Cutting down coil spring?

[camp9k]

Can I cut a Deaver linear rate coil to lower ride height? I don't want stock and 2.5 is a bit to high for what I want?

Thanks
John

 

[reynard101]

You could, but you may want to install the springs and see if the height settles a bit as you drive it.

Easy to cut the spring down. Hard to add back to it.

The spring also has some alignment to the upper and lower "bucket" that you may have to take into account.

 

[Doyle]

The spring rate will go up for every coil you remove. It will get slightly stiffer.

 

[dao1980]

Coils have gotten purty dern cheap these days..

Cut coils make me think of honda civics south of the border where you can't buy parts, and an acetylene torch is used to lower AND lift vehicles.

Though, I guess it is possible that 2.5"ers are the lowest non stock height spring all of the major vendors make these days?

 

[slowRoaner]

i bought some used 3.5" wh coils, thinking that they were 2.5". Had way more lift than i wanted, which also caused my caster to be out of its proper bounds. Needless to say, I didnt have much money at the time, and just wanted a lower ride height. So i cut the coils down, and now have 1.5" of lift in the front.

The spring rate did go up, but not significantly. If i recall, it increases by a ratio proportionate to the number of coils that you have. So if you start off with ten coils, and you cut one off, than your new spring rate will increase by roughly %10 of what the origional spring rate was.

With a bronco, you have to cut the coil on the bottom side, due to the factory fasteners on top. Bronco coil springs are also flat on the bottom, so when you cut the first coil off, you have to start the spring into the bottom cup, the force/push it into the upper bucket. This is because you no longer have a flat bottom mounting. And you have to do a full coil cut as well.

The first full coil you cut off the bottom will not gain you much if any drop. Maybe a 1/2". This is because the bottom coils is very close to the coil directly above it, and (in my opinion) has a primary duty to locate the coil instead of adding to the spring rate as the other "middle" coils do.

So i ended up cutting two full coils off, which droped her down to 1.5" of lift. I am running the taller 4" bump stops, so i only have about 1.5" of up-travel before im on bumps. So the increased spring rate(which i find to be comfortable) wasnt a bad thing for my situation with little up travel.

Overall, you get a goofy sitting coil apon mounting, that has no exact way of telling you how much lift you will net when its all said and done. Im still on these coils, but wouldnt do it again. They work, and have kept me driving and on the road, but im looking to get into another set when i get a chance. I will get some actual 2.5" lift coils or go big with 5.5" and make an adjustable upper mounting bucket to achieve my desired 2" of lift with some added droop.

hope this helps give you some direction on your coils.

Some other numbers i have found:

SuperFlex coils are: 190 in/lb rate
WH crawler coils are: 205/375 in/lb
WH regular coils are : 235:375 in/lb
BC broncos coils are : 250 in/lb

I couldnt get the 3.5" wh coils to touch bump before i cut them. Even when at max articulation, and alot of force on the front end. I want a coil that will be able to compress all the way to bump while off road, but give me some decent road manners as well. I think the Superflex JBG coils might be a little soft for the road, but are looking pretty attractive due to being single rate and giving me another inch of lift while still being able to compress to full bump.

If you want to trade coils for keeps, id be more than happy to pay for shipping both ways! ;D

slow



(and long winded)

 

[slowRoaner]

here are some pics

 

[Broncobowsher]

Cutting a coil spring will increase the spring rate. For a single rate spring it is fairly easy to calculate the change. The math if you want to play that game...
Lets call a 200 pound spring and say it has 10 coils. Apply 200 pounds, the spring compresses 1 inch. Or each coil compressed 0.1 inches.
Cut a coil off and apply 200 pounds and the remaining coils are the same material. Each coil will still compress 0.1 inches, but you only have 9 of them now. So the compression is 0.9". 200/0.9 (200 pound per 0.9") is the new spring rate, or 222 pounds per inch after going back to the per inch rating.

If I do this right, the formula goes something like
New rate = old rate / (new number of coils / original number of coils)

 

[jckkys]

I had a similar problem and wanted a 1 1/2" more hieght in front. The venders only had 2 1/2" lift coils so I went with TRW-Moog replacement variable rate coils for '78 Broncos. They call them cargo coils so the part # is CC814. They gave me about 1 3/4" lift. The rate is about 20 percent higher but the front no longer bottoms out and the stance with stock 4900lb. GVW rear springs is a lot less nose down. It doesn't look lifted. It just has a better stance. I just now found them on ebey for 80 dollars shipped. So they're not too expensive.

 

[camp9k]

Thanks for all the information! I will soak it all in when I get home tonight! JBG has some 1.5-2.5 coils but not in stock and have a pair of Deaver 2.5 sitting in the garage. I know I cant cut the top but maybe a little off the bottom. This is for driving in town and hunting so I want to keep it easy to get in and out of but more capable than stock.

 

[73azbronco]

Are there not any more places which do leaf spring repair and replacement? Surely they could do a really good job of dialing in your exact height for a nominal fee?