19s on a MS3

[gerasimatos]

the rolling diameter for a 176 wheel compared to a 19 wheel is quite a bit.

To Calculate the Diameter of a Tire
diameter = wheel diameter + tire width x aspect ratio
1270
EXAMPLE: Tire size 195/70-14
195 = tire width
70 = aspect ratio
14 = wheel diameter
diameter = 14 + 195 x 70
1270
diameter = 14 + 10.75
diameter = 24.75 inches


To Calculate the Required Aspect Ratio to Meet a Particular Diameter
Lets say your original tires are 195/70-14 as in the example above. So the original tire diameter
is 24.75 inches.
Maybe you would like a wider tire, like a 235. What aspect ratio should you use so that you
maintain the same overall diameter?
aspect ratio = (desired diameter - wheel diameter) x 1270
tire width
EXAMPLE: What aspect ratio do I need on a 235-14 tire if I want to maintain
a diameter of 24.75 inches?
aspect ratio = (24.75 - 14) x 1270
235
aspect ratio = 10.75 x 1270
235
aspect ratio = 58.1
You should use a 235/60-14 tire


To Calculate the Speedometer Error
Perhaps you want a different tire that will not be the same diameter as the original tires. Maybe
you have a friend that will give you a set of 235/70-14 tires. You really want to use them
because they are FREE. But what will that do to your speedometer?
You first need to calculate the diameter of the original equipment tire, then calculate the diameter
of the optional tire. Then apply this formula:
actual speed = speedometer reading x new tire diameter
original tire diameter
EXAMPLE: The diameter of the original 195/70-14 tire is 24.75 inches. The diameter of the
235/70-14 tire is 26.95 inches. When my speedometer reads 45mph, how fast
am I really going?
actual speed = speedometer reading x new tire diameter
original tire diameter
actual speed = 45 x 26.95
24.75
actual speed = 49mph
When the speedometer reads 70mph:
actual speed = 70 x 26.95
24.75
actual speed = 76


To Calculate the Odometer Error
What will the different tire size do to my odometer reading?
odometer error = new tire diameter
old tire diameter
EXAMPLE: What will be the odometer error for the preceding example?
odometer error = new tire diameter
old tire diameter
odometer error = 26.95
24.75
odometer error = 1.089
So when your odometer increments 1 mile, you have actually traveled 1.089 miles.
What happens after 20,000 miles?
20,000 x 1.089 = 21,780 miles
When your speedometer reads 20,000 miles, you have actually traveled 21,780 miles.

 

[SwampAss]

The 14 inch wheel fitament is moot anyway. 16 is as small as someone with an MS3 can go.


This is more along the lines of what I am talking about:


Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
215/45-18 3.8in 12.8in 25.6in 80.5in 787 0.0%
225/35-19 3.1in 12.6in 25.2in 79.2in 800 -1.6%

 

[gerasimatos]

1.6% is actually quite a large difference. Dont you think when comparing a final drive ratio.

 

[SwampAss]

lol. No, I don't.

 

[gerasimatos]

To each his own then. I still hold my beliefs.

 

[camrycev6]

Actually I found a couple tires on tirerack.com that are 225/35-19 that have an overall diameter of 25.5" The OEM tires on are 25.7" In that case, you are only talking about a 0.778% difference. At least in this case, your speedometer and overall mileage would be very close. At 70 MPH (OEM tires), you would really be going 69.45 MPH with the 19s. Hardly worth consideration. I wouldn't go to the 19s because of the loss in ride comfort. It is stiff enough as it is.

 

[SHAGwagn]

18s with a lip are basically 16s to the naked eye. There are a few MS3s on the forum with lipped 18s and personally i think they should just put the stock wheels back on. What would the offset have to be to make 19x8.5 work on a MS3? Thanks

 

[SHAGwagn]

Is everyone stumped?

 

[camrycev6]

Sorry...I don't do much with tire / wheel mods. (I am all about engine / performance, and while the right tires are important, they aren't the first thing I think of when modding a car.) I could take the time to research it, do the math and answer, but I am sure someone here knows the answer from experience.

 

[SwampAss]

I did the wheels on my car first as a performance mod first, looks mod second. 6lbs difference per wheel is huge. It's also "free hp" in the sense I am not taxing the motor or jeopardizing any sort of vehicle coverage. I think my wheel swap did MORE than my CAI. Then again, $1400 is a bitter pill to swaller.

 

[SHAGwagn]

20 inch gold plated knock offs?

 

[SwampAss]

HOLLA at ya boi!

 

[SHAGwagn]

Im guessing your not dropped then? Im looking to put 19x8.5s and i just wanted to know what offset i would need to get to be able to drop 1-1.5 inches

 

[SwampAss]

I heat sagged the springs and rolled my fenders myself. It's not the greatest job but I'll fix it with a body kit. My car is 3.5-4.5 inches all around. I'm going with bags and a compressor though. Then I'll set it on the ground.

 

[voiceKoil]

I heat sagged the springs and rolled my fenders myself. It's not the greatest job but I'll fix it with a body kit. My car is 3.5-4.5 inches all around. I'm going with bags and a compressor though. Then I'll set it on the ground.

You serious??? lol

 

[BradC]

Time to leave from work, so this p-chop is a quick and nasty...but here goes...

God that chop job sucks, i am ashamed to say i took all of 2 minutes to do it, lol

 

[voiceKoil]

LMAO that looks perfect! lol(puke)

 

[SwampAss]

that's pretty close! Add chrome lower door panels and it's almost a dead ringer.