I have 195s on my bus that should have 185s

the speedo is 29 ks low and the ks are 0.4 ks over per 10ks

is it better to have the 185s? will it use more fule or less?

Ta

Philip

you sure they are straight 195s & not 195/75 ?
if straight 195's the gearing will be raised allowing marginally more speed for the revs you are doing, but the economy is 6 of one halve a dozen of the other,
reason being you may have to use more throttle to accelarate or hold a given speed against wind resistance or up hills

Well if You went smaller You would use More fuel as the engine would be revving harder...

The engine will be revving less with the 185s, so You may save some fuel on the flat or on a down hill run...
But You may use slightly more fuel to go up a hill...
or it may be the same....
Not a lot in it....

Lee