Originally Posted by
RiceAWay
When properly fit to the proper rims they measure the same. I measured the deep carbon clinchers with 25 mm Vittoria's and Deeper carbon tubeless with the GP5000TL's and they measure the same width with a micrometer. Within measuring error.
I'm not worried about Vittorias. I'm specifically curious about 4000's vs. 5000's. Conti tires (including the 4000's) have traditionally measured up to 4mm wider than marked. (The 25mm 4000's on my ENVE wheels measure 29mm wide.) Rumor has it that the 5000's are now more true to the marked size -- meaning they are somewhat narrower than the equivalent "sized" 4000. So, switching from a 25mm 4000 to a 25mm 5000 may yield a different width tire on the same wheel.