Stock is 110/80-19, not 110/90-90.
Firstly, this is a solved problem: there are already some excellent sporting tires available in the correct size, including the Continental Road Attack, the Bridgestone BT-023, and the Michelin Pilot Road 3.
Secondly, the DL has a 2.5" wide front rim. A 120/70-19 tire would require a 3.5" wide rim. Sure, you could stuff it on there, and it might even fit under the fender, but it would be pinched pretty far out of shape. Handling would be mighty goofy at best, and very possibly dangerous.
In sum, there's no earthly reason to dink around with tire sizes when excellent 100% pavement sporty tires are already available. Plus, the lower profile tire size you have in mind requires a much wider rim, which will goof up handling.
2002 Suzuki DL1000 V-Strom, Dark Metallic Space Blue
1983 Suzuki GS850G, Cosmic Blue
2005 KLR685, Aztec Red - Turd II.2, the ReReTurdening
Last edited by bwringer; 04-29-2013 at 06:17 PM.