These P Zero Race 4S tires were designated 26c. But they were just 24 mm wide when mounted on Dura-Ace WH-R9100 C40 rims. Measured with a digital caliper. They replaced a prior model - the P Zero Velo 4S in 25c. Those tires were 26 mm wide when mounted on the same rims. I had wanted to go a bit wider but instead got the opposite. To be fair, the prior tires had outstanding performance. Just unhappy that Pirelli changed their sizing.
I have been riding the Pirelli Velo 4s 28s for the last 2 years. I have been very happy with them and was looking forward to the new Race 4s. As I mounted them on the wheels this morning I was surprised by how narrow they are. They look more like a 26 than a 28. I am looking forward to riding them later this week and will update this review. BTW, they mount up pretty easily so no sore thumbs or pinched tubes.
P 4S feels soft and grippy to the touch as all faster tires do. Mounts easier than most new tires and rolls very quiet and smooth. Does stop well on wet pavement. May be best option for training and fast group rides . The 28mm is on the small side of 28s. It is only 68mm laying flat and appears 1.5mm smaller than a GP5000 x 28mm mounted on a HED rim. I find this smaller 28mm a sweet spot for a smooth fast tire.
The 26mm are great quality and easy to hand mount on 25mm wide rims.
Grippy, easy to mount, quick feeling
