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I'm in the same predicament as you. I need to choose what size I want to run on the square set up. I want a fatter tire on the rear....
Let me know if you have any suggestions. I like your choice above of 305 rear and 275 front.
This is hard info to find. Yeah the 305’s would be great for the rear but there is not much selection out there for that size. Seems like there is more to choose from with the 295’s. Maybe someone will chime in with some pics and tire sizes with 18’s.
Running 295/35/18 squared on my 04 z, never had a tcs/and light come on. Seems to be hit or miss for others perhaps, but mine has never come up. Ill get some pictures when i get home.
I'm also running square 295/35/18's with 4x OEM 18x10.5 wheels. No issues on the street, autocross, or the track. Works flawlessly and handles great, very well balanced.
I’m sure a 305 will work but as others have said the tire selection is slim for that size. I will add one more advantage of 295 square, easier to replace if you get a spare/damaged tire. Yes you can deal with insurance but I just keep a spare or 2 from my previous set in case I get a flat, ive had 2 since I daily drive and it’s really nice to have a spare tire on hand in a pinch since they’re not run flats.
295x35x18 Toyo R888R's on OEM 18x10.5 wheels front and back at stock ride height. Toyo's run a size wide, so they fit more like a 305. Tires stick out substantially, even with -2.1* of camber in front. I'll be running -2.6* of camber next season, so they should tuck in nicely. Other than sticking out, there are no problems whatsoever. Even when ran hard on the track and doing u-turns on the street, there are no clearance issues or rubbing anywhere.
Last edited by Quickshift_C5; 11-01-2017 at 06:49 PM.
295x35x18 Toyo R888R's on OEM 18x10.5 wheels front and back at stock ride height. Toyo's run a size wide, so they fit more like a 305. Tires stick out substantially, even with -2.1* of camber in front. I'll be running -2.6* of camber next season, so they should tuck in nicely. Other than sticking out, there are no problems whatsoever. Even when ran hard on the track and doing u-turns on the street, there are no clearance issues or rubbing anywhere.
Thanks. I have been searching for photos like these. I am considering switching from the 17x9.5" front rims to the 18x10.5" rear rims in the front of my '99 FRC, but most likely with a 275/35-18 tire so that is will not stick out quit as far. The Z06 may not have any AH/TC issues with a true square wheel/tire setup, but I am not sure it that can be said for the base/FRC models.
I have been considering running a square 295 for street and square 315 rivals for track. I tried the 315s this weekend on the front at an autocross. My only concern is that since the tires stick out of the fenders, if I hit a big enough bump will they hit the fender and cause damage? I'm lowered all the way on stock bolts.
Do you think the extra width of a 295 over a 275 is worth the heavier tire and heavier wheel compared to a 17" rim? I was also considering just putting 275s on the front.
Not only a square setup, but same wheel specs, so I can truly "rotate" my wheels/tires to balance wear (except for the "4 rears" approach, some run square tire setup on front and rear spec 18's...that's a no no in my book). On top of that, car has never handled, turned in or felt better since I've owned it. Best modification decision I've ever made for this car...and it's been through about 4 different builds, to the extent it was different colors, widths, forced induction and not. I've been through the process with this car...this is the purest and most capable, balanced form it's ever been in. I feel the car is a "GT3'esque" approach. It's under 3000lb's on the scales with 1/4 tank, has plenty of brakes and suspension. It's compliant but has very little roll and is completely tunable from a suspension perspective. In terms of steering response and turn in...best feeling Corvette I have ever had (owned all gens except C1 and C7)
Last edited by KnightDriveTV; 12-06-2017 at 02:36 PM.
Not only a square setup, but same wheel specs, so I can truly "rotate" my wheels/tires to balance wear (except for the "4 rears" approach, some run square tire setup on front and rear spec 18's...that's a no no in my book).
So what wheels are you running? That's a beautiful car btw...
Not only a square setup, but same wheel specs, so I can truly "rotate" my wheels/tires to balance wear (except for the "4 rears" approach, some run square tire setup on front and rear spec 18's...that's a no no in my book). On top of that, car has never handled, turned in or felt better since I've owned it. Best modification decision I've ever made for this car...and it's been through about 4 different builds, to the extent it was different colors, widths, forced induction and not. I've been through the process with this car...this is the purest and most capable, balanced form it's ever been in. I feel the car is a "GT3'esque" approach. It's under 3000lb's on the scales with 1/4 tank, has plenty of brakes and suspension. It's compliant but has very little roll and is completely tunable from a suspension perspective. In terms of steering response and turn in...best feeling Corvette I have ever had (owned all gens except C1 and C7)
GREAT looking car!
How do you like the C6 big brakes?
Did you notice the increase in rotational mass from a "seat of the pants" perspective?
I'm considering going to 18 X 10.5 C5 Z06 Speedlines up front and going to upgrade to C6 Z06 brakes.
Silverbird
Last edited by silverbird; 01-04-2018 at 08:24 PM.
295x35x18 Toyo R888R's on OEM 18x10.5 wheels front and back at stock ride height. Toyo's run a size wide, so they fit more like a 305. Tires stick out substantially, even with -2.1* of camber in front. I'll be running -2.6* of camber next season, so they should tuck in nicely. Other than sticking out, there are no problems whatsoever. Even when ran hard on the track and doing u-turns on the street, there are no clearance issues or rubbing anywhere.
Just wanted to double check a couple things with you on your setup.
Looks like you have keep the ride height near stock, correct?
Do you have to run any spacers with the 18x10.5" rear rims up front to clear those AP calipers? I have seen others use the 18x10.5" rears up front with the C6 Z06 setup and they clear that setup without spacers. I also know a couple NASA racers that needed thin spacers with these 18x10.5" rears up front to clear a full wide body Wilwood caliper that uses the wider 20mm pads.
When you say you have no rubbing issues during turn-in, are you running front brake ducts like the GM #15829066 & 15829067 units from the C6 Z06 and/or 3" hoses to something like the Lambert #08112DK competition spindle kit?
Just wanted to double check a couple things with you on your setup.
Looks like you have keep the ride height near stock, correct?
Do you have to run any spacers with the 18x10.5" rear rims up front to clear those AP calipers? I have seen others use the 18x10.5" rears up front with the C6 Z06 setup and they clear that setup without spacers. I also know a couple NASA racers that needed thin spacers with these 18x10.5" rears up front to clear a full wide body Wilwood caliper that uses the wider 20mm pads.
When you say you have no rubbing issues during turn-in, are you running front brake ducts like the GM #15829066 & 15829067 units from the C6 Z06 and/or 3" hoses to something like the Lambert #08112DK competition spindle kit?
TIA.
The only modifications to the car are 18x10.5 wheels, R888R's, GM T1 Sways, and the AP Radi-Cal Kit. I have literally done nothing else but bolt it all together. So, no spacers, no custom steering stops, and using factory GM brake duct with no aftermarket extensions or spindle kits. With that setup, there are no clearance or rubbing issues either in the fenders, liners, or brake caliper clearancing.
Car is at 100% factory ride height. I don't think you have to KEEP stock ride height, since I feel I could likely drop it a bit with no issues. I just don't put much value into ride height, so I haven't done anything with it yet. Some common sense applies: If you really slam it down, your chance of running into issues is very high.
Last edited by Quickshift_C5; 01-05-2018 at 12:13 PM.
Car is at 100% factory ride height. I don't think you have to KEEP stock ride height, since I feel I could likely drop it a bit with no issues. I just don't put much value into ride height, so I haven't done anything with it yet. Some common sense applies: If you really slam it down, your chance of running into issues is very high.
Especially with the rear end and the factory C5 Z06 shocks - you run out of travel fast. With a really low ride height, the car does "odd" things like steps out on you mid corner unexpectedly if you hit a bump or swale due to bottoming out the rear shock. I been warned not to drop the rear end much more than say about 1/2" below the factory ride height setting if I am still running the C5 Z06 shocks. Now its a different matter with say a set of shorter length Bilsteins.
Especially with the rear end and the factory C5 Z06 shocks - you run out of travel fast. With a really low ride height, the car does "odd" things like steps out on you mid corner unexpectedly if you hit a bump or swale due to bottoming out the rear shock. I been warned not to drop the rear end much more than say about 1/2" below the factory ride height setting if I am still running the C5 Z06 shocks. Now its a different matter with say a set of shorter length Bilsteins.
Totally agree. We can run much lower ride height the closer we get to a "race suspension" setup where there isn't much deflection/compression.
11-01-2017, 12:14 PM
