2QUIK4U

iTrader: (1)

I did a search before I started this thread and it was information overload. I ordered chrome C6 18x9.5 (4) wheels for my 91Z28. Bruce from Hawka suggested a 1.5" rear adapter an 2" front. I will be running a 245/40 18 on the fronts and a 285/35 18 on the back. Is there anything I need to watch out for? Where will it be close, and what kind of modification should I do to make it work? Thanks

Orr89RocZ

iTrader: (20)

Rears watch out for front inner wheel well to tire clearance if lowered a good bit. May need to hammer those in.

I had to for my 295/30/19 and more with the 305/35/19. You'll be touch thinner but depends where they sit with the backspacing. 2" may be better for rear as well, i gotta look up the specs on those wheels

2QUIK4U

iTrader: (1)

Wow, You can fit a 305 in there? I would need a wider rim for that, but I feel safe with these 285's now. Thanks!

Skinny Neb

iTrader: (2)

Use 2" spacers on the back if you have a stock width rear.
And you may want to pick a wider front tire than a 245 unless you like the tuner stanced look. I had 275/35/18s on my 18x9.5/18x8.5 C6 wheels.

Orr89RocZ

iTrader: (20)

I'd leave the 245-255 size up front. Thats stock width. Gives you full steering clearance lock to lock with lowered car. Mine rubs with 255's but I'm lowered pretty good up front and using 1.7" spacers with C5 brakes which are suppose to push mounting hub out .3"

2QUIK4U

iTrader: (1)

I already have the spacers and tires ordered. Bruce at Hawks said I could swap the 1.5" rear spacers if it didn't work. I like the stance of the more narrow tires in front. I was currently running a 225/50-16 and 255/50-16 and it made the car look more aggressive IMO. How long does it usually take for wheels to arrive from Hawks thirdgen? I ordered them 2/27/15 and the status is still awaiting shipment. The adapters say they shipped already. Just wondering if Hawks has them in stock or if I get them direct from OE wheels. Lol I did realize that I could have saved money by ordering direct from OE. I don't mind though. I like the customer service and the philosophy at Hawks.

paul_huryk

You are going to be severely handicapping your handling and braking performance by going 245/255 instead of 275 up front. 275-35-18 has dozens of tire options and with the right suspension is an easy way to get a 1g+ street car that looks aggressive as F.

Orr89RocZ

iTrader: (20)

I thought it was more suspension setup than just tire size. Most exotics have much bigger rear tires than fronts

paul_huryk

Understand that most exotics are rear/mid engine and have more than 1/2 their weight bias on the rear wheels. You will also notice that even the best exotics are unlikely to stop better than say a Corvette, which has much wider front tires - regardless of brake technology.

You must also understand that with front heavy RWD cars such as f-bodies (of all generations), they understeer mechanically just due to the weight bias. Skewing that in the wrong direction by putting more tire on the rear only exaggerates that tendency. That said, putting the same tire (275-35-18 in your case) on all 4 corners makes the car much easier to drive fast and control.

Orr89RocZ

iTrader: (20)

Interesting. C6 z has 275 fronts and 325 rears. Seems to handle good for front engine car with good balance.

An fbody with aluminum heads and good rear end isnt all that front biased. Not 50/50 but not 60/40 either. My car with excessive turbo junk up front is 57/43. Thats over 100 lbs of turbo setup weight that normally wouldnt be there.
Mine never seemed to understeer once i got the shocks dialed in with factory 36/24 sway bars. It actually oversteered when rear shocks were to stiff and fronts to loose i believe it was. Idk i'm def no autox guy so just speaking on limited experience of what my car feels like

My stock z28 91 car does understeer alittle on factory rubber. It feels very light tho

2QUIK4U

iTrader: (1)

My car is set up for just cruising and going to the strip once in awhile. I'm running stock brakes now. I figure the staggered sizes can't make it worse than the 225 and 255/16's I had on before. I just like the look and the less rolling mass in front for a drag race.

paul_huryk

It depends on the car - you can dial a lot of under/over steer out or in to a vehicle's handling by changing a myriad of variables.

The stagger sometimes makes no difference. A 3rd gen with 275/315 tires may understeer a lot less than a 245/275 combo due to the steering axle having enough steering angle to feel neutral. I'm no expert either!

It depends on the car - if your car is 55/45 from the factory, in a 3400lb baseline it would be 1870/1530. Still front heavy by 240lbs. Even 52/48 is 1768/1632.Knowing how weight bias affects handling has given me a lot of respect for BMW, which strives for 50:50 - people love the more neutral handling characteristics - but loose is faster most of the time at the track.

The good thing is that you have many options for sway bar sizes (factory bars), spring rates, shocks/struts, and other things (like tire pressure and shock valving) that can make a wildly off-neutral car get back close to neutral.



[QUOTE=Orr89RocZ;5888371]Interesting. C6 z has 275 fronts and 325 rears. Seems to handle good for front engine car with good balance.

An fbody with aluminum heads and good rear end isnt all that front biased. Not 50/50 but not 60/40 either. My car with excessive turbo junk up front is 57/43. Thats over 100 lbs of turbo setup weight that normally wouldnt be there.
Mine never seemed to understeer once i got the shocks dialed in with factory 36/24 sway bars. It actually oversteered when rear shocks were to stiff and fronts to loose i believe it was. Idk i'm def no autox guy so just speaking on limited experience of what my car feels like

My stock z28 91 car does understeer alittle on factory rubber. It feels very light tho[/QUOTE]