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Rex, I'm puzzled by the size nomenclature of these repro tires.
The Goodyear vintage Bluestreak racing tires have sizes like 500-15, 600-15, 700-15, etc. I run 600 and 700 tires on my Grand Sport because there is wheel well room for them. The 700 tires are huge.. Vintage racers out here who race more normal C2s tend to run 500-15 all around because that's all the tire they can get inside their fender wells.
So how were you able to get 700-15 repro Goodyears to fit? Are these actually smaller (more narrow) than the currently-produced bias ply racing tire of the same size?
Also, I've looked at the Coker web page for the Firestone tire and can't tell if they actually intend it to be used in vintage competition or not. I tend to think it's a display-only tire. Do you know?
Rex, I'm puzzled by the size nomenclature of these repro tires.
The Goodyear vintage Bluestreak racing tires have sizes like 500-15, 600-15, 700-15, etc. I run 600 and 700 tires on my Grand Sport because there is wheel well room for them. The 700 tires are huge.. Vintage racers out here who race more normal C2s tend to run 500-15 all around because that's all the tire they can get inside their fender wells.
So how were you able to get 700-15 repro Goodyears to fit? Are these actually smaller (more narrow) than the currently-produced bias ply racing tire of the same size?
Also, I've looked at the Coker web page for the Firestone tire and can't tell if they actually intend it to be used in vintage competition or not. I tend to think it's a display-only tire. Do you know?
Jim
Hi Jim,
Yes I understand exactly what you're saying. However, please note that in my comments I said the 700-15 GY BS tires on my 67 were of 1970s vintage....................meaning that they are a set of original 1970s GY race tires. They were hard as a rock and being 40+ years young, certainly NOT for road use. Sorry if I wasn't clear in my comment. Goodyear's current 700-15 offerings are definitely LARGER than the ones I had displayed on my 67. On my #2 Gulf car from 5 years ago, I had the current version of GY BS with 600-15 on the front and 700-15 on the rear. They were mounted on a set of 8.5x15 magnesium TT D wheels and since the car was not flared, the tires protruded too far outside the wheel well body lines. Therefore I did not use them and actually sold them to a guy our in your neck of the woods. Don't remember his name but I DO remember shipping those huge tires wasn't economical.
How tall are those tires? I'm looking for between 26.5"- 27" tall. Anything shorter just won't fill up the wheel well enough.
Originally Posted by jim lockwood
Rex, I'm puzzled by the size nomenclature of these repro tires.
The Goodyear vintage Bluestreak racing tires have sizes like 500-15, 600-15, 700-15, etc. I run 600 and 700 tires on my Grand Sport because there is wheel well room for them. The 700 tires are huge.. Vintage racers out here who race more normal C2s tend to run 500-15 all around because that's all the tire they can get inside their fender wells.
So how were you able to get 700-15 repro Goodyears to fit? Are these actually smaller (more narrow) than the currently-produced bias ply racing tire of the same size?
Also, I've looked at the Coker web page for the Firestone tire and can't tell if they actually intend it to be used in vintage competition or not. I tend to think it's a display-only tire. Do you know?
Jim
==============================
I have heard it is a Display only tire.
I have been using Mickey Thompson Sportsman S/R tires for the last 8 years. Except for the 400 wear rating they have been great. Being 8-9 years old I do not trust them so I am in the market for new tires. I have researched tires for the last 2 years but find that anything the right size comes with hard rubber (400) except for racing tires and Avons/Michelins at $500 each.
I also had a problem with getting tires too small to fit the rear wells. In '09 I ordered for the front 25x10 R15LTs (girth 10.1, tread 8.8, diameter 26.1, rim 7-9, speed H) and for the rear 26X12 R15LTs (girth 12, tread 10.6, diameter 26.1, rim 8-10, speed H). I found when completing the new engine/rear end build and putting the body back on about a year later that the tires were visibly too small in the back. I removed the 26x12s and installed 28x12R15LTs (Girth 12.1, tread 10.4, diameter 28, rim 8.5-10, speed H).
FR 25x19R15, RR 28x12R15
From what I have seen the cobras do not use as large a tire on the rear as I have used.
I did have a set of Goodyear Vintage Sports Car Specials/Blue Streaks/Billboards (Cobra) on the car just before the Mickey Thompsons and they looked and handled great (but were illegal on the street). I had on the front 26.5x8-15 (girth 11, tread 7.9, diameter 26.5, rim 8) and on the rear 26.5x10-15 (girth 12.9, tread 10.2, diameter 27, rim 10).
For me, anything less than 27 on the rear does not look right.
OK, I'm now waiting for someone to say they found a set of tires with a soft compound.
Don't have any tire suggestions, Bill, but I do have an observation.
Comparing this picture of your GS:
...to a similar photo of our D&D, I notice that your car sits higher than ours.
Laying a straight edge on the high point of the rocker moulding in the picture, that straight edge intersects the wheels of our car approximately 2" below the wheel centerline.
The same test done with the picture of your car suggests the the intersect point is about 1" below the wheel centerline.
Our car runs tires which are 25.5" tall in front and 26.5" tall in rear; the proportions look right with respect to the wheel well openings.
I'm thinking that if you just lowered the frame/body of your car, you wouldn't need to resort to such tall tires for everything to look right.
As usual I think Jim is bang on the money and has put his finger on the source of your woes. I wonder also whether you have the correct spring rates fitted at the front? Was it originally set up for a big block?
Of course you're going to have to balance the compromise between ground clearance and getting the look right.
FWIW …...here is a photo of my GS as it currently is awaiting restoration. Sitting on Torq Thrust 'D's shod with BF Goodrich Radial T/A's admittedly not a direct comparison because it's a 3/4 view rather than a profile and it's a bit dark but it gives you a fair idea how the arches look fuller with a similar size to what you have been running. Don't intend using on the track either.
Front rim 8.5" x 15" Tyre 245 x 60 x 15 diameter 26.6" section width 9.8" tread width 8.0"
Rear rim 10" x 15" Tyre 295 x 50 x 15 diameter 26.7" section width 12.2" tread width 9.5"
I read this article and it reminded me of our recent discussions regarding, the Gulf Corvette, and the different tires we try to make look right.
Here is a fun article dealing with the Gulf car, Tires, and another one of my favorite cars. I'm sure there are other fans here who can appreciate this and enjoy it.
Don't have any tire suggestions, Bill, but I do have an observation.
Comparing this picture of your GS:
...to a similar photo of our D&D, I notice that your car sits higher than ours.
Laying a straight edge on the high point of the rocker moulding in the picture, that straight edge intersects the wheels of our car approximately 2" below the wheel centerline.
The same test done with the picture of your car suggests the the intersect point is about 1" below the wheel centerline.
Our car runs tires which are 25.5" tall in front and 26.5" tall in rear; the proportions look right with respect to the wheel well openings.
I'm thinking that if you just lowered the frame/body of your car, you wouldn't need to resort to such tall tires for everything to look right.
FWIW....
Jim
Jim, I have coil-overs all around and set the suspension on the front to get 2 3/4" ground clearance in the front (Headers) and in the rear avoid rubbing the rear wheel to fender on hard bounces. I would reduce the front except when I encounter a speed bump I have to crawl over it to keep from hitting. I understand the Stahl makes a set of equal tube length headers for our cars with the tube frame but have not done that yet. I could not find a picture of my car with the smaller rear tires but they were really obvious enough for me to buy new tires especially after taking off the Goodyear Blue Streaks. If anyone has a side view with 26" tires I'd like to see it.
The changeover to an Appleton/Sweet style rack happened at #039 and both #039 and #040 are known. It's safe to say yours is at least #041.
The changeover point to the 2nd style body happened around #050 but I don't have a specific VIN. I thought I could distinguish 1st/2nd body styles from the profile but I can't be sure. I think you're GS has the 2nd design body, putting it north of ~#050.
There is another detail to check. Look at your headlight covers. Does the fender peak extend an inch or so into the covers (1st body design). Or does the fender peak stop before it reaches the headlight cover (2nd design body).
The graphic listing D&Ds for which I have some information is just that.... a graphic. Those are not intended to be clickable links. Sorry.
Jim
Jim, the fender peak does not go into the headlight cover.
Jim, I have coil-overs all around and set the suspension on the front to get 2 3/4" ground clearance in the front (Headers) and in the rear avoid rubbing the rear wheel to fender on hard bounces. I would reduce the front except when I encounter a speed bump I have to crawl over it to keep from hitting. I understand the Stahl makes a set of equal tube length headers for our cars with the tube frame but have not done that yet. I could not find a picture of my car with the smaller rear tires but they were really obvious enough for me to buy new tires especially after taking off the Goodyear Blue Streaks. If anyone has a side view with 26" tires I'd like to see it.
I do understand the ground clearance issue. I assume your issue is header/collector clearance where the tubes pass under the frame, yes?
The early D&Ds have their own, unique clearance issues. The motor mounts on early cars place the engine (too) low in the frame. With a normal depth oil pan, our D&D has less than 2" ground clearance. The bottom of the scattershield has been trimmed by 1" to keep the clearance from being even less.
Here is the best, readily available picture I have of our D&D prototype with 26" rear, street tires. This was made before we had the steering geometry reworked by Guldstrand. In addition to fixing the horrendous bump steer, he lowered the car as part of his work.
When you do track days, you might consider lowering the front of your car just for the day. With that Nassau hood, your car will develop significant front end lift that can be partially mitigated by dropping the nose, creating a downward rake to the car.
Here's another picture of our D&D with 26" rear tires. Also prior to the lowering done by Guldstrand.
The tire/fender flare gap isn't as easy to discern in this picture. I posted it just because it gives me a giggle.
I was driving down the hallway of a casino for inside display. There are pictures on the wall to the right and the blast from the side pipes caused them all to shake and vibrate.
Such fun....
Sharp-eyed readers will notice the GS appears with two different KO adapters in these pictures. It now has a third (and final) custom set of adapters which give a GS-correct appearance.
As usual I think Jim is bang on the money and has put his finger on the source of your woes. I wonder also whether you have the correct spring rates fitted at the front? Was it originally set up for a big block?
Of course you're going to have to balance the compromise between ground clearance and getting the look right.
FWIW …...here is a photo of my GS as it currently is awaiting restoration. Sitting on Torq Thrust 'D's shod with BF Goodrich Radial T/A's admittedly not a direct comparison because it's a 3/4 view rather than a profile and it's a bit dark but it gives you a fair idea how the arches look fuller with a similar size to what you have been running. Don't intend using on the track either.
Front rim 8.5" x 15" Tyre 245 x 60 x 15 diameter 26.6" section width 9.8" tread width 8.0"
Rear rim 10" x 15" Tyre 295 x 50 x 15 diameter 26.7" section width 12.2" tread width 9.5"
Marty
A question regarding your wheels. What brakes are on your car ? Reason I ask is the clearance between inner wheel surface and the caliper. The PSE wheels are very close in fact so close that a bit needs to be taken off the caliper ribs for wheel clearance. If you have C-4 brakes on your GS how much clearance do the wheels have ? I considered this type wheel when I built my Mongoose a few years back but could not determine if that style wheel was big enough inner diameter to clear the calipers. Thanks, --- Ken
I do understand the ground clearance issue. I assume your issue is header/collector clearance where the tubes pass under the frame, yes?
The early D&Ds have their own, unique clearance issues. The motor mounts on early cars place the engine (too) low in the frame. With a normal depth oil pan, our D&D has less than 2" ground clearance. The bottom of the scattershield has been trimmed by 1" to keep the clearance from being even less.
Here is the best, readily available picture I have of our D&D prototype with 26" rear, street tires. This was made before we had the steering geometry reworked by Guldstrand. In addition to fixing the horrendous bump steer, he lowered the car as part of his work.
When you do track days, you might consider lowering the front of your car just for the day. With that Nassau hood, your car will develop significant front end lift that can be partially mitigated by dropping the nose, creating a downward rake to the car.
Jim
Jim/Bill just went out to see what my GS fleet has on it. The D&D chassis #049 has PSE bolt ons with 235 60/r15 GY Eagle GT's on front and 295 50/r15 on back. Front wheels are 8'' with 4''bs. Rears are 10'' width with 6'' bs. The Mongoose has PSE k/o's 8'' front 10'' rear with Mickey Thompson 28x12 on rear and 26x10 on front. They fill the wheelhouse better than the ones on the D&D. My D&D bay the way does not have the fender peak into the headlight covers. It starts right behind the cover. ---Nice talking about this stuff again !! ----Ken
FWIW: Our MAI GS came with the late C4 brakes (not Z06 or whatever it was) consisting of two pot PBR calipers and .8x12 rotors. Jeff L. had trimmed the caliper fins only slightly so they would clear the PSE wheels... probably like was done on your Mongoose
Early C4 brakes, single pot caliper and .8x11.5 rotor, clear PSE with lots of room to spare.
And if you are highly motivated (I was), you can even make up a C5-based brake system which will clear PSE wheels: C5 two pot calipers and 1.25x11.6 rotors:
The brakes are late C4, 2 pot callipers with 12" rotors and yes clearance was an issue. We needed to machine the calliper fins slightly to fit. When mounting/demounting the wheel to the hub it needs to be aligned so that the wheel weights will miss the calliper, its fine once fully home. Backspace on the rims both front and rear is 3.77". This is perfect for the fronts but, the rears run slightly proud of the wheel arch and ideally would be better at 5". With the rear small wheel arch extensions fitted as on car #004 it will be ok though. BTW the fender peak extends an inch into the headlight covers denoting 1st body design.
Regarding wheel weights..... if you look at the picture of the C5 caliper I posted earlier, you'll notice it doesn't clear the wheel by much. About .050", actually.
There isn't any room for tape weights. I had a lip machined into the inboard side of the wheel so I can use clip-on weights.
Last edited by jim lockwood; 03-26-2017 at 12:05 AM.
03-20-2017, 01:48 PM
Don't remember his name but I DO remember shipping those huge tires wasn't economical.
