My mom got a flat on her cruiser bike, and I was about to replace the inner tube when I noticed that the spoke ends stuck out really far and the rim tape didn't seem to be doing much of anything:



She doesn't get many flats, but this one was a rip on the rim side of the tube, and I'm thinking I should replace the rim tape, with cloth, this one appears to be plastic. Am I right?

As long as the spoke ends haven't fully penetrated the rim strip you should be ok. But rim strips are cheap and if you have any doubts, replacing it is trivial.

Yep.
Cheap upgrade that's well worth the few bucks. Be sure and get the correct width tape though.

Rim tape is relatively cheap, even Velox, which is pretty much considered the best. Get two rolls of the right width and redo both wheels.

If the spokes come through the nib you can file it down and then it will not cut the tube

She's already had one flat on the rim side of the tube. If you don't do anything to fix the problem that caused it she'll get more.

They're Rubber rim strips, Go ahead and throw another one on top of the existing rim strip.

Check each spoke nipple , file off any protruding spokes ,
mass produced, big box store bikes some times have spokes that are too long

Velox rim tape is far superior to the rubber band you've got. Adding another rubber band won't make it any better.

The original one deformed around the spoke head, add ing #2 pads over them
a bit more.
It's just a cruiser , and so narrow velox, alone will not be good enough.

Velox tape spans holes in double wall rims.. , but is still thin , can creep sideways

not made wide enough for wide cruiser rims.

Higher tech? surrounding each spoke head with a rubber washer , glued down, will soften the edge
presented by the spoke head .

maybe some Mr Tuffys as a rim strip?.
better than in their under the outside of the tube location.

There's a solution to that. Buy the right size. There's no reason to use some Cletus 'solution' when the right one is easily available and cheap.

Velox comes in three widths 10, 17 and 22 mm. One of those should work nicely.

PVC tape will work rather well on a lower psi tyre and is better than the rubber band that came with a rim... 2 layers is prudent.

Can't count the number of old bikes that have come in with electricians tape serving as a rim strip with no flats... any protruding threads should be filed down on a single walled rim as these are what cause the punctures.

On higher psi tyres you want really good rim tape as the internal pressure pushes out much harder and with double walled rims you do not want poor tape allowing the tube to press into the inner drillings.

Rim tape is relatively inexpensive and comes in many widths and sizes but in a pinch you can make like McGyver.