Originally Posted by
Nessism
The 4k's are definitely bigger than the 5k's. Great tires either way.
I found this too. The GP4000's always sized up larger, a 23mm was more like a 25mm tyre. The new GP5000's seem to be more "correct" in their sizing.
Interestingly I also found the GP5000's harder to fit! Not difficult, but I could fit GP4000's with ease whereas the GP5000's seem to take a bit more wrestling to get on and off. Not a deal breaker.