| Volvo 240 Suspension Page |
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UPDATED: March 21, 2023 CONTACT |
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If you have any comments or if you can help to improve this information, please email me. CONTACT
| As
a Volvo 240 fan who's owned and modified a lot of 240s going back over 30
years, I've collected a fair amount of suspension experience. This page
will try to address that. Please take it for what it's worth. The way I have done things may not always be the "CORRECT" way. Over the past 30 years much of my experience has resulted from EXPERIMENTATION and CORRECTING MISTAKES, which I think creates more valuable experience than just doing what others tell you to do. So feel free to experiment with suspension settings and parts so you can find what works best for your 240 and driving enjoyment. |
| Viewing Dave's Volvo Pages on MOBILE DEVICES Viewing these page may be best when your mobile device is set to view as a DESKTOP Site in your browser Settings menu. Try that and see. Thank you, Dave 
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| 240 FRONT SUSPENSION | ||||||||||||
  Back when i was fairly new into 240s, when I found the old rubber suspension bushings were suffering, I decided to follow the popular trend of replacing every bushing possible with polyurethane. And of course because I was going all in, some bushings got replaced with custom made solid rod ends, such as sway bar end links, torque rods and the Panhard bar.    My limited experience at the time didn't consider just how much noisier a 240 could become when you eliminate so much rubber damping. I really didn't mind the all of the extra noise and rattles that much. Now, many years later, I've changed my mind on some of those preferences. I still think polyurethane bushings are just fine for MOST places when you want to improve responsiveness, and my current 240 still has a number of them, but not everywhere like before. For example, I removed the clanky solid end Panhard bar and installed an iPd one with poly bushings, which is quieter. And I'll be staying with rubber bushings for now on the front lower control arms. I'm planning on installing of some Hybrid Adjustable Torque Rods from Kaplhenke Racing, which have rubber bushings on the chassis end. When that installation is complete, I'll include some photos in this page.
The Volvo 240 was equipped with rubber damped upper strut mounts. These mounts help to keep unwanted vibrations and noises from entering the cabin. The rubber in these mounts will eventually crack or fail as it ages. The old used mount in the first photo below had over 200,000 miles of use, but cracks and distortions began appearing in the rubber. These mounts can have serious failures if neglected long enough. In extreme cases the strut top can break through the damaged rubber and collide with the bottom of the hood.  
PERFORMANCE PARTS OPTION If your goal is to improve suspension performance, you might consider a serious performance strut mount instead of another rubber one. The mounts I installed below are the 240 Offset Spherical Mounts from BNE Dynamics. Included was the upper spring perch, which has BNE's Luxe Steer roller bearing. There are several benefits to using the special Luxe Steer roller bearing at the spring top. This bearing is located between the spring and top mount and can be seen in a photo below. Luxe Steer removes most of the load that is normally felt by the spherical bearing in the mount. This reduces side loading forces on your struts, increasing the dampening performance and service life of the strut cartridges, while reducing steering effort. INSTALLATION IN MY 1984 242 TURBO
I installed these BNE Dynamics strut mounts below along with coil-overs and Koni Sport dampers. These mounts are versatile, so they can also be installed with stock springs or factory style sport springs if that's what you prefer. More information about coil-overs for 240 can be found HERE. More information about Koni Sport dampers for 240 can be found HERE.   These strut mounts have a variety of adjustments and a number of variations are possible, ranging from nearly STOCK to very AGGRESSIVE. This is done by selecting which mounting holes to use for the three top mounting studs. As seen in the photos above, the RIGHT SIDE mount is marked "A" (it's engraved on the top) and the LEFT SIDE mount is marked "B." This RIGHT-LEFT configuration is the most common use, but these mounts can also be swapped LEFT TO RIGHT for even more configurations and settings if preferred. A more detailed list of configurations and options can be found in the BNE Dynamics site. SETTING UP MY MOUNT CONFIGURATION For the configuration I chose for my 240, I inserted the three top mounting studs into holes marked with TRIANGLES. This made it easy to set up without getting the holes confused. This TRIANGLE position is described as, "The preferred position for street cars using 2.5 inch coil-overs." That's my car. This position offers the maximum positive caster (approximately +3.0 degrees over stock) and a good range of negative camber. IS MORE CASTER BETTER? More information about the benefits of positive caster can be found in the Alignment section HERE.   There was no need to cut any sheet metal on my car, but additional negative camber can be added if desired by trimming some sheet metal on the strut tower (I didn't do any trimming for my installation). 
Here's a subject that needs some clarity. The 240 front strut housing was designed for the use of an OPTIONAL bottom spacer, which was used only when installing certain damper cartridges, which were too short to fit without a spacer. 
The first two photos below show the bottom of an early 240 strut housing. NO bottom spacer is present in these 1984 strut photos. This style housing was used until 1989. If you look closely you can see an internal retaining ring, which is set in a groove inside there. The strut damper cartridge is then inserted from the top and it rests on top of that retaining ring.   NOTE: This is a DeCarbon gas damper inside there (ABOVE) if you're curious. Here's a Bilstein HD strut cartridge being fitted in a pre-1989 strut housing. No bottom spacer is used in a 240 with the Bilstein HD cartridge and it fits correctly. The top gland nut (second photo below) is designed to be fully threaded down into the strut housing as shown. The Bilstein HD strut cartridge is too tall to fit correctly into a post-1989 strut housing (more info below), because the later housing uses a permanent spacer, which prevents the top gland nut from becoming fully seated.  Here's the removable Strut Spacer. Volvo PN 1229423 (this part is NLA).  SOME STRUT CARTRIDGES require a spacer and some do not. If you install a SHORTER cartridge and forget the spacer, the cartridge won't be tight in there and you'll know it from the rattling coming from your suspension. When a spacer is added as shown in this photo below the strut cartridge then rests on the spacer. The actual LIFT that this spacer provides is small. It's the same as the thickness of that wide top rim shown above, which is about 3.8 mm. 
SUBSTITUTE SPACERS: 
Since the factory Volvo spacers are no longer available, an option will be to try to find a used set. If that's not possible, a simple substitute could be used. Spring steel shims with an outside diameter of 45 mm combined to a thickness of close to 3.8 mm should work. Try these 45 mm OD spring steel shims from McMaster Carr, available in multiple thicknesses. 1 mm Shims: https://www.mcmaster.com/98055A346/ or 2 mm Shims: https://www.mcmaster.com/98055A576/ If you try these shims, please send me an email and some photos on how they worked out: CONTACT Late 240 Strut Housing 1989-93 PERMANENT (INTEGRAL) SPACER This permanent spacer makes installing some dampers a bit troublesome on a later 240. 
Sometime during the 1989 model year Volvo made a change to the 240 front strut housing for late 1989 240 and all 1990-93 240 models. This newer style strut then came on 240s with ABS. Volvo permanently added the spacer in the bottom. It is not removable. Apparently Volvo thought 240 owners would no longer ever need to install certain gas dampers. This photo below shows an attempt to install a Bilstein HD strut cartridge into a later housing. It's not working out very well because a Bilstein HD is too tall to be installed with that permanent spacer inside. The top gland nut will accept only a few threads, but it will not fully thread into the housing. 
Here's a discussion thread on this subject with more photos: https://forums.turbobricks.com/showthread.php?t=358034 So far it's known that the Koni Sport or Bilstein Touring strut cartridge will fit this later housing. Other cartridge brands are not fully known. If you decide that you must use a strut housing without the spacer, some later 240 owners have solved this problem by fitting early strut housings or by using coil-overs which are made using early strut housings.
The lower control arm and tie rod position becomes important when considering modifications to your 240 front suspension. If you plan to leave your 240 at factory height, your control arms and tie rods should be just fine as they are, but since so many people choose to lower the ride height, the position (or geometry) of these parts becomes more critical. Even if you only plan to use sport springs (i.e.: iPd), which will lower the car only a small amount, you should still pay attention to this. There are a lot of lowered 240s running around with poor front suspension geometry.  The control arm and tie rod should be HORIZONTAL at ride height. The ABOVE RIGHT image shows a lowered suspension with a Roll Correction Spacer. More on that below.   Here are some real world examples ABOVE of good versus bad control arm and tie rod position. Both of these cars are lowered and on the ground with suspension at rest. This first photo above shows pretty bad geometry. In the second photo a set of BNE Dynamics Quick Steer Roll Correction Arms have been installed to correct the geometry for this lowered 240. QSRC Spacers from BNE   I installed a set of these Quick Steer Roll Correction (QSRC) Arms into my 242. The set I installed is the first photo above. These have been revised by BNE since I bought mine and the newer style is in the second photo above. BNE also offers an optional version (shown below) which can be adjusted for STEERING ACKERMANN ANGLE. You can learn more about Ackermann in the Alignment Section HERE.   This QSRC device is meant to be installed on the bottom of your strut housing in place of your original ball joint mount. Originally your ball joint bolts to the ball joint housing, which bolts to the bottom of the strut. If a video will help you understand how this ball joint is removed, here's one: https://www.youtube.com/watch?v=k-wUVcp_31A  So then your existing ball joint bolts up to this new ball joint housing/steering arm exactly as it would bolt up to your factory housing. Your steering tie rod then attaches to the new steering arm instead of the old one.   TO CUT OFF or NOT TO CUT OFF the Old Steering Arm The old steering arm may get in your way when attaching or detaching the outer tie rod to your new QSRC arms. I prefer to use an impact driver to remove that nut. That method will not be possible if the old arm is there in the way. Removing the old steering arm from your strut housing is optional and it requires a certain commitment. If you decide to remove it, a sawzall with a new, sharp, fine-tooth blade will take it off in a few minutes. A QUICK NOTE ON THE BRAKE BACKING PLATES    These above photos show the installation of these spacers in a 240 owned by smoothdurban in Turbobricks. His build thread is linked below. For this installation the brake backing plates were kept in place (unlike in my installation). He found that the QSRC spacer arms contacted the backing plates, so you can see above that he "clearanced" the backing plates with some heat and a hammer. http://forums.turbobricks.com/showpost.php?p=6077897&postcount=139 ALIGNMENT TIME The instructions in the BNE site will tell you that you should get your toe alignment setting adjusted after installing these. You should prepare yourself, because the geometry changes brought by these arms will change the toe setting a lot. So YES, definitely get that adjusted. This photo below is the front tires on my 242 immediately after installing these. They went from 1/8th inch TOE IN (stock setting) to 4.8 inches TOE OUT, just like THAT! The QSRC arm geometry changes may not take all the blame, since it's possible the new camber adjustment setting might have also helped to increase the toe out measurement. So this might be a good time for you to learn how to adjust the toe setting yourself. If that interests you, CLICK HERE for the ALIGNMENT section.  This info below may help if you will be adjusting the toe setting yourself. Adjustments needs to be made with the suspension compressed normally. Car on the ground. But since getting under my car is tight, I set the tires down on some 6 inch wooden blocks. After installing these arms in my car and finding my TOE setting at 4.8 inches OUT, I wanted to see how much range existed when adjusting the tie rods. So I began by adjusting the tie rods all the way IN and measured again. This resulted in a setting of 1.5 inches TOE IN. Then I adjusted FOUR full turns OUT on each tie rod, which brought the setting to 1/8 inch TOE OUT. Now I was getting very close. Then I made some smaller adjustments. 1/4 turn IN on each side brought the setting to between 1/16 and 1/8 inch TOE IN (measured at the tread). That's a pretty good setting for a power steering car.  (PHOTO ABOVE): Here's how the final setting looked. Once done with your alignment setting, check your steering wheel position. It may need to be re-centered. 240 ALIGNMENT SPECS  The toe-in setting ABOVE for a power steering 240 like mine will be under "A-a" and is shown in millimeters. 3.0 mm ±1.5 mm (0.118 inch ±0.06 inch), which comes to about 1/8 inch ±1/16 inch.
  There are things you can do to improve the 240 chassis stiffness. Volvo thought of this too. Back in 1978 the 242 GT came equipped with upper diagonal suspension tower braces.  The 242 GT also came with lower suspension braces for one year (1978), which were similar in size to the upper braces. The lower braces bolted to the bottom of the cross-member at the front and to the bottom of the control arm bushing housing at the rear. Other than stiffening the front end, this appears that it was an attempt to better stabilize or strengthen that rear bushing housing. Variations of reproduction upper and lower braces are available from a few Volvo performance parts places. https://yoshifab.com/store/volvo-240gt-style-strut-tower-plates.html https://www.bneshop.com/products/240-strut-brace?variant=9741110277 https://www.wagonmeister.com/240-firewall-brace-set https://www.wagonmeister.com/s https://www.ipdusa.com/products/5051/GT-Strut-Braces-for-Volvo-IPD-103611 http://www.retroturbo.com/?product=volvo-240-242-series-flathood-adjustable-strutbar
240 BALL JOINTS Volvo used two different 240 front ball joint designs. MANUAL STEERING This ball joint below is PN 275117. It fits both the right and left sides. It was made for manual steering cars.  POWER STEERING Power steering ball joints (BELOW) are OFFSET FORWARD to provide an additional ONE DEGREE of positive caster. An increase of caster improves automatic centering in steering, however it will also increase steering effort, which is typically not noticed in a car with power steering. LEFT SIDE: PN 274118. RIGHT SIDE: PN 274119.  If you're interested in a good article of alignment basics, including detailed info on how Camber, Caster and Toe will affect handling, try this one: https://grassrootsmotorsports.com/articles/what-camber-caster-and-toe-handling-basics/ This article was originally published in the May/June 1997 issue of Grassroots Motorsports. 
I built my own Trammel Bar more than 30 years ago after learning about it in the book How to Make Your Car Handle, by Fred Puhn (images below).    I haven't had a reason to take a 240 to an alignment shop for toe adjustments since then. A Trammel Bar can be very accurate and it's easy to build using scrap parts. It's very easy and quick to use without needing a helper. The bar I built below uses an old u-channel extruded aluminum curtain rod part. It's very stiff, so it doesn't flex much. Total length is 60 inches. Plus I used a couple pieces of sheet metal and a metal ruler, all riveted together as shown below. It doesn't have to be made of metal. it can be wood also.   CHECKING TOE ALIGNMENT If I intend to adjust the toe setting, I find it easier to get under the car if the front tires are on some blocks. This can be pieces of wood, like shown here. The important part is that the suspension is settled and compressed as if it's on the ground.  When I want to check toe alignment, I begin by finding a consistent line in the tire tread (or you can scribe or draw a line with a marker while spinning the tire). You'll need to do this for both front tires and use those lines when measuring at the front and back of the tires.  With the tires on the ground or on blocks, place the trammel tool against the tires IN FRONT of them. Line up a part of the tool with the line you selected. Then measure the distance between width of the lines on your right and left tires. You don't need to know the total distance. Only that they are close to the same. One measurement is taken with the trammel bar FORWARD of the tires and one measurement taken BEHIND the tires. If you're goal is 1/8th inch toe-in, then the front measurement will need to be 1/8th inch less than the rear measurement.  
The toe setting below for a power steering 240 will be under "A-a" and is shown in millimeters. 3.0 ±1.5 mm (0.118 ±0.06 inch), or about 1/8 inch ±1/16 inch. 240 ALIGNMENT
Here are some similar Trammel Bars in use.   
Even if you still plan to visit an alignment shop, a tool like this will get you set up just right after replacing a rack or other front end parts and then you can verify your work at the alignment shop. Here a good page to read about DIY Alignment with more Trammel Bar pics: https://lugnutz65chevystepside.weebly.com/alignment-tools---easier-than-you-think.html And here's a similar method of someone using a very expensive professionally built Trammel Bar: https://www.youtube.com/watch?v=V3RsOYY5gK0 This looks like the bar he is using: https://www.amazon.com/Longacre-52-79620-79620-Toe-In-Gauge/dp/B001NNFZ2Q There are other methods, such as a string alignment. Long video here: https://grassrootsmotorsports.com/video/video-diy-string-alignment/ Using Toe / Camber Plates These are available and they seem to be fairly affordable, depending on options. DIY Alignment with Toe / Camber Plates https://www.youtube.com/watch?v=0PXA4immC18 |
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You might not know or care about Ackermann steering, since it's not something that can be adjusted or tuned in a 240. Not a stock one at least. But it's possible with this item below.  EXPLANATION: Taken loosely from wikipedia.org/wiki/Ackermann_steering,
Ackermann is the relationship of angles between your front tires when making a
turn. It can get more complex, but if you were to adjust your Ackermann angles, you would be adjusting the angle relationships of your tires, because the inside and outside tires in a turn need to follow circles of DIFFERENT sizes to smoothly roll across the pavement without one of the tires slipping or skipping. Rear tire Ackermann can become involved for cars with REAR STEER. It can get very complex. So if your 240 front suspension is stock, then your Ackermann angles are not adjustable. It is, however, potentially adjustable using this BNE Dynamics device below. This is the BNE Dynamics 240 Quick Steer Roll Correction Steering Arm. It does a few things. It attaches to the bottom of your 240 strut and replaces your ball joint housing, while at the same time adjusting your roll center to accommodate a lower-than-stock ride height. It provides the steering link to your tie rods and offers three different tie rod mounting locations, to allow an adjustment of steering speed or leverage ratio (your choice of STOCK, 20% faster or 35% faster). And it offers an adjustment for Ackermann steering changes as well. More info at: BNE_240-quick-steer-roll-correction If you want to see the write-up I did when I installed these in my 240, CLICK HERE.
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 Should you change the ride height of your 240? How? This question comes along often enough. You have to decide if you like your car at the original ride height (because you like it that way or you drive on unpaved or flooded streets?) or if it looks better and handles better if it's a little lower (and a little stiffer). Sometimes the road conditions in your area will help you decide, since lowering a car usually creates a more harsh ride and less under-car clearance. If you want to first determine or compare your existing ride height to factory original height, the 1981 New Car Features Greenbook lists the height of the 240 GLT, GL and GLE (at curb weight) from the ground to the center high point of the roof at 1427mm (56.2"). You should pay attention to your SUSPENSION TRAVEL. When changing or lowering your suspension, you need to consider if your car will have proper suspension travel. Lowering a car can have the result of reducing that travel. So pay attention to bump stops and if your shocks could be bottoming out before hitting bump stops. If you want to know how much suspension travel your car has, there's a quick and simple way to find out by placing a zip-tie on your shock tube and simply going for a drive. Here's a quick video showing how that's done. https://youtube.com/shorts/GTOm9mquYsM Keep in mind that if you lower your 240 (even a little) there can be issues with your front suspension geometry. But you're in luck. 240 front geometry can be now be corrected in a lowered car. CLICK HERE for the Lower Control Arm Section. When you decide you want to lower it, here are some options to consider below.
Most available sport springs will lower your 240 about 1.25 to 1.75 inches and will stiffen the ride by a small amount (maybe about 30%). iPd Sport Lowering Springs are by far the most popular sport springs in the U.S. for a 240. Other spring companies offering 240 sport springs: B & G Suspension, King Springs (Australia), Classicswede.co.uk (UK). These springs will be the same diameter as stock springs (about 6.5 inches wide for fronts, 5 inch for rears). Their UNINSTALLED length will be noticeably shorter than stock when you set them side by side (the front sport springs will be 4 to 5 inches shorter). This usually results in an easier job installing them. As mentioned, your ride will be a little stiffer with a sport coil, which can offer more responsive handling. It will be very important to use good struts and shocks, which will be able to control (properly dampen) a stiffer spring, or you'll suffer unsatisfying bouncing. Bilstein HD or Koni adjustable (yellow) shocks are considered a very good match to iPd sport springs. I'll include more information on these dampers and others in the strut/shock section below.
It's important to note that other numbers have been published on iPd springs since then and some separate testing has also been done over the years, resulting in a range of rates. Other measurements of iPd springs have been given as between 130 and 190 lbs/in. for front and between 120 and 150 lbs/in. for rear, so use this info along with your best guess. Here's a thread started in 2016 that began compiling measurements on many Volvo Spring Rates: https://forums.turbobricks.com/showthread.php?t=325739 This thread notes that ordinary STOCK 240 springs (not GT or HD overload coils) will generally measure about: FRONT: 80-95 lbs/in.; REAR: 90-115 lbs/in. Here's some math nerd stuff: Due to the position behind the axle, a rear spring rate on a 240 may be calculated using a motion ratio of about 1.5, which means a rear spring rate of 200 lbs will be equal to an adjusted rate of about 300 lbs. Real world "seat of the pants" feel may be quite different. Also sway bar thicknesses can alter the feel of springs to a point. If you're interested in a good article on Calculating Spring Rates, click on the image below. This article was originally published in the May/June 1997 issue of Grassroots Motorsports. 
  BNE Dynamics coilover pieces are shown above. Coil-overs are a GREAT choice if you have more money to spend on your suspension and if you want to be able to better tune your suspension. These offer a wide range of adjustment, allowing the use of a variety of standard, off-the-shelf coils in many different stiffness settings. And the upright threaded sleeve allows for considerable adjustment of ride height. Most kits will use standard 2.5 inch ID front coils and 5 inch ID rears, all of which are available in various lengths from a number of manufacturers. Choosing spring rates can be difficult for a beginner, so reading up on what others have done and what sort of uses they have planned for the car will help (street, track, etc.). If you plan to use springs stiffer than sport springs, keep in mind that you may lose your comfy ride. You can also ask a coil-over supplier for help if that supplier has experience with 240 springs. Coil spring sets are inexpensive enough that you can experiment and try something different if you change your mind. Springs come in various lengths and your spring length must also be chosen. This choice will be affected a little by your spring rate choice and of course by the choices you make about your ride height. The most common FRONT length for a 240 seems to be 10 inches for spring rates between 200 and 400 lbs. Stiffer spring rates and a lower ride height may allow for an 8 or 9 inch front spring, although a shorter spring will more greatly limit suspension travel. A 12 inch length will also be possible for many rates under about 250 lbs. There will be lots of ride height adjustment possible on that 6 inch tall upright threaded sleeve. Similar concerns will apply when choosing a REAR spring length. 11 or 13 inch lengths seem to be the popular choices for a 240. Again, there will be a few inches of height adjustment available with the threaded sleeve. When I purchased the below coil-over kit for my 245 Turbo many, many years ago (about 2004), I knew little, so I asked the builder for a spring recommendation. Based on mostly street use (it was a daily driver) and an occasional track-day, the recommendation given to me was as shown below, which seemed to work very well for me. FRONT SPRING: 2.5 x 10 inch, 200 lb. rate. REAR SPRING: 5 x 11 inch, 175 lb. rate. These spring rates were noticeably stiffer than the iPd sport springs they replaced.   Barrel Shaped Coil Springs Some spring suppliers offer barrel shaped springs. This is something you may want to consider for your front coil-overs for a bit of extra clearance between the spring and the strut. I now recommend barrel shaped 2.5 inch front springs after I found that my standard springs had a habit of flexing enough to damage the threaded sleeve in the below photo. Using a barrel shaped spring will improve this clearance. 
 So, will a barrel shaped coil interfere with the wheel/tire? NOT LIKELY. You can decide after looking at this photo.  Eibach and Hyperco (Hypercoil) both offer barrel shaped coilover springs in their catalogs. BNE Dynamics (Kaplhenke Racing) uses only barrel shaped springs with their coilover kits.
Or if you're handy, you can build your own set of coil-overs. Here are some resources for the DIY builder: 240 Coilovers: The Kyote Way DIY 240 Series Coilover Instructions https://forums.turbobricks.com/showthread.php?t=334283 Search the Turbobricks forum for more.
  There are people out there who will scream at you to never cut your springs! I think it's because there have been more failures from inexperience than great success. Yes, it can be a less precise solution, but it certainly can help for those on a lower budget, as long as you know what to expect. The key to getting it right is experience (or following someone with experience). Getting it right is definitely possible. The above 1983 245 is sitting on cut stock springs with 17x8's and 17x/9's and tires: 245/40-17's all around. It's cut roughly 3 coils (https://turbobricks.com/index.php?threads/classicswede-lowering-springs.337116/page-2).
And for more info on cutting springs, you can read the following threads. You may want to pay particular attention to posts from Tuff240, author of the above spring cutting tutorial. He has more experience cutting 240 springs than anyone else I know. So this is the best information I know on this subject: https://forums.turbobricks.com/showthread.php?t=310040 https://forums.turbobricks.com/showthread.php?t=337116 https://forums.turbobricks.com/showthread.php?t=165499 Calculating Spring Rates for CUT COILS 
For those interested in calculating the new spring rates for cut coils, it's a simple math equation, assuming you know the original spring rate. For example, looking at the above images, a factory 240 FRONT spring appears to have 7.5 active coils. Cutting off 2 coils (5.5 coils remain) will increase the spring rate by 36%. The math is: 7.5 ÷ 5.5 = 1.36. So if the original spring rate was 100 lbs, then the new rate is 136 lbs. A factory 240 REAR spring appears to have 8 active coils. Cutting off 2 coils (6 coils remain) will increase the spring rate by 33%. The math is: 8 ÷ 6 = 1.33. So if the original spring rate was 100 lbs, then the new rate is 133 lbs. This thread started in 2016 has compiled SPRING-RATE MEASUREMENTS on many Volvo Springs: https://forums.turbobricks.com/showthread.php?t=325739 This thread notes that ordinary STOCK 240 springs (not GT or HD overload coils) will generally measure about: FRONT: 80-95 lbs/in.; REAR: 90-115 lbs/in. The source for the SPRING RATE MATH above is this article on Calculating Spring Rates, which was originally published in the May/June 1997 issue of Grassroots Motorsports. |
Here is a factory high-pressure gas strut cartridge that originally came in a 240 GT, GLT and Turbo model. This was made by DeCarbon in France. The 240 Turbo also reportedly came with Boge high-pressure gas dampers, although the specific years is not known to me. These front struts were fitted in 240s without using a bottom strut spacer. These will not fit in a 1989 or later strut housing with a permanent spacer.  
BILSTEIN The Bilstein HD (B6) is the most popular aftermarket strut/shock combination when using sport springs on a 240. They will generally give pretty good damping with stock springs or with sport springs, however it was my experience that the REAR Bilstein HD shocks combined with iPd sport springs were a bit too soft for the heavier REAR of a 245. I had no complaints when using these with iPd sport springs on several different 242s or 244s, but if you plan to use springs that are stiffer than sport springs (like from iPd), then my recommendation is to NOT USE THESE DAMPERS. These front struts are to be fitted in a 240 without using a bottom strut spacer. These will not fit in a 1989 or later strut housing, which uses a permanent spacer.  Volvo 240 Front Strut Bilstein HD: PN F4-P36-0081-H0 Volvo 240 Rear Bilstein HD: PN F4-B46-0296-H1 The Bilstein HD is a high pressure gas damper. The high pressure gas chamber helps to prevent foaming of the damper oil, giving the advantage of more consistent damping during heavy use. The gas chamber is pressurized at 25 bar (about 350 psi) and this tends to force the shock toward the open position. This opening force is about 40 lbs, which may raise the ride height slightly compared to a non-gas shock. The Bilstein HD strut has an internal bump stop inside the tube at the bottom. It can be easily accessed by removing the nut on the bottom and threading the rod out through the top.This way you can trim down the bump stop if needed for a very low ride height. There are a number of videos. Here's one: https://www.youtube.com/watch?v=RU-p0qTNVIY  BILSTEIN TOURING (B4) NOTE: I have never personally used Bilstein Touring shocks, but most opinions I've read concluded they will offer satisfactory damping with stock springs, but poor damping when combined with any spring stiffer than stock, such as sport springs. Bilstein offers rebuilding and custom damping settings for their Bilstein HD's. https://www.bilstein.com/us/en/technology-and-knowledge/service/ If you plan to use springs in your 240 that are stiffer than typical sport springs, I would recommend either moving up to a higher level damper or having custom dampers created. KONI SPORT Koni Sport (yellow single-adjustable) struts/shocks are considered to be a higher level compared to the above Bilstein HD because of their adjustable rebound. These front struts must be fitted in a 240 with a bottom strut spacer. So these will also fit just fine in any year 240 when using a strut spacer, or in a 1989 or later strut housing, which has a permanent strut spacer.  The single-adjustable Koni Sport (240 front strut: PN 8641-1245; 240 rear shock: PN 26-1129) is adjustable for rebound stiffness (upward suspension movement). The compression stiffness (downward suspension movement) is not adjustable on the Koni Sport.  The adjustment on a Koni Sport damper will be made either internally (before installation) or with an external adjustment knob (depending on model). The Koni front strut shown above for a Volvo 240 is externally adjustable using a knob placed at the top of the strut. Turning the adjustment will be smooth, without detents. If you're setting it to full soft or full hard, I have seen a recommendation to leave the adjustment a few degrees away from the full limit to best protect the internal valve.  Koni Sport front strut adjuster knob shown above.
The Koni Sport front strut uses an external bump stop which is placed at the TOP. It will fit inside a coil-over spring. The bump stop can be shortened or trimmed down if needed for a very low ride height. The boot or dust cover is optional and it is often left off when installing a Koni with narrow coil-over springs because there's not much room. The barrel shaped spring in the below photo will usually offer enough room for the boot if you want.   
KYB SHOCKS I had only one experience with a set of KYB Gas-A-Just struts/shocks on a 244 with iPd sport springs many years ago. These were considerably cheaper than Bilsteins and came with a few positive recommendations from other 240 owners. I CANNOT offer a recommendation for these. These were noticeably worn out in 11k miles and I then switched to Bilstein HDs. GAZ 
Gazmatic International in the UK offers GAZ adjustable struts and shocks. GAZ GAI FRONT adjustable front strut inserts for Volvo 240 offer an adjustment range for rebound only, similar to the Koni sport front. GAZ GT REAR adjustable shocks are available in single adjustable (rebound only) or double adjustable. A double adjustable shock will adjust both compression (bump) and rebound stiffness from a single control knob on the outside of the shock body. 
Compression and Rebound Stiffness 
In simple terms, COMPRESSION DAMPING (or sometimes called bounce) will control the mass of the suspension as it compresses or closes the damper. Koni will tell you it makes compression stiffness non-adjustable in their yellow sport dampers because the mass of the suspension doesn't really change. REBOUND DAMPING controls the mass of the chassis as it extends or opens the damper. If you stiffen the rebound stroke, it can increase the response of the chassis to steering inputs, however as rebound becomes stiffer, less traction will be realized. So moderation is needed. Rebound tuning can help refine the breakaway characteristics or the balance of the car:
There are also higher-level DOUBLE-ADJUSTABLE dampers that will allow compression stiffness to be adjusted too. Koni and Gaz both offer double adjustable options. Tuning the compression damping is generally done at a more advanced level. If you know what you're doing, you can closely match the damper compression setting to your spring rate to improve the mechanical grip of the tire, but it's easy to go too far and degrade traction. This kind of tuning is done in track settings and not really something for a novice. Most street drivers will not really need double adjustable dampers. If you would like more reading on the subject of dampers, here's a good article originally published in a 1997 issue of Grassroots Motorsports. https://grassrootsmotorsports.com/articles/understanding-shock-absorbers-dampers-and-struts-h/ Over the years I've compiled some useful info below. If you can help improve or add to this information, please email.
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| Here's a good video on shock damping stiffness that will explain a lot for you. https://www.youtube.com/watch?v=rA0vz_bLrwg 19:30 - Damping rebound. 19:48 - Low speed damping. 20:28 - Mid speed damping. 21:40 - High speed damping. 26:39 - Single adjustable shocks settings. 26:56 - More front rebound. 27:56 - Too much front rebound. 29:37 - Too little front rebound. 31:31 - More rear rebound. 34:37 - Too much rear rebound. 36:30 - Too little rear rebound. |
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This image below from a 1990 iPd catalog caught the attention of many Volvo enthusiasts who wanted improved handling.  I have always considered a good set of iPd anti-sway bars to be a great first step in improving a 240 suspension. Every 240 I owned had a set. You can call it better handling, better grip, better road manners, etc. If you want your car to perform better on the road, part of that is how well your car inspires confidence in the twisties. Whether the car has too much body roll is part of that. Just don't go too far. Keep this in mind; Reducing body roll for the sake of just reducing body roll will not always make your car corner faster, however in most cases it will. One reason for doing this is that a flatter cornering car will most likely have more tire grip. For a 240, the front tire grip will usually be greatly improved by flatter cornering. This is because with the McPherson Strut front suspension design, the front tires lean over when the car does. Reducing that lean helps the tires to keep a better contact patch. Due to the live axle rear end, the grip of the rear tires on a 240 is not affected as much by body roll, but it can still be improved by reducing roll. This is obviously not a 240, but the suspension design is similar. This photo below will help explain how front camber can be affected by body roll with a McPherson strut front suspension. This below car is in a high-speed turn and the body roll is roughly 3 degrees. While the front left (outside) tire is doing its best, the suspension geometry allows the tire to pitch over a few degrees. The front right (inside) tire has a greater pitch of maybe about 6 degrees. Luckily that right (inside) tire isn't needed as much for grip, but still, losing any portion of a contact patch in a turn like this will reduce grip and it may increase understeer. The rear tires, of course, will have no change in camber angle due to the live axle design.  So if reducing body roll is good in most cases, will a car with NO BODY ROLL corner even faster? No. Your car has a suspension for more than one reason. Not just for a comfortable ride. Since roads are not perfectly smooth in corners, your suspension needs to flex to even out the changes as your tires struggle to grip when rolling over bumps or other surface imperfections. More suspension movement and more body roll will almost always also give the driver more information about when the car is reaching its limit. This can help explain why removing all of that movement will usually make the car suddenly less forgiving as you approach or exceed the traction limit in a turn. Even a far less-forgiving racing 240 had some body roll (not very much though). The ultimate goal is to find the right compromise to fairly serve your desired performance, comfort and road surfaces you'll be cornering on.  The rubber in your tires helps to even things out too, but their role in evening out surface imperfections is smaller. The springs and shocks help the most with this, but there will always be bumps which will momentarily lessen tire grip in a corner, and an ultra-flat cornering car won't absorb those bumps as well and can give an unwelcome surprise if you're near the limit. Stiffer anti-sways bars will also affect your comfy ride quality. A stiffer anti-sway bar will make your car corner flatter, but it adds some compromises. It will also transmit harsh bumps into the cabin a bit harder than a smaller sway bar would, especially in a corner when the bar becomes loaded. In most cases, a slightly harsher ride is a small price to pay for the improvement a stiffer anti-sway bar will usually offer. If you would like to learn much more on the subject of reducing body roll,and how anti-roll bars are designed, here are good articles, which were originally published by Grassroots Motorsports. https://grassrootsmotorsports.com/articles/lean-less-what-body-roll-and-how-reduce-it/ https://grassrootsmotorsports.com/articles/what-anti-roll-bar-and-how-does-it-work-handling-b/
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