Recommended tire pressure on NC

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pdxa4
Posts: 76
Joined: Sun Nov 05, 2006 1:58 pm

Recommended tire pressure on NC

Post by pdxa4 »

Hi Brian,

Wonder if you could chime in and recommend good tire pressures for both street and spirited mountain runs.

I have just got new Dunlop Direzza II's, I ended up getting them in 215/45/17 size. And I have them on the stock 17x7 NC wheels.

I was running a weird 225/55/16 size for a number of years on my car, so it it time for something more normal :)

Many thanks
06 Sunlight Silver NC, Sport LSD.
H&R coilovers, Goodwin RACE exhaust, several other mods.(Sold)
19 Artic White ND2, Club with Brembo, BBS and Recaro
Goodwin Race exhaust, RoadsterSport suspension package
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Brian
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Re: Recommended tire pressure on NC

Post by Brian »

I say start at 30 PSI and then tune to taste. For canyon driving days try a bit more at 32 to 34psi. For long comfortable freeway road trips try lower like 27psi.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
pdxa4
Posts: 76
Joined: Sun Nov 05, 2006 1:58 pm

Re: Recommended tire pressure on NC

Post by pdxa4 »

Brian wrote:I say start at 30 PSI and then tune to taste. For canyon driving days try a bit more at 32 to 34psi. For long comfortable freeway road trips try lower like 27psi.
Excellent Brian, thanks for the recommendations. It gives me a great starting point...
06 Sunlight Silver NC, Sport LSD.
H&R coilovers, Goodwin RACE exhaust, several other mods.(Sold)
19 Artic White ND2, Club with Brembo, BBS and Recaro
Goodwin Race exhaust, RoadsterSport suspension package
99 NB 10th Anniversary
StephenW571
Posts: 35
Joined: Sun Nov 03, 2013 4:11 pm

Re: Recommended tire pressure on NC2

Post by StephenW571 »

Hi Brian
I know this is rather subjective but what would be a good tire pressure starting point for 235/40/17 on 17x8 Enkie PF01 for
A) comfortable freeway.
And
B) spirited twisty back roads?.

Thks
Steve
Brian
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Re: Recommended tire pressure on NC

Post by Brian »

Same numbers....for those twisty back roads 32 to 34psi.....but ideal pressure will depend much on surface conditions, lower pressures to max grip on rougher roads. For long comfortable freeway road trips try lower like 27psi.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
NaregM677
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Joined: Fri Jan 31, 2014 1:48 pm
Location: Pasadena, CA

Re: Recommended tire pressure on NC

Post by NaregM677 »

Brian wrote:I say start at 30 PSI and then tune to taste. For canyon driving days try a bit more at 32 to 34psi. For long comfortable freeway road trips try lower like 27psi.
Really? I would have thought just the opposite. I would have figured a higher psi for the freeway (no real bursts of acceleration, cornering or braking) and a lower psi for better traction through the mountain roads, knowing that the heat being put in the tires would increase the psi as well. Help me understand what I'm missing here.
2013 Miata Club "Shadowfax"
"And the road becomes my bride..."
Brian
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Re: Recommended tire pressure on NC

Post by Brian »

Notice he said "comfortable freeway". If he had said the goal was max MPG...then higher PSI on the freeway would make sense.

As for the canyon roads, 27 PSi might feel a bit sloppy on a good smooth road, allowing sidewalls to roll over....which means the tread is not working for you because the contact patch is rolling off the surface. Adding pressure helps the turn-in response, stabilizes the tire on the rim, helps keep the contact patch on the ground instead of rolling over. That's all true at least on smooth roads...which is why I noted 'but ideal pressure will depend much on surface conditions', because the rougher the road, the lower pressure you need for max traction.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
NaregM677
Posts: 69
Joined: Fri Jan 31, 2014 1:48 pm
Location: Pasadena, CA

Re: Recommended tire pressure on NC

Post by NaregM677 »

Makes sense. I had figured that with psi nearing 34, the tire may be so stiff and sturdy that it may encourage oversteer. Thanks for the explanation!
2013 Miata Club "Shadowfax"
"And the road becomes my bride..."
StephenW571
Posts: 35
Joined: Sun Nov 03, 2013 4:11 pm

Re: Recommended tire pressure on NC

Post by StephenW571 »

Thanks the advise
:D
avera01
Posts: 80
Joined: Mon Jun 27, 2011 2:20 pm

Re: Recommended tire pressure on NC

Post by avera01 »

Brian wrote:I say start at 30 PSI and then tune to taste. For canyon driving days try a bit more at 32 to 34psi. For long comfortable freeway road trips try lower like 27psi.

Hi Brian,

Will these values be useful for the ND?

I plan on going up to the North Carolina mountains in 2 weeks to drive the Dragon Tail and other local mountain roads. My car is a 2016 GT with stock tires and suspension except for your RoadsterSport SB set to the middle hole and your Wilwood LBBK with the 12.19" rotors.

I normally have the pressure set around 28/29 for local South Florida roads as I find the lower levels more comfortable for daily driving and long runs of 100 plus miles, but on flat smooth roads. I figured I used that level (or a bit lower like 27) for the long highway drive up then change it to suit the mountain roads. I expect air temps to be in the 50s possible warming up a little bit mid day, depending on any cold front shifting down.
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