The diameter 215/60/15 is 33 mm higher than 225/50/15 and the speed at 100 km / h will be 5 km / h higher
That might be true
ONLY if the nominal size of your chosen 215/60/15 tire is
EXACTLY what the
actual size of that tire is.....
and very VERY few tires are!! :sour: Those Internet comparison guides are only correct
IF the tire sizes you are comparing are exactly the same size as their nominal sizes, and for most, that's simply not the case!
And the 5km fast thing is only likely to be correct if you assume your Speedo is accurate too, and virtually all Spyders leave the factory with speedos reading faster than what your true speed anyway!! :lecturef_smilie: In fact, virtually all vehicle manufacturers try
very VERY HARD to make sure that every Speedo in a car they sell reads anything up to about 10% faster than the vehicle's true speed! Let alone doing this to avoid potentially expensive litigation if one of their Speedos reading slow can ever be shown to have resulted in a speeding ticket, many States & Countries around the World actually legislate to make sure that speedos don't read slow!! Supposedly, amongst other things, it's intended to keep everyone safer.....
So there's a really good chance that by fitting a 215/60/15 tire to your Spyder, its Speedo reading will be closer to 'correct' than when it was running the OE Spec Kendas, and you might actually be doing 95 kmh when the speedo reads 100 kmh instead of the 91 or so it was more likely doing with the OE Spec Kenda fitted!! :shocked:

hyea: :2thumbs:
There again, there
are some speedos that
DO read closer to 'accurate' with the OE Spec tires fitted..... but you won't ever really know that unless you check your speedo reading at a given speed against a certified correct speed device.... and I can tell you, they ain't cheap &/or all that easy to access! :shocked: Altho a 'proper GPS' that uses multiple satellite signals & adds in at least one relatively strong land based signal can get
fairly close.... :dontknow: