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Discussion Starter #1
I figured it would be an obvious answer considering the 18 inch wheels have low profile tires but the 18 inch set up weighs 10 pounds more than the stock 16 inch set up. Do some actually prefer the 16's?
 

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The answer depends on what you expect from the car. Handling is more the tire and suspension than the rims. Lighter rims are always better. Heavy rims make the suspension work hard and the car rides rough as a result. Really heavy rims will actually effect performance, ie braking and acceleration.
There is no single right answer as to which rims are better. My answer is neither one or the other. Both the OEM wheels are heavy. I chose 17x7.5 Tracklite Gears at 15.5 lbs each.
 

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Well, I use(d) 18" for summer and 16" for winter and for me the 16" does not seem really "enthusiast driver" friendly, so I'm switching to 18" also for winter. Car came with 18" and it seems also suspension is set up for heavier wheels, 16" feel like they're jumping sometimes as I hit a pothole, while with 18" and same hole the wheel just absorbs the hit and thats it. As the car has just some 16k miles the suspension is almost new so it can't be due to worn out parts. Also cornering with 16" was not as stable as with 18", but that could be also due to used rubber (Michelin PA4's)..
 

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I am leaving my 18's for 17's.
I also have used 16's from December to March the last few years. Granted the 16's have winter tires on them.

I cant wait for what the 17's feel like, the ones I got are 17x7's and weigh 18 pounds.
I am also looking at getting a set of Winter tires on 17's or 18's moving forward.
 

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Answer is completely subjective.
 

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Well, I use(d) 18" for summer and 16" for winter and for me the 16" does not seem really "enthusiast driver" friendly, so I'm switching to 18" also for winter. Car came with 18" and it seems also suspension is set up for heavier wheels, 16" feel like they're jumping sometimes as I hit a pothole, while with 18" and same hole the wheel just absorbs the hit and thats it. As the car has just some 16k miles the suspension is almost new so it can't be due to worn out parts. Also cornering with 16" was not as stable as with 18", but that could be also due to used rubber (Michelin PA4's)..
The suspension is actually in fact quite good if you let it do its thing. You can't "set up a suspension for heavy wheels". Heavy wheels keep the suspension from moving fast enough to react to bumps. As you said "with 18" and same hole the wheel just absorbs the hit and thats it". That problem with that is you don't want the wheel to absorb the hit, you want the suspension to move. The 18" wheel weighs in at over 50lbs, so the suspension can barely move quick enough with that attached to it. You can actually break things or blow out a tire or bend a rim if the suspension does not move as it should. Lighter is always better, always. With a lighter tire/rim combination, the suspension is free to move and keep the tires in contact with the road instead of skipping and bouncing over bumps. Also, you drive around large potholes, not into them.
As for the cornering, if you use decent tires the car will be just fine. Use cheap or worn out tires and they won't work so well.
 

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well, maybe I've not explained that correctly, the car was delivered with 18"s from factory, but the car feels bouncy to me with 16"s through steering wheel.
And to the suspension set up, the shocks and springs must be set up with some wheel weight in mind (for bound and re-bound speed), and weight diference between 16"s and 18"s is pretty huge. Once you set up the rebound for 50lbs and put there 30lbs wheel then after hitting pot hole the spring will push the wheel down with "more force", so wheel gains higher speed till hitting the ground. As 16"s have lot of rubber the wheel could feel bouncy (at least for me) till it stabilizes again.
Avoiding pot holes is what I try to do, but we have some places where we can drive just 5mph as roads are in so bad conditions after winter, and once you drive trhough new area you don't know what to expect after next corner, than you get to a place where you avoid 1 hole but hit different 4, so sometimes it is better to hit just one, not all of them.
I also expected 16" Michelin Pilot Alpin 4 would be really good snow tire (only one in my area fulfilling all Mazda recommendations regarding speed and weight), but I'm gonna change them for some 18" snow rubber, as I don't feel confident with so shaky tires. Michelin Pilot Sport 3 in 18" is imho pretty decent summer tyre. And allweather is nothing for me, as though year we have here between -30 to +40 °C (-22 to 104 F) and sometimes also 1m of snow in winter, so I need good tires for both conditions..
 

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That is not how it works. Google unsprung weight and do some research on the effects it has on the cars handling and suspension, and read up on how the suspension works in general. Tires don't generally bounce unless the shock are bad.

If you have bad roads with a lot of potholes, big heavy rims and low profile tires are not what you want. What you need are smaller rims with taller softer sidewalls. Snow tires are pretty stiff in general and don't ride as well as regular all seasons.
 

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Discussion Starter #11
Great info guys. thank you very much! I think I'm going to look into an after market light weight 17 or 18" wheel. Thanks!!
 

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18" will handle better for 2 reasons..

1 - Lower profile tires with smaller sidewalls = less flex (but harsher ride)
2 - Given two setups of the same diameter and weight, the one that has more of it's weight on the outside will suffer. Therefore Tire weights comes into play and typically a low profile 18" tire will weight less than 16" with larger sidewalls and more rubber. The wheel itself, although bigger and maybe a bit heavier, distributes that weight overall and not just on the circumference.


Now before getting slammed... note # 2 (of the same weight). So if you go from say a 30 lbs 16" (just making up the numbers) to a 40 lbs 18" .. then the 16's would handle better.
 

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Given two setups of the same diameter and weight...typically a low profile 18" tire will weight less than 16" with larger sidewalls and more rubber
It's been my understanding that due to more steel being required to maintain the shape of the lower-profile and stiffer tire, an 18" unit would typically weigh more than its 16", same-diameter counterpart.

Can you give us one or more examples of 16" and 18" tires that we might reasonably choose for our MZ3s where the 18" tire weighs less than the 16" tire, including the brand and model? Or, maybe, where they weigh the same.
 

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18" will handle better for 2 reasons..

1 - Lower profile tires with smaller sidewalls = less flex (but harsher ride)
2 - Given two setups of the same diameter and weight, the one that has more of it's weight on the outside will suffer. Therefore Tire weights comes into play and typically a low profile 18" tire will weight less than 16" with larger sidewalls and more rubber. The wheel itself, although bigger and maybe a bit heavier, distributes that weight overall and not just on the circumference.
Thats not how it works at all. Wheels are unsprung weight. It does not matter how the weight is distributed. Heavier wheels mean the suspension is slower to react. A slow moving suspension means the car won't handle or ride as well as it could.

Lower profile does not necessarily mean a harsher ride or less flex. This is entirely dependent on tire construction. For example, the Conti DW has notoriously soft sidewalls. Even the low profile sizes flex a lot. The new Conti ECS has an 86% improvement in sidewall stiffness and the higher profile sizes are quite a bit stiffer than the low profile DWs.

Heavier construction makes the weight difference between profile sizes pretty minimal. Generally when upgrading from 16" to 18" rims the tires are substantially wider, so the tires end up a pound or two heavier anyhow.
Here is a typical example:
Dunlop Signature HP- OEM size 205/60R/16 is 20 lbs. The smallest 18" size available, 215/45R/18, is OEM for the Mazda 3 and weighs 22 lbs.
 

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If I drove on a smooth race track at high speeds, I would select wide, low-profile tires with large-diameter alloy wheels. Their race-proven design is ideal for that type of environment.

However, I primarily drive at highway speeds on public highways that are becoming increasingly rough every day. At highway speeds there are limited things I can do to avoid potholes and other road irregularities and still maintain safe lane discipline. So, I chose the 16-inch rims which take tires that provide more cushioning effect on the road, even though today they are not considered as stylish.

I also chose the 16-inch factory alloy wheels because they are lighter than the steelies. And although the factory alloys are often a few pounds heavier than some of the sleeker aftermarket models, they are very robust and take the hits well. I've heard stories of some light aftermarkets failing when put to the test against potholes at speed.

My OEM 16" alloy wheels with the stock Yoko P205 60R 16 tires are reasonably light at about 39 pounds each. I think they give me the best performance for my driving environment. So far, so good.
 

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I agreed that lowering unstrung weight is a key to better handling -- and why many race cars even more their shocks inboard.

The question however I feel is paramount, what is our intended use for our cars? If we are auto crossing, racing on a traditional race track, or are driving at 8/10's+, better handling is hugely important.

However, to be honest with ourselves, how many of us have the courage to drive our cars at better than 7/10's (other than a really intermittent romp on an interstate ramp or similar). I go for drives with many of my sports car friends, and being candid here, for most of them their car's capabilities are so, so far in excess of the both their driving skills and also their courage take a turn at anywhere near their car's capabilities.

As an example, I am track trained/experienced, and my Z06 (which has a heads up display with a "G meter"), will do 1.14G, whereas our Mazda's do around .84G. Do I ever, on even my favorite, totally-isolated, curvy country road exceed .95 G? NO, I do not. (Though I do have the courage to drive at 1.10+G on a race track with huge/safe run off areas.)

So which is more important to you, IMO the better looks of an 18"+, and paying (if you choose wisely) just a few pounds weight penalty, or additional, more than our Mazda's .84G handling capability, that most never use nor need?
 

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I agreed that lowering unstrung weight is a key to better handling -- and why many race cars even more their shocks inboard.

The question however I feel is paramount, what is our intended use for our cars? If we are auto crossing, racing on a traditional race track, or are driving at 8/10's+, better handling is hugely important.

However, to be honest with ourselves, how many of us have the courage to drive our cars at better than 7/10's (other than a really intermittent romp on an interstate ramp or similar). I go for drives with many of my sports car friends, and being candid here, for most of them their car's capabilities are so, so far in excess of the both their driving skills and also their courage take a turn at anywhere near their car's capabilities.

As an example, I am track trained/experienced, and my Z06 (which has a heads up display with a "G meter"), will do 1.14G, whereas our Mazda's do around .84G. Do I ever, on even my favorite, totally-isolated, curvy country road exceed .95 G? NO, I do not. (Though I do have the courage to drive at 1.10+G on a race track with huge/safe run off areas.)

So which is more important to you, IMO the better looks of an 18"+, and paying (if you choose wisely) just a few pounds weight penalty, or additional, more than our Mazda's .84G handling capability, that most never use nor need?
Well, actually, going from 50+ lbs per corner to about 37 on a fairly light car like the Mazda 3 makes a huge difference across the board, not just at race speeds. Most people notice the difference right away. The suspension works so much better, the car rides better and feels lighter. Those OEM 18" boat anchor wheels should be the first thing to kicked to the curb.
 

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Oh yes. I can not imagine how much more poorly an extra 13 pounds per corner would affect even day-to-day handling.

Most however would not notice 2 or even 3 pounds per corner unless tracking or similar. Hell, many drivers drive around with some tires seriously underflated, others overinflated and never even notice. A driver study about a year ago found that 33% of American drivers admitted to driving around for several weeks or more with a check engine light without doing anything. Very sad.

Just yesterday leaving a store, I hear this horrible, to me unmistaken sound, saw it was a totally flat rear tire of a Ford P-U being driven by a man about 50 years old, with someone who looked like his son in the passenger seat. I drove after them for about a mile, trying to get their attention (they were going the same direction as I was), and when they finally got to the cell phone store they were heading to, I pulled up near them, walked over and asked, "Hi, there, do you know you have a flat tire?" Driver said, "no." His passenger said, "no." And they both walked back about 30' toward the truck with a look on their faces, "can't be, let's check and see if that guy is telling the truth."
 

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So which is more important to you, IMO the better looks of an 18"+, and paying (if you choose wisely) just a few pounds weight penalty, or additional, more than our Mazda's .84G handling capability, that most never use nor need?
Looking at stopping distances, what's important to me in the context of the .84g skidpad result is that the 18" OEM tires have a 'B' traction grade (more here: https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48&affiliate=EB8). That translates to poor stopping distances in the wet, which concerns me greatly as the car is my wife's daily driver. At 182', the stopping distance in the dry isn't anything to write home about either. Fortunately, she drives at the speed limit or slightly below it.

Well, actually, going from 50+ lbs per corner to about 37 on a fairly light car like the Mazda 3 makes a huge difference across the board, not just at race speeds. Most people notice the difference right away. The suspension works so much better, the car rides better and feels lighter. Those OEM 18" boat anchor wheels should be the first thing to kicked to the curb.
This.

For summer use only, to improve both handling and stopping via weight reduction and stickier rubber I have the following combinations on my radar screen. The prices are mounted, balanced, and delivered from the Tire Rack.



The first of those is the most practical package. The light weight and much lower price of the Kosei/ECS combo is certainly attractive, even if its 1" drop isn't.
 

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For summer use only, to improve both handling and stopping via weight reduction and stickier rubber I have the following combinations on my radar screen. The prices are mounted, balanced, and delivered from the Tire Rack.



The first of those is the most practical package. The light weight and much lower price of the Kosei/ECS combo is certainly attractive, even if its 1" drop isn't.
I have been checking out the ECS too. They seem to run wide as many performance tires do. I think TireRacks numbers are more in line with industry standards not the actual tire size. Those who have them already say that the 205s seem somewhat wide, and would probably work even on an 8" rim. I'll be putting the 205/50 17s on 7.5" TrakLite Gears very soon, next week maybe if it warms up a bit. :smile2:
 
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