Hey guys, did the shop put the wrong size tires on my SI? (235/40 ZR18 '95W' instead of '91W')

[Emig5m]

Hey guys, did the shop put the wrong size tires on my SI? Stock tires are 235/40R18 and the ones the shop put on are 235/40ZR18 95W. They look like they don't fit quite as wide on the rim as the stock tires. Think these will be OK? I had a blow out over an hour from home and like they where the only shop in the area open today and my stock tires had 45,000 miles on them and one already had a plug anyway so I decided to have them replace all the tires instead of having one brand new one with three tires with 45,000 miles. The brand is Kumho and model is Ecsta 4X II. Also, they had about 43psi in the tires, should I drop them back down to the tire pressure inside the door sticker (33psi front, 32psi rear). Also, what's the 'Z' in the size? Is that mean that they're 'Z' rated for higher speeds? Thanks.

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[86salmon]

https://m.tirerack.com/tires/tirete...mY-WmXSpavQQiGkP06QCAIsAW0F-79jhoCoYkQAvD_BwE


This article will explain it all



Also, use the recommended psi on your door

 

[Emig5m]

https://m.tirerack.com/tires/tirete...mY-WmXSpavQQiGkP06QCAIsAW0F-79jhoCoYkQAvD_BwE


This article will explain it all



Also, use the recommended psi on your door

Huh...so these are better tires in a way with a higher load rating? Weird how the stock tires seemed to overshoot or at least be equal to the sides of the rims (built in rim guards?) and these kind of sit inside the rim leaving the rim more exposed to curb rash (not really worried about curb rash since I'm ultra careful how and where I park).

I put the PSI back to stock as labled on the door sill, but bottom line, I'm good to go with these tires? The rubber feels softer/more stickier than the stock compount, maybe they'll grip better, but I loved the durability of the stockers...they just didn't want to wear down!

 

[Vic_L]

Huh...so these are better tires in a way with a higher load rating? Weird how the stock tires seemed to overshoot or at least be equal to the sides of the rims (built in rim guards?) and these kind of sit inside the rim leaving the rim more exposed to curb rash (not really worried about curb rash since I'm ultra careful how and where I park).

I put the PSI back to stock as labled on the door sill, but bottom line, I'm good to go with these tires? The rubber feels softer/more stickier than the stock compount, maybe they'll grip better, but I loved the durability of the stockers...they just didn't want to wear down!

Correct, the stock tires have a "rim protector" built into them.

43 PSI is waaaay too high.

Both stock (Goodyear Eagle Sport A/S ?) and these Kumho tires are classified as UHP all-season tires.
Going by the treadlife warranty, the Kumho tires may be using a softer tire compound.
They will grip better than the stock Goodyear tires, but may wear faster.
That is usually the trade-off, better grip, and durability goes down...
Can't exactly have both at the same time...

 

[BarracksSi]

Also, they had about 43psi in the tires, ...

(rant)

Why the hell do tire shops know so little about tires? Most car owners don't know how to check their tire pressures and never seem to care until they're sliding off the road, so what the hell kind of benefit is it for a shop to overfill them by 30%?

jfc...

(/rant)

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