what's recommended and where can I get one online?

 

I would use anything that gives you repeatable readings and is close to accurate. It's more important that the relative pressures are correct than absolute accuracy. Mechanical gauges have the additional disadvantage of parallax error reading the gauge. I personally use a $10 Radio Shack digital gauge that I've verified against my previous mechanical gauge.

 

I would recommend www.racerpartswholesale.com they have them there. $20bucks and they are certified. If you really want to step up, go with Longacre digital. www.longacreracing.com

 

Things to look out for:

-avoid those pencil gauges, especially the cheap ones. They can burst under pressure when you most need it.

-get something that you can read at night, i.e. no LCD display without light. most needle gauge and lighted digital ones are fine.

-something that reads up to 60psi for the spare is nice, but not so important

-some designs are stupidly engineered to be difficult to get a clean attachment to the valve stem

-practice letting out air with your ignition key and time how many psi you let out per second. this is pretty handy at the track if the tyre gauge doesn't have a fast air release mechanism.

-check pressure as soon as you get into the pits, don't wait around.

Good luck!

///Robin