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Discussion Starter #1
I searched (and read) every thread in this forum that had the word "tire" in the title but can not find my answer.

CAR:
1965 Sprint GT
Stock Suspension

PROPOSED WHEELS:
Rota (Panasport copies)
15" X 7"
30mm Offset
73mm Hub Bore
4x108 Bolt Pattern

TIRES:
That's my question!
I want to fill up the wheel well but I do not want them to rub
I like a taller sidewall but not super wide.
Speedo accuracy is not an issue.
I was thinking about 195/70/15 OR 195/75/15
It would be slightly wider and 1" to 2" taller
For example: I love the look of "alfarestore"s car shown in this post:
http://www.alfabb.com/bb/forums/showthread.php?t=28833&highlight=tires
I made the chart below to help my understanding of the sizes.

Tire Size Width Diameter Sidewall Rev/Min
155/80/15 6.1 24.76 4.88 840 Factory
185/50/15 7.28 22.28 3.64 933.5
185/55/15 7.28 23.01 4 903.9
185/60/15 7.28 23.74 4.37 876.1
185/70/15 7.28 25.19 5.09 825.7
195/50/15 7.67 22.67 3.83 917.5
195/55/15 7.67 23.44 4.22 887.3
195/60/15 7.67 24.21 4.6 859.1
195/70/15 7.67 25.74 5.37 808
195/75/15 7.67 26.51 5.75 784.6
205/50/15 8.07 23.07 4.03 901.6
205/55/15 8.07 23.87 4.43 871.3
205/60/15 8.07 24.68 4.84 842.7
205/70/15 8.07 26.29 5.64 791.1

I guess the question is; while keeping the tire relatively skinny how tall can I go without rubbing.

As always; Thanks in advance!
Tony
 

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Let me say right off the bat that I don't know the answer to your question.

And, I'll bet that nobody knows for sure - that no one else has used the exact combination of wheel offset, wheel width, spring height, shock stiffness, and tire size that you are envisioning. So, buy some tires that seem right, and cross your fingers.

I suppose you would learn a little by bolting the wheels to the suspension with no tires mounted. Support the suspension so that the springs bear the full weight of the car (a little tough to do in front). See how close the outer and inner edges of the rims come to the fenderwells and suspension components. Check the fronts with the wheels turned full lock L & R. This will give you some sense of how far the tires can extend beyond the rims.

You had asked: "...how tall can I go without rubbing?". I doubt the diameter of the tire will be the issue - I'm guessing that width will be the limiting factor. That is, you will first encounter interference between the outside of the sidewall and the inside of the fenderwell as you increase tire diameter & width. But again, how far you CAN go will probably require some experimentation.

In terms of filling out the wheel well - I have always had to shorten my springs to achieve a ride height that looks right. But again, that's the degree of freedom in the vertical dimension - interference will occur in the horizontal.
 

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Discussion Starter #3
Hopefully I'll get some replys like "I'm using the following size tires with a stock suspension and have no issues".

Maybe I'll get lucky!

A good assumption may be that if I take the 15" equivilent of "alfarestore"s 14" tires they should fit with no problems.

We'll see, but thanks for the input.

Tony
 

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Tony,

I can't speak from personal hands-on experience on the step-nose cars, but the experts I've talked with caution me: the rear wheel openings are flatter on top than the later GTVs and that causes clearance problems as the wheel well lip drops down farther than on the rounder, later cars.

So, overall width is critical, as is offset, which, of course, locates the the wheel laterally (further in or further out).

While drooling, I mean "researching", GTA reproduction wheels, I was told to avoid any wheel wider than 6" (which was the original size) and stick with a 185 section tire, max.

Personally, since you have such a nice, original car, I'd hope to see it remain original, with either the skinny steel wheels or a more proper vintage sized alloy. I've decided to see if I can live with my skinny OE wheels and some matching REALLY skinny tires. It was a tough decision, because these bodies look so sexy with Daytonas, GTA wheels, even Panasports and fatter tires. I figure I'll ask for a set of GTA wheels for Christmas and have them in case I succumb to tempation...:D

Post some more pictures of your progress!

Hope all is well!

Chuck
 

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Discussion Starter #5
Chuck,

I was looking for the Rotas as a fun wheel/tire set up to have in addition to the new skinny tires that I will be buying.

I'm going to put the "fun" wheels on hold for now.

Stock it is!

Tony
 

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Which (or whose) skinny tires are you thinking about?

I've been persuaded that it was common "in the day" to replace the OE 155/80R15s with 165/80R15s in order to obtain a slightly more relaxed cruise (since the 165s have a slightly larger circumference) and a bit more grip (since they're slightly wider). They're also somewhat easier to find these days, so I'm going to try a set.

My car's original owner/PO had managed to squeeze some 185/70s on the steel wheels, so going back to even the 165s is going to be interesting visually, and perhaps a handling improvement. (My spare is still the original 155 Pirelli).

Keep us all posted!

Chuck
 

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Discussion Starter #7
I just ordered 4 155SR15 Vredestein tires from Euro Tires in NJ.
$288.00 for all including shipping.
No way I'm paying the prise for the re-original tires.
 

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Good for you, vespaholic! I bought a set of the 155-15 Vredesteins for my Giulietta and love 'em. I understand that everbody loves the look of meaty tires but do you want to look at them or drive them? To lose that wonderful, light, responsive steering and feedback defeats the Alfaness built into these things. We should face it: 80 to 100 hp isn't going to overdrive 155-15 tires. All this says nothing about the fatigue inducing stress to steering and other chassis components that comes with larger tires. My 105 has out of scale 165-15s on it now courtesy of the PO. Unfortunately, they're wearing like iron. I might just have to make boat dock bumpers out of them anyway.

Mike Hollinger
Atlanta
 
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