Continental Grand Prix 4000 S: How true to size do they run?

[Climb01742]

Reading reviews of the Continental Grand Prix 4000 S tires, a number of people say they can run larger than the stated size. I was wondering what folks here have found: do they run true to size or bigger? If I got some, I'd probably run them on a wider rim, a HED or H Plus Son. Thanks.

[fa63]

Bigger on wide rims: 23 mm GP4KS2 measure 26 mm on my HED Plus rims.

[m_sasso]

New on Campagnolo 20mm rims, 23s measure 23.4mm @ 95psi.

[Bradford]

My 25's run 27.2 on Archetypes.

[eddief]

run just over 30 installed on A23 rims at about 80psi.

The only way to fly.

[John H.]

Grand Prix 4000 II runs about 1 size wider than labeled sizes.

25 is close to 28mm.
28mm is 31-32mm.

The 700x28 do not fit many true road bikes. Or if they do fit the clearance is minimal- usually under the fork.

The Grandprix 4000 4 seasons runs fairly true to size.

[mnoble485]

Grand Prix 4000 II runs about 1 size wider than labeled sizes.

25 is close to 28mm.
28mm is 31-32mm.

The 700x28 do not fit many true road bikes. Or if they do fit the clearance is minimal- usually under the fork.

The Grandprix 4000 4 seasons runs fairly true to size.

I'm using GP 4000's on my Hampsten with HED Belgium rims. Plenty of room at the back but sooo close (1/8") under the ENVE fork. So close I may go back to 25
on the front.

Mike

[Macadamia]

just measured my 28mm gp4kii's, 28.5mm on a Mavic Aksium, and 28.7mm on a Mavic Open Pro. I'm not really sure how to accurately measure the tire "height" though. Figure both of those rims are pretty narrow, so the tire is more lightbulb shaped.