Winter tires: 235/40-18 vs 245/40-18 vs 255/40-18

[Victorofhavoc]

No not the big chart of numbers, click test data under the compare button , then click analysis when the video in the new window pops up. That’s where you can see the direct comparison between tires that tire rack tested , I should have been more specific

You might have to post a screenshot because I don't see any way to get a direct same day comparison between the two tires. There are different test reports, yes, and you can read into that data all you want, but comparing that data from two different test events means virtually nothing.

They did compare the wintrac to the alpin 5 (because the pa4 is very old compared to both), and the alpin marginally won out in their test. That test also didn't include dry weather performance or talk about handling balance, because they were also testing the ice and snow tire in that test.

I will say, if you go down the pa4 route, they have a 265/40. That'll bring more comfort to it and you can reduce pressure quite a bit more.

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[ITS ITS ITS]

You might have to post a screenshot because I don't see any way to get a direct same day comparison between the two tires. There are different test reports, yes, and you can read into that data all you want, but comparing that data from two different test events means virtually nothing.

They did compare the wintrac to the alpin 5 (because the pa4 is very old compared to both), and the alpin marginally won out in their test. That test also didn't include dry weather performance or talk about handling balance, because they were also testing the ice and snow tire in that test.

I will say, if you go down the pa4 route, they have a 265/40. That'll bring more comfort to it and you can reduce pressure quite a bit more.

Here

, I circled where to click in red

Direct comparison . Same day, same car

 

[Victorofhavoc]

Here

, I circled where to click in red

Direct comparison . Same day, same car

Yes, that's correct. That's the alpin 5. It doesn't come in a reasonable size for this car and a 9.5 wheel. And again, that was a winter only comparison that didn't deal with any dry winter or handling analysis. Comfort and dry grip are usually what performance winters give up to get more snow and ice traction.

That is not the alpin pa4 vs wintrac. That hasn't been directly compared.

 

[ITS ITS ITS]

Ok I see what you’re saying. I will take another look at the win track pros. Thanks for the help.

 

[ITS ITS ITS]

And I was just using the alpin 5 tire as an example where to click, I realize it doesn’t come in the right size. So looks like it’s between the wintrac and the alpin pa4

I did a tire size comparison and the 265/40-18 is a much larger tire than the stock PS4S tire. The side wall would be bigger but the handling characteristics would change ?

 

[Victorofhavoc]

Yes, they are a bit taller. Handling "characteristics" don't necessarily change with the wheel size difference. The suspension still compresses and behaves as it does. Your roll center will go up by half the height difference. The car will produce a bit less torque at the wheel, but that won't be as drastic of a feeling as having winter tires on anyway. In theory the car will spool slightly sooner due to the added resistance, but again marginal differences here. Top speed will be higher, not that it matters. Top end will feel slightly faster as well. Low end will feel slightly slower.

Also, a professional race car builder named Dean Palmer spent some time with me on track and recommended, for handling, a larger sidewall! With the larger sidewall you have greater load bearing and pressure changes can more easily be used to alter the tire's spring rate. We were talking a 295/30/19 vs a 295/35/18 slick, but the same applies to a dry winter tire. If you want more stiffness, just up the pressure a few psi. Want more dry grip? Drop the pressure a bit. More snow and ice grip? Pump it high.

 

[Ayzoterik]

Can confirm. My winter setup is 235/40R18 on 18x8.5 wheels with a +38 offset. I bought mine from Tirerack fully assembled (including TPMS sensors, hub centric rings, and lug nuts specific to the wheels).

That tire size will get you the closest diameter to stock so you don't have to worry about the speedometer/mileage counter being off.

I also have a 235/40R18 setup for winter, but with 18x8 and a + offset of 45mm.

 

[Ayzoterik]

Yes, they are a bit taller. Handling "characteristics" don't necessarily change with the wheel size difference. The suspension still compresses and behaves as it does. Your roll center will go up by half the height difference. The car will produce a bit less torque at the wheel, but that won't be as drastic of a feeling as having winter tires on anyway. In theory the car will spool slightly sooner due to the added resistance, but again marginal differences here. Top speed will be higher, not that it matters. Top end will feel slightly faster as well. Low end will feel slightly slower.

Also, a professional race car builder named Dean Palmer spent some time with me on track and recommended, for handling, a larger sidewall! With the larger sidewall you have greater load bearing and pressure changes can more easily be used to alter the tire's spring rate. We were talking a 295/30/19 vs a 295/35/18 slick, but the same applies to a dry winter tire. If you want more stiffness, just up the pressure a few psi. Want more dry grip? Drop the pressure a bit. More snow and ice grip? Pump it high.

Really interesting thread, thanks for sharing these infos.

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