PS AS 4+ ZP - 9", 12" width?
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Cruising
Joined: Aug 2025
Posts: 14
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PS AS 4+ ZP - 9", 12" width?
I'm looking to mount a set of OEM spec PS AS 4+ ZP tires on 9" and 12" rims respectively (vs. the stock 10" and 13"). According to Tire Rack, these are within the acceptable range of width for 275/30r20 and 345/25r21 (respectively).
https://www.tirerack.com/tires/tires...5YR1PS4S4PZPXL
https://www.tirerack.com/tires/tires...3YR0PS4S4PZPXL
The measured rim width for these is 9.5" and 12.5"---btw.
Is there any reason that these will not work with 9" and 12"? Are ZP/ Run-Flat tires problematic for a narrower fitment, but still within the MFG listed range of recommended rim widths?
p.s.
I'm asking because at least one wheel vendor states that even 21x12.5" is too narrow for the 345/25r21 ZP.
https://www.tirerack.com/tires/tires...5YR1PS4S4PZPXL
https://www.tirerack.com/tires/tires...3YR0PS4S4PZPXL
The measured rim width for these is 9.5" and 12.5"---btw.
Is there any reason that these will not work with 9" and 12"? Are ZP/ Run-Flat tires problematic for a narrower fitment, but still within the MFG listed range of recommended rim widths?
p.s.
I'm asking because at least one wheel vendor states that even 21x12.5" is too narrow for the 345/25r21 ZP.
Last edited by Temerity; Aug 26, 2025 at 12:41 PM.
Le Mans Master
Joined: Mar 2001
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From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
It states right in the specs: rim width range 12-13", and that's per Michelin. Yes, the Z06/E-Ray use 10" and 13" wide wheels, but as long as you meet the manufacturer's minimum width, it will work safely. Back when 17-18" wheel diameters were more common, running a tire at it's minimum wheel width could result in some undesired behaviour (more "squirm"), especially noticeable on the front as turn-in response wouldn't be as good. This was often combated by running a little higher pressure. However, the sidewall is so short on these sizes that I'm not sure running at the minimum wheel width would even be noticeable to most drivers.
