no place to stop to refill bottles? if so, a hydration pack is a good idea, but most folks prefer to avoid carrying the weight on their backs. a couple of large bottles can go a pretty long way.

I like my hydration pack because it is so small, and it has become my go-to-work backpack with no water in the bladder. I can sweat a whole lot, so I prefer water bottles in most cases except mountain biking, where the bottles can get bounced out. I have a long ride coming in August, and am planning to put one of those double-bottle triathlete seat-post things on my bike, giving me a total of four bottles. Until I drop another 30+ pounds, additional weight isn't much of an issue.

I had a 70 oz Camelbak Lobo for a long time and found it was plenty in conjunction with some sports drink in my bottles. I would sometimes need to stop and refill it on a longer ride in the middle of the summer. I have a newer 100oz Lobo now, but the extra 30 ounces had nothing to do with that choice. Mostly wanted the little extra carrying capacity of the newer model. The old one was easier to fill.

I would debate that statement. I think hydration pack usage is about 50% on the club rides I go on. The racers tend to not use them, but the recreational riders like myself do.

I don't use one unless I am going where there is no water and I prefer the 70oz model. I have used the 100oz and it is a bigger pack as well as a larger resevoir.

That sample seems rather skewed. It may depend on the type of rides you do. I don't think I've ever seen one on the fast Tuesday night ride. Perhaps one on a Saturday ride we do which is a bit more casual.

Yesterday's century, around 500 riders, I recall seeing one Camel Back, and I noticed it, because it stuck out.

I actually own a Camel Back, and will use it in the rare situation, but in my experience, their use on the road is far from prevalent.

I will strap one one only when doing very long rides in new territory or when I'm not exactly sure of the distance between stores. I can generally carry 3 bottles comfortably along with other supplies so that's 3 hours worth of water for me under normal circumstances.

i have a hydrapak reyes which has a 100oz bladder. i usually fill it about 3/4 of the way up.

i know it's not a super popular choice to wear a hydration pack as a road rider but i really like it a lot, it's very practical for me as a city rider. i bought my specific pack because it is a bit bigger, so i can carry some stuff in there too. i throw my (fairly large) chain, pump, lights and a little bag that contains my multitool, a spare tube, etc. in the main compartment, and i have room to spare for some snacks, wallet/keys/cell, and an extra shirt (or whatever) as needed.

i adjust what's in it by the ride... for a shorter ride, i can remove the bladder and just use it as a small backpack if I want. for organized events (such as centuries) i ditch the chain/heavier crap and use it pretty much just for hydration and to hold some snacks.

as mentioned above, water stays pretty cold in it and i actually love that the hydrapak has a really easy filling mechanism where the top opens up completely, so it's easy to fill with water and/or ice. i can stop at a rest stop or store and just throw a big chunk of ice in it.

I'm an (open-minded) racer and designed my last frame around using a CamelBak (and I bought the smaller CamelBak as well as the jersey with the integrated bladder pocket in preparation for the frame). I ended up using bottles instead, for races and for general rides.

CamelBak advantages:
- insulated
- lots of capacity
- "out of the way" on the bike
CB disadvantages:
- first bit is not insulated (the fluid in the tube)
- can't tell what's left
- "in the way" of pockets

I now use insulated bottles instead.
Advantages:
- insulated
- can tell what's left
- first sip is ice cold
- not in the way of pockets
- the Podium Ice bottles works well enough that after 1+ hours in 90+ degree heat I still have ice in the bottle.
- refilling is easier, especially compared to the jersey version of the CB.
Disadvantages:
- bottle is bigger than regular
- bottle is less flexible than regular
- takes up room on frame
- doesn't have the same shoulder as other bottles so doesn't hold quite as tight (but with the Specialized RibCage I've never dropped one, even on rough courses that cause moved bars, moved levers, flats, and damaged rims).

I am grateful for these helpful responses. Thanks for taking the time to write.

I actually have two bikes to ride this summer: a Trek FX 7.3 for my daily commute and errand running, and a cannondale R600, which I acquired about two months ago for road riding. Last year I took the Trek on 3 rides of 75 miles each and one century. Since these were solo rides, I had to take everything with me. I packed food in my panniers and took four bottles of liquid (water and gatorade) in a small insulated cooler strapped to the rack. This summer the cannondale will be my horse - no rack, no panniers. Anything I take will be in a back pack. I have opted for the Camelbak Rogue, 70oz, which will, I hope provide a compromise of volume, weight, and a little space to carry my spare tube etc. I also have a fanny pack that I might end up using. I am not a racer - I am training for distance.

Thanks again for your help!

I use a 100oz Lobo and have never had a problem getting at my jersey pockets with a Camelbak on. Maybe that is with one of the larger models?

Really, the use of a hydration pack is nothing more than a personal preference, there is no correct or incorrect to it. Nor is it a non-road accessory, unless you strictly adhere to the rules. Me, I'm not so religious. Texas summers and long rides means a full Camelbak and two bottles for me.

I have a CB Mule w/ 100 oz bag. I use it mostly off road. I prefer the bottles on road. However, there are some long road rides in the mountains of SoCal (like Azusa Canyon to Dawson Saddle) where food, water and assistance (if anything goes wrong) are just not available. So for those kinds of rides, I take the CB.

Also, CB offers insulated tube covers so your first sip is always cold.