No. Not if you stay within the bounds of tires that will fit in your Spyder's current configuration, anyway; altho you should try to basically try to keep the relationship between front and rear tire rolling diameters reasonably similar.
Despite what some dealers might suggest, the Nanny can easily handle tires that vary in size/rolling diameter from completely flat tires to (slightly) over-size and over-inflated tires, which covers a pretty big working range, so while the generally accepted limitation in tire size to avoid concerns is no more than a 20mm change in Rolling Radius, it really takes a pretty significant variance in tire sizes to make any real impact on the Nanny's performance; and if you go a little bigger up front and on the rear, the relationship between the two won't have changed much at all! So unless maybe you're doing something outrageous like stripping the front guards and fitting 35" Mud Terrains or something similar up front while changing the rear tire to a 205/40R15, you're not at all likely to have any issues with the Nanny!
