I have the exact same bike. The OEM stock front wheel on these bikes is 19 inches, hence the 110/80R 19 designation. If your front tire is a 120/70R17, then you have a 17 inch front wheel...
The DL 650 VStrom's sister bike is the street SV 650, which is very similar, but is tuned for more sporty on road riding and carries a 17-inch wheel. As @KSRider650A said, a previous owner probably wanted quicker steering response and a wider tire selection. Your rear tire should be a 150/70R 17 Tubeless.Kind of makes sense. I will look at my wheel to see if is actually a 17”. I would be very surprised if it is, can’t imagine Suzuki would make both a 17” and 19” wheel for that bike?
Well the tire sidewall should be enough information. You can’t just put a 17” tire on a 19” rim. Post a picture of your bike, it should be pretty obvious which size front wheel you have.That’s my plan, run the front as is with a new 150/70 R17 rear. Still going to see if the front wheel is a 17”, are there markings on it to know for sure?
If that's what the PO was trying to accomplish, then the Shinko 705s don't make much sense.If they were a road only rider, it might be that the 17 inch wheel allows for a much wider choice of tire and can steer quicker too.