Is there a standard for water bottles?

Question

It's prudent to use water bottle cages that will adapt to bottle diameters within some range, to allow using multiple bottles in the same cage.

Naturally, this flexibility is to be hedged against safety. If the bottle needs to be squeezed in or out, that just distracts from the road.

In any case, I ordered a water bottle cage that turned out to have a fixed diameter of about 2 3/4", or about 70mm. A smaller bottle will rattle, and the full circle enclosure won't allow anything bigger.

A fixed size might be a good thing. If there exists some international / conventional size for bike water bottles, then a perfect fit will ensure that pulling a bottle and returning it can be done effortlessly (and hence safely).

Does such a conventional diameter exist?

I'm rather partial to metal containers glazed with ceramic, since these guarantee they won't react with the water, but since these seem to be available only in carabiner format that's not suitable for cycling, I'll have to settle for plastic bottles.

Update (following Carel's answer)

After two searches it's clear which brand Carel means. A big advantage is that those bottles are indeed listed as having ⌀ of 71, and so perhaps there does exist some convention at that diameter.

There are also stainless steel bottles from other makers, which should be perfectly safe, as well as ecological since they would last forever (unless/until lost).

I see an ISO standard for bikes and another for bottles, but no ISO standard seems to exist for bike bottles.

Update (following Vladimir F's answer)

It's nice that the standard size is quoted in a wikipedia article (though without references). I wish the manufacturers were notified of the existence of this convention. Cycling aside, it would be nice if knapsack makers also followed the same convention.

As for getting a bottle-cage pair as one product, I'm not crazy about getting bottles and holders from the same maker, because I would have a hard time deciding what's better, to get a bottle from a bike maker or to get a cage from a bottle maker.

Answer 1

Product recommendations are generally not the thing here. There is however a reputed 4-letter Swiss company that has been producing internally glazed aluminium water bottles especially for cycling, properly fitting in standard bottle cages for many decades now.

And since it is Swiss it will certainly go on for much longer. The problem however with internally glazed metal bottles is their relative fragility. cycling bottles tend to be dropped and hard contact with the ground damages the coating which makes the bottles expensive garbage.

Most modern plastic bottles no longer have that specific 'plasticky taste' that cycling bottles used to have and can be used without restriction. Also all companies produce recyclable ones and some are even biodegradable after some months when lost in the outdoors, if this helps to lighten your conscience.

Concerning cages: cages that have a certain flexibility and that are slightly tighter keep a much better hold of bottles on rough terrain. When pros ride on cobbles the team mechanics often stick strips of skateboard tape to the cages to give the bottles a better hold.

Answer 2

There is a common format used by all major bottle and holder makers. At least the typical plastic ones, I do not use any other.

Wikipedia specifies it as: "The standard size of bottle cage holds a bottle 2-7/8 inches (2.875") or 73 mm in diameter and five inches (5") or 127 mm tall, or with an indentation that far from the bottom for the tab on the cage to engage." https://en.wikipedia.org/wiki/Bottle_cage#Bottle

Various other shapes are used on time-trial racing bikes and their shapes are within the limits regulated by UCI.

You will find out, however, that there are small differences in sizes. In some holders (e.g. B'twin, several pieces) I had problems with Tacx bottles (several, bought separately) as they are slightly wider and very hard to get out of such a holder. A narrower bottle will however be loose in a wider holder and may come off unexpectedly (I broke some this way). The bottles and hlders from the same maker usually work the best.

Since then I separate my bottles into groups and keep track which holder they work well with and try to sick with the vendors I know when bying replacements.

Answer 3

If you are going on a ride with folks who are not regular cyclists, the key number to remember is this:

73-74 mm

This is the standard diameter of a water bottle that will fit in a bicycle water bottle cage.

Hence you can ask, for example: "I have an extra cage on my bike. Can you take a 73-74 mm-diameter water bottle?"

Speculating, the origin of this unusual number may be empirical: (3 − ⅛)″ [i.e. 2 ⅞ ″] is 73.025 mm.