A while back, I tried to the point of exhaustion and fingers going numb to mount the GP5000 TDF 25mm tire on a H Plus Son TB14 box rim. I didn’t have a tire jack (but have since bought one) but decided if I couldn’t get the tire mounted in the comfort of my home I was not going to hit the road knowing it would be nearly impossible to remove and reinstall the tire in the field so I mounted another tire instead. It’s the only tire and rim combination that I’ve come across that was so difficult.
I’ve mounted GP5000 Transparent 25mm tires on modern rims with no problems. Unfortunately I gashed the sidewall on one of those expensive tires that only had 500 miles on them. I just ordered a replacement tire.
I couldn’t flip that last stretch of tire over the box rim and didn’t have a tire jack at the time.