I grabbed a 30 x 3.5 tube and mounted it in a 30 x 3 tire. It mounted and inflated fine. Is there a safety or other issue leaving the mistake in place?
In my opinion, as long as it holds air, it should be fine.
Having folds in the tube can result in more flat tires. Using oversized tubes in an emergency should be considered a temporary "Fix".
Brian, do you lightly inflate the tubes before install? And do you put something like talc powder on them to prevent sticking?
If so, your probably ok, (I know I wouldn't lose sleep on it), and you shouldn't have the issues Les described that could happen if you didn't do the above things.
Brian, if it was a new tube, you are probably OK. A used tube, stretched to fit a 30 x 3.5 tyre, may be creased when fitted in a 30 x 3 tyre. This may/may not cause failure. You will find out one way or another.
Allan from down under.
Allan; new tire, new tube, new glasses
Chad; Powdered, inflated, bounced several times, de-then-reinflated.
Thanks to all.