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      09-17-2012, 10:42 PM   #23
Finnegan
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and off the rails the thread goes!
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      09-18-2012, 12:36 AM   #24
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I've been researching tire sizes for my 19" setup. The recommended up size is 245/35 front and 275/30 rear. They are slightly smaller diameter than stock. Assuming 19" wheels are same weight as stock, you'll loose weight because 19" tired weight less than 18" tires.

I think the choice between 18 or 19 depends on what is most important to the owner. Look, performance, ride , tire selection, etc....
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      09-18-2012, 03:32 AM   #25
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Quote:
Originally Posted by RobMCoupe View Post
I've been researching tire sizes for my 19" setup. The recommended up size is 245/35 front and 275/30 rear. They are slightly smaller diameter than stock. Assuming 19" wheels are same weight as stock, you'll loose weight because 19" tired weight less than 18" tires.

I think the choice between 18 or 19 depends on what is most important to the owner. Look, performance, ride , tire selection, etc....
Nono, tires for 19s should weigh more usually. They have to reinforce the carcass since they've got shorter sidewalls and less room for error so to speak.
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      09-18-2012, 04:23 AM   #26
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ive had on 17's, 18's, 19's, and 20's... . for looks i like 19's but for tire selection and tire price i prefer 18's.
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      09-18-2012, 06:43 AM   #27
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Quote:
Originally Posted by mfanatic325 View Post
Nono, tires for 19s should weigh more usually. They have to reinforce the carcass since they've got shorter sidewalls and less room for error so to speak.
They weight more due to tread width. You go with same width and adjust the aspect ratio between 18s and 19s. Tire Rack have PSS 255/40ZR18 = 25 lbs. and 255/35ZR19 = 24 lbs.

I am debating if I should use stock size and adjust aspect ratio for my next purchase. The diameter is exactly the same for the rear and just a tag over for the front.

Here are the data I compiled.

Front 225/45/18 225/40/19 Difference

Sidewall Height: 3.99 3.54 -0.45
Section Width: 8.86 8.86 0.00
Overall Diameter: 25.97 26.09 0.12
Circumference: 81.59 81.95 0.36
Revs per mile: 776.52 773.12 -3.4
If you speedometer reads 65. You're going approximately 65.29

Front 225/45/18 245/35/19 Difference

Sidewall Height: 3.99 3.38 -0.61
Section Width: 8.86 9.65 0.79
Overall Diameter: 25.97 25.75 -0.22
Circumference: 81.59 80.9 -0.69
Revs per mile: 776.52 783.17 6.65
If you speedometer reads 65. You're going approximately 64.45

Rear 255/40/18 255/35/19 Difference

Sidewall Height: 4.02 3.51 -0.51
Section Width: 10.04 10.04 0.00
Overall Diameter: 26.03 26.03 0.00
Circumference: 81.78 81.77 -0.01
Revs per mile: 774.76 774.88 0.12
If you speedometer reads 65. You're going approximately 64.99

Rear 255/40/18 255/35/19 Difference

Sidewall Height: 4.02 3.51 -0.51
Section Width: 10.04 10.04 0.00
Overall Diameter: 26.03 26.03 0.00
Circumference: 81.78 81.77 -0.01
Revs per mile: 774.76 774.88 0.12
If you speedometer reads 65. You're going approximately 64.99

Rear 255/40/18 275/30/19 Difference

Sidewall Height: 4.02 3.25 -0.77
Section Width: 10.04 10.83 0.79
Overall Diameter: 26.03 26.03 -0.53
Circumference: 81.78 81.77 -1.68
Revs per mile: 774.76 774.88 16.27
If you speedometer reads 65. You're going approximately 63.66
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      09-18-2012, 09:35 AM   #28
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Quote:
Originally Posted by RobMCoupe View Post
Here are the data I compiled.
Great data. Thanks for sharing the results of your research.
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      09-18-2012, 01:17 PM   #29
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I guess it depends on brand and model of tire hehe
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      09-18-2012, 01:34 PM   #30
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Quote:
Originally Posted by mfanatic325 View Post
I guess it depends on brand and model of tire hehe
WHS ^

Track variety tires are built for sticky and low mile wear-(read lighter material use).

Street tires get exponentially heavier the higher their wear rating I've found. Forget about runflats.....they are almost a chunk of steel and rubber with their sidewalls
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      09-18-2012, 05:14 PM   #31
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and off the rails the thread goes!
nah, all these puns suck. Thats why I didn't bother
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      09-18-2012, 05:26 PM   #32
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Quote:
Originally Posted by mfanatic325 View Post
I guess it depends on brand and model of tire hehe
Yes. It depends on brand and materials for tire construction. I want to provide another view where most say 19s are heavier.
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      09-19-2012, 02:18 PM   #33
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Quote:
Originally Posted by mfanatic325 View Post
Unless you're going to be driving all-out at the limit of adhesion every single minute that the car is on, I wouldn't worry too much about the "better handling" and "slower" arguments toward 19" wheels.

In direct comparison, yes, apples to apples, 19s are supposed to be heavier overall as they do have an additional inch in diameter of material on each wheel and on each corner after all. However, this can be remedied with a good set of forged wheels. There are even 17" wheels that are heavier than my 19s for example. Some more weight differences come in to play when tires are mounted on, but again that's another one of those things where you can make a decision on what to buy depending on how "hardcore" you drive your car; as better tires tend to weigh more.

On the topic of tires, 19s admittedly have relatively more expensive tires when compared to 18s. And it is also true that ride comfort is comparatively worse off than an 18" set of wheels/tires.

What does it for me on a daily basis is the fact that even though I track a lot, it's still a street car and not a full-on dedicated track car. Therefore, I can make do with the slighter harshness in ride comfort, the slightly more expensive tires purchased every year or so, and in my opinion the negligible difference in performance; all for the sake of aesthetics. Plus, I don't think the stock rims will clear my Brembo BBKs

All in all, it's your pick between "performance" and "looks". My opinion is that for 99.9% of owners, the performance aspects of the car are plenty strong as-is from the factory. And any differences in upgrading an inch worth of material on each corner isn't going to jeopardize anything at all for the 99.9% of us. So at the end of the day it all boils down to taste and preference (and any sacrifices in between); as do all decisions of this nature
Judging from most of the responses and this one in particular, I am thinking a switch to lightweight 19's will provide significant looks upgrade at a minimal cost to performance and comfort

Let the search begin and cheers to all who replied
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      09-19-2012, 02:53 PM   #34
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i didn't want to lower it at all(driveways are already an issue at stock height), so i opted to fill that wheel gap as much as possible...with 19's. you're overthinking it. no one ever gets 19's and says "they're too big", but you may get 18's and think "i could've gone bigger".

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      09-19-2012, 03:23 PM   #35
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midn12ght, your car looks great with those wheels... I think the main take away from this thread is that, if you choose your wheels and tires carefully, you can have your cake and eat it too! That is, you can step up to 19' rims and realize the improvement in appearance with no increase in weight or tire diameter and therefore no deterioration in performance as is often incorrectly attributed to larger size rims.
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      09-19-2012, 03:37 PM   #36
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Quote:
Originally Posted by jrainlay View Post
Not necessarily... With properly spec'd tires, the net wheel/tire diameter with 19s should be identical to the 18s; therefore, there should be no noticeable deterioration in braking and acceleration due to larger wheel diameter (and no increase in speedometer error). Tire sidewalls will, of course, be lower profile and this can lead to some increase in ride harshness; however, if you choose the right tires you can minimize this issue. When i moved up from OEM M style 18s to 19s, I fitted my new CSLs with Conti Extreme Contact tires which resulted in no noticeable change in ride quality vs. my OEM Contis on the 18 inch M rims.
Negative. The weight of the 19's is pushed further out to the edges of the wheel/tire combo vs 18's. Even if both weigh the same, the 19's will have more rotational inertia due to the distribution of the weight. Noticeable or not, it's something to consider if going for ultimate performance.
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      09-19-2012, 04:01 PM   #37
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i also like to add in brakes, to this equation... mine were lighter on every corner, both rotor and caliper.... add in lighter nuts/stud.... unsprung wise i lost a decent amount going to the 19" csl over the stock units.....

however i also now have a set of 18s which is use for the track.... again i notice no difference if im honest.
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      09-19-2012, 04:27 PM   #38
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Here's a quick pic with 19s just to help OP splurge


note: my usual # is 3, as that's my birth month, as well as my lucky #. However, during this track event, the hosts were offering free time trials, which meant free additional track/seat time. So I said to myself "HELL YEAH!" and got whatever number they assigned to me; which happened to be #166.

note2: also, I ran over something on the way down to SoCal for that track day, and therefore my front bumper underpanel was knocked somewhat loose at the time. It has since been patched up.

note3: at the time that this particular pic was taken, I was just coming out of a left-hander and starting the main straight @ Buttonwillow.

note4: the red thing up front is the transponder that we used for time trials and lap timing. I attached it to my tow hook since I knew I wasn't going to spin out and therefore wouldn't need a tow

note5: an E46 M3 totally bit it that day and wrecked his car decently well. He didn't have a tow hook (silly him, should've come to me for one lol!), so they towed his car and dragged it over cement with flat/blown/non-existing tires which ultimately ruined his nice track wheels...youch.

Last edited by mfanatic325; 09-19-2012 at 04:37 PM..
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      09-19-2012, 05:07 PM   #39
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There's no 'cake and eat it too' scenario. There will always be a compromise.
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      09-19-2012, 05:49 PM   #40
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Quote:
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There's no 'cake and eat it too' scenario. There will always be a compromise.
He speaks TRUTH.
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      09-21-2012, 07:57 AM   #41
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Quote:
Originally Posted by johanness View Post
There's no 'cake and eat it too' scenario. There will always be a compromise.
Now you're really splitting hairs... My point is that with proper specification the tradeoff can be minimized to the point where the difference in performance is completely unnoticeable to the driver and virtually unmeasurable. Of course, a lot depends on the application (street, track mixed). In any case, the key is careful specification of the 19" wheel/tire combination. There are some who argue that properly spec'd 19" wheel/tire combinations outperform the 18" alternative because other positive characteristics more than offset the relatively insignificant negatives. Of course, the devil is in the details... it all depends on specifically which wheel/tire combinations are being compared. Point is, broad generalizations about the pros and cons of 18' vs 19" wheels/tires are meaningless and if a person prefers the look of 19" rims, they should not feel they have to pay some huge price in performance to make the change.
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      09-21-2012, 12:25 PM   #42
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well said. I totally agree! ^
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