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Cutting coil springs to lower 65

  • Thread starter Thread starter BillyD65
  • Start date Start date May 20, 2009
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BillyD65

New Member
Jan 31, 2006
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Mesa, Arizona
May 20, 2009
#1
  • May 20, 2009
  • #1
I'm replacing the upper A arms on my 65 and want to lower the front end 1 or 2 inches while they are out. Can somebody give me an idea how much to cut?
Thanks
 
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rebel65

Member
Feb 1, 2004
363
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17
SF Bay Area
May 21, 2009
#2
  • May 21, 2009
  • #2
i would get drop springs, once you start cutting stock springs especially old ones they don't hold the same amount of weight. your suspension will be relatively weaker. i cut some big block 1" drop springs however. but i don't need 750lbs springs, i figure after cutting 1/2 a coil it's still probably above 620? lol. but seriously i would go for some drop springs instead of cutting..

have you got the shelby upper arm drop?
 

blown65

Founding Member
Jul 7, 1999
1,938
4
39
Queen Creek Arizona
May 21, 2009
#3
  • May 21, 2009
  • #3
For a street car I liked my 620's with the 1" drop built in. Was about perfect in height for my car.
 
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68RCodeConv

New Member
Oct 2, 2003
345
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Houston, TX
May 21, 2009
#4
  • May 21, 2009
  • #4
I cut 1/2 a coil off of some Grab-a-trak 550 lb springs and it dropped it about 1.25".
 

iskwezm

10 Year Member
May 24, 2005
4,159
20
79
Rowland Heights,California
May 21, 2009
#5
  • May 21, 2009
  • #5
I cut 1 coil from my 620's and it dropped another 1.5-1.75"
 

coupe5.0

Founding Member
Oct 31, 2000
117
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16
May 21, 2009
#6
  • May 21, 2009
  • #6
Cutting coils will raise the spring rate. i cut one full coil off my stock 68 springs (pics are in link in my sig) and lowered it about 1.5- 2 inches.
 

zookeeper

Founding Member
Aug 25, 2001
3,415
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109
Rogue River, Oregon
May 21, 2009
#7
  • May 21, 2009
  • #7
I cut one coil off my stockers and it dropped it about 2". Since the stock '68 springs are so spongy, it made the spring rate much more liveable.
 

zookeeper

Founding Member
Aug 25, 2001
3,415
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109
Rogue River, Oregon
May 21, 2009
#8
  • May 21, 2009
  • #8
rebel65 said:
i would get drop springs, once you start cutting stock springs especially old ones they don't hold the same amount of weight. your suspension will be relatively weaker.
Click to expand...
Just wondering where you heard that?
 
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2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 21, 2009
#9
  • May 21, 2009
  • #9
BillyD65 said:
I'm replacing the upper A arms on my 65 and want to lower the front end 1 or 2 inches while they are out. Can somebody give me an idea how much to cut?
Thanks
Click to expand...

The best thing you can do is relocate the upper arm bolts 1" lower. Better stability, better handling, and it'll sit 5/8" lower without any adverse effect on ride quality.
 
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rebel65

Member
Feb 1, 2004
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SF Bay Area
May 21, 2009
#10
  • May 21, 2009
  • #10
zookeeper said:
Just wondering where you heard that?
Click to expand...

on here multiple times whenever someone asked if they should cut their springs or not.
 

bdepedro

Member
Nov 6, 2006
362
2
19
Outer Banks, NC
May 22, 2009
#11
  • May 22, 2009
  • #11
Just remember, it's better to cut less spring and have to cut more later than to cut too much. I would cut either 1/2 or 1/4 coil at a time and see how that affects your ride height and handling. Better safe than sorry. I cut 1/2 coil off of my 620 lowered Grab-a-trac springs and will cut another 1/4 coil off and that should get me where I want.
 

zookeeper

Founding Member
Aug 25, 2001
3,415
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Rogue River, Oregon
May 22, 2009
#12
  • May 22, 2009
  • #12
rebel65 said:
on here multiple times whenever someone asked if they should cut their springs or not.
Click to expand...
I hear lots of things on here as well, but you need to be more careful about what you repeat. I've dropped cars for over 30 years, so I'm speaking from my experience, not someone else's theory, and I can tell you flat out, there isn't even a grain of truth in it. Spring rates will increase if you lop off a coil, and that's because there are a couple of things that determine spring rate, one is the diameter of the wire used to make the spring. Larger wire equals a stiffer spring, just like sway bars. The other thing that makes a spring softer or stiffer is the number of coils. More coils means a softer spring, just as less coils means a stiffer spring. However, having said that, the difference is barely noticeable from the seat of the pants, in my experience (there's that word again) cutting one coil off an early Mustang spring takes it from waaay too soft, to merely too soft.
As for making the suspension weaker, how could it? Stiffer spring would make it better for heavier loads if anything, wouldn't it? Like I said before, advice on any internet forum can be a crapshoot, so be careful what you believe and even more careful about what you repeat as fact.
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 22, 2009
#13
  • May 22, 2009
  • #13
zookeeper said:
Spring rates will increase if you lop off a coil, and that's because there are a couple of things that determine spring rate, one is the diameter of the wire used to make the spring. Larger wire equals a stiffer spring, just like sway bars. The other thing that makes a spring softer or stiffer is the number of coils. More coils means a softer spring, just as less coils means a stiffer spring. However, having said that, the difference is barely noticeable from the seat of the pants, in my experience (there's that word again) cutting one coil off an early Mustang spring takes it from waaay too soft, to merely too soft.
As for making the suspension weaker, how could it? Stiffer spring would make it better for heavier loads if anything, wouldn't it? Like I said before, advice on any internet forum can be a crapshoot, so be careful what you believe and even more careful about what you repeat as fact.
Click to expand...

All true, but I like to start with a stiffer spring and a 1" drop, then see if I want to trim the coils.
 
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RollinOut

New Member
Sep 18, 2006
10
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Phoenix, AZ
May 23, 2009
#14
  • May 23, 2009
  • #14
BillyD65... I opted for the same thing @ 8 years ago on a '67. Had stock V8.
I pulled the driverside spring, cut 1/4 of a ring off, put it back on, drove it around the block hitting all the right bumps & driveways to settle it in, and then took a look. after 6 attempts, I had it lowered perfect on the driver side, "one finger"... not quite tucked in. Then I pulled the Driver side and cut of total = to the drivers side - 1 1/2".

worked great, looked great, but you will sacrifice suspension performance. Im a cruiser, so not a big deal for me. Because the spring rate was set for a factory ride height with the factory suspensin travel (I rebuilt front sus. withe oem parts, nothing special) I found the front would bottom out easier, specially while turning.

Best bet is to do like the others - 1" drop or 620 springs.

On the new 67 I building now, I got rid of all that and went with the TCI Mustang Custom front end... love it! car sits nice & low in front, looks great and has the firmness not to bottom out. Plus a power rack & I got tons of room in the eng comp. Im also fabricating a boilt in core support like the Tri-5 & camaro... so dropping in the engine is so easy. Its pricy, but if you have access to a 240v Tig & plasma cutter, you can have it in in a weekend easy and save a ton of cash.

anyway, went off topic a bit.

-Mike
 
2

2+2GT

10 Year Member
Apr 25, 2009
3,333
10
79
Southeastern Pennsylvania
May 23, 2009
#15
  • May 23, 2009
  • #15
You can't beat relocating the upper arms down 1" for cost-effectiveness. You drill four holes and reassemble the car. The only cost involved is a wheel alignment, and if you are replacing suspension parts, you'll need that anyway, so the mod is free. Makes a BIG difference, and as i said, lowers the front 5/8" as a side effect. With a good spring compressor, you can have the whole job done Saturday morning before lunch, then carefully drive over for wheel alignment. Special springs etc. are really nice, but this is more than enough to satisfy the performance goals of most, and you don't even have to sacrifice ride comfort or suspension function. Holy cow, it doesn't get any better than that.



http://www.thecarsource.com/shelby/restore/lowering.html
 

zookeeper

Founding Member
Aug 25, 2001
3,415
63
109
Rogue River, Oregon
May 23, 2009
#16
  • May 23, 2009
  • #16
I agree, you really need to drop the A-arms first. Not only does it drop the car ( I measured 3/4" of drop on mine) but it greatly reduces body roll. From there you can decide if you are happy with the look and feel or if an additional drop is what you want. There is absolutely no downside to dropping the A-arms. The tires wear more evenly, the car handles better and ride quality is unaffected, plus, it's free. Free is good.
 
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mtlman22

Member
May 14, 2005
89
2
6
NY
Jun 29, 2009
#17
  • Jun 29, 2009
  • #17
what end did you cut the spring on?? top or bottom?
 
M

mtlman22

Member
May 14, 2005
89
2
6
NY
Jun 29, 2009
#18
  • Jun 29, 2009
  • #18
anyone have any alingment issues afterward?? all my adjustments are maxed out and its still just out of Spec!
 

66 Restomod

Member
Jan 2, 2007
203
0
16
Raleigh, NC
Jun 29, 2009
#19
  • Jun 29, 2009
  • #19
Cutting a portion of the coil (don't cut the flat end or top, cut the pigtail or bottom) will give you negative camber and also affect the toe. I just cut a 1/3 of a coil from a pair of one-inch-drop 620's and the front dropped another 3/4". The alignment added -.4 degrees of negative camber with that change. I also recommend swapping out the rubber bushings in the spring perches with greased polyurethane ones. That change made a huge difference allowing the upper control arm to freely move with the bumps in the road and I think they were only about $20.
 

66 Restomod

Member
Jan 2, 2007
203
0
16
Raleigh, NC
Jun 29, 2009
#20
  • Jun 29, 2009
  • #20
I should mention that if you have the upper control arms out you can add or remove shims from the front and rear thru-bolts of the upper arms. This will affect camber and caster. What part of your alignment is out of spec? And which specs are you using?
 
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