I don't have any eyelets on my bike to screw in bottle cages, and I consider thirst and important issue to address - especially as I might be taking this singlespeed bike touring in the near future. At the moment my options seem limited to the behind the saddle mounts such as these: http://www.wiggle.co.uk/minoura-sbh-300-dual-bottle-cage-bracket/ but do you have any cheap ideas to stick a bottle cage on the frame? Riding with a camelback is another option I would rather try to avoid, Thanks!!
Halfords do some plastic zip-tie type things that have bottle cage mounts built in. I've got a set on my my raleigh - I seem to remember they were only a few quid.
Wilkinsons do a cheap one which mounts both ways. However it looks flimsy so I'd certainly add some inner tube to make it last more than a week.
Second vote for protective wrap + jubilee clips. Still solid and attached after 30 years on my old Raleigh Merlin.
I like the retro look of handlebar mounted bottles. I appreciate though that handlebars can get a bit cluttered, what with computers, lights, etc.
Zefal Gizmos are what you need. http://road.cc/content/review/11601-zefal-gizmo-extra-bottle-cage-mount
The VIP Elite ones (Halfords & other places per Numbnuts link) are OK. Put a few wraps of insulating tape around the frame first though, as on metal they seem to rotate around however tight you do them. Some cages need longer bolts than those supplied, but you don't want them too long. The wraps of tape help protect the frame if bolts are a fraction too long. If a fraction too short a tiny piece of blu-tak can help hold the nut "up" so the bolt thread can engage.
Zefal gizmo is what I had but stupidly mine are big. If you measure your frame and want a pair Lete know by PM I have them sitting in the box of bike bits
http://www.decathlon.co.uk/apb-300-bottle-holder-bracket-id_4766980.html is what Daughter and Wife have on their bikes.
I've looked into this before .... see Adding Water Bottles. Some really neat solutions. I especially like the ones that look like seatpost clamps, but last time I searched I couldn't find them in the UK.
Tried those... don't bother would be my advice. Found it impossible to get them tight enough to stop them rotating around the downtube under the weight of a full bottle. Try for the next notch to get them tighter and the rubber band snaps. Have a look at http://www.bikebuddy.co.uk too.
I had no problems with the ones from Decathlon rotating although the screws were just long enough to mark the paintwork on the frame.
I used the ones that came with the bottle cage rather than the adapter. the fixing eyelet is also quite thick on the decathlon bottle cage i used. sometimes cheap does mean value
I bought some of those Halfords jobbies for one of my kids. Honest review: a faff to fit and came loose so easily that I took them off. ----------------------------------- Sent mobile phone stylee