Originally Posted by
terrymorse
As will any tire. The design upper limit for tires is typically 90C. At 120C, tire rubber is soft enough to deform plastically.
It is not true that innertube rubber, IIR (aka butyl) has the same working temp range as the butadiene and natural rubbers used in sidewalls and treads, and is in fact lower for butyl than it is for BR or NR, with natural rubber’s critical temp reaching upwards of 200ºC. The 140ºC mentioned by the Vittoria guy as the upper limit at which “all kinds of tubes will be destroyed” is still below the critical temp for BR, too.
It should be clear that when it comes to temperature induced failure in bike tire/wheel systems, the butyl innertube is the weakest link.