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Old 08-27-2013, 04:40 PM   #1
TexasAxMan
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Default Suspension question

I have a '66 coupe with a SBF. Did the Shelby drop and installed 620 lb., 1" drop springs. It dropped way too low while driving around the neighborhood. I'm running 225-45R17's on the front on 8" wide wheels.

It's so low that your can't get your finger between the tire and the fender lip. Does this make sense to anyone? I wanted it low in the front, but not as low as it is. There is only 17 miles on it since being put back together ...

John's Mustang Parts sells stock height, heavy duty springs. Is that what I should switch to?

I'm afraid there is something else wrong, but I'll be darned if I can find it. I've had 2 buddies look at it and the consensus is that I have to change springs.

Any help will be appreciated.
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Old 08-27-2013, 05:03 PM   #2
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The Shelby drop will reduce ride height because it lowers the perch location by approx. half of the arm mount drop, so ~1/2". Then you add drop springs, that may or may not actually be 620lb springs, a lot of places list springs as 620's and they're actually like a 400-500lb spring max. So then they sit lower even still. You could have as much as a 2" drop in the front without realizing it.

Maier sells 500 and 600lb springs that are what they say they are, and they sell them uncut so you can adjust to the ride height you want. They're short enough to install without a compressor (uncut) but sit higher than any other spring I've used that was listed as a 1" drop spring.
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Old 08-27-2013, 06:59 PM   #3
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Thanks for the response.

I really want to take my kid to school in it on Friday, so I'm hoping the ones at John's are what they say they are. He's been pretty good to me, letting me return stuff after 30 days and always standing behind his products.

I expected 3/8-5/8" drop from the Shelby drop, but these springs would make a stocker drag the ground. I've also considered Grab-A-Track springs, heard good things.
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Old 08-27-2013, 07:52 PM   #4
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I find this confusing? this car has the Arning drop with 1" lower GT springs and it sits higher than some cars I have seen that just have old saggy suspension?

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Old 08-27-2013, 09:16 PM   #5
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Whats the offset on the wheels? 4.5"?
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Old 08-27-2013, 11:20 PM   #6
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I have the Grab-A-Trak .620" dia springs (which are ~540lb) and have done the Shelby drop on my '67fb. The front still sits a bit higher than I'd like, definitely not as low as you're describing. I'm planning on cutting half a coil or so when I get a chance to drop it to a more conventional ride height.
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Old 08-27-2013, 11:58 PM   #7
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Coupe, I agree. Love the stance of that car too.

Iskwezm, I believe they are 4.5 backspacing.

It had a great stance until the drive last Saturday, but started rubbing the tires, it seems that it just sunk. For $80 I'm gonna try the HD springs from John's, if too high I'll cut them.
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Old 08-28-2013, 02:47 AM   #8
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Quote:
Originally Posted by TexasAxMan View Post

Iskwezm, I believe they are 4.5 backspacing.
on a 8" wheel you should have a 4.75" BS and a 235/45/17 tire.that will bring the wheel in 1/4" and the tire is 10mm narrower
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Old 08-28-2013, 10:02 AM   #9
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Quote:
Originally Posted by Iskwezm View Post
on a 8" wheel you should have a 4.75" BS and a 235/45/17 tire.that will bring the wheel in 1/4" and the tire is 10mm narrower
That wouldn't solve a spring problem. After remeasuring, they are 4.75" backspacing. Also, a 235 is 10mm wider, not narrower.
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Old 08-28-2013, 11:30 AM   #10
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Quote:
Originally Posted by TexasAxMan View Post
That wouldn't solve a spring problem. After remeasuring, they are 4.75" backspacing. Also, a 235 is 10mm wider, not narrower.
oops, sorry i thought i read it was a 245.I put that same wheel/tire on another mustang with lowered coils(and cut 1 coil out)and didnt have any issues.How much negative camber do you have?

Can you measure the distance from the wheel center to the fender lip?

Last edited by Iskwezm; 08-28-2013 at 11:34 AM.
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