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Sun Jun 21, 2009 7:11 pm

I'm still undecided on the KYB's or Gabriels. I'm leaning towards the Gabriels this hour. wait an hour or so and I will be going with the KYB's.

Sun Jun 21, 2009 7:45 pm

Cheap shocks are bad economy. Almost as much as cheap Korean tires.
In the end, they cost more.

Wait a month and spend the extra $100 on the Bilsteins.
Or find a NAPA.

Sun Jun 21, 2009 9:04 pm

loogy wrote: There is another option that I would seriously consider.

I am running the NAPA brand shocks on my stock '84 I have to admit that I really like them. Now, you have to understand that I have always been one to promote and run very high end shocks, but these Gas Grand Fleet (Gas Series 60) shocks are really, really nice compared to the other cheaper shock options out there. In fact, I like them better than Bilstiens! Oops, did say that out loud?

Fronts are part # NS 76970 @ $40.09
Rears are Part # NS 76971 @ $40.09

Chris, good suggestion! Do you like these shocks better because the rebound dampening might be more controlled than Bilsteins? Have you tried these and shorter springs?

Sun Jun 21, 2009 10:05 pm

buildyourown wrote: Wait a month and spend the extra $100 on the Bilsteins.Or find a NAPA.

that's the thing,I don't have the cash and will not have the cash to buy the Bilsteins. KYB and Gabriel are my only choice from the tire shop I have my account at.

Sun Jun 21, 2009 10:33 pm

hiram6 wrote: Okay, let's continue the KYB discussion here. What I DON'T like about my current suspension is the amount of "dive" and "lift" I experience. By that I mean on braking my front end dives, and on acceleration (such as it is) I get front end lift. Is this attributable to my KYBs? Or are my springs to blame. I do have the stock 85 Westy springs which are a little higher than most vans.

My shocks are about 15 months old, less than 10K on them.

First of all, the name "shock absorber" is somewhat misleading. They don't actually absorb shock as much as they control energy. But since everyone calls them shock absorbers, so will I. However, keep in mind that the real job of the device is to control energy.

Shock absorbers have two distinct modes of operation, compression and rebound. Depending on the design of the shock, there are two valves attached to the shaft. These valves and the shaft rise and fall inside the shock body as a unit as the suspension of the vehicle cycles.

As the shock is extended or compressed, oil flows through these valves. The design of the valve(s) is what controls the speed at which the shock can extend or compress (damping rate). The damping rate is what creates the stiffness or the softness felt in the suspension via the shocks.

Most street shock absorbers have more rebound damping than they do compression damping.

To make matters even more complicated, shocks have valving that can react variably depending on the speed at which the suspension is moving. The variable speed valving means that you can have a shock that acts very soft at slow speed suspension movements (undulating bumps, braking, going slowly over speed bumps, cornering, etc.) yet can act very stiff during high speed suspension movements (expansion joints, speed bumps at high speed, washboard roads, etc.). It is also possible to have a shock that acts very stiff at slow speeds but becomes very stiff at higher suspension speeds. Don't forget that I am referring to suspension speed as the speed at which the suspension is ether being compressed or extended, not the actual vehicle speed.

Early shocks were progressive, meaning that the faster the suspension movement (actually the faster the shock absorber shaft speed), the higher the damping rate. In other words, the faster the suspension moves, the stiffer the shock becomes. The problem is that the rate of increase in the damping rate gets progressively higher than the suspension speed. The characteristics of this shock are such that at slow suspension speeds, the suspension is poorly controlled, while at high suspension speeds, the suspension is overly controlled.

Up until somewhat recently, modern shocks were considered linear. The valving in a linear shock allows the shock to maintain control at low suspension speeds while not over controlling the suspension during higher speeds. In other words, the shock's control characteristic is more linear to the suspension speed versus a progressive shock.

Modern day shocks have what is called "digressive valving". Digressive shocks are basically the opposite of the progressive shocks in that the faster the suspension speed, the softer the shock becomes.

With a digressive shock, your vehicle will feel firm/stiff on the smooth roads because the slow suspension speeds are when the digressive shock has the highest damping rates. But when you encounter a sharp bump, the suspension speed will increase dramatically. During this time, the digressive shock will exude it's softest dampening characteristics allowing the tire to comply with the obstacle. The digressive shocks give you the sporty, controlled feel to your vehicle when you want it, yet the softer, more compliant ride when you need it.

If you think about it, this is really what you want in a shock absorber because it allows the most control over the suspension while helping to keep the tires on the ground under all circumstances. Go into a smooth, fast corner with a digressive shock and the shock is stiff which helps control body roll. Hit a sharp bump in the middle of that smooth, fast corner (which dramatically increases suspension speed) and the shock becomes compliant to allow the wheel to go up over the bump without upsetting the body of the vehicle too much. If the shock had progressive damping characteristics instead, the vehicle would go into the smooth, fast corner and have to rely solely on the spring rate and anti-roll bar to prevent body roll. Hit a sharp bump in the middle of the smooth, fast corner with the progressive shock will get stiff very quickly resulting in the transfer of the jolt from the tire to the vehicle which would not only make for a rough ride, but also result in the tire being unable to maintain proper contact with the road.

I mentioned earlier that most street shocks have more compression damping than rebound damping. The reason for this is because when the spring in the suspension compresses, it stores up energy. Remember when I said that a shock absorber doesn't really absorb shock but rather controls energy? Well, all of that energy that the spring stored up during it's compression needs to be controlled during it's release or the result would be a very bouncy ride as the spring continued to store and release energy.

The reason that the compression damping is so much softer than the compression damping is because as the spring compresses, it naturally reaches a point where it has stored as much energy as it can, given the input from the wheel/weight of the vehicle. Compression damping is simply to help that spring find it's final energy storage point in a controlled manor. Shock damping can only do so much to help control the compression of the spring. With too much compression damping, the ride will feel harsh and choppy. With too little compression damping, the spring may actually compress to the point that the coils touch each other. Compression damping's job is help find that happy medium. With degressively valved shocks as described above, it is possible to have a shock that has stiff enough valving to have some real input into the compression of the spring at slow suspension speeds yet allow the spring to compress as needed at higher suspension speeds.

Low spring rates usually require more compression damping to help compensate for the soft spring's natural lack of compressive resistance. If the compression damping of the shock is too low for the given spring rate, the vehicle can exhibit excessive body lean in corners and nose dive during braking. This low compression damping rate combined with low spring rates can result in the suspension speed being too great during higher speed suspension movements. This can result in a bouncy ride and can even result in a harsh ride under extreme conditions.

At the same time, a low spring rate will generally require less rebound damping because the lower spring rate has less potential to store energy. With less potential to store energy, the spring has less energy with which to extend the shock. With a low spring rate and a high rebound damping rate, the spring can actually be held compressed for long periods of time resulting in a harsh ride, especially during road conditions where the suspension does not have time to recover, like washboard roads. Under these conditions, the suspension can actually by held in a semi-compressed state.

Conversely, higher spring rates can get away with less compression damping from the shock due to the spring's natural desire to resist compression.

However, higher spring rates need higher rebound damping to control the greater energy that gets stored by the higher spring rate. With too little rebound damping, the higher spring rate will simply override the shock absorber's attempts to control the energy. This results in a bouncy ride that feels out of control.

There is a whole lot more that I could say about shocks and springs, but I suppose now is a good time to sum up what this means to you and you KYBs.

I have not studied the KYBs closely enough to now the exact problem, but I am fairly certain that they suffer from not enough low suspension speed compression damping and too much high suspension speed compression damping (much like the progressive or maybe linear shock described above). To be honest, its been so long since I have driven a Vanagon with KYBs, I really don't remember what the rebound damping feels like.

When you combine your fairly low spring rate with the alleged (by me) too soft low suspension speed damping, you get can the conditions that you described - excessive nose dive during braking and lean upon corner entry. The lower spring rate could also be a factor in the harsh ride felt by some if the rebound damping in the KYBs is too stiff for the spring rate, but that's pure speculation.

If the rebound damping of the KYBs is too stiff for the spring rate, you would feel it most when the tires experience "dropping out". This would be when you encounter what feels like a bump in the road, but it's actually that the road surface drops. Like an expansion joint that sits 1" lower than the road surface. The high rebound damping rate will not allow the tire to follow the road because the spring is not strong enough to extend the shock fast enough. The result is a jolt to the vehicle body which feels like bump in the road.

Mon Jun 22, 2009 7:53 am

hiram6 wrote: This dive/lift is what I've had from day one with the KYBs though, so I don't know if it's the shocks or just how the van is.
My change to KYB's was for the same reason...KYB Gas adjusts's were recommended by the local FLAPS...Thet don't even adjust....should've known better
They did help with the dive, say when enyering a gas station...but otherwise the ride is a lot too harsh

Mon Jun 22, 2009 9:28 am

hiram6 wrote: Okay, let's continue the KYB discussion here. What I DON'T like about my current suspension is the amount of "dive" and "lift" I experience. By that I mean on braking my front end dives, and on acceleration (such as it is) I get front end lift. Is this attributable to my KYBs? Or are my springs to blame. I do have the stock 85 Westy springs which are a little higher than most vans.

My shocks are about 15 months old, less than 10K on them.

I have Bilsteins on as well and have the same issues and complaints as Hiram6. I would like to avoid the nose dive I experience in traffic and around town driving. When I get new shocks, I plan to get the Koni adjustables. 1621 has a good write-up of his experience with them.

Loogy - that is a nice write-up, thanks

Mark

Mon Jun 22, 2009 2:59 pm

I concur,great write up loogy. I went with Gabriels due to the fact that they will be here this Wed. and I will be having surgery very soon and need to get shocks on before I'm one handed. plus I'm a cheap. the KYB's would not have been here until the following Wed. and I'm going to a show that night (Robben Ford)and that Friday (Robin Trower),then surgery.

Mon Jun 22, 2009 5:02 pm

TSR53 wrote: loogy wrote: There is another option that I would seriously consider.

I am running the NAPA brand shocks on my stock '84 I have to admit that I really like them. Now, you have to understand that I have always been one to promote and run very high end shocks, but these Gas Grand Fleet (Gas Series 60) shocks are really, really nice compared to the other cheaper shock options out there. In fact, I like them better than Bilstiens! Oops, did say that out loud?

Fronts are part # NS 76970 @ $40.09
Rears are Part # NS 76971 @ $40.09

Chris, good suggestion! Do you like these shocks better because the rebound dampening might be more controlled than Bilsteins? Have you tried these and shorter springs?

Yes, the NAPA shocks have a very nice rebound feel to them when combined with the stock GL springs. THe compression feels pretty good with the stock springs as well. I have not tried them with anything other than the stock springs, so I can't really say how they would feel with something like a Weitec or H&R spring which have higher spring rates than the stock springs. My guess is that might feel pretty decent, but that really is a guess.

For the money, if someone had a set of Weitecs (which I know you have) or H&Rs, I would really be tempted to try a set of just the fronts to see how they feel.

Mon Jun 22, 2009 5:05 pm

Bruce Wayne wrote: I concur,great write up loogy. I went with Gabriels due to the fact that they will be here this Wed. and I will be having surgery very soon and need to get shocks on before I'm one handed. plus I'm a cheap. the KYB's would not have been here until the following Wed. and I'm going to a show that night (Robben Ford)and that Friday (Robin Trower),then surgery.

If you have the time, once your new shocks are mounted up, it would be great hear your opinion of them. Just like tires and paint color, everyone will have a different opinion about them, but the more reports we can gather, the better informed we will be in order to make future decisions.

Have fun at the concerts and good luck with the surgery!

Mon Jun 22, 2009 5:17 pm

loogy wrote: Bruce Wayne wrote: I concur,great write up loogy. I went with Gabriels due to the fact that they will be here this Wed. and I will be having surgery very soon and need to get shocks on before I'm one handed. plus I'm a cheap. the KYB's would not have been here until the following Wed. and I'm going to a show that night (Robben Ford)and that Friday (Robin Trower),then surgery.

If you have the time, once your new shocks are mounted up, it would be great hear your opinion of them. Just like tires and paint color, everyone will have a different opinion about them, but the more reports we can gather, the better informed we will be in order to make future decisions.

Have fun at the concerts and good luck with the surgery!

I don't really know anything about shocks,but I will let you know what I think. should have them installed Friday. better start hitting the nuts and bolts with the PB Blaster now.

Wed Jun 24, 2009 6:05 pm

got them today,will install Friday.

Wed Jun 24, 2009 8:48 pm

Loogy I didn't want to let this thread pass on without saying what an excellent writeup that was. As I said above I only have very general knowledge about the suspension stuff and reading that I learned plenty. First rate!

Thu Jun 25, 2009 8:13 am

Pretty good discussion there. I have a set of US made shocks that I put on my first 87 Vanagon a LONG time ago, maybe 1994 or so. I think they might have been Gabriels, possibly Monroe? They actually performed and lasted very well. (Still on there 100k miles later, but the engine exploded!) My main complaint was that they seemed to have no way to handle the extreme cold weather. At below zero temps, the first few miles felt like the suspension was SOLID! On long drives, it would smooth out after a while.
I think Bilsteins are over rated for normal passenger car use. Call it German tuner snobbishness maybe? Everybody in the automotive aftermarket world knows Konis are best and always have been. Too expensive for me, though.
I pretty much like the shock write up on the Bus Depot site. Ron has done a good job on this and I agree. His Boges and other premium German shocks probably are the best buy for 80% of us. I just bought the black Boges. First ones lasted 16 years and 120k miles. Not bad, really.
Al

Thu Jun 25, 2009 8:43 am

Bruce Wayne wrote: my two options for shocks from my local tire shop are:
Gabriel Supreme $33 each or
KYB GR2 for the front ,Gas Adjustable for the rear about $60 each.
anyone have any advice on these two shocks? good or bad?
going on a 85 GL with a poptop bolted on over the big sunroof. thanks

Nope.....

Konis

Internet sales

the pony is dead

Thu Jun 25, 2009 8:36 pm

put the new (Gabriel) rear shocks on today. the old Cofaps that were on there were toast. pushed them down and the stayed,no recoil at all. I could hear a squishing sound as well. basically anything I put on would have been an improvement. fronts tomorrow and then a test drive.

Thu Jun 25, 2009 9:31 pm

tencentlife wrote: Loogy I didn't want to let this thread pass on without saying what an excellent writeup that was. As I said above I only have very general knowledge about the suspension stuff and reading that I learned plenty. First rate!

Thanks, man! I really appreciate such kind words. As you know, it is sometimes very easy to write a book about something that you are passionate about.

Thu Jun 25, 2009 9:42 pm

Yeah, well, you get going and....and.....and....

Thu Jun 25, 2009 10:29 pm

Exactly!

And I forgot to thank the other guys who relayed kind words themselves. Thanks guys! And I'd like to thank my third grade teacher, Mrs. Detwiller, and my parents for supporting me through the hard times, and I'd like to thank the academy....

Fri Jun 26, 2009 1:06 pm

put the fronts on this a.m. it had KYB's on there and those were toast too. ride is much improved. can't really compare it to anything as I no nothing about shocks and the old ones were shot. the price was right for me as I could not afford Koni's or Bilsteins at this time.