Shimmy ?? Today I changed the 12" tires for some 14" wraped with 185-60R14 tires. At 80 km/h, I thought the wheels would come off the truck ! They started to shimmy like crazy. Do you guys with the same set-up have the same problem ? There is no shimmy with the 12" wheels even at 100 km/h. Second thing I noticed while checking the speed with my GPS is that with the original 12" tires, the indicated speed on the speedometer is higher than the real speed of the truck. I would get 87 km/h on my speedometer and 80 km/h on the GPS. Is it common to all mini trucks ?