700 x 32c tubes
 

hi, i have a specialized sirrus hybrid with 700x32c wheels/tires...i CANNOT keep an inner tube inflated. i think my local bike shop is selling me the wrong innertube. ive got 2 of them in front of me. one says 700x25-28. it lasted for about a week and went flat. today they gave me a 700x18-23. it stayed inflated for about an hour. ive checked the wheel and tire multiple times for debris, theres nothing there. are these tubes blowing out because they are the wrong size? ive gone through 3 now.

also, i noticed today when i was changing the tube that the tires are directional. they had them installed backwards. ive put about 500 miles on them backwards. does that matter?

additional info: the front tube is still the original, so im not really prone to getting flats.

You need to find the leaks in the tubes.

Air up the tubes and place them under water if you don't see or feel the leak right away.

Once you do that you can look at the same area inside and outside on the tire for tiny wires or pieces glass.

but putting a 700X18-23 tube on a 700X32 wheel is fine? just wondering, because it seems like they wouldnt put sizes on them if they were one size fits all

it works, but it isn't ideal.

Inner tubes stretch- but that makes the rubber thinner so the air leaks out quicker. Ideally, you would get a tube marked 700 x 28/32 or similar.

I agree with 10- you need to figure out what is causing the puncture. Look around the inside surface of the tire- sometimes you can see what's poking through. Run your thumb along the inside - usually that will locate what's stuck in the tire.