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.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)..
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.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
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.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.
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.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?
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.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?
This.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.
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: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.