Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Poor Quality - Pre-blown for your convenience!

I bought four of these... two for each bicycle. Well, two of them went flat within days. One split on a seam (no corresponding hole in tire), and the other split at the stem (same as above). My tire sidewalls specify 50 - 75 psi, and we regularly run at 70 psi. We ride mainly on streets, sidewalks, and paved bike trails.They are awkward to change out, as they are so stiff. It would be well worth it, if they weren't falling apart.