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Will much wider tires 'slow' down my GC from drag and rolling resistance?

3603 Views 23 Replies 16 Participants Last post by  santy92
I want it all: Looks, performance, reasonable cost, and to maintain my mpg.

My concern is that although braking performance and turning grip should improve thru the use of wider tires and larger rims, that my acceleration and the sensation of power will be reduced due to the additional inertia from these larger componenents.

What have the other big rim guys noticed as far as this aspect of performance?

The really lightweight rims, well I can't spend that sort of money on my GC. And truthfully there is a notable amount of weight gain from the larger tire itself and that it being further from the fulcrum it's much more relevant anyways.


The only rims I''ve found that meet my requirements for size, flushness, and cost are the S5:Fs although I'm not enamored w/ the aesthetics of them.

The size I would purchase would be:
F: 19" x 9.5" +25 w/ a 245/ 35 x 19" Hankook V12.
R: 20" x 10.5" +33 w/ a 295/ 35 x 20" Hankook V12

Input is appreciated.
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The stock 19" track wheels and the Potenzas are not exactly lightweight to begin with.. you dont have to go to the super expensive forged wheels to save some weight. IIRC my varrstoen 3.3.2 with Hankook V12's are lighter than the stock track setup (although not by much). As long as your aftermaket setup is lighter or same weight as stock, your acceleration performance will not be "reduced".

I have seen on other threads that you are determined to run 19" front and 20" rear. My concern is your tire size. According to various tire size calculators, switching from 245/40/19 (stock size) to 295/35/20 (your listed size) is a 5.02% difference, and this might throw off the traction control.

A better size to run will be 275/30/20, and that will only have a 0.83% difference in overall diameter. Also, a lot of people generally agrees that 275 is a good size to run on a 10.5" rear wheel. It will not be stretched, and you dont have to run crazy camber to make it fit flush with the rear fenders.

Good luck.
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Input: Don't stagger diameter front to rear.

Otherwise of those 4 things you want, the tires will be the biggest deciding factor, not the wheels.
Quote: "Will much wider tires 'slow' down my GC from drag and rolling resistance?"

Yes it will, but it will be so slight you will never know the difference.


The weight I gained from my larger tires was more than offset by my lighter wheels & you can get lighter good quality wheels w/o spending a fortune.
+1 Agreed with above.
I say get the setup you mentioned in the OP just change the 295 rear tire to a 285 and you'll be golden! A few guys i know with 350z's run 18" up front and 19" in the rear or 19" front and 20" rear and i think it looks killer!
The stock 19" track wheels and the Potenzas are not exactly lightweight to begin with.. you dont have to go to the super expensive forged wheels to save some weight. IIRC my varrstoen 3.3.2 with Hankook V12's are lighter than the stock track setup (although not by much). As long as your aftermaket setup is lighter or same weight as stock, your acceleration performance will not be "reduced".

I have seen on other threads that you are determined to run 19" front and 20" rear. My concern is your tire size. According to various tire size calculators, switching from 245/40/19 (stock size) to 295/35/20 (your listed size) is a 5.02% difference, and this might throw off the traction control.

A better size to run will be 275/30/20, and that will only have a 0.83% difference in overall diameter. Also, a lot of people generally agrees that 275 is a good size to run on a 10.5" rear wheel. It will not be stretched, and you dont have to run crazy camber to make it fit flush with the rear fenders.

Good luck.
I agree with what you're saying except that I believe the traction control issue is caused by the diameter of the front tire in relation to the rear. Not just by going with a different diameter than the stock sizes. From my understanding the tractional control only kicks in when it detects wheel spin, the rear tire spinning faster than the front by a certain amount.

When looking at the stock setups on the GC with the 18" and 19" wheels, the 18's have a difference of 2.7% front and rear where as the 19" it's 2.4%.

Using this calculator...Tire size calculator the sizes he wants to run have a difference in diameter, front vs. rear, of 9.2%. That being said, if the car needs to be close to the OEM % specs of 2.4% - 2.7% then 245/35/19 and 275/30/20 would be alot closer at 2.9% difference front vs. rear.

Maybe my understanding of the traction control is way off also so someone who knows exactly how the TC works could correct me.
I like your idea and the rims do look good, but those rims weigh in close to 30lb a piece, not to mention 20" in the rear is also going to kill your acceleration more..if i was you i would look at something lighter. the Varrstoen series are just a touch lighter then the stock. also you could go something like forgestar f14 in a 18"x8.5"F and 19"x9.5R combo i bet that would look killer(about $1,500 for wheels alone idk if thats you price range or not) and you would be saving yourself a bit more weight. overall, your don't really need anything over 10" wide tires i would imagine just like you said it would inevitably put more drag on the car and effect mpg. post pics on what you decide to go with.
I was pretty eager to buy rims but a few things happened.

1) I just couldn't find rims that I loved and that had great specifications. I like the Varrstoens but they are just too extreme in width and offset imo.
2) I had some junk come up and my additional expenses this year have been about $10K. There goes ALL of my spare money.
3) One of the unexpected things that occured that cost me $ was that my front tires were accidentally destroyed due to very sharp rocks. It shredded my sidewalls. I had to make a decision to buy new wider rims w/ tires that fit them right then or just purchase two tires for the stock rims. I now have two new stock sized Hankooks on a car w/ only 6K miles on it.

Maybe in the next year I will find exactly what I desire as far as rims go. If not, the stock rims really look great and I'm happy w/ them.
oh that sucks to hear, wellyou can always paint your stock rims that looks good IMO, idk if you saw it or not but just in case you do go the 20" route here is a like i thought was cool

http://www.GenCoupe.com/wheels-tire...eel-fitment-step-step-2010-genesis-coupe.html
If not, the stock rims really look great and I'm happy w/ them.
The stock track wheels with a decent drop + spacers look better than a lot of the aftermarket wheels people "upgrade" to. Sorry about the crap coming up, though.
Agreed Kid. I mostly wanted the extra width and lighter weight that aftermarket wheels could offer me but from a looks and quality standpoint many of the aftermarket wheels really aren't much of an upgrade over Track 19's.

Still though, stock 370Zs, G37s, and M3s come w/ wider and lighter rims that have the potential to offer a performance advantage and I wanted some of that action.

Thanks on acknoledging the other crap but it's cool. Just one of those years for me I guess. I don't let it get me down, life is just fine!
I've been told plenty of times by freinds that I'm insane for wanting to get new wheels. They all love the way my car looks with the slight drop, spacers and track wheels. I really like the look of the track wheels as well, and that's the a major reason that I haven't purchased new ones. I even saw the track wheels on the Genesis Sedan today and thought they looked great.
^^ I agree as well.

If the OEM Track wheels were at least 9" in the rear for a 275/35, I'd probably keep them on. They are pretty heavy but they look great IMO.
Yea, I agree with the width as well, wish they had come with at least 8.5f/9r.
I was out canyon carving today and was diving into this tight lefthand turn w/ a sign labeled "20mph" and as I was braking I blinked down at my speedo as it swept downwards past 80mph. Probably hit the turn at about 55mph. I couldn't help but think: How much faster do I need to go for Gosh Sakes?
I'm probably going to get flamed for this, but w/e...

The other day I was on zilvia, and they were discussing putting on rims that are normally for Mustangs.

Godspeed Omega Deep Dish Wheels | Rims
Godspeed Omega Ultra Deep Dish Wheels and Rims

I know a lot of you guys won't like the way it looks, but I dig em...maybe you will too Suns_PSD? They're a bit cheaper than the 5-axis and I think they're lighter too. Hope you get your finances worked out! :)
I'm probably going to get flamed for this, but w/e...

The other day I was on zilvia, and they were discussing putting on rims that are normally for Mustangs.

Godspeed Omega Deep Dish Wheels | Rims
Godspeed Omega Ultra Deep Dish Wheels and Rims

I know a lot of you guys won't like the way it looks, but I dig em...maybe you will too Suns_PSD? They're a bit cheaper than the 5-axis and I think they're lighter too. Hope you get your finances worked out! :)
Those aren't much different than the Axis Shine. As an example:

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I like the huge lip in the rear, just not for the front.

It's actually so old school looking. When I was a very little kid in the '70s there were always old hot rods around that had larger and deeper rims in the back than the front.

I'm always paying attention and if something comes out that catches my eye I'll buy them eventually.

Probably Enkei or TSW.
The stock track wheels with a decent drop + spacers look better than a lot of the aftermarket wheels people "upgrade" to. Sorry about the crap coming up, though.
Best post in this thread. The 19's is sex!!!!
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