Rim size affecting performance

[IronAnaconda]

I know rim size can affect performance, that bigger rims aren't ideal for speed, so my question is, would 20" rims noticeably affect my car's performance? I saw 20" chrome rims on a G35 and they look nice, but I'm not sure if I am willing to go 20 inches if that's going to compromise my car's performance. Also, anyone know what those lights on the front spoiler are called and where I can find that online? (like in the following pic)



Thanks.

[NastyG]

You will need to buy that front kit new. I have seen it on ebay. I have seen the same kit in person on a silver G in my hometown. It looked nice.

[yelnatsch517]

Depends on the wheels. The only reason bigger wheels affect performance is weight so its just a simple math calculation. Just find out the weight difference and you should get a rough estimate on how much it would affect performance. If you are going to get 20's I am probably going to say a couple hundred pounds of extra weight.

Metal and rubber weigh a lot...

[IronAnaconda]

cool thanks. one more question, theres no problem with taking hard turns with 20" rims right? (answer only if ur sure)

Thanks.

[TgduMg]

I know rim size can affect performance, that bigger rims aren't ideal for speed, so my question is, would 20" rims noticeably affect my car's performance? I saw 20" chrome rims on a G35 and they look nice, but I'm not sure if I am willing to go 20 inches if that's going to compromise my car's performance. Also, anyone know what those lights on the front spoiler are called and where I can find that online? (like in the following pic)

Maybe not to the butt-dyno, but any increase in weight will alter your power to weight ratio as well as increase your stopping distances.

The Ice Blue G coupe is sweet. Those are probably driving lights since the G-coupe comes with integrated fog lights. I would say that the customer has a choice of which will go in the Kenstyle lower valance.

www.kenstyleusa.com/G35

One more question, theres no problem with taking hard turns with 20" rims right? (answer only if ur sure)

With 20" tires you will have noticeably less sidewall flex because there will be less sidewall there to flex. The rims also will play a factor as they will likely be much heavier than OEM. The wheel width and offset selected as well as the front tire size will affect your steering range.

Danisiti 1

[Sprjin]

Depends on the wheels. The only reason bigger wheels affect performance is weight so its just a simple math calculation. Just find out the weight difference and you should get a rough estimate on how much it would affect performance. If you are going to get 20's I am probably going to say a couple hundred pounds of extra weight.

Metal and rubber weigh a lot...

PLUS couple hundreds of pounds??? wow.... i've never imagined it would be THAT much!!

[Q45tech]

Actually you must multiply rotating weight by some factor to get the real effect on acceleration.

Maybe 100 pounds of increased static weight my affect acceleration like adding 200 pounds to the sprung weight reducing quarter mile by a few tenths.

Heavy unsprung weight will show up more as how the car feels when you turn or brake. Extra stress on wheel bearings shocks etc.

[jhoke]

I have a formula, if I can find it, that equate unsprung weight to hp. It seems it was 4 lb equals 11 hp. Unsprung is tires, wheels, rotors, etc. I'll see if I still have this on my computer at work. It was posted on the roadfly forum for bmws.I getting new wheels, but weight is going to be a big factor in which I buy.

[87ninefiveone]

Its not that simple. Not only is it adding weight to the car, its adding unsprung weight which adversely affects handling characteristics like stopping and turning.

Then there's the fact that 20" rims will concentrate additional weight farther from the hub which means more torque will be needed to make them accelerate (or decelerate) which translates to slower 0-60 times in addition to any added weight.

Big rims are only cool if there's big brakes inside. Don't go any bigger than you have to if your into speed and handling more than looks.

[DOHCscreamer]

I have a formula, if I can find it, that equate unsprung weight to hp. It seems it was 4 lb equals 11 hp. Unsprung is tires, wheels, rotors, etc. I'll see if I still have this on my computer at work. It was posted on the roadfly forum for bmws.I getting new wheels, but weight is going to be a big factor in which I buy.

That is not correct. First of all, you mean rotational weight, not unsprung weight. Unsprung weight affects the handling. Rotational weight affects the acceleration and braking. Some components contribute to rotational and unsprung weight. Several years ago there was confusion about the effects of reducing or increasing the rotational mass by changing wheels on another site i am a member of. I did a calculation because everyone seemed to think their car would be so much quicker with lightweight forged alloy wheels. What i found is that (provided you keep the outer diameter of the tire the same) a reduction of 1lb to the wheel/tire combo is equivalent to removing 1.5lb stationary weight from your vehicle. similarly an increase of 1lb to the wheel/tire combo is like adding a 1.5lb weight in your trunk. I don't have the calculation anymore but can do it again for those that think i'm full of it.

[jhoke]

I have a formula, if I can find it, that equate unsprung weight to hp. It seems it was 4 lb equals 11 hp. Unsprung is tires, wheels, rotors, etc. I'll see if I still have this on my computer at work. It was posted on the roadfly forum for bmws.I getting new wheels, but weight is going to be a big factor in which I buy.

My memory was off. The formula is:1 lb. unsprung weight = 4 lb. of total weight11 lb. total weight = 1rwhp.

[DOHCscreamer]

My memory was off. The formula is:1 lb. unsprung weight = 4 lb. of total weight11 lb. total weight = 1rwhp.

read the post above yours

[Q45tech]

Increased sidewall stiffness requires LESS camber gain from suspension to maintain perpedicularity of tire to tread under load so you might want to decrease static negative camber slightly------go more towards negative -.5 or -0.25 degrees.