I would think that most auto parts stores should have them.

Cabelas has a nice dial gauge for around $10 or $15. I have one in each of my wheelers along with a repair kit.

Dennis Kirk will deliver it to your front door, in a day or two!

I had to experiment a lot to find the right tire pressure and suspension setting to make my 2004 650 cat ride the best with me on it. About 8 psi in the front helps mine turn better. Add another rider and the suspension needs to be bumped up. I usually don't bother because of how slow I drive with a rider. I run my tires a little fuller (10-12) in the winter to keep the chains tight when pulling the fish house. Keep the suspension soft and tires low when on hills to handle better and bounce the back end less. Rode my friends polaris and it was way different.

I ran my tires at 15 for a long time and always wondered why the ride was so stiff. Then I lowered it to 4, now that makes a difference!!!