Originally Posted by
burnthesheep
See if a local will save an old tire to try in back for you before they toss it. Gp5000 fit true to size. 4000 were way bigger. So worth a shot.
I have my rear wheel off because the bike is on the trainer and have it up next to the front wheel. The rear GP4000 is clearly wider than the GP5000 in front. This then begs the question, if a GP5000 in a 25 is the same size as a GP4000 in a 23, where is the advantage? Just because it is stated as being larger it won't make much difference on the ride over what I have if in actuality it is the same size.
In any case I'm not going to pin any improvement on a few mm of tire width.