For the past few weeks I've been eyeing cross bikes. Our area has several mountain ranges with some awesome climbs, and while I love riding on the road, these trails have been calling me. Most of these are fire roads but some are singletrack. I'd prefer to get a cross bike since I'd also be interested in racing this fall. Are cross bikes feasable going up 6-10% dirt roads with 1k to 7k of gain, or do I need the traction of a mountain bike?