Per page 117 of the owners manual, the factory recommended COLD tire pressures for the GSX-S1000 is 36F and 42R
. That is for solo and
I used to run just those pressures on my CBR929 and CBR954 but realized they were a touch too 'firm' for solo riding when I was getting my freak on in the curves. With experimentation, I found I liked about 34F and 39R (again, COLD) when riding by myself, with no luggage, and being aggressive/having fun with the bike. The GSX-S1000 seems to like those pressures, too. But I'm a 'big boy' (250 lbs) so I need a bit more pressure than the next guy, I'm sure.
If you put someone on the bike with you, please(!) use the factory recommended 36F/42R. If you are riding on a trip and have the bike loaded up with luggage, again, the factory pressures are going to give you a better safety margin and a bit more tire life.
When I was doing track days, they suggest you lower your tire pressures. I started off with what they recommended (30F/28R) and found I did not like the way the bike felt at all. I experimented and found I needed the front to be at 32 psi COLD to 'feel' right (to me.) I also figured out that 28R psi was too low and 30R psi felt 'right' at the track for me, using the tires I had (usually Michelins.)
Again, I would never run those track pressures on the street! AND, it should be pointed out that running those pressures at a track day ruined a set of Michelin Pilot PURE tires I had. They were never grippy on the street after that track day. In fact, they felt so slippery I had to replace them well before their tread life was used up. The heat from the low pressures at the track day ruined them. I will note that those tires didn't remain in Michelin's line-up for very long, so I suspect I wasn't the only one that experienced that 'problem'.
So what should YOU run? You decide. I wouldn't go below 33F/36R on my street bike rides. And - keep in mind - tires are losing air pressure constantly. If you run such low pressures, you need to check them more often because you are on the edge of safety. If you filled your tire a week ago, I would bet they have dropped by a psi or two already since then. True story. Check it out for yourself. I had one tire that lost air faster than that (about a psi every two days) but I never could find a leak or object in the tire. That's just the way it was for that particular tire. Kind of a pain.
Another consideration is that different maker's tires feel different. Bridgestones seem to have 'stiffer' carcasses than Michelins in my experience. I can run a Michelin at 33F/36R and it will feel just a touch too soft and mushy in cornering until it really gets warmed up. But a Bridgestone at those pressures would feel great to me. That being the case, I would put a bit more air in the Michelins to get the 'feel' I'm used to because of the slightly softer carcass/sidewalls. Can't speak for all the other brands (they vary, as you would imagine) but those two are very distinct from each other, so they make good examples.
Final thought - the lower you run your tire pressures, the hotter they will get and the greater INCREASE in pressure you will get once they are hot. For example, imagine you ran your front tire at 30psi COLD; after riding around for an hour, you jump off the bike and check it and find it is now up to 36psi HOT. That represents a 20% increase in pressure from hot to cold. That is too much. You are running the tire at too low a pressure. Let's then say you then run the tire at 33psi COLD and after an hour of riding around you get off and check the pressure and find it is 36.5 psi HOT. That represents about a 10% increase in pressure from hot to cold and that is what you are looking for - a 10% change from hot to cold.
Ride safe. Have fun. Live the dream.