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20" Gianna Wheels and Kumho Tires?

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Old 08-02-2007, 12:17 AM
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him
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20" Gianna Wheels and Kumho Tires?

Hi. I know nothing about tires, fitment, offset, etc....

Just wondering... Anyone out there with 20" wheels? Anyone out there with Gianna Wheels? I remember reading good things about Kumho tires, right?

Anything I need to watch out for if I get 20" wheels? What offset should I get? (Don't even know what the heck offset means....) Anything else I need to be watching for? Is 20" a bad idea all together? Please help... I feel so helpless.
Old 08-02-2007, 12:36 AM
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They will be very "bling" but impractical for anything but looks. They will be heavy, have no sidewalls...and therefore handle poorly

Offset on the stock is +50....will need something around there if you want it to fit...say +45-+35 with reservations depending on rim width
Old 08-02-2007, 12:41 AM
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I have 20" wheels with Hankook V4 225/35/20 tires. The 225 is the width of the tire in mm, the 35 is the offset, and the 20 is obviously the size of the rim. My wheels are Boss 318 with black chrome.The wheels are definitely a headturner. The only thing you have to watch out for is that because the rims have less tire surrounding them, if you hit a curb you scrap the rim. Also, you have to watch out for pot holes, because they could possibly damage your rim if they are deep enough. If you are going to be racing I would not recommend them because they are heavier, but if you just want them for looks, I would say go for it.
Old 08-02-2007, 01:53 AM
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fanatic, 35 is not the offset....Tires don't have offsets, only wheels...
35 is the sidewall profile, in percent of the tire width....so 35% of 225mm is 78.75mm sidewall height. In the most basic terms, offset is how many mm the center mounting hub is away from being perfectly centerline... picture the basic hoop of the wheel without any spokes....then install the wheel spokes/mounting lug hub 'disc' plane directly in the middle of the hoop... that is zero offset... these would not work on an RX-8 because the wheel (and tire) would stick out too far and hit the fender under compression. So instead, mount the spokes/mounting lug hole disc plane 50mm towards the outside lip...that is called +50 offset, and effectively brings the wheel hoop (and tire) in, towards the center of the car; now there is no wheel rubbing issues. The more plus you go, the less rim lip you have exposed (how much lip is showing depends on how wide the wheel is to begin with). If you mount the spokes -50, then you have tons of lip showing, but now your wheel hoop (and tire) are really sticking out and you need a wide body kit. Get it? Performance wise, 20s are ridiculous, hell my 19's are pretty bad too.
Unsprung weight is high (and in all the wrong places too), rotational inertia is high; you basically create 4 huge gyroscopes that take alot more energy to spin, and once they are spinning, don't want to turn or change direction.
Then there are stopping distance issues too. Tire prices are still astronomical for 20s, wheel choices are more limited, but if you want baller status, these are your Huckleberries.
Old 08-02-2007, 02:06 AM
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lots of good info here...

but you have to take the time to read it..

http://www.1010tires.com/tech.asp

beers
Old 08-02-2007, 03:40 AM
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Originally Posted by Chamberlin
fanatic, 35 is not the offset....Tires don't have offsets, only wheels...
35 is the sidewall profile, in percent of the tire width....so 35% of 225mm is 78.75mm sidewall height. In the most basic terms, offset is how many mm the center mounting hub is away from being perfectly centerline... picture the basic hoop of the wheel without any spokes....then install the wheel spokes/mounting lug hub 'disc' plane directly in the middle of the hoop... that is zero offset... these would not work on an RX-8 because the wheel (and tire) would stick out too far and hit the fender under compression. So instead, mount the spokes/mounting lug hole disc plane 50mm towards the outside lip...that is called +50 offset, and effectively brings the wheel hoop (and tire) in, towards the center of the car; now there is no wheel rubbing issues. The more plus you go, the less rim lip you have exposed (how much lip is showing depends on how wide the wheel is to begin with). If you mount the spokes -50, then you have tons of lip showing, but now your wheel hoop (and tire) are really sticking out and you need a wide body kit. Get it? Performance wise, 20s are ridiculous, hell my 19's are pretty bad too.
Unsprung weight is high (and in all the wrong places too), rotational inertia is high; you basically create 4 huge gyroscopes that take alot more energy to spin, and once they are spinning, don't want to turn or change direction.
Then there are stopping distance issues too. Tire prices are still astronomical for 20s, wheel choices are more limited, but if you want baller status, these are your Huckleberries.
Hey Chamberlin... thanks for the info I thought the 35 was the offset of the rim, but I guess I was wrong.

Last edited by Nopstnz8; 08-02-2007 at 03:43 AM.
Old 08-02-2007, 12:20 PM
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No problem man - happy to help out.

-C
Old 08-02-2007, 12:23 PM
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Old 08-02-2007, 11:24 PM
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Mu ha.. ha...
 
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Old 08-04-2007, 09:40 AM
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20" rims are very possible to fit on the 8....kumho tires are good tires but so are alot of brands....toyo, falken.....If you were to run 20's I think the best tire size is a 245/30/20

ive never heard of gianna wheels but if you like 'em then go for it
Old 08-09-2007, 10:44 PM
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if you use 20" just make sure you have a very high offset. and you will have NO problem at all. Just remember 20" and performance wont go together so good.
unless ofcourse you have a lot of HP

Old 08-10-2007, 02:04 AM
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angeljoelv, those wheels are awesome.

However, I'm not daring enough to get the 20" anymore.... Instead, I'll be sticking with 18x8 all around (Tork Champion) with Bridgestone 960AS 225/45R18.

Thanks for all your advices! I'll post some pics once they arrive and are installed.
Old 08-10-2007, 02:53 PM
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I am EXTREMELY happy with Kumhos. I have them on my rx8 now, and also have them on my mazdaspeed protege and 86 honda crx. They are not always the BEST performing tires out there but are normally rated about 85% as good and generally run about half the price of the big guns.

Highly recommend ASTs and ASXs.
Old 08-13-2007, 01:43 AM
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mine's better
 
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i've forgotten about the boneheads around here... wowzers
Old 08-13-2007, 01:56 AM
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before its too late....get 245/40 instead of 225/45. you won't regret it. 245 will fit just fine in those 18x8.
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