I am currently running 245/45 g-force KDWSs. I now live in MS and don't really need any snow traction so I plan on getting the g-force KDW2s. They only have 245/40 and 255/40. Will a 40 sidewall ratio as opposed to 45 make any significant difference with my speedometer or anything?

 

I fould a calculator online. I guess ill go with the 255/40 and my speedo will only be off my 1.5mph at 60.