17" X 9.5" Wheels with FX3

[93Rubie]

Ok, so 93 Corvettes without Z07 have a staggered stance 17x8.5 in front and 17X9.5 in rear. While the Z07 has 17x9.5 all around. Supposedly they went to the staggered setup for better handling. My 93 has the FX3 suspension on it and the staggered wheels. I am considering doing a brake upgrade to this...Vette Brakes & Products, Inc. - Detail. I currently have chrome sawblades on it, but I want to run early C6 style wheels. It says you can run 17X9.5" wheels so I assume that the C6 style being of that size will work properly. My question is will I give up anything by running 17X9.5's all around on my FX3 car versus the staggered 17X8.5 and 17X9.5? Improved handling is a goal of mine but at the very least I do not want to hurt the already excellent handing.

 

[vetteoz]

Supposedly they went to the staggered setup for better handling.

They reduced the front rim width on the std cars to keep the golf club set happy regarding complaints about tracking on ruts / grooves in the road.The same reason they softened up the suspension in the later years
Most would advocate the widest rubber if handling is your aim

 

[Black Bart]

They reduced the front rim width on the std cars to keep the golf club set happy regarding complaints about tracking on ruts / grooves in the road.The same reason they softened up the suspension in the later years
Most would advocate the widest rubber if handling is your aim

I agree, I have 9.5 on the front and 11" on the rear with FX3

 

[Tuna]

Improved handling is a goal of mine but at the very least I do not want to hurt the already excellent handing.

Since the ZO7 Vettes were supposed to be the 'better' handling cars and they came with the wider tires and wheels up front, the answer is right there. If you want better handling, go wider up front.

As vetteoz stated, the narrow front wheels were added to make the golf club crowd happy as the narrower front tires don't follow the ruts and cracks in the road as much as the wider tires do. They didn't help handling.

 

[93Rubie]

I'm guessing they went to the bigger style seats in 94-96 C4's , C5's, and C6's for the same reason. The more rounded folks did not fit in the good seats. That and they are harder to get in and out of. Cry me a river, you want a sports car or a stink'in Buick take your pick.

Thanks for the input, looks like I will get the 17X9.5's. Another advantage to this is that I will be able to rotate tires front to rear. I assume the 275/45/17 would be the tire size to use on them?

 

[Rabbit]

Precisely!

 

[vetteoz]

I assume the 275/45/17 would be the tire size to use on them?

You could possibly go 285/40 /17 ; that was the size used on the 93 -96 rears with the 8.5" fronts

I'm guessing they went to the bigger style seats in 94-96 C4's , C5's, and C6's for the same reason. The more rounded folks did not fit in the good seats. That and they are harder to get in and out of. Cry me a river, you want a sports car or a stink'in Buick take your pick.

Remember ; the Vette is marketed as a luxury / performance car.
Many cashed up new buyers buy them for the pose / prestige value , not for the performance / handling aspect.
Look what happened back in '84 .Half the new buyers ticked the Z51 "perf handling "option then complained when their fillings fell out .
GM then made Z51 only available with a manual ,picking that someone prepared to shift gears would have a better appreciation of the handling qualities and lack of ride comfort

 

[Hib Halverson]

The gain in at-limit handling by going from the base 93-96 tire package to the Z07 package will not be great. In fact, it will probably be so small as to be measurable only by test equipment or by a very experienced performance driver. Additionally, the base stabilizer bar package is balanced for that tire configuration. You may find the bigger tire in front may actually "loosen" the car up a bit.

Now...if you also add the springs and stabilizer bars that went with Z07, then you'd have a significant improvement in handling.

 

[Tuna]

Hib makes a good point here: The ZO7 Vettes got better handling through a combination of the bigger front tires and suspension changes to the springs and bars. I had a '92 FX3 car and it came with the 9.5" wheels and the 275 tires all around from the factory. I checked the C4 Suspension chart (available here on the CAC) and noted that the only difference between the '92 FX3 suspension and the '93 FX3 suspension was the size of the rear bar - '92 got a 22mm bar and the '93 got a 24mm bar.

The ZO7 cars got much stiffer springs and a bigger front bar.

 

[93Rubie]

Thanks Hib and Tuna, that is what I was really looking for. I do plan on adding bigger front and rear bars in the future. I am going to retain the stock springs but when I get my shocks rebuilt I plan on getting the upgraded (stiffer) valving put in them by Bilstein. I usually ride around in the sport setting and I do not find it too stiff at all. Performance is nice for curving up the back roads, I want something even stiffer for the track so that is why I want the stiffer valving. Retaining the stock springs will help keep the ride ok. Do you have recommended set up for sway bars? I know that the wrong set up can spoil a cars handling if not be down right scary. I want to keep the car neutral as it is now. Corvette Central has 1.25" tubular front bars and 1" tubular rear bars. Good/Bad??? Oh, and before someone catches it I didn't have the tire size right in my post the Z07's have 275/40/17's on them. Not the 275/45/17's as I had stated. Vetteoz, I could run the 285/40/17's however tire selection is more limited than with the 275/40/17's so I think I will run that size at all four corners.

 

[Hib Halverson]

If you are going to do track day events with the car, you will find the base springs and the Z07 stabilizer bars unsatisfactory for race track use. If you go to the big bars, you need the higher rate springs (especially in the rear) or the car is going to understeer like a pig and will be way too soft...perhaps to the point of bottoming on tracks with a lot of ride movement.

You have to decide...

Do you want performance on the race track, or....
Do you want a nice ride on the street.

With C4, you can have both.

As for the shocks, Bilstein can revalve SRC shocks and the results are quite nice. I have revalved shocks on my 95 and just the improvement in rear rebound valving was worth the cost of the job.

 

[93Rubie]

If you are going to do track day events with the car, you will find the base springs and the Z07 stabilizer bars unsatisfactory for race track use. If you go to the big bars, you need the higher rate springs (especially in the rear) or the car is going to understeer like a pig and will be way too soft...perhaps to the point of bottoming on tracks with a lot of ride movement.

You have to decide...

Do you want performance on the race track, or....
Do you want a nice ride on the street.

With C4, you can have both.

As for the shocks, Bilstein can revalve SRC shocks and the results are quite nice. I have revalved shocks on my 95 and just the improvement in rear rebound valving was worth the cost of the job.

So unless I go with higher rate springs it might be best to leave everything alone? Could I just run the 275/40/17's up front and rear then have my shocks rebuilt with stiffer valving? Otherwords, what is the best combo? As you stated with a C4 you can have both. Sorry to be a pain in the butt, but I am trying to figure out what I need/want to get the car where I want it.

 

[Hib Halverson]

So unless I go with higher rate springs it might be best to leave everything alone? Could I just run the 275/40/17's up front and rear then have my shocks rebuilt with stiffer valving? Otherwords, what is the best combo? As you stated with a C4 you can have both. Sorry to be a pain in the butt, but I am trying to figure out what I need/want to get the car where I want it.

What is the best combo? Well...as I said before, there is no "best combo" which will give you competitive track performance and a the ride quality you have now. You need to decide if you want best performance on the race track, or a nice ride on the street.

If you want the car to do well on the race track, then you're going to have to accept a more harsh ride than you have now. If you want to maintain the ride quality you have with base suspension, you're going to have to accept a compromise in race track handing. Give us an idea of which of those two you want to emphasize and then we can offer some good advice.

 

[93Rubie]

What is the best combo? Well...as I said before, there is no "best combo" which will give you competitive track performance and a the ride quality you have now. You need to decide if you want best performance on the race track, or a nice ride on the street.

If you want the car to do well on the race track, then you're going to have to accept a more harsh ride than you have now. If you want to maintain the ride quality you have with base suspension, you're going to have to accept a compromise in race track handing. Give us an idea of which of those two you want to emphasize and then we can offer some good advice.

Well since I will spend most of my time on the street/backroads a all out track set up is undesirable. I will occasionally use it on the track but I am not out to beat anybody just for my enjoyment on the track. Keeping the car balanced is my main goal with increased grip/less body roll/ and a crisper turn in. I was thinking that a good sticky tire and different valving in my shocks might be all I need. Keep springs and roll bars stock. If re valved shocks are stiffer on the street I can run the softest setting and then when I go to the track to get a bit better cornering just turn the knob.

As I said in an earlier post I ride around in the stock FX3 Sport setting most of the time, I find Touring to be too soft. Performance is nice when I want to curve some corners.

 

[Hib Halverson]

Snip

As I said in an earlier post I ride around in the stock FX3 Sport setting most of the time, I find Touring to be too soft. Performance is nice when I want to curve some corners.

Well...I forgot about that. If that's how you like to drive now, you're not going to care much about harsh ride.

Convert the car to Z07 springs and bars, revalve the shocks then get used to driving on the street with the shocks in tour. The Bilstein's "Moraca" valving will stiffen up even the tour range. You can find out more about revalving here: C4 Corvette's Selective Ride Control - Six Steps for a King's Ride. For alignment, dial in half a degree negative at all four corners, as much front caster as you can get, and stock toe settings.

The tough part is finding the OE Z07 springs, but search wrecking yards, eBay and other sources for used parts and you may find them. You also can go aftermarket, such as Vette Brakes and Products.

 

[93Rubie]

Well...I forgot about that. If that's how you like to drive now, you're not going to care much about harsh ride.

Convert the car to Z07 springs and bars, revalve the shocks then get used to driving on the street with the shocks in tour. The Bilstein's "Moraca" valving will stiffen up even the tour range. You can find out more about revalving here: C4 Corvette's Selective Ride Control - Six Steps for a King's Ride. For alignment, dial in half a degree negative at all four corners, as much front caster as you can get, and stock toe settings.

The tough part is finding the OE Z07 springs, but search wrecking yards, eBay and other sources for used parts and you may find them. You also can go aftermarket, such as Vette Brakes and Products.

Thanks a bunch Hib, I have read your article before but is been a while I just got done re-reading it and noticed that you revalved your shocks before considering going to a Z07 set up. I think I will try the same and go from there. I totally agree with this statement in your article, "We spent a lot of time," Scott Allman recalls, "tuning the Tour position to be the most comfortable then, basically, made the Performance position rock hard for the race track or autocross. The Sport position-the middle position-offered improvements in body control (over tour) but unless you were on a road with body input-1-hz or 2-hz-you weren't going to distinguish much. Sport snugged the car down enough, particularly out west, at highway speeds, so you didn't have to go to Performance and its impact harshness."

That is why I use sport most of the time it buttons the car down. I hate that up and down "Freeway" hop that old worn out Buick's do. I took a trip to Ohio and noticed that in touring the freeway hop was almost nauseating. Put it in sport and it buttoned the car up, no more undue body motion.

 

[Hib Halverson]

Thanks a bunch Hib,

You're welcome. Glad to be of service.

I have read your article before but is been a while I just got done re-reading it and noticed that you revalved your shocks before considering going to a Z07 set up.(snip)

There is one difference, though, I don't run track days with my car.

In fact, I have most of the parts necessary to convert to Z07, I just need the rear spring. I will probably do that next year.

With the revalved shocks, I run mine in Tour most of the time.