I own a KTM 990 Adventure R and a KTM 500 EXC. I have been riding both dual sport and adventure bikes for several years now. I ride both off-road and the experience is very different. I was a little initimidated when I bought my first ADV bike riding it off-road. But once you get used to it and you know it's limitations, you can go nearly anywhere a smaller bike can go and have just as much fun. It's just at a slower speed. The challenge of riding a heavy bike makes it interesting on trails that would be boring on a smaller bike.
The mindset is different... When I'm on my adventure bike I am out looking to explore and cruise. I want to be comfortable and enjoy the scenery. When I"m on my small dual sport, I'm out there to haul ass and tear it up. It is very physical and fast paced. The point is to get a thrill out of attacking the trail on a smaller bike for me. You can do that in spurts on the big Adventure Bikes as long as you are cautious.
1) Is there a place for adventure touring motorcycles off-pavement?
Yes, but this is not a replacement for small dual sports. The purpose of having a big Adventure Bike is for long distance multi-day touring that includes camping. You need a big bike to carry all your gear. You want something comfortable and fast enough to keep up with traffic on the highway. Then riding on dirt roads that are not too rocky or technical is absolutely a blast. But you don't want to take on the Rubicon Trail. Use a different bike for that.
2) Can a rider on a lightweight dual-sport with DOT knobby tires survive much time on the asphalt—if so, how much? What are your views on each motorcycle design?...Join this forum and share your off-pavement experiences and preferences!
I don't think you should be on pavement for more than 20-30 minutes at a time on a small dual sport. I just feel like I'm eating up my knobbies and it's uncomfortable. Also, you just don't have enough range on the tank for long blasts on the highway if your goal is to get to a trail. Put the bike in the truck to get to the trails, then ride all day. If you need to get on the pavement to link up trails for 20-30 minutes it's fine.
I don't think people should try to learn how to ride off-road on a full sized adventure bike. That's a mistake a lot of people make. Start with a small dual sport or smaller adventure bike in the 650cc range to learn off-road riding technique.