On the road, the bidon rules, and hydration packs are a hard sell, but the CamelBak RaceBak is, uniquely, built into a base layer.
A quality base layer is vital in any clothing system, so it was imperative that CamelBak got this spot-on, or the RaceBak would be a non-starter.
Thankfully the sleeveless design performs admirably. It copes with moisture well; it’s breathable and comfortable. It’s snug, thanks to compression fabric, but keeps the bladder still. The medium size is only just large enough for a 10-stone whippet, so try before you buy.
The bladder pouch is between your shoulder blades, with a separate mesh insert, insulating from body heat, and improving comfort. At full capacity (two litres), it feels cumbersome, 1.5 litres is OK, but about a litre is perfect for optimum comfort. Body heat does warm it a little, which is almost unavoidable, but it could be a plus in winter.
It will never replace the lowly bottle but the CamelBak RaceBak has potential, especially for time trials, winter epics and sportives. You could also use the RaceBak together with a bottle, not instead of, so it’s possible to have different carb/electrolyte solutions on board.