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Discussion Starter · #21 ·
This is useful knowledge, thank you. I went from an 89V (OEM - 1279 lbs) to 95Y (1521 lbs). Sounds like you're suggesting running something like 36/34 might be closer to the factory spec of 38/36 due to the different load rating and higher sidewall stiffness of the Contis?

I had not thought of this but will certainly try if that sounds right.
Here is a chart I found for adjusted air pressure based on changing load ratings.

Tire Pressure Calculator

-JE
 

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Here is a chart I found for adjusted air pressure based on changing load ratings.

Tire Pressure Calculator

-JE
Seems to be saying i could drop 4 lbs, but then it's off on the load rating by 250, so i'll probably start with 2 lbs. Thank you for this!



OEM Size (215/45R18 SL) Load Capacity: 1279 lbs. @ 38 psi.

New Size (235/40R18 XL) Load Capacity: 1283 lbs. @ 34 psi.


Calculate New Pressure
 

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Discussion Starter · #23 ·
Seems to be saying i could drop 4 lbs, but then it's off on the load rating by 250, so i'll probably start with 2 lbs. Thank you for this!



OEM Size (215/45R18 SL) Load Capacity: 1279 lbs. @ 38 psi.

New Size (235/40R18 XL) Load Capacity: 1283 lbs. @ 34 psi.


Calculate New Pressure
You are welcome. It also supports what @arathol has been saying that it’s more load ratings than speed rating.

I noticed on the chart it doesn’t even take speed rating into consideration.

-JE
 

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I split the difference and went with 17s.
215/50 R17 PIRELLI CINTURATO P7 ALL SEASON PLUS II.
Same diameter as the stock 18s.
Big improvement in comfort, and more importantly, stopped bending rims/bubbling tires every 2 months (lol).
If I live in a good road state, I'd have probably stayed with 18s, but couldn't afford the constant damage here.
But the comfort/noise reduction was a huge side benefit as well. Minimal change to the handling.
Stayed with the 35psi pressure. No issues year+ later (knock on wood).
 

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Discussion Starter · #25 ·
I split the difference and went with 17s.
215/50 R17 PIRELLI CINTURATO P7 ALL SEASON PLUS II.
Same diameter as the stock 18s.
Big improvement in comfort, and more importantly, stopped bending rims/bubbling tires every 2 months (lol).
If I live in a good road state, I'd have probably stayed with 18s, but couldn't afford the constant damage here.
But the comfort/noise reduction was a huge side benefit as well. Minimal change to the handling.
Stayed with the 35psi pressure. No issues year+ later (knock on wood).
Thanks for chiming in with your experience!!! What pressures are you running? Is your tire v or h rated?

Can’t go wrong w/ 17’s!!!!! I wanted a big sidewall so went w 16’s. I think the vintage look is cool!!!

-JE
 

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Doesn’t fit the car entirely because the new Mazda is so classy, refined, and sleek: but it does pay homage to the past.
It’s your car, it’s your money, the nod to something old is kinda cool, I find it interesting that Japanese cars can now be collectors’ cars too. Personally I want to see a 4th gen hatch as a proper rally car.
 

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Discussion Starter · #27 ·
It’s your car, it’s your money, the nod to something old is kinda cool, I find it interesting that Japanese cars can now be collectors’ cars too. Personally I want to see a 4th gen hatch as a proper rally car.
Thanks brother. I meant the matte grey doesn’t fit. IN person its too far of a shade difference than the metallic gray paint. I’m getting the wheels dipped and coated in gloss black next wednesday.

Rally car would be sweet!!!

-JE
 

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You are welcome. It also supports what @arathol has been saying that it’s more load ratings than speed rating.

I noticed on the chart it doesn’t even take speed rating into consideration.

-JE
agreed. I was riding at 36/34 warm this evening, and that did feel closer to OEM on 235s. You lose a smidge of turn-in, but gain a smoother ride, so i may switch to 34/32 cold in the next few days now that fall temps have settled in.
 

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Discussion Starter · #29 ·
agreed. I was riding at 36/34 warm this evening, and that did feel closer to OEM on 235s. You lose a smidge of turn-in, but gain a smoother ride, so i may switch to 34/32 cold in the next few days now that fall temps have settled in.
I went all the way down to 30/30 based on that chart from 38/36. World of difference.

I have new Yokohama’s comingIn tomorrow. Gonna compare those at 30/30 against the pirelli.

I’ll keep that one that is the most comfy. I’ve been impressed by the handling of the pirelli’s I must say.

-JE
 
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