Cutting coil springs to lower 65
- Thread starter BillyD65
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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?
have you got the shelby upper arm drop?
blown65
Founding Member
For a street car I liked my 620's with the 1" drop built in. Was about perfect in height for my car.
iskwezm
10 Year Member
zookeeper
Founding Member
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
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.
on here multiple times whenever someone asked if they should cut their springs or not.
bdepedro
Member
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
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.
All true, but I like to start with a stiffer spring and a 1" drop, then see if I want to trim the coils.
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
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
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
http://www.thecarsource.com/shelby/restore/lowering.html
zookeeper
Founding Member
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.
66 Restomod
Member
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
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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