Boiler2

I will be upgrading my '66 427/425 (no P/S) to 17" Rev 107 Rally wheels (search eBay) with zero offset and 4" backspace . I want tighter tires for general purpose driving to improve handling and safety. Sloppy 15" high profile tires are unsettling and, at times, almost scary to me. Plus, I love the Rally style wheels. I am not looking for strong acceleration or performance handling......just a much more confident and connected feel for tour driving.

The issue is tire size and the need to avoid potential interference issues. Based on what I have read, I believe that a 225/55 would not be a problem. I'd rather go to a lower profile. Based on tire specs, I believe that a 215/50 has about the same section width and a slightly smaller tread width than the 225/55's, though it is about 1.3" smaller in diameter (that's a plus for me). Increasing to a 225/50 results with a 0.2" larger section width and 0.9" larger tread width as compared to the 225/55's....and 0.9" smaller diameter.

I would like to go with 225/50's but am concerned that about potential interference issues. Any assistance will be appreciated.

PS. No wise cracks please about get a newer car if I want better handling. I also have a C7 Z06 to satisfy my craves for performance driving.

LouieM

You can safely go wider than a 225 tire if you like. My stock-fender 67 currently runs 235/45/17 Kumho Ecsta LE Sport tires. I used to have 245/45/17 Nitto NT-01 tires (for autocrossing). Wheels are 17x7x4.75 backspacing, so you can go 0.75 more on the backspacing if, like me, you have the parking brake brackets moved from the outside to the tops of the trailing arms ($100 job). The added backspacing will move the tires away from the precious fenders, so that’s good.

When it came time for new tires, the Nittos were going to be around $1,200 and Tire Rack was having a special on my current Kumhos for $79 --- a no brainer. The Kumhos are Max Summer tires that have full tread and they stick like glue --- way beyond the capabilities of a C2 suspension. I’ve run hundreds of autocross laps on the Kumhos, and driven on them for the past three years with no issues. Given the price, which is still only $99 at one online vendor, they are unbeatable.

245/45/17 Nittos:







A 225/17 tire will of course fit on the same wheel.

outrunm

Those fit with just moving the parking brake tabs? This is looking more affordable already.

LouieM

Yes. Having a welder cut off the parking brake brackets and re-weld them to the tops of the trailing arms is a necessity at the rear. The function or action of the parking brake is not affected in any way.

Just as crucial is backspacing. I heard and read every informed and uninformed opinion under the sun about wheel width and backspacing for stock-fender C2s with factory fender lips, but didn't trust anybody until I saw an actual C2 with 245/45/17 tires on 17x7x4.75 backspacing rims. A friend CLAIMS that 17x8 wheels with 5.0 backspacing work on C2s, but I remain a skeptic until I can see it myself. Too much expense and possible bodywork damage to risk anything. The only times I've seen 8" wide rims on C2s, the cars were hardly driven and were basically for cruise-night shows.

With my setup of 235 or 245/45/17 tires, the tires rub on the frame rails at extreme lock, so they leave a shiny spot there. The tires NEVER rub on the frame in normal driving or autocrossing (see pics below). You will only notice the rubbing (via the steering wheel) when maneuvering in a parking lot, etc.

As you can tell, I'm very conservative when it comes to tire/wheel fitment on my precious 67 rag top, and the tire/wheel combo has to work in the real world as well as on an autox track.

If my wheel/tire combo pulled me through this episode of brain-fade, then I predict you will have no trouble with fender interference on the street:






Lou

outrunm

My first move after a disc brake upgrade on this is to install 17" TT2's and tires. I already planned on recessed trailing arms. After seeing your post I remembered an article from like 15 years ago in Corvette Fever about relocating the parking brake tabs.

This is going to be a long project. I am still fighting with the wife over putting it in the garage. Let's just say I've got the tip in for now.

dados66

Nice looking wheel/tire combo! I am considering this wheel size (17" x 7") and would appreciate some more details on your suspension setup. I like how well the tires fill the wheel wells...is your car with a stock ride height? Are you using offset trailing arms or just parking brake bracket relocation? I am trying to select a suspension kit (probably from Vansteel) and don't want a set of 17" wheel/tires that look like they "float" in the wheel well. The only one that looks like it actually lowers the car some (do you need to do this?) is the Street & Slalom Kit but I wonder if it's too stiff of a setup? I intend this to be a briskly driven street car and not for track use. It needs to look good and be able to transport my wife in reasonable comfort. The car is having a frame-off resto currently.

Also, I am interested to know how you are running a 235 series tire in front without it rubbing on the frame when you turn hard either direction? I had 205/60 tires in the front (on my stock 5.5 inch wheels) and they would rub the frame when turning at parking speeds.

Thank you for any advice/assistance!

LouieM

My 67 has stock ride height. I added Chevy F41 (heavy duty) springs front and rear when the original 40-year-old springs were too soft and let the body roll too much in autocrosses. If you have original springs on your car, maybe you’d be happy with a set of new non-F41 springs, for a smoother ride. I don't know if there’s a ride height difference between base and F41 springs, but someone here will know. I’ve relocated the parking brake brackets as the only chassis mod and I don’t use offset trailing arms.

I use Bilstein Heavy Duty (not Sport: too stiff) shocks and they work well on the street and autox course. I used QA1 shocks for one season, but they are too hard to adjust on a Midyear, so I sold them. I run the standard front sway bar that came with the car; I’ve tried various combos of thicker front bars plus a rear bar, but the car understeers too much for me when set up like that.

I would think seriously about a suspension kit, esp. if it lowers the car. The car doesn’t need to be lowered and suspension kits will add only marginally to handling while likely degrading the ride. During autocrosses this year I was often as fast or faster than a few C5s and C6s. I suggest looking at the Tire Rack site and seeing what tires are best at the qualities you want the most, or call them and get their advice. The right tires will do as much or more for you than a suspension kit IMHO.

My front tires definitely rub on the frame during parking maneuvers, but never when doing normal driving or autocrossing. This is not an issue as far as I’m concerned.

BTW the very best street tires I’ve had on my 67 were Nitto NT01 meats. They feel fantastic on the street and track; the car really feels planted. I can’t run them in the competition class I’m in now, but I would if I could. Despite their tread, they work in the rain too.

I hope this info helps.

Lou

65hihp

I found this tire size calculator very helpful when I was shopping tires for the 64.
https://www.tacomaworld.com/tirecalc

dados66

Thanks so much, Lou! That is very helpful to me in my planning. I am having the frame powdercoated and would really prefer not to have it "shined up" with tire rub after going to all that trouble. So perhaps the front tires need to be narrower...and/or I need to plan the offset of the wheel carefully to move the wheel out toward the fender a little. I just don't know how much.

In terms of ride height, I may be perfectly happy with a "mild" suspension kit such as this one if I don't need to lower the ride height. On the other hand, it is very hard to figure out how to avoid the car looking like the one below from the stl-vettes C2 wheel page--beautiful car, beautiful wheel/tire combo but the body just sits 1-2" too high in my opinion. Or do those fenders look like they have been cut for clearance?

Henry

65hihp

those wells are opened up and flared. How someone could think that is attractive, heaven only knows.

GTOguy

I dunno.....enough people think 24" wheels are attractive to make it a huge industry. Tattoos seem to be attractive, too, usually to the same folks who like the huge wagon wheels. Piercings and gauges in the ears, too. It's all subjective. Personally, not my style either, but...........

sub006

If tire companies hadn't kept their 70-series future secret, Chevy might have gone with flares, gotten an exclusive on Wide Ovals over two years in advance and made the C2 an even bigger win.

(Bill Mitchell would have thrown a kicking and pounding the floor tantrum about losing his trademark "beltline" on the Sting Ray!)

GTOguy

"Bill Mitchell would have thrown a kicking and pounding the floor tantrum about losing his trademark "beltline" on the Sting Ray!"...
And Frank Lloyd Wright insisted on designing the furniture for his houses.....he felt his clients were not as qualified as himself to understand the full scope of his art, and how it should be presented. I believe that both men were right. You can cut up a classic design all you want, but it doesn't improve it. It detracts. That said, I've seen some flared C2's on this forum that are absolutely wicked. But are also in another class.

LouieM

Henry,
Good luck finding the right combo for your car. I once put a fiberglass SSBC rear spring and matched shocks on my 67 and found the ride to be too floaty for me; but others like it. With luck, you'll find a car set up the way you want and see how it rides and handles. Maybe Vansteel will point you toward such a car around where you life.

Lou

dados66

Many thanks!

sub006

Some might agree that no '67 will EVER look as good as the Holy Split Window, which needs no dumb stinger hood to be the best.

But not me, I like 'em all, stock AND kustom. But then, they're just cars. Kool, but cars

And I did have the privilege or visiting Wright's Fallingwater masterpiece several years ago.

RJ1

I have 17 x 7 front and rear with 4 inch off set. Tires are Kumho Ecsta 225/50 front and 235/50 rears with offset trailing arms. Have Van Steel suspension front and rear. Four wheel coil over set up. Car lower slightly and no rubbing problems.

bcwaller

I have 16x8 w/ 4-1/2" backspace (0 offset) wheels on my car and have not had broken fiberglass. It can be close, depending on the exact tire and size. I used to have BFG 245/45/ZR16 Comp T/A R1 tires and they cleared the body just fine. There is a shiny spot on the frame from full lock turns, but no big deal. These were R1s and the car was driven hard (Willow Springs and Buttonwillow).

When I got the car back on the road last year, the 245/45 tires were really expensive so I went to 245/50 street tires. I test fitted them before buying. These are really really close to the body. I have them and will live with them, but would not go and tell you they are cool and no big deal.

I used to have 235/60R15 tires and they also shined the frame, but cleared the body with no trouble.

Go with the 235s and you will be very happy I'm sure.

jstewart10

Lou,
Do you have pictures of your car with the 235/45 tires on it?

thanks, jason

LouieM

Sure thing, Jason. Here are pics of the 245/17s on my car; you’ll have to imagine the tires 5mm narrower on each side, but that would pull the tires farther from the fenders, so not an issue.









Even in the violent maneuverings of autocrossing, the stock fenders are safe from the tires.



I hope these help. You do have to keep in mind that midyear bodies never, ever sit squarely on their frame, but are always ¼ to ½ inch off center, so don't be concerned if the tires on one side (esp. the rears) are closer or farther from the fender lip than on the other side.

Good luck with all this!

Lou