So I've searched quite a bit here on Corvette forum and I haven't really found a conclusive answer, but why do people opt to go for wider tires and larger diameter wheels?

I've read that the safe consensus for C5 wheels is something like an 18inch wheel by 9 inches wide up front with a 275/35/18 tire and 19 inch 10.5 inches wide rear with a 305/30/19 tire.

The main reason for why I ask is that I am mainly interested in improving my car's handling and driving characteristics and I assume the larger tires help with traction, but every time I read a thread about C5 tires people chime in about the negative effects on gearing, higher weight, etc with the larger wheels and tires.

I guess a tertiary thing that I was also considering was the larger wheels and tires filling up the wheel-wells better and that being an advantage from an aesthetic perspective, but I saw a black C5 in a parking lot today with 18inch fronts and 19inch rears the tire sidewalls just looked thinner while the wheel gaps were still pretty apparent. If that's the case, I'm totally fine with stock wheel sizes and I'll just lower as desired.

Anyways, can anyone give any insight into good wheel and tire sizes from a pure handling and performance perspective?

 

Wider tires give a better footprint on the ground. This, in turn, can give better handling and braking.

As far as filling the wheelwell, that depends on tire diameters.

Example

C5 wheels and tires
Front 17x8.5 245/45-17 25.7 tall
Rear 18x9.5 275/40-18 26.7 tall

C6 wheels and tires
Front 18x8.5 245/40-18 25.7 tall
Rear 19x10 285/35-19 26.7 tall

No difference in overall height so no filling up of the wheelwell. More rim and less tire sidewall can yet further enhance handling and braking. This comes with an expense of more overall weight. Is the tradeoff worth it? GM thought so.

 

I have 18x10s up front and 19x11 in back with 275/35/18s and 325/30/19s The rears fit inside the wheel well and don't rub the cooling ducts, but they are as close as you can get. The rears are Nitto Invos which I hear run a little narrower than most other 325s. My car is an 04 Z06

 

I am currently running c6z06 wheels on my car. I'm more of a straightline person. So I run a bit narrow on the front versus OE c6z06.

Front 18x9.5 245/40-18
Rear 19x12 325/30-19

 

Everything is a trade off. The C5, out of the box, is a well designed automobile. But is designed for a variance of demographics. Once you receive your car, you have the ability to tweak it to change its characteristics, more toward your style of driving. Some people like to tour with their C5, Some people like to have a boulevard cruiser. Some people use a C5 for a Daily Driver. Some People Drag race, and some people Road race. The C5 is an Ideal platform for all of these .
Many people personalize their C5, and are willing to give up some aspect slightly to increase another slightly. EG. better handling usually means a harsher ride. EG more HP usually mean less fuel economy.
People put a spoiler on their car, because they like the sporty look but it will cost them fuel economy in drag. A spoiler is designed to work at speeds in excess of 100 mph to achieve more down force, even at the expense of more drag.
Wide tires increase the tire contact real estate. Its this contact patch that transfers HP from the drive train to the road, pushing the car forward. Too much HP and not enough frictional coefficient and HP is lost through loss of traction. If you have 600 HP and cant get it to the ground, you need stickier tires and more foot print. Sticky tires wear out much faster than touring tires, because they have more rubber ( soft ) and less Carbon ( hard) Touring tires have more carbon ( hard last longer )less rubber ( soft ) ( Hard tires do not perform as well but last longer) ( Soft tires perform much better but wear out faster )
Everything is a trade off.

 

OUTSTANDING! Well Stated!!!!

Bill C

 

Could not be said better in any way possible !

Thank You !

 

I've been saying this here since I left GM . " Everything is a trade off "... so tell me why have I received all the flack from 872 different individuals over the last almost 14 years here on this very thing ?
This has nothing to do with the other 1975 pieces of disrespect I've received from other issues.. Gotta Love this place.
It helps to keep my heart pumping....

 

That's an easy answer. The wonderful thing about people is their differing opinions. The bad thing about people is their differing opinions. And let's not bring in the abrasive negative insulting. But I still like you

 

18x9.5 front and 19x13 rear
265/35zr18 and 345/30zr19

1) looks absolutely incredible
2) fits humongous brakes
3) cornering power saw incredible gains... as well as braking

All of this costs money... but this bit of money sure bought happiness.

 

wider tires, wide fenders = wide smile

 

Thanks for all of the replies I really appreciate it.

So I prefer for the car to be optimized for road course handling I guess the question is, what tire/wheel size combo would be the most appropriate for this? Let's say the car makes around 400rwhp.

 

If you don't mind me asking, how exactly did the cornering improve?

In my opinion the cars already have a ton of grip, but in my opinion they do feel a little twitchy and unstable at times. Do the wider tires help with this or do they just help improve grip?

 

Why have you received all the flack??....Because everything is a trade off. If you want to reap the benefits of the forum, the best way is to participate. The more you participate the more likely you will expose the disrespectful individuals.

I agree with your analysis - quite common sense really.

 

Grip either lateral or for traction. Some have the wider is better mentality, but I just try and find the best balance.

 

Tires alone do not make a road course car. Suspension engineering, aerodynamics corner weighting, alignment, down force, all have to be balanced together with the available HP, speed and g forces to keep as much HP and tire on the road under all circumstances.

 

Exactly! Balance is key. You wouldn't wear track shoes to an ice skating event.

 

Yes, exactly. But I'm trying to find tire sizes, wheel combos, etc that seem to work for people so that way when I way make other decisions about my build so I can try to find a balance.

I very much plan to build the suspension, bring the horsepower up, align it, etc. I want a balanced car. To me, that was never really the question. I'm honestly just hoping to see some general wheel/tire combos that have worked for people, hearing about their experiences etc, so that way I can make a decision about trade offs.

For instance 400rwhp probably isn't too too much for these cars to handle so at a certain point larger and wider wheel/tire combos stop paying as many dividends. So it makes sense for me to go "hmm well at this tire sizes I'm just putting on extra weight for minimal gains in traction on my car, but at this tire size I'm maybe adding a few pounds but for a good improvement in traction but I'm not adding unnecessary weight" (or whatever the case may be)

 

Very simple answer to your question. Size wise. the Sizes tested for the C6 Z06 handle 430/460 HP nicely. You can choose any Tire compound combination in thise sizes you like. More performance, better stick, but shorter tire longevity. You can choose an all out performance compound, to a mellow touring compound in those sizes.. The C6 Zor was tested at GM's performance track in excess of 180 mph.
at this point , you need not over think " tires " ...
when you build a road car. the first thing you do is establish the HP you want to build. 400 HP or 800 hp. once you establish that, you decide where you want to race ( Track ) and calculate the G forces required in the turns, and build the suspension to allow the car to bring 800 Hp to bear, and brake quickly and get back up on the RPM. Once the engine is built, you will know what demand you need for suspension, down force, brakes, and lastly tires.... So what you say you want , and what you actually want are two different things.. I think you are just looking for tires, with no real intention to put 30 to 40 K into an all out built road car. Go with what a million dollars worth of GM testing has produced, and go with the Best GM has to offer and adjust the rubber compound to your style of driving... no need to make it anything more than the simple thing it is.

 

I think you are over thinking this a bit much. If anything the type of tires you chose could make a difference over the sizes. I am over 600 to the wheels and aren't running much over stock sizes.