Colossal: Challenge Parigi-Roubaix and Strada Bianca


Tonight I mounted up some fresh Challenge Tires.

The 700x27C Parigi-Roubaix


The 700x30C Strada Bianca.


Both tires are handmade, open tubular tires with a puncture protection strip under the tread. Both tires were a bitch to mount up. You need three hands. My thumbs hurt like a motherfucker.

Two tips for mounting these:

  1. Mount them on a spare rim, without a tube to stretch them out a bit.
  2. Use a slightly smaller tube than usual, use a new tube, ideally.
  3. Be careful of pinch flats, because the tire is so tight, and so flat, it’s easy to do.

When mounted, the deflated tire is very flat:


Once mounted, which took about 90 minutes, for two tires (Yeah, fuck that), I inflated both to 100 psi to measure fit and width.

On the rear, the 700x30C Strada Bianca measures 31mm wide on a Sun Assault (18mm wide x 19mm high) rim. The tire/rim combination measures 47mm high. As you can see, there’s plenty of clearance in the back.


On the front, the 700x27C Parigi-Roubaix measures 29mm wide, by 44mm high on a Sun Assault rim. There’s not much clearance left, about 3mm. With only 3mm of space, there’s no hope of fitting a Strada Bianca in there.


Realistically, I won’t run these tires at 100 psi. 75 front/60 rear is probably closer to where I would start out on gravel, and that might allow me to just squeeze a Strada Bianca in the fork, but what would the value be, if the tolerances are so close that adding a few psi causes the tire to rub?

I’ll test ride these in the next day or so, and write up a review.