Conti GP4000s 25mm v. 23mm

[LegendRider]

Does anyone know whether the 25mm GP4000s will create a noticeably different profile on Hed Belgium rims than the 23mm version?

[FlashUNC]

FWIW, my 23mm Gatorskins ended up being about 23mm on my HED Belgiums. My 28mm GP 4 Seasons actually came out about 26mm or so on the same rims. Though I know Conti's generally tend to run a bit narrow, I can't say whether that's due strictly to the wider rim.

[LegendRider]

This post has a picture of my 23mm tires measuring nearly 26mm on the Hed rims.

http://forums.thepaceline.net/showthread.php?t=107698

[dave thompson]

Measured with digital calipers, my GP4000s measure an actual 27.0 on the HED C2 and 27.2 on Velocity A23 rims.

[LegendRider]

Originally Posted by dave thompson

Measured with digital calipers, my GP4000s measure an actual 27.0 on the HED C2 and 27.2 on Velocity A23 rims.

Are the sidewalls parallel to the rim or do they bulge? Any clearance issues?

Thanks

[dave thompson]

My tires slightly protrude beyond the rims, about 1~2MM. I don't have any clearance issues on my bikes but it really depends on the fork and chainstays of a particular bike.

[Black Dog]

I am now running 25mm GP 4000's on my Heds and there are no issues. They roll smooth and fast. I run them at a bit lower PSI than the 23mm and that is what makes them a bit smoother. They do not squirm during cornering. I will be staying with the 25mm.

[joev]

Added caution, check the clearance to the brake bridge. My Scott CR1 has enough clearance to the seat and chain stays but can't take the increase from the 23's to the 25's w/o rubbing below the binder bolt area of the bridge.

[beungood]

Originally Posted by Black Dog

I am now running 25mm GP 4000's on my Heds and there are no issues. They roll smooth and fast. I run them at a bit lower PSI than the 23mm and that is what makes them a bit smoother. They do not squirm during cornering. I will be staying with the 25mm.

What pressure do you run them at?