Rim Size and Offset Questions

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Rim Size and Offset Questions

Postby Reitrof » Thu Sep 22, 2016 7:23 pm

I am looking to change my rim and tire size next year and have been checking this site and am unsure of which tire width and rim width to select.

Current setup

16x8 offset 50 Mazda RX7 rims with 225/50 16.
KW V3 coilovers RX8 sways
Camber is 1.5 in the front and 2.0 in the rear.

Car is a daily driver and I autox about 16 times a year. I also flat tow it behind my RV for 5000 miles each year.

Looking to improve my autox times.

Trying to decide to go with 235 or 245 tires with either a 17x8 or 17x9. Also not sure which offset would be correct, either 45 or 48. I had to do a mild roll the rear fenders for my current setup.

Thank you for any info
2008 PRHT Touring True Red, MazdaSpeed body kit
RSII, RX8 Sways, KW V3 Coilovers
Kenwood DNX7100, Nautilis Horn
Reitrof
 
Posts: 81
Joined: Sun Aug 20, 2006 1:36 pm
Location: Carleton Place Ontario

Re: Rim Size and Offset Questions

Postby Brian » Fri Sep 23, 2016 8:55 am

Lots of detail on fitment on the front page of NC wheel section. My suggestion is look at our 6UL 17x9 wheels and run 235/40 tires because that combo is plug and play....and that is MUCH faster than 16x8 combo you have now, perhaps 3 seconds faster on average autocross course. That 6UL wheel comes in several colors choices on the site, picture below of the Tungsten color on a PRHT like yours.

Brian

Image
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
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Re: Rim Size and Offset Questions

Postby Reitrof » Sat Sep 24, 2016 8:28 am

Hi Brian,

Thank you for the reply. Sounds like that's the rim for me.

The tire I want to use, RE-71R's come in 234/45-17, not in 235/40/-17. Will this fit?
2008 PRHT Touring True Red, MazdaSpeed body kit
RSII, RX8 Sways, KW V3 Coilovers
Kenwood DNX7100, Nautilis Horn
Reitrof
 
Posts: 81
Joined: Sun Aug 20, 2006 1:36 pm
Location: Carleton Place Ontario

Re: Rim Size and Offset Questions

Postby Brian » Sat Sep 24, 2016 10:49 am

The 235/45 is too tall...by a lot. In that tire you could use 245/40 and given that you have already rolled fenders it should clear on this 6UL rim.

Brian
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
Brian
Site Admin
 
Posts: 7433
Joined: Tue Feb 15, 2005 11:44 am
Location: San Diego CA

Re: Rim Size and Offset Questions

Postby Reitrof » Tue Sep 27, 2016 6:15 pm

Brian wrote:The 235/45 is too tall...by a lot. In that tire you could use 245/40 and given that you have already rolled fenders it should clear on this 6UL rim.

Brian


Ok Thanks Brian.
2008 PRHT Touring True Red, MazdaSpeed body kit
RSII, RX8 Sways, KW V3 Coilovers
Kenwood DNX7100, Nautilis Horn
Reitrof
 
Posts: 81
Joined: Sun Aug 20, 2006 1:36 pm
Location: Carleton Place Ontario


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