walked out to the garage this morning and notice the new arrangement in the tire rack. this gentle men is why your speedometer is off. the 890 started out at a 31 in tire then when US Royal became Uniroyal they dropped to a 30 in tire. 700 15s are a 29.5 tire and the 235 started out at a 29 then they have shrunk to 28.5. I did find out that you can still get the correct tire for your car but you have to want it in 3 or 5 in. white walls none other is offered.