Spring rates

carl

True Classic
Back in May of 2019 I started a thread about what were the stock spring rates. This was due to the fact that the new Vic coilovers I got were way to stiff for my use on the bad local roads. The coilovers came with 165/225 springs. For my driving the stock spring rate was fine and as I had noted then the stock springs with one coil cut was very nice. I got a lot of great responses but the idea of what was stock was all over the map.

I realize that the Vic coilovers do not have rubber mounts like the stock and aftermarket struts and that obviously is a factor. Going to pull off a coilover today to measure the spring size and can then see what's available. Plan is to put the 165s that are on the front on the rear and just buy something less stiff for the front and see how that works.

I think some of my initial complaint was aided by the fact the coilovers were new and maybe had some sticktion in the operation as the ride does not seem as bad but it's still stiffer than I want. If I was doing track days or street squid driving I would probably leave them as is.

This is more an update on my original thread, not really looking for help. You are all certainly welcome to comment though.
 
The struts have a main spring which is 7" long and helper spring that is 3.5" long for a total of 10.5". I went on the Summit Racing catalog and they don't have what I want in a 7" spring but they do have 150 in/lb spring in 10". So I'm thinking of just chucking the helper spring. Also, if my physics is right, a longer spring will be effectively softer. Opposite reasoning of cutting stock springs makes them harder.

To recap, in the front, going from a 7" spring that's 165 in/lbs to a 10" spring that is 150 in/lbs....makes sense for a softer ride?
 
Hey Carl. First off....you have not said this...what DIAMETER springs do the Vicks coilovers use ?? i assume - but could be wrong - that Vicks use a standard "racing spring" in their coilovers. Which are available in a variety of length - AND diameters. So of course you will have to source the proper sized springs that you want.

The "racing springs" standard is always measured by the ID of the spring. In North America they are usually inch sized. 2.5" is the most common - likely what Vicks use. So measure the ID of your existing ones. By the way, 2.5" "racing springs actually measure a little OVER 2.5". By maybe a 1/16" or so. Of course other sizes are available - next common being 2.25" ID.

Then they are available in a number of lengths - which of course is always the free length. 8", 10", and 12" are the most common. Look around enough and you can find shorter or longer - or also 9" and 11".

Since you do not seem clear on this - a 2.5" racing spring rated at say 150 lbs/inch - will be available in several lengths. BUT...all will yield exactly the same stiffness and ride !! The only difference - and this is important - will be where lower spring perch needs to end up. So carefully choose the correct length so the lower spring perch ends up within its travel on the threaded strut tube.

Whether or not you will be able to chuck your helper springs will depend on a number of factors - like vehicle weight, chosen spring rate, chosen ride height, and the shock travel.

I would suggest that you try about 140 lbs/inch in the front and 165 lbs/inch in the rear. I am not familiar enough with the Vicks units to say what length springs you will need - and whether you still need the helpers. But i suspect about 9" or so.

Hopefully someone from Vicks will see this thread and chime in. They designed them so they would surely know.....
 
According to actual measurements on a professional spring dyno that a friend of mine performed, the stock spring rates are about 132 front and 212 lbs/in rear.
They have quite a constant spring rate for their normal working range, unlike the progressive lowering springs sold for the X1/9 that most people in Europe are using.
Obviously, racing springs are very constant in their rate as well.

Carl, since these stock rates are not that much lower than the coilover rates that you found too stiff, I assume that it is the shocks that you felt as being too stiff.
It is the shocks that mainly determine how stiff the ride of a car feels.
Are the coilover shocks adjustable?
 
Carl, I'm confused about the helper springs you mentioned. I thought the helper springs collapsed all the way down when a minimal amount of weight was applied. Therefore they don't contribute any spring rate, they just keep the regular springs from flopping around when the suspension goes into full droop.
Yes I understand that the collapsed height of the helper spring adds to the overall height of the spring stack, but you should have enough adjustability in your threaded tubes to compensate for that.
I'm surprised that you couldn't find a 7" spring that would work for you. There are quite a few folks out there that offer 2 1/2" springs, Summitt might not be the best vendor for springs. I may have some, I'll go take a look.
 
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The springs are 2.5" inside diameter. The length dimensions I gave are free length. 150lb was the lightest springs I could find and only for a 10" length from Summit. At the front, the threaded collars are about 1.5" up from the bottom so I assume a 10" spring without a helper spring would fit.

I did wonder if the shock itself may be the source of the stiffness and since I got the non-adjustable ones I'm stuck with what I have. My plan was to get the 150s and if that made no difference then I would assume it was the dampening rate of the shock that is the issue.

I don't know if anyone is playing with these struts so I feel like I'm on this quest by myself (with input from you guys). I'm willing to buy one pair of springs but unlike Weber jets I don't plan on a big collection of them! The Summit springs I'm interested in are about $65 each.

Ed has these struts on his car and they seemed fine, guess I'll have to go take another drive in his car.
 
I don't know if anyone is playing with these struts so I feel like I'm on this quest by myself (with input from you guys). I'm willing to buy one pair of springs but unlike Weber jets I don't plan on a big collection of them! The Summit springs I'm interested in are about $65 each.

I am watching this thread with interest. I also purchased the non adjustable coil overs from vicks. I lowered my car to where I think it looks good, which is probably to low. At this setting the car is really stiff. It handles great on smooth roads, but on our roads the stiffness hurts the performance. So last week I raised the car up just below stock ride height. This made the shocks operate much better. Still a little stiff. If these new springs work for you carl it would be great to here about it. What I would ultimately like to do is lower the car again with more compliance.
 
You might recognize the member that started a earlier thread about spring options (below). There were a few suppliers mentioned in that thread:
https://xwebforums.com/forum/index.php?threads/coil-over-spring-source.37100/#post-324956

In my experience with the non-adjustable coilovers from the source being discussed, the inserts ("shocks") are not stiffly dampened. In fact they are a bit on the weak side for my taste. And they wore out very quickly so they became very under dampened after a few miles, and are completely ineffective ("blown out") at this point. Therefore I don't think the harsh ride is due to the insert being too stiff. I imagine softer springs will help a lot, but as has been mentioned the urethane mounts and solid ball upper joint are a major issue with respect to the ride quality.

I attempted to get replacement inserts from the vendor of this product but could not get any response after several attempts, so I have to assume they are not offered separately. My research on the part number stamped on them found zero hits; very odd because I've never be unable to find some sort of reference to any part number, so I suspect possibly they were a single large initial batch and no longer made? However the coilover units are offered with other 'brand name' (adjustable) inserts, so unless the actual coilover bodies are made differently then perhaps replacement inserts can be located from those companies...if the part number can be determined. That would be a definite upgrade for these coilovers.
 
The springs are 2.5" inside diameter. The length dimensions I gave are free length. 150lb was the lightest springs I could find and only for a 10" length from Summit.

Hey Carl. Your search mojo was not working too well today......

Springs lighter than 150 lbs are readily available. Even from Summit. Go here:
https://www.summitracing.com/int/se...&keyword=Coilover Springs&kr=Coilover Springs

and use the filters down the left side. At a brief glance they have:
7" - 100lbs, 125lbs, and 150lbs
8" - 100lbs, 125lbs, 140lbs, and 150lbs
9" - 140lbs, 150lbs
10"- 125lbs, 140lbs, and 150lbs.

if you want other rates or lengths, there are plenty of other choices out there on the web. Easy to find anything you want....
 
OK, Carl, I took a look at my spares. All of my coil over springs are 2.5" but I don't have any 7" x 150#. I have 7" springs in: 200#, 325#, 340#, 400#, and 450#. I also have 8" springs in: 140#, 165#, 185#, 200#, and 450#.
The only springs I have in 150# are 6" tall. I bought these from Ground Control some years ago. Eibach made them for Ground Control. Some manufactures will custom make springs for you, but I doubt you want to go that route.
BTW: The 6" 150# springs are currently mounted on Koni's, set full soft, on the front of the orange '77 (with AC). The ride is good, but it's not very sporty. I would describe it as smooth and comfy. Maybe a front sway bar would help?
I did find some 8" X 150# springs reasonably priced made by Eibach.
https://accutuneoffroad.com/product/eibach-2-5-id-springs/
https://www.speedwaymotors.com/Eiba...er-Spring-150-lbs-in-2-5-ID-8-in-,325845.html
 
Not sure I want to go softer than 150, although I realized I'm shooting in the dark. Kind of like picking carb jets.
 
According to actual measurements on a professional spring dyno that a friend of mine performed, the stock spring rates are about 132 front and 212 lbs/in rear.
Going by this, and that typical aftermarket "sport spring" (i.e. street use) rates are often claimed as around 20% stiffer than stock, that would mean almost 160 lb front and 250 lb rear. The more you lower the ride height, stiffer springs may be needed to prevent bottoming out with larger bumps. These numbers aren't too far off from the rates you said came on the coilovers. So I'm guessing the springs are only a small part of the problem. To go softer in the front I imagine the 150 lb springs may be a decent choice.
 
For the ride height I like, the springs are hardly compressed at all, in fact you can turn the springs by hand when the car wheels are off the ground.
 
In my experience with the non-adjustable coilovers from the source being discussed, the inserts ("shocks") are not stiffly dampened. In fact they are a bit on the weak side for my taste. And they wore out very quickly so they became very under dampened after a few miles, and are completely ineffective ("blown out") at this point.

This is very disappointing to hear, as I was planning on buying a set for my Scorpion. Is there no warranty offered?
 
Have been running Vick’s setup with 225/275 spring rates. The ride is very comparable to my previous Koni Red setup. I might swap in a set of 165/225 to soften it up a bit. In my opinion the stiffness comes from the solid mounts more than the springs or shocks.
If I could mount them using the OE rubber mounts I would. Don’t think that’s possible without a bunch of extra work.
Overall I’m happy with the ride.
 
When running our kit very low you may be riding on the bump stops or be so close to them that you hit them constantly. This takes a firm ride and quickly makes it harsh. You can use a zip-tie on the strut to check for that. Should you be hitting and wish to maintain the ride height anyway then look to trim the polyurethane to get more travel. You can also remove the dust boot and run without or try to find an alternative boot. Ours have a very thick top. Any time you alter the bump stops you should check to be sure you won't fully compress the strut. It is recommended to have at least 3/8" extra strut compression.
 
When running our kit very low you may be riding on the bump stops or be so close to them that you hit them constantly. This takes a firm ride and quickly makes it harsh.
Good point. If I'm not mistaken I seem to recall theses coilovers are a little shorter than the stock struts(?), which would give a bit lower ride already. And there seems to be a good amount of travel on them, so I'm guessing the ride height would need to be extremely low before the bump stops hit?

While we have your input on this, please advise us on getting replacement inserts/dampeners for these coilovers. Can any of the upgrade ("adjustable") ones be installed in the housings that originally came with the non-adjustable "Hydrasport"? And how do we go about buying replacement dampeners? Thanks
 
Hey @carl,
I am around for the next couple of weeks... I would be glad to meet somewhere and see if we can measure how much weight it takes to bounce the front and rear... I have not ridden in your car, but mine seems to have a comfortable ride...

Could it be that my ride height is higher so I have more room to compress?
My car weighs more so it absorbs more?
Tire sidewall stiffness?



Ed
 
Ed, hopefully we can get together next week. Any excuse to get together for lunch. We could meet with Walter as he as the MWB coilovers on his X.

Zip tie on the strut shaft is an old motorcycle trick to check for shock (or mc front fork) travel.

The Vic struts seem to have lots of travel and as I said, I have it adjusted just enough to have the springs sit with no rattle so I don't think travel is an issue. Maybe I'm just a sensitive old man.
 
Aha...I put a zip tie on the front strut at full extension, let is down and sitting static got 2" of available travel...need further investigation!
 
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