Is cyclocross tire (CX) taller than normal road bike's?

There are several things that may be at play here.

Tires bulge like a balloon out of the rim. Thus, tire height in general is more than tire width because tire is higher than a half circle. So it is untrue that a 25mm wide tire is 25mm high too.

Firstly, most road tire purchasers look at tire weight and make a purchase decision based on the tire weight. Thus, your current 700x25c tires may actually not be 25mm wide but they may be 23mm wide instead. By selling a 23mm tire as a 25mm tire, the manufacturer is able to make it lighter than its competitors. Soon every manufacturer starts to do this to gain the same benefit of light weight, and we have lots of tires sold with incorrectly marked size. This would mean that 23mm tire is 25mm high, i.e. tire is 8.7% higher than it is wide.

If you take this effect into account, 33mm tire should be about 36mm high.

Cyclocross tire manufacturers do not have as large incentive to sell tires with incorrectly marked size, because cyclocross tire purchasers do not make decision on the weight of the tire.

Secondly, cyclocross tires have knobs. They do not contribute to width but contribute to height. If a 33mm wide tire which is 36mm high has 5.5mm high knobs, the tire total height is 41.5mm.

BB height is a measurement that depends on too many ill defined parameters to be useful.

A rough approximation for three height of a tyre is to take its nominal width. That leaves us with a discrepancy of about 8 mm. Spezialized seem to have used either a height from the tyre manufacturers data sheet or actually measured themselves.

Tyres deviate from a perfect toroidal shape. For example, a fully inflated tyre on a narrow rim might be much taller. Rim and casing will determine the actual cross section.

There is also a layer of thick rubber to roll on and, in the case of the CX tyre knobs.

Lastly, for a real measurement one has to consider tyre drop* of the tyres. For road riding up to 15% is typical. CX tubular tyres might be depressed by 50% however.

Finally, Spezialized's road section might use different conveniens l conventions than their CC section or MTB section.

Overall there is so much guesswork in interpreting that value that you might only find out that BB height means by asking Spezialized themselves.

• Tyre drop is a measure of the reduction of a tyre's extension in radial direction under a radial force oriented towards the hub.