The 18 v 19 inch debate

[baege]

While I realize there is a wheels and tires section, I don’t find it gets much traffic and so thought I would indulge everyone with a thread here.

I recently searched 3.0si coupe on youtube (it was a slow afternoon) and came across a great short film of a black z4 coupe on 19 inch beyern rims that sat just right. The size of the 19inch rims with a nice rear lip really seemed to give the car a great look. It reawakened a debate in me about whether to get some 19 inch rims.

So for those of you who have made the switch from 18’s to 19’s, what has been your experience:

Is there a significant difference in ride?
Handling?
Acceleration?
Overall are you happy with the switch?

Thanks in advance to anyone who has some relevant experience they share.

[Kgolf31]

19s will be slower in all categories.

18s have less weight, lower moment of inertia. As well, you can add a thicker sidewall on 18s which will increase handling.

Your ride comfort will also decrease with 19s

[mfanatic325]

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

[Beedub]

Originally Posted by mfanatic325

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

nail. hit . on . head.

my cars back on 18s right now.... i swear to god i noticed no difference coming from 19" csls.... no difference at all.

[mfanatic325]

Originally Posted by Beedub

nail. hit . on . head.

my cars back on 18s right now.... i swear to god i noticed no difference coming from 19" csls.... no difference at all.

You'd have to be outdriving the car constantly to feel the difference. It's definitely there, but extremely marginal indeed for the majority of folks that are faced with this kind of decision-making. We're not professionals unfortunately

[itdnwiwbp]

I went from stock 18s and RFTs on a 3.0si coupe to 19" VMR V710s with Faulken 452s. The fronts were the same weight and the rears were exactly two pounds heavier each. Going from RFTs to conventional tires the ride actually got better despite the upsize. Also, handling improved with the new tires because I wasn't always being thrown around by the RFTs riding the ruts. That said this was only street experience. From a high performance standpoint what everyone else has said is true.

[seank]

How about better tire selections and price point with 18's, not counting the amount of money saved by not having to replace bent rims. I have 19's on one car and I won't do it again.

[mfanatic325]

I highly doubt a good set of 19s will get bent out of shape, but can never underestimate our state's spendings--and ultimately the repairs on our public roads

[ZeD4Mr]

It also depends on the road condition where you frequently travel. I love my 19". They're lighter then OE 18" and looked way better. I can feel the lighter setup every time. The roads that I travel are glass smooth so 19 is my street setup. even though I track a few times with my 19s, I want to go 18s and lighter (17-18 lbs) for the track next season.

[pokeybritches]

I've had to replace two OEM 18" wheels on my 3.0i due to cracks at separate times through the years. I can only imagine how much worse it would have been with 19's. On an M, the 19's will have the same amount of sidewall as 18's on a non-M, so I think you can get away with them. On a non-M with 19's, you'll have to be very careful about where you drive.

An equal weight 18" and 19" wheel may have identical unsprung weight (and therefore the suspension will react the same way), but braking and acceleration will be worse with a larger diameter wheel. This would probably only be noticed at the track.

I went from OEM 18's to aftermarket 18's and saw HUGE advantages on the street. After dropping ~38 lbs in unsprung weight, I can put power down over bumps; the DSC light doesn't flicker anymore when cornering on rough roads; and the car responds infinitely more quickly.

The ride will be rougher with 19's vs equal weight 18's. However, heavier 19's may actually have a better ride, because the wheel responds so slowly that it effectively smooths bumps. This is a very bad thing, and I would never upsize to a heavier wheel to try and improve ride quality. Go for softer springs first.

Tirerack has done several comparison tests with varying wheel/tire combos. Check them out.

[baege]

Thanks for all the replies so far, some very informative and relevant experiences shared.

Here's the video I referred to, car's stance is very nice, hence the deliberation.

[jrainlay]

Originally Posted by pokeybritches

...but braking and acceleration will be worse with a larger diameter wheel.

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.

[jrainlay]

Stance is more directly related to suspension and lowering of ride height. The car in this video is clearly lowered at least one inch vs. stock. This can be achieved with after market lowering springs or adjustable coil overs.

[ZStig]

After going from 27lbs 19" wheels to 16.5lbs 18" forged wheels, I'm never going back to 19s

[Finnegan]

Weight of wheel + tire is going to be the biggest factor here IMO. Harshness, tire selection, potholes, etc. are all factors to consider.

But 18" or 19", no one is going to argue that a heavier weight wheel/tire combo is going to outperform a lighter one. Lightness and lower unsprung weight always wins.

So, 18" or 19", look at the weight of the wheel compared to stock, and make sure at least whatever setup you're considering is not going to be heavier. If you can find one that's lighter (and strong enough, which probably means forged in a 19", and more $$$) then by all means go with that.

[jrainlay]

OEM style 224 5 spoke M 18" wheels weigh 25 lbs front, 26 lbs rear. CSL style 19" wheels actually weigh about one lb less respectively. Sure, you can buy 27 lb 19" wheels, but who would want to when there are so many attractive and much less heavy 19" alternatives?

[ZStig]

tire weight is also part of the equation, don't forget

many people move up to a wider front tire, which weighs more than stock (including me)

[Finnegan]

Yep, wheel + tire. Important to look at the total weight of the combo, especially when moving up in tire width.

[ZStig]

I know the thread title has a potential for a penis size joke, but I can't figure it out

[Kgolf31]

Originally Posted by Roffle Waffle

I know the thread title has a potential for a penis size joke, but I can't figure it out

The smaller it is the better it feels?

[RADRACR]

My ride quality actually improved when I went up to a 19" Hankook from the 18" OEM Conti.

Like others have said, size is irrelevant; weight is king. My 19" Advans weigh slightly less than the 18" OEM Z4MC shoes. Will a 18" Advan weigh even less? Sure. Will I find it more attractive? No.

As for 19" being susceptible to damage, I took a "Top 5" pothole with the Advan and it took it like a champ.

[mfanatic325]

Originally Posted by Roffle Waffle

I know the thread title has a potential for a penis size joke, but I can't figure it out

Yeah, I've got 4 (count them; FOUR) 19-inchers....and they got some girth on them too