tyre pressures

[bunburylad]

Hi all

My 1980 110 atc has a rated tyre pressure of 2.2 psi. Now, no-one i know has a gauge that goes down that low. Someone said that they found the best and most accurate way of getting your tyre pressures spot-on is to measure the circumference and adjust accordingly. He seems to recall that his old three wheeler had a measurement of 69 inches, mine are 80psi atm and seems right, though i don't know what pressure they are at currently. Has someone used this idea before?.. if so , what is the circumference measurement when your tyres are at 2.2 lb?

[Mobular]

I use a sports ball pressure gauge. It reads 0-20 lbs nicely. As for recommended pressures, my 84 200M also says 2.2 lbs, but I run 3-5 lbs in them depending on how the tires respond to the terrain that I'm riding on.

[NOS_350X]

motorcycle shops or offroad shops have low presure guages, about $8 for a cheap one, I run mine at about 3 and in the sand 11

[madmanwithmouse]

Walmart sells a keychain digital gauge that goes 1-99 in 0.5 lb increments, cost $6. The circumference will change with air, but I dont think it is a accurate enough measurement. personaly I'd just adjust them till you like the handling and then leave it alone(dont forget to note the presaure when you get there).