Cold air Box 57 at 2012 Hershey Hillclimb

[David G.]

I thought that I was hearing things when Frank Buck told me that he wanted to run his restored 57 Cold Airbox Corvette in the Hershey
Hillclimb last weekend. He was originally going to run his vintage #3 57 F.I. race car, but decided instead to run his # 57 Corvette. The Icing on the cake was that he asked me to drive the # 3 F.I. car. The event was for vintage race cars from 1901 thru 1959. Franks' two 57s were the newest cars to run the event, Officially called the Grand Ascent at Hershey. It was a 2 day hillclimb, with a car show (The Elegance) on Sunday. The Elegance was a showing of cars similar to Amelia Island or Pebble Beach. Anyway, we each got to run about 17 runs in two days. The runs were very aggressive, despite the rarity of all of the cars. One of my favorite cars was an Allard with a Ardun Flathead, originally owned by ZORA DUNTOV.
The fast time of the weekend was a very powerful and very light Lotus. We placed 9th and 13th, but were some of the crown favorites. I think that it was the distinctive sound of an open exhaust V8 Corvette.
Although I still can't believe that the # 57 car was back in action after all of these years, It was amazing to see how well the car performed.
So much for rare cars just being museum pieces!! I will try to get some photos of the cars.

Dave Gray
Carlisle, Pa.
NCRS 3627

[David G.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Photo of # 57 car7377172300_5866d22141_b.jpg

[Bill H.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

I can't believe that they're still running the Hershey Hillclimb, I used to go to them like a million years ago.

Very cool to run both cars.

[David G.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

# 3 FI Corvette

[Bruce B.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Dave,

Thanks for the posting, very interesting and pretty cool stuff.

Bruce B

[Duke W.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

What specific tires are these cars on - make, model, size?

Duke

[David G.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

What specific tires are these cars on - make, model, size?

Duke

The requirements of this sanctioning body VSCCA are to run the type of tires that were
used when the cars were in active competition. The # 57 car was on 6.70 X 15 bias and the
# 3 car was using a tire of similar size. I would have loved to run the Hoosiers that are normally used on the # 3 car.

Dave
# 3627

[George J.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Dave,
that's great stuff. Thanks for posting. Can you post a larger version of the second photo, and maybe some more? Also, can you find out the details on the tires that Duke was asking about? Make, where bought, etc. Thanks.

George

[Duke W.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

The requirements of this sanctioning body VSCCA are to run the type of tires that were
used when the cars were in active competition. The # 57 car was on 6.70 X 15 bias and the
# 3 car was using a tire of similar size. I would have loved to run the Hoosiers that are normally used on the # 3 car.

Dave
# 3627

Are you saying you were running 6.70-15 reproduction bias ply tires? As George mentioned, I'd like more details - manufacturer and model.

Was there any evidence of tread chunking after the event?

My experience with the OE General Jet Aires on my SWC was poor. One day of hot lapping Kent caused noticeable tread chunking, and they didn't have much grip.

Back in the late fifties there were a few purpose built racing tires like the Firestone Super Sport 170T, and I think Goodyear introduced their Blue Streak Sports Car Special in the early sixties. Some guys ran Michelin X radials, so depending on how the rules are actually written, you might have more options.

I installed a set of 6.70-15 Michelin X radials, and they easily survived several more days at Kent over the next four years and lasted 47,000 miles before I replaced them with a set of 205HR-15 Pirelli Cinturato CN72s in 1968.

Duke

[George J.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Duke,
I am not sure you have seen, but the Pirelli Cinturato CN72 is now available in a V-rating. I think the "V" is for Very Expensive, this time. Do you know what the specs are for this tire, ie, is it's rev's per mile consistent with the Pirelli P4000's we now run? I couldn't find it on the website liested below:

http://lucasclassictires.com/pirelli_cinturato.html

George

[Duke W.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Wow... and they're right down the road from me in Long Beach. They're listed right on the home page of that site as "in stock".

The CN72 is about the same OD and revs/mile as the 6.70-15, so they are slightly taller than 215/70R-15s and about the same OA width.Assuming these "new" CN72s are constructed the same as originals, they are fabric, not steel belted. Early steel belted radials had a reputation for "sudden breakaway", and I can confirm this was the case with the steel belted 6.70-15 Michelins. Pirelli claimed that their fabric belt design had much more benign breakaway, and this was true, but the industry eventually learned how to make steel belted radials more benign at the limit.

I might be tempted to buy a set of these CN72s, even though they are priced like the Michelin XWX, but last fall I got one of the last sets of 225/70R-15 102V Firestone Firehawk PV41 police pursuit tires, so I'm set for life.BTW, I replaced the CN72s with steel belted 225/70R-15 CN73s in the mid-seventies, which were essentially the same in all dimensions as the 205HR-15 CN72s. They also had very similar tread patterns.

Duke

[George J.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Duke,
I was hoping you'd say you would buy a set. I didn't want to shell out that much on an experiment.
How were you able to use 225's on a mid year? I'm sure you've told us before, but forgive my memory.
Also, what would be the disadvantages of a fabric constructed tire compared to a steel belted one. For those of us that didn't grow up with the change over, all of this is a little confusing.

George

[Duke W.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

When I first installed the CN72s on the OE 5.5" wheels, I was not happy with their performance compared to the Michelins. They just weren't as precise in terms of steering response.

Pirelli's technical literature stated that proper wheel width for the newer wide tires was critical, so I took a chance and bought a set of '68 Corvette 7" wheels and remounted the Pirellis on them. The additional offset in the negative direction required that I shave down the fenderwell lips at the tops of the fenders, which I did. and I will never in my lifetime "restore" them. Of course, this has no effect on the external contour of the fender. You have to feel with your fingers or squat down to see that the horizontal lip has been shaved.

Pirelli was right. The car was transformed - the steering precison of the Michelins, more grip, and more benign breakaway characteristics. They worked absolutely great. I never ran across a another car that could keep up with me on twisty roads with those CN72s including one great dice with a 911S on California Highway 1 south of Big Sur on a glorious February day in 1971. Other than the two of us the road was practically deserted. I caught him, passed him, and easily pulled away. He couldn't keep up, and I know he was trying.

Being as how the replacment CN73s were so dimensionally close to the CN72s no further work was required to fit them. The only issue was both sets rubbed on the steering gear carriage bolt heads at full lock, which was not big deal.

As I said before, Pirelli claimed their fabric belted radials broke away less suddenly than steel belted radials, and that was true back in that era, but as time progressed the industry was able to soften the breakaway response of steel belted radials and Pirelli gave on fabric belted radials. The CN73 was steel belted, and it's performance and characteristics were at least the equal of the CN72 - maybe a little better.

Of course the V-rated steel belted CN73s had nylon cap belts, and this construction continues today on all radials with H and above speed ratings.

Duke

[George J.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Of course the V-rated steel belted CN73s had nylon cap belts, and this construction continues today on all radials with H and above speed ratings.

Duke,
I think that these CN72's are not steel belted radials from what I was reading. Would they fit a midyear with a 6" wheel like I am running without needing to modify the fenders? I'd love to be able to try these out, or hear opinions before spending $2,000 on a set of tires.
Great story of you and the 911S. These midyears are so under-rated when it comes to handling. I think that comes from people driving cars that are incorrectly set up. There are so many poorly set up Corvettes out there it tends to color people's opinions in the sports car world. In my opinion, of course.

George

[George J.]

Re: Cold air Box 57 at 2012 Hershey Hillclimb

Duke,
In addition to the question above, do you know what the aspect ration of the CN72's is? I couldn't find it anywhere.
Thanks,

George