patching thorn resistant tubes - a theory and request for help
 

i don't know how many times i've tried patching my thorn resistant tubes in the past few days but its a lot. (and for review - what makes them thorn resistant? thicker rubber, nothing more) they always fail in the same manner - a blister forms over the puncture which grows until it finds the edge. the exact same technique works perfectly on normal tubes.

if we didn't think of these as bike tubes, how would we patch it? what kind of tube uses thicker rubber? this stuff isn't rocket science even if it varies a bit from normal cyclist technique.

I think they are a waste of money. If you're riding off-road get some kevlar belted tires. If you're on a road bike stay out of the grass and weeds.

Yeah, skip the patches and thick tubes, buy some regular tubes you can patch. If you need thorn resistance get some Mr Tuffy liners.

Clean the tube with acetone before patching. Make sure you let the glue fully dry before putting the patch on. If you've cleaned it with acetone, the patch will practically weld itself to the tube and never leak.

I tried cleaning the spot with acetone (via nail polish remover) and i made doubly sure that the rubber cement had dried. It was a bit slower to fail but still failed.

Unless someone gets back to me with a new idea, i'm considering thorn resistant tubes to be patch resistant and therefore junk.

+1 ^^^this

I use the thicker rubber thorn resistant tubes and haven't gotten a flat for 35,000+ miles on my road bike. I also don't get flats on my MTB with them but there, and on my road comfort bike, I use plastic tire liners that fit between the tire and the tube.

I use these tubes for one reason, I want to ride, not get flats. I do have multiple wheel sets and have a faster wheelset with regular tubes and Vittoria Open Corsa EVO tires for faster rides.

I have repaired many a tube and have never had a problem. I scuff the area well with sandpaper and then put the glue on and let it dry for a few minutes until it's tacky. I make sure the glue is wider than the edge of the patch. I put the patch on then I press the patch down by rolling it with a round tire lever. I've used both the glue in the patch kits though at home what I prefer for economical reasons is a can of tire patch glue from the auto parts store. You want the glue to say vulcanizing which means melting rubber, you'll get a better seal.

Most nail polish remover isn't pure acetone (some don't have any) and have some oil included to reduce drying to the nails and surrounding skin. Either use pure acetone from the hardware store or use sandpaper to buff the oxide layer form the outside of the tube.

Then let the "glue" dry completely without blowing on it to rush it before applying the patch.

Lastly stitch the patch down to ensure a good bond, using something like the curved back end of an adjustable wrench, to apply intense pressure working your way over the entire patch. Patch companies sell stitchers consisting of a flat edged wheel on a stick for this job, which is the key to a permanent bond. A properly applied patch won't come off without taking some of the tube with it.

As for whether thorn resistant tubes make any sense, the jury's out. If you live in the southwest they do reduce the likelihood of thorn punctures, but otherwise don't do much to prevent flats from other causes.