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Your 275s will be just fine but your 315s could create a problem if the offset is not correct. Remember that C4 ZR1 315 sized tires required Chevy to make a different rear clip-- actually stretching it wider-- to accommodate the larger size tires so they fit under the well.
Are you looking for autocross/hdpe tires? That is what these are made for, not so much for everyday tooling around. If for autocross the 315 will be ok, but you may still be better off with a 295 on the 10.5" rears. Stock was 265 front and 285 rear on the Z06.
Yes, the ZR1 has a 3" wider rear end than the standard cars. However, they did put the 315s on the grand sports also and all they did was add on a fender lip (flare) to cover the tire. It all depends on the offset of the wheel on how much it will stick out. The ZR1 had a 36mm offset adn the GS had a 50mm. If you put the ZR1 wheels on the GS, they will stick out even further than the fender lips that were added. I believe stock Z06 wheels are a 56mm offset so they won't stick out as far as the GS wheels would. Just make sure of clearance on the inside. In reality it isn't a big deal if they are sticking out unless you live in a state that really requires the tire to be covered.
Are you looking for autocross/hdpe tires? That is what these are made for, not so much for everyday tooling around. If for autocross the 315 will be ok, but you may still be better off with a 295 on the 10.5" rears. Stock was 265 front and 285 rear on the Z06.
Yes, the ZR1 has a 3" wider rear end than the standard cars. However, they did put the 315s on the grand sports also and all they did was add on a fender lip (flare) to cover the tire. It all depends on the offset of the wheel on how much it will stick out. The ZR1 had a 36mm offset adn the GS had a 50mm. If you put the ZR1 wheels on the GS, they will stick out even further than the fender lips that were added. I believe stock Z06 wheels are a 56mm offset so they won't stick out as far as the GS wheels would. Just make sure of clearance on the inside. In reality it isn't a big deal if they are sticking out unless you live in a state that really requires the tire to be covered.
Yes, I would be autocrossing.
I believe in PA tires need to be covered but I can see dozens of trucks with improper flares so I'm not worried about half an inch!
Okay, with real OE C5Z wheels, your front wheel would have 54mm offset. That and your proposed tire size is perfect for a C4. No fitment problems there.
The rear wheels will have 58mm offset. They will fit without any issues as is - lots of people have put these on C4s. They will also fit on the front, btw (more about that in a following paragraph). Everything I'm about to say for the rear of your car also applies to front fitment. The 315/30/18 will fit on these rims, and they will definitely fit within the fender wells of a C4 on that wheel. They are also within the proper diameter range for a C4 (perfect match to the 275/40/17 fronts, too). There's a chance you'd need 5mm spacers to make them fit without any rubbing on the inside - that Falken is a pretty wide and square tire, meaning it's pretty wide at the tread/sidewall corner for its nominal section width. If I had to bet, I'd put money on your not needing spacers, but if you have to run 5mm spacers you should be able to do so safely with the stock stud length. With this fitment, your tires won't stick out illegally. Below is a pic of my 96 with 18x11 et50 wheels and 315/30/18 BFG Rival S tires front and rear. On the OE C5Z rear wheels, your tires would poke a little less than mine, even if you have to use 5mm spacers. These didn't rub front or rear, even at full steering lock. People underestimate how wide a wheel and tire can fit on a C4, but you need to get the offsets right. When people ignore offsets and tire diameter, you get the goofy fitments we see so often in pictures.
If you're even halfway serious about autocrossing and you're going to run in a class that allows any wheel and tire size (and clearly, you are), then I would strongly recommend going with 18x10.5 or 18x11 and 315s front and rear. There's no downside other than cost. The upsides are that you will gain front grip and people will tell you how badass your car looks (even if they don't realize why it looks so aggressive). Most (all?) 315/30/18 tires will give a recommended rim width of 10.5-11.5". IME, 10.5" is kind of a pinched fitment for any competition tire, the Falkens included. If you can afford them, 18x11 is a better-performing choice, but you won't find that in a used OE wheel. For example, the wheels on my car were Forgestar CF5s. That said, if you find a set of OE C5Z wheels or get a set of 18x10/5 et56 repros from a place like OE Wheels, they will still work pretty well and they will be cheaper. Honestly, 18x12 is an even better choice for these tires for competition, but 11" is about the max for a C4 if you don't want the tires to poke out of the fender edges at the top.
Now let's talk tires. The Falken is a really good autocross tire, and it also works well on track (it can get a bit greasy when it gets really hot, but it still provides good grip and won't get too overheated on a car of the C4's weight). You can drive them on the street, but it won't be great in the rain and it will wear quickly (you probably already know this). They are not quite the best autocross tire now, though. The Yokohama A052 is faster, but it wants lots of negative camber. You should run -3.0 degrees or more up front and -2.0 in back (you should do this no matter what tire you choose, though). It also doesn't hold up to lots of consecutive laps, but it would be a killer time trial track tire (a couple laps at a time, IOW). It's better in the rain and can also be street driven. After I sold my car, I got a chance to drive it on the Yoks and it was great. If I'd kept it, those are the tires I would have put on it for the following season. The other "best autocross tire" right now is the Bridgestone RE71RS. Problem is that all their sizes start with a "2". But with an 18x11 wheel, the 295/35/18 would fit and work well. It's a bit taller than the 315/30, but still within OE C4 tire diameters. I know people running these on 18x12 and that works well - they run wide and like to stretched - so they would be great on 11" wheels. The 295/30 might actually be really good, but at only 25" tall it's a bit short. That isn't bad for performance, but you might not love the look. These tires are basically as fast as the Yoks, but they tolerate heat better and should last a little longer. We are still trying to figure out some of their quirks (tire pressure needs seem to change as you put heat cycles on them), but they are really fast. BTW, the are $52 cheaper per tire than the Falkens. If it were my C4, I'd have a hard time choosing between the Bridgestones and Yoks right now.
PS - If you're in PA, you should connect with Shawn Bauman (93Rubie on this forum). He's great driver and has lots of experience with C4 autocrossing. Also, Sam Strano is in your neck of the woods and knows everything about everything related to autocross and track work.
Okay, with real OE C5Z wheels, your front wheel would have 54mm offset. That and your proposed tire size is perfect for a C4. No fitment problems there.
The rear wheels will have 58mm offset. They will fit without any issues as is - lots of people have put these on C4s. They will also fit on the front, btw (more about that in a following paragraph). Everything I'm about to say for the rear of your car also applies to front fitment. The 315/30/18 will fit on these rims, and they will definitely fit within the fender wells of a C4 on that wheel. They are also within the proper diameter range for a C4 (perfect match to the 275/40/17 fronts, too). There's a chance you'd need 5mm spacers to make them fit without any rubbing on the inside - that Falken is a pretty wide and square tire, meaning it's pretty wide at the tread/sidewall corner for its nominal section width. If I had to bet, I'd put money on your not needing spacers, but if you have to run 5mm spacers you should be able to do so safely with the stock stud length. With this fitment, your tires won't stick out illegally. Below is a pic of my 96 with 18x11 et50 wheels and 315/30/18 BFG Rival S tires front and rear. On the OE C5Z rear wheels, your tires would poke a little less than mine, even if you have to use 5mm spacers. These didn't rub front or rear, even at full steering lock. People underestimate how wide a wheel and tire can fit on a C4, but you need to get the offsets right. When people ignore offsets and tire diameter, you get the goofy fitments we see so often in pictures.
If you're even halfway serious about autocrossing and you're going to run in a class that allows any wheel and tire size (and clearly, you are), then I would strongly recommend going with 18x10.5 or 18x11 and 315s front and rear. There's no downside other than cost. The upsides are that you will gain front grip and people will tell you how badass your car looks (even if they don't realize why it looks so aggressive). Most (all?) 315/30/18 tires will give a recommended rim width of 10.5-11.5". IME, 10.5" is kind of a pinched fitment for any competition tire, the Falkens included. If you can afford them, 18x11 is a better-performing choice, but you won't find that in a used OE wheel. For example, the wheels on my car were Forgestar CF5s. That said, if you find a set of OE C5Z wheels or get a set of 18x10/5 et56 repros from a place like OE Wheels, they will still work pretty well and they will be cheaper. Honestly, 18x12 is an even better choice for these tires for competition, but 11" is about the max for a C4 if you don't want the tires to poke out of the fender edges at the top.
Now let's talk tires. The Falken is a really good autocross tire, and it also works well on track (it can get a bit greasy when it gets really hot, but it still provides good grip and won't get too overheated on a car of the C4's weight). You can drive them on the street, but it won't be great in the rain and it will wear quickly (you probably already know this). They are not quite the best autocross tire now, though. The Yokohama A052 is faster, but it wants lots of negative camber. You should run -3.0 degrees or more up front and -2.0 in back (you should do this no matter what tire you choose, though). It also doesn't hold up to lots of consecutive laps, but it would be a killer time trial track tire (a couple laps at a time, IOW). It's better in the rain and can also be street driven. After I sold my car, I got a chance to drive it on the Yoks and it was great. If I'd kept it, those are the tires I would have put on it for the following season. The other "best autocross tire" right now is the Bridgestone RE71RS. Problem is that all their sizes start with a "2". But with an 18x11 wheel, the 295/35/18 would fit and work well. It's a bit taller than the 315/30, but still within OE C4 tire diameters. I know people running these on 18x12 and that works well - they run wide and like to stretched - so they would be great on 11" wheels. The 295/30 might actually be really good, but at only 25" tall it's a bit short. That isn't bad for performance, but you might not love the look. These tires are basically as fast as the Yoks, but they tolerate heat better and should last a little longer. We are still trying to figure out some of their quirks (tire pressure needs seem to change as you put heat cycles on them), but they are really fast. BTW, the are $52 cheaper per tire than the Falkens. If it were my C4, I'd have a hard time choosing between the Bridgestones and Yoks right now.
PS - If you're in PA, you should connect with Shawn Bauman (93Rubie on this forum). He's great driver and has lots of experience with C4 autocrossing. Also, Sam Strano is in your neck of the woods and knows everything about everything related to autocross and track work.
Thank you for your thorough reply. I am halfway serious about autocross, but budget is a real concern. Honestly if I was totally serious about it I wouldn't have bought a c4! Haha.
Playing around on tirerack I can't seem to find 200TW tires in sizes for these z06 wheels I already bought. Maybe these were a mistake!
Best I can do is RT660s in
275/40/17 which is 25.7" diameter front
275/35/18 25.6" rear For about $1,150.
I wish someone made a 275/40/17 and a 295/35/18...I don't think anyone makes both of those? Bridgestone only makes a 245/45/17 front...
I feel like 275 square is better than 245 front 295 rear.
Thank you for your thorough reply. I am halfway serious about autocross, but budget is a real concern. Honestly if I was totally serious about it I wouldn't have bought a c4! Haha.
Fair enough...although with the revisions to CAM-S aero rules in SCCA, I actually think a properly executed C4 has a chance to be competitive. However, that's not where you are at this point, so let's move on!
I still think you should do wide wheels and tires front and rear. It may be prohibitive to buy two pairs of rear C5Z wheels. An alternative is any one of several OE Wheels repro designs in 18x10.5 et56 (here's an example). You can get a set of four of these for less than $800. With 2mm less offset than the C5Z rears, you have even less chance of needing to use any spacers. Then get four of the Falkens in 315/30/18 or the Bridgestones in 295/35/18 and send it. Honestly, the Bridgestones are a nominally better fit for a 10.5" wheel, they are cheaper, and they ride better (and quieter) on the street. They are probably better in rain, too. They won't last quite as long, but for the price difference it's probably a wash.
Fair enough...although with the revisions to CAM-S aero rules in SCCA, I actually think a properly executed C4 has a chance to be competitive. However, that's not where you are at this point, so let's move on!
I still think you should do wide wheels and tires front and rear. It may be prohibitive to buy two pairs of rear C5Z wheels. An alternative is any one of several OE Wheels repro designs in 18x10.5 et56 (here's an example). You can get a set of four of these for less than $800. With 2mm less offset than the C5Z rears, you have even less chance of needing to use any spacers. Then get four of the Falkens in 315/30/18 or the Bridgestones in 295/35/18 and send it. Honestly, the Bridgestones are a nominally better fit for a 10.5" wheel, they are cheaper, and they ride better (and quieter) on the street. They are probably better in rain, too. They won't last quite as long, but for the price difference it's probably a wash.
I snuck an edit in above you. I've already bought these z06 wheels so I'm probably sticking with 17x9.5 and 18x10.5 for at least a year or two.
Playing around on tirerack I can't seem to find 200TW tires in sizes for these z06 wheels I already bought. Maybe these were a mistake!
Best I can do is RT660s in
275/40/17 which is 25.7" diameter front
275/35/18 25.6" rear For about $1,150.
No, with the 10.5" rear wheels I would go with 275/40/17 front and 315/30/18 rear for Falkens, like you originally proposed. This is the perfect fitment for your wheel set, since you have the 17x9.5 front wheels, and both sizes are in stock.
I wish someone made a 275/40/17 and a 295/35/18...I don't think anyone makes both of those? Bridgestone only makes a 245/45/17 front...
In Bridgestone you could do 245/45/17 front and 295/35/18 rear. The rear diameter would be about 1/2" taller than the front. This would probably work well and be slightly faster than the Falkens, but not last quite as long.
No, with the 10.5" rear wheels I would go with 275/40/17 front and 315/30/18 rear for Falkens, like you originally proposed. This is the perfect fitment for your wheel set, since you have the 17x9.5 front wheels, and both sizes are in stock.
Oof, you're hurting my wallet. But yeah looking at pictures a 275 is too stretched...295 would be okay and 315 looks awesome. Just expensive!
Oof, you're hurting my wallet. But yeah looking at pictures a 275 is too stretched...295 would be okay and 315 looks awesome. Just expensive!
A 275 will go on an 11" wheel - it's even within the rim width range spec'd by tire manufacturers for that size. It's just that how stretched or pinched a tire is will change the steering response, and I'd prefer front and rear to be sort of similar in that respect. You could definitely do the Bridgestone in 245/45/17 front and 275/35/18 rear, though. Those rears would be about $27 cheaper than the 295s, which are already a lot cheaper than the Falken 315s. And they would be the same diameter front and rear that way. And I think they'd still be faster than the Falkens. They just wouldn't look quite as mean.
As a reference, on my 1LE Camaro, 285/35/19 Bridgestones on 19x10 front and 19x11 rears are significantly faster than 305/30/19 front and 315/30/19 rear Falkens. I wish Bridgestone made a section width starting in "3", but they don't.
A 275 will go on an 11" wheel - it's even within the rim width range spec'd by tire manufacturers for that size. It's just that how stretched or pinched a tire is will change the steering response, and I'd prefer front and rear to be sort of similar in that respect. You could definitely do the Bridgestone in 245/45/17 front and 275/35/18 rear, though. Those rears would be about $27 cheaper than the 295s, which are already a lot cheaper than the Falken 315s. And they would be the same diameter front and rear that way. And I think they'd still be faster than the Falkens. They just wouldn't look quite as mean.
As a reference, on my 1LE Camaro, 285/35/19 Bridgestones on 19x10 front and 19x11 rears are significantly faster than 305/30/19 front and 315/30/19 rear Falkens. I wish Bridgestone made a section width starting in "3", but they don't.
I think I'm resolved to the 275 and 315 falkens. Just gotta spend the money! Who doesn't love a fat tire?
I currently have the falkens on my Miata and like them, but I've never driven a different 200tw tire to compare.
Just FYI, here is my 91 with 275/18 on C5 magnesium 18x9.5 on front and 295/18 on aftermarket 18x10.5 on the rear. Tires are Federal 595RS-RR on front and 595RS-R on rear, only difference between them is the tread pattern. My aftermarket 10.5 wheels are not able to go on the front of my car without a spacer/adapter. The wheel will actually contact the sway bar on turns and doesn't go full lock.
If you want to pick up a couple more rear Z06 rims, look up house of wheels here on the forum. He sells brand new wheels that he orders from Italy where they were originally made. They were about 350 each, but I don't know what they are now.
Just FYI, here is my 91 with 275/18 on C5 magnesium 18x9.5 on front and 295/18 on aftermarket 18x10.5 on the rear.
In your pic, those rear tires look really short. They must be 295/30/18? That would only be about 25" tall. We were really talking about 295/35/18, which is 26.1" tall.
Thank you for your thorough reply. I am halfway serious about autocross, but budget is a real concern. Honestly if I was totally serious about it I wouldn't have bought a c4! Haha.
Playing around on tirerack I can't seem to find 200TW tires in sizes for these z06 wheels I already bought. Maybe these were a mistake!
Best I can do is RT660s in
275/40/17 which is 25.7" diameter front
275/35/18 25.6" rear For about $1,150.
I wish someone made a 275/40/17 and a 295/35/18...I don't think anyone makes both of those? Bridgestone only makes a 245/45/17 front...
I feel like 275 square is better than 245 front 295 rear.
I consider a C4 a great car for Auto Cross on a budget. Newer Corvettes have some advantages but they also have some big disadvantages. Get rid of the AC and all the Smog stuff and you can see all 8 spark plugs. A valve adjustment should take an hour. You should be able to change out the Clutch Disc in 6 hours. Try doing that in a newer Corvette
For Autocross has a 315 and 335 combo been tried ? Fairly certain Hooser offers the A7 in these sizes have not looked else ware.
Sure. The problem is that most classes in most sanctioning bodies require "street tires" as defined by a UTQG tread wear rating of 200 or higher. Hoosiers aren't that. They are sublime to drive on, though. But you also wouldn't put a 335 A7 on an 11" rim width: Hoosiers run wide and like to be stretched, so a 315 is the most you'd ever use, and even that is pushing it (but it works great: I've used 315/35/17 A7s on 17x11 wheels).
The last 200tw tire that came in those sizes was the BFG Rival S. Unfortunately, it's no longer competitive. The Falken is semi-competitive and the widest they offer is the 315. The Yokohama is fully competitive but their max is also 315. The Bridgestone is the new hotness and all their sizes start with a "2".... Also, a 335 really requires a 12" rim width to work best, and it isn't going to fit within the stock fenders of a C4 at either end unless that C4 is a ZR1. I know that Nokones on this forum has run the 315/335 Rival S combo on his C4, but he has flares.
Last edited by MatthewMiller; 06-21-2023 at 08:24 AM.
In your pic, those rear tires look really short. They must be 295/30/18? That would only be about 25" tall. We were really talking about 295/35/18, which is 26.1" tall.
Actually I just looked last night and they are 285 on the rear.
06-16-2023, 06:05 AM
Tire size on c5z06 wheels
. Also, a 335 really requires a 12" rim width to work best, and it isn't going to fit within the stock fenders of a C4 at either end unless that C4 is a ZR1. I know that Nokones on this forum has run the 315/335 Rival S combo on his C4, but he has flares.
