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in ride comfort? I am thinking of getting either 17s or 18s but right now I am leaning toward getting the 18s because they might look better on the car. Right now my car has the hubs on so I was wondering if the ride comfort will decrease/increase with 17s vs 18s.
 

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You should expect some decrease in ride quality over a comparable 17 inch, but so much depends on the tire you choose. You could have a 17 inch with worse ride quality than an 18 inch. Ask yourself what attributes are most important to you and select a tire that meets those criteria.
 

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Discussion Starter #3
You should expect some decrease in ride quality over a comparable 17 inch, but so much depends on the tire you choose. You could have a 17 inch with worse ride quality than an 18 inch. Ask yourself what attributes are most important to you and select a tire that meets those criteria.
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Well I am going to use these rims on my car daily so I would like to have good ride comfort but yet good tread life, also there are a lot of potholes where i live so would that make a difference in hitting one with 17 vs 18?
 

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Well I am going to use these rims on my car daily so I would like to have good ride comfort but yet good tread life, also there are a lot of potholes where i live so would that make a difference in hitting one with 17 vs 18?
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You have less sidewall with an 18 vs 17, so damage done by potholes to your wheels is more likely because you have less impact absorption. Your likelihood of getting a longer-wearing, smoother-riding tire is much better with 17s than 18s. Sounds like you should stick with 17s.
 

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the difference between a 17 rim diameter and an 18 inch rim diameter is almost nothing..


ive got a cool little spreadsheet that kevin gave me and i just plugged in the numbers and here's what i got...


wheel sets
W1 W2
17 18
215 235
50 40

rim weight 22.0 22.0
tire weight 25.0 25.0
total weight 47.0 47.0


with the same weight setup, the difference is almost negated by the change in diameter of the 18inch setup,

Derived dimensions wheel 1 wheel 2
linear acceleration in ft/sec^2 13.97 13.97
wheel rotat'l accel'n radians/sec^2 13.16 13.20




Car Speed Change, MPH 60
Time Required, secs 6.3

Results for All 4 Rims and Tires: W1 W2
Torque Loss due to Rotation ft-lbs 49.3 51.8
Torque Loss due to Translation ft-lbs 86.5 86.3
Total Torque Loss at 4 Wheels ft-lbs 135.9 138.1


given, there is still flaws in the calculations because its almost impossible to get a function of the wheel density. so, yeah, if you drop some weight in the wheel and tire, which is certainly possible, in fact, 18's can be faster than 17's.
 

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Only if the weigh loss is massive. The larger the diameter, the further the weight is pushed out from the center, and the greater the effect.

Please see the sticky of the thousand or so articles and forum posts reinforcing the discussion.

Recently the altima guys did a study their own with acceleration tests between all the OE wheels. I'll try to snag the article, but basically if you had the latest altima with 18 inch wheels, running those instead of the older style wheels was equivilant to adding 268 lbs of static weight to the car in terms of the effect on forward acceleration.

This reinforces the otaking/mrtea track testing of the 16's vs 18's, where a variance of 0.3 to 0.5 seconds in the 1/4 existed between running the 16's (faster), and the rx8 18's (slower). 268 lbs would be about 0.3 seconds slower in the 1/4.
 

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weight loss need not be massive to do so, in fact, getting a 18by 8 20 pound rota rim, and some 22 lb tires, you would be faster (and have more grip) than stock.

now, sure jumping from 16 to 18 is a big difference, and 16's are very light. therefore your pushing the advantage the other way, its obvious that 16 would be faster because they are generally lighter and of course have alot of mass positioned 1 inch closer to the center of the wheel than the 18.


i mean if you think about it, the difference in positioning of the weight in the rim between a 17 and an 18 is only a half an inch. thats not a big difference at all.
 

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The Pirelli P Zero Nero M+S on the stock 18's ride very comfortable to me, the only problem is the low sidewall, I already slightly bent one rim.
 

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i mean if you think about it, the difference in positioning of the weight in the rim between a 17 and an 18 is only a half an inch. thats not a big difference at all.
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Although mass is important, when calculating the mass moment of inertia the radius about the axis will always have a greater affect than the actual mass since the radius is quadratic.

If you want looks then I think 18s look best, however if it were me I'd try to find some light and decent looking 17s. I like toyoguy's advice: Ask yourself what attributes are most important to you and select a tire/wheel that meets those criteria.
 

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all i know, is that i can get a better performing( than stock) wheel/tire combo in 18's by just dropping the wheel weight to 20 lbs, and the tire weight to 22lbs.

thats not a massive wheel weight change.

in fact, keeping the same weight and increasing the size you only lose 4 ft lbs of torque to get the car from 0-60. somthin like stock is 50.4 ft lbs and the 18 (same weight) is 54.2 ft lbs.


so minimal, and small.
 

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When I was looking to replace the stock 16's I was in the same situation. I ended up getting 18's and I am happy for doing so. Nothing would piss me off more than getting aftermarket 17's and then seeing how they dont look as nice as 18's and wanting those. Get the 18's. I love how everyone one is talking performance, remember that if you wanted performance you would have gotten a real performace car not a 4 dr sedan. I love to drive fast as much as the next guy, but the 3 hundreds of a second that I am gonna loose cause I have awesome looking wheels I can live with....
 

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im in the numbers boat, and 18's will not kill your car's acceleration or braking if you buy them, in fact they could be better than the stock 17's with only 3 pounds lost per wheel/tire combo.
 

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Which is why everyone buys cold air intakes to shave off a tenth or two off their 1/4 time, then plops on 18's and add's 3 to 4 tenths back to it. (vs 16's)
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:laugh:

Now I knew there was a reason why I haven't bought an intake or 18s yet, and probably why I won't either... :)
 

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The big thing everyone overlooks is strength.

Yes, 18's can be made lighter than stock. They can NOT be made as light as aftermarket 17's- they require more metal. They're an even further cry from the weight of 16's.

Yet, lightweight 18's remain. How is this possible given that they require more metal?

Well, there's no magic here. If they're light, they're weak. They'll break. And since 18's require lower profile tires, they ought to be STRONGER than lightweight 17's, not weaker.
 
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