Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Ride of the Month Challenge!

1 - 18 of 18 Posts

·
Registered
Joined
·
507 Posts
Discussion Starter #1
Ok I have a 67 with a 302 in it. Stock gears (boy do they suck). So here is my question, I dont understand spring rate. Everybody on here usually recommends 620 from the posts I have read. I bought some lowering springs from CJPony before I knew anything about spring rate (568#). At the same time I did the shelby drop(arning). Now my car is sitting super low to the point that the tires are rubbing so I decided to go back to stock springs. I ordered a set of Moog off of Amazon.
Before I install these which i just discovered is 260 spring rate. I want to know how it will impact my ride. I read somewhere that the ride will be smoother. I am trying to get the stance right But I also want the ride to be comfortable.Right now with the lowering springs and the drop if there is a dip in the street the nose of my car scrapes he asphalt.
I understand the number represents how many poinds it takes to compress the spring 1 inch... I have stock leaf springs in the back
The car is a every other weekend cruiser,street car, no track time
So once again here is my question how will 260 spring ratte affect my ride comfort. Why is everyone so fixated with 620 spring rate
Hoping someone can answer before i install them so I know what I am up against.
By the way I dont know if it matters but you guys alwas say we need more info.
I have 235/55/17s up front and I plan on installing a "posi" rear end with 3.50 gears this weekend
 

·
Registered
Joined
·
21,335 Posts
Well "620" sounds cool. 620 refers to the diameter of the wire which is .620". Scott Drake sells this spring and according to their specs is rated at 600 pounds per inch. That's a stiff spring.

Part of the rubbing issue had to do with a couple things. The suspension geometry is not the best. It does the opposite of what you want, pushing the top of the tire out at the top under compression. This is positive camber gain, you want negative camber gain. Another issue is wheel offset. I have American Racing 15x7 that have lousy back spacing.

For a more sporting ride, I'd suggest the GT spec spring Ford used. It's a little stiffer and will lower the car slightly from stock. More involved would be doing the Arning drop which lowers the upper control arm 1". This will also lower the front by about 1/2". More importantly it improves suspension geometry and greatly reduces the amount it pushes the top of the tire out as the suspension gets compressed. Not to mention how it improves how the car drives!

I run the 620 spring on my 66. Yes it's a stiff spring and it's a spring I gave a lot of thought before using. I was avoiding it at just about all cost. So why am I using it? Well I have a full Street or Track suspension. There are no rubber bushings at all, steel bearings. One thing I never saw coming was exactly how much binding there was in the stock suspension with rubber bushings. The bushings add artificial spring rate. When I did my suspension I had put the GT spec spring it. The car was so soft with just a second person in the car I was on the bump stops or very close just sitting. The 620's work well on my car. Firm but not harsh. I agree with you, I don't think I'd want to use them on a stock suspension on the street every day. Some will have different opinions.
 

·
Registered
Joined
·
10,123 Posts
Ok I have a 67 with a 302 in it. Stock gears (boy do they suck). So here is my question, I dont understand spring rate. Everybody on here usually recommends 620 from the posts I have read. I bought some lowering springs from CJPony before I knew anything about spring rate (568#). At the same time I did the shelby drop(arning). Now my car is sitting super low to the point that the tires are rubbing so I decided to go back to stock springs. I ordered a set of Moog off of Amazon.
Before I install these which i just discovered is 260 spring rate. I want to know how it will impact my ride. I read somewhere that the ride will be smoother. I am trying to get the stance right But I also want the ride to be comfortable.Right now with the lowering springs and the drop if there is a dip in the street the nose of my car scrapes he asphalt.
I understand the number represents how many poinds it takes to compress the spring 1 inch... I have stock leaf springs in the back
The car is a every other weekend cruiser,street car, no track time
So once again here is my question how will 260 spring ratte affect my ride comfort. Why is everyone so fixated with 620 spring rate
Hoping someone can answer before i install them so I know what I am up against.
By the way I dont know if it matters but you guys alwas say we need more info.
I have 235/55/17s up front and I plan on installing a "posi" rear end with 3.50 gears this weekend
What’s the Moog number of the spring from Amazon?

ex-Global West GM
1991-1995
 

·
Registered
Joined
·
36,500 Posts
I agree with Huskinhano, stock GT springs, or something close to it, and absolutely do not use lowering springs with the Arning drop. The drop lowers the car about 5/8" as a side effect.

Here's the drop with stock GT springs-
745569
 

·
Registered
Joined
·
507 Posts
Discussion Starter #5

·
Registered
Joined
·
507 Posts
Discussion Starter #6
I agree with Huskinhano, stock GT springs, or something close to it, and absolutely do not use lowering springs with the Arning drop. The drop lowers the car about 5/8" as a side effect.

Here's the drop with stock GT springs-
View attachment 745569
Now you tell me...lol thats exactly what I did arning drop and lowering springs. I am putting stock ride height springs on tonight. Or should I just get an alignment
 

·
Registered
Joined
·
36,500 Posts
Springs, then alignment.
 

·
Registered
Joined
·
10,123 Posts
Ok I have a 67 with a 302 in it. Stock gears (boy do they suck). So here is my question, I dont understand spring rate. Everybody on here usually recommends 620 from the posts I have read. I bought some lowering springs from CJPony before I knew anything about spring rate (568#). At the same time I did the shelby drop(arning). Now my car is sitting super low to the point that the tires are rubbing so I decided to go back to stock springs. I ordered a set of Moog off of Amazon.
Before I install these which i just discovered is 260 spring rate. I want to know how it will impact my ride. I read somewhere that the ride will be smoother. I am trying to get the stance right But I also want the ride to be comfortable.Right now with the lowering springs and the drop if there is a dip in the street the nose of my car scrapes he asphalt.
I understand the number represents how many poinds it takes to compress the spring 1 inch... I have stock leaf springs in the back
The car is a every other weekend cruiser,street car, no track time
So once again here is my question how will 260 spring ratte affect my ride comfort. Why is everyone so fixated with 620 spring rate
Hoping someone can answer before i install them so I know what I am up against.
By the way I dont know if it matters but you guys alwas say we need more info.
I have 235/55/17s up front and I plan on installing a "posi" rear end with 3.50 gears this weekend
Moog 8306 has a 1519 load rating, a 262 lb/in rate and 0.6" wire diameter. It's going to be pretty soft.
We generally used a small block application at 0.67" wire diameter, which resulted in a 540 rate.
The stock style springs are quite bit less, but not as low as 260.

ex-Global West GM
1991-1995
 

·
Registered
Joined
·
5,629 Posts
Going from 560# to 280# should more than double the ride comfort, right? Or will it make it half as stable? IDK.

Before anything else, where is it rubbing? Taller springs ain't gonna fix it easily if its rubbing the front of the well. In that case changing the alignment might fix it but 235/55-17 is a hella lot of tire to squeeze in that hole with most any combination. Thats like modern Mustang size. Did they fit before with the sagging and worn out springs?
If your main concern is looks I'g get the BB springs then after a hundred miles or so start chopping 1/4 coil at a time till it looks like you want it to. With little room to spare you'll want the higher rate.

PS. Never trust Amazon's part x-referencing.

Well "620" sounds cool. 620 refers to the diameter of the wire which is .620". Scott Drake sells this spring and according to their specs is rated at 600 pounds per inch. That's a stiff spring.

/QUOTE]
That's some BS SD tomfoolery sales gimmick. A real 620# spring is ~.6875, the number of coils should determine wire size to get to the real in/lb#(in a perfect world)..
 

·
Premium Member
Joined
·
6,099 Posts
I'm running 620s, since 1993 now. I am older and would like a softer ride sometimes, but I don't want a boat-like ride. I considered 480s. But a taller tire sidewall and decent shocks keep me pretty happy. At least until I hit a new pothole that wasn't there before...
 

·
Registered
Joined
·
507 Posts
Discussion Starter #11
Moog 8306 has a 1519 load rating, a 262 lb/in rate and 0.6" wire diameter. It's going to be pretty soft.
We generally used a small block application at 0.67" wire diameter, which resulted in a 540 rate.
The stock style springs are quite bit less, but not as low as 260.

ex-Global West GM
1991-1995
GT289 so what does all of that mean in laymans terms "It's going to be pretty soft" what does that mean, using context clues I am assuming softer means a more comfortable ride the shocks and springs will do their job and soak up most of the impact? I am assuming harder means that a pothole in the road is like getting punched in the face...hard. Thats kind of what i have right nor if I hit a bump it currently makes my teeth chatter.



1 ofamillion,

Going from 560# to 280# should more than double the ride comfort, right? Or will it make it half as stable? IDK
Well if you dont know I definitely sure as hell dont know lol. As far as stability goes, I have an export brace, monte carlo bar, 1 inch sway bar (not currently installed) and frame connectors so I think I should be ok with stability lol

22GT
mentioned dont use lowering springs with the arning drop, which is my current situation.

Once again I am after 3 things
1)Knowledge on what spring rate means, softer , harder
2) how to make the ride more comfortable
3ride height

235/55/17 I thought this was a pretty common tire size
2)
 

·
Registered
Joined
·
4,901 Posts
235 is a little wide on these early cars, 225 is a better choice up front (assuming 8" wheels) and where most of us land, your looking at 10 mm wider or little less than half an inch. if a 1/4" more of clearance will fix the issue 225s are the answer. As for springs and spring rates, less is less. Personally, I would send the moogs back, they sound hella soft and order standard height GT springs unless you don't mind changing springs and want to see where the soft ones get you. I hate it so I would go for the right spring. If the ride height is too high, you can cut them down from there to find the sweet spot.

One last piece of advice, if you want to end your problems once and for all, call Eaton and tell them exactly what your dream is and they will send you the exact spring for your car. It won't be cheap but it will be right. They understand these cars. Spring rates vary across the cheap vendors, rate and ride height is a crap shoot, just search ride height on this forum and see all the complaints.

If someone says they got 620s or whatever rate and they lvoe it, ask which vendor and buy that vendor - across the cheap options its a crap shoot.
 

·
Premium Member
Joined
·
6,796 Posts
235/55/17 I thought this was a pretty common tire size.
Not for the front end of '67 mustangs. Even with optimum wheel backspacing it is both slightly wider and considerably taller than recommended. Especially combined with a lowered suspension it's well into the danger zone for rubbing.
 

·
Registered
Joined
·
507 Posts
Discussion Starter #14
Not for the front end of '67 mustangs. Even with optimum wheel backspacing it is both slightly wider and considerably taller than recommended. Especially combined with a lowered suspension it's well into the danger zone for rubbing.
oh its beyond the danger zone,,,, its official lol
 

·
Registered
Joined
·
507 Posts
Discussion Starter #16
So after reviewing all of the posts I have decided Im going from the current tires I have down to 215 45 17. Additionally I am going to Keep the MOOG Springs so that I can get real world experience on softer springs and develop my own opinion of them. If I dont like them or the ride height I can cut down the coils as someone suggested until I get the stance I want. Also I believe I read somewhere maybe here that when you cut the springs they get stiffer so I can get more real world experience into the whole soft vs hard spring rate.

Thanks guys I appreciate the insight. I will also look into eaton springs
 

·
Registered
Joined
·
10,123 Posts
GT289 so what does all of that mean in laymans terms "It's going to be pretty soft" what does that mean, using context clues I am assuming softer means a more comfortable ride the shocks and springs will do their job and soak up most of the impact? I am assuming harder means that a pothole in the road is like getting punched in the face...hard. Thats kind of what i have right nor if I hit a bump it currently makes my teeth chatter.
Yeah. IDK what you want. A (stock) vintage Mustang is not necessarily a comfort ride. A 260 rate where
a 480 normally resides is REALLY going to be a lazy ride.
There's more to it than mere coil spring rates. It's a steel-on-steel pivot on the upper control arm with bad
geometry and dubious strength and a horrendously inadequate, stiff and slow to react lower arm bushing.
A lot of the BAD is in the design of those two arms.(where handling, ride, etc. are the criteria)

The only thing good about stock Mustang control arms is......... no wait, there isn't anything. Maybe
coucours judged events.

ex-Global West GM
1991-1995
 
  • Like
Reactions: Huskinhano

·
Registered
Joined
·
507 Posts
Discussion Starter #18
Wow,,,, what a difference a few inches make ( thats what she said).....I took someones advice on here and took out the Moog springs and reinstalled my lowering springs, Then I went to the tire shop and got some 215/45/17 tires and,,,,, amazing,,, no rubbing the car didnt bottom out or anything. I also installed my KYB Gas adjust Shocks in the back , that could have helped as well but for the first time in 2 years I enjoyed driving my car,, i have an appt for the alignment shop on monday. Getting some eaton springs tomorrow, wondering if I even need them.
 
  • Like
Reactions: MUSTANG65FBK
1 - 18 of 18 Posts
Top