cmxPPL219
Well-Known Member
- Joined
- Feb 7, 2019
- Threads
- 2
- Messages
- 575
- Reaction score
- 561
- Location
- Toronto, Canada
- First Name
- Eric
- Vehicle(s)
- 2019 Mustang GT PP2
Gotcha - No I agree with you completely.Actually, a 245/40R19 is 0.5" more in diameter than my 305/30R19 so they are the best size match for a PP2 if you want to keep the speedo and such happy. I have heard to keep tire diameter within 3% is safe.
A 245/45R19 would be 1.5" in diameter more and throw the speed off by -5.3%. I would be doing 60 when my speedo read 56.8mph. Not terrible but I am sure it would get me into trouble.
I tend to like to keep the tire diameter as close to stock as possible. I have heard it can mess with traction control too. The 275/35R19 is also very close to stock diameters but is on the hairy edge of finding a winter tire. They make them but not many.
I should have clarified / added more context to my previous post, in that the benefit of having the slightly taller sidewall of the 245/45 compared to the 245/40, is the additional flex you get from the sidewall, which can be beneficial in the way the tire contact patch is able to "grip" and dig into certain hard-packed snow/ice situations, especially during cornering, where there is more lateral movement on the sidewall, before the contact patch gives up, and the car starts to slide - which happens sooner with the shorter sidewall.
The other benefit is due to the freeze/thaw and all the potholes and road damage that happens with winter, it also provides more cushion to absorb the impacts, if say you can't dodge them in time.
But I agree, yes, for the 245/45, the downside is its also just sliiightly out of the park for dimensions that keep the rolling stock within the oem 305/30 %s for the speedo and such.
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