Which rim tape for 700x28 tires? Which rim tape should i use for 700x28 tires? I can only find 700x17 or 700x14...

I just measured my 26" and the (outside) base of the rim is 24mm... and i used rim tape that is 20mm wide... it fitted fine.

Now for my 700 tire, the base of the rim measures some 23mm... almost the same as the 26"...  yet the tape will be 3mm short. will that make any difference?

Also, would i be able to use the 26" tape on the 700?
As long as it covers the back sides of the nipples and isn't interfering with the bead you'll be fine.

The tape is just there to protect your tube from and sharp edges, getting worn through over time or blowing out down a spoke hole.

See Sheldon