Originally Posted by
cicatrize
That seems to be the common feeling about them, but check this out:
http://www.amazon.com/Continental-Gr.../dp/B00PUE4NKY (9% 1 star, interesting photos of sidewall blowouts)
These type of reviews are found all over the web on sites that sell the GP4000s II's. It's more so than other tires, but obviously one can argue that at this price point, people are more willing to get online and write a bad review about issues than a $25 tire.
What's a good PSI to run the 25s at?
I seriously doubt those failures you allude to are true sidewall failures in which the wall simply gives way and explodes. Most likely they are due to sidewall cuts, which are rare with the Contis but nevertheless do occur. The cut slit pinches the tube and results in a blowout. All tires are prone to sidewall cuts to some extent.