Graval bike

[madcyclist09]

Hi all, ATM I have 2 hard tails and a road bike
I am thinking of getting rid of the road bike and one of the hard tails
Getting a graval bike, one hardtail is 10 and the other 12 speed what advantage of the graval bike over a hard tail
TIA

 

[ColinJ]

Lighter, tyres with less rolling resistance?

 

[N0bodyOfTheGoat]

Gravel bike will put you in a more aerodynamic position, so you will go faster for your effort {power} above approx 20kph (12mph) and this gets increasingly important as your speed increases.

More likely to encounter such situations on the road, but can happen offroad.