single adjustable shock-compression or extension adjust?

[High Plains Mopars]

I've been shopping around for a single adjustable shocks and notice there are some that offer compression adjustment and others that offer extension adjustment. What are some pros/cons of the two different approaches in a street application? Does that criteria change when used in an autocross where transitional control is of huge importance?

[Bryce]

compression

short answer I know. I will add more later.

[79T/Aman]

Who offersa compression adjustable only shock? most are rebound adjustable

[68sixspeed]

QA1's are adjustable on compression. (on my 68)

[JRouche]

Well beyond the scope of my knowledge but I would think if I had to pick one I would want it adjustable in bump. I just picture the bump as being the more active side of the stroke and I would want more control over that. Ideally it would be double adjustable. Cause on rebound the springs will want to slam the tire back down pretty hard. So maybe they have a fairly stiff valve for rebound on a single adjustable shock. Are the DA shocks that much more? I think I had to pay an additional 200 bones (maybe less, I forget) per shock for mine. They are air ride tech spring/shocks (shockwaves) though. JR

[The WidowMaker]

maybe mark will chime in, but i thought that the CA single adjustable adjusted both the bump and rebound. the doubles allowed them to be adjusted seperately, but the singles still did both at once.

Tim

[79T/Aman]

I need to look into the single adj. more but 3 way shocks adjust the rebound but wher some get confused is how they are listed in comp/reb. %, the comp. stays the same it's just the % from comp. to reb. that changes.

[BMR Tech]

QA1's are adjustable on compression. (on my 68)

QA1 single adjustable (Stocker Star) shocks change both compression and rebound at the same time when they are adjusted. This is fairly typical of most single adjustable "Street" shocks as Tim mentioned earlier.

[High Plains Mopars]

Who offersa compression adjustable only shock? most are rebound adjustable


Spax and Afco both offer shocks in single adjustable models that can be made in either compression or rebound modes.

Yes, double adjustables certainly are the schiznit for the application, but at $150-200 more per shock, that is just a bit hard on the budget right now.

So QA1 have an incremental increases on both rebound and compression for each click. Is that a more reasonable performance compromise to having a shock with one mode with fixed valving and the other motion adjustable?

[Marcus SC&C]

Almost all single adj. shocks are rebound only. This applies to both onroad and offroad. QA1 and Chassisworks Varishocks are exceptions and both adj. compression and rebound. The DA versions of both obviously adj. comp./rebound individually. The QA1 use linear curves, Varishock are progressive/digressive which I find gives them more usable settings. It`s hard to explain well in this "online post it note" format but it makes them a little like a poor mans double adj. by altering the comp. and rebound rates differently at comparable points in their respective curves. A little dampening slight of hand as it were. ;) Mark SC&C

[68sixspeed]

QA1 single adjustable (Stocker Star) shocks change both compression and rebound at the same time when they are adjusted. This is fairly typical of most single adjustable "Street" shocks as Tim mentioned earlier.

you are correct, I thought of that after posting!

[amx2334]

QA1 Proma Star, Stocker Star, Pro Coil are compression and rebound.
QA1 Ultra Ride, Aluma Matic, Street Star are rebound only.

[High Plains Mopars]

Hadn't look at Vari-shock before. Very nice set up. I really like that they have a variety of lenghts to fit non stock ride heights. That is very cool since my car sits quite a bit lower than stock and the twin tube design should be decent for the street. I'd like to find some more technical info on them since their online catalog kinda sucks.

Another option I came across is Strange. They have a double adjustable mono-tube shock for around $250. That is considerably lower than any other double adjustable I've seen out there and jsut a little bit more than most single adjustables. Anyone have any expereince with Strange?

Something I've also noticed in a couple of catalogs in a price difference in drag shocsk vs an ovaltrack or road race shock. I could see this in a single adjudtable version, but if you have a shock with double adjustable options, what would the big differences between a drag shock and oval track shock be?

[Marcus SC&C]

Feel free to give a call for more info on the Varishocks. We`ve been using and selling them for quite a while now so we know them very well.

I haven`t used the Strange shocks but as a rule nothing violates the old standby that you get what you pay for, ;)

The difference between the ranges of adjustment. Ie. if a drag shock may allow less rebound dampening adj. than a circle track shock. A Circle track shock will have adj. ranges starting firmer and ending firmer than a street shock etc. You can probebly get a middle of the road setting with any of them but they`ll allow more adj. in the range that that discipline uses most. Mark SC&C

[silver69camaro]

Unless if you are paying $800+ for a shock, each adjustment will change both compression and rebound, even if the manufacturer states only one is changed. What happens is say one click adds 10% to rebound, but also happens to add maybe 5% to compression.

[silver69camaro]

Another option I came across is Strange. They have a double adjustable mono-tube shock for around $250. That is considerably lower than any other double adjustable I've seen out there and jsut a little bit more than most single adjustables. Anyone have any expereince with Strange?



Strange makes very good shocks, and their valve type is almost identical to a Koni. Problem is, most are designed for drag racing. The Strange units we use are valved for our specs.

I'm going to be a bit blunt here, but it sounds like you aren't very familiar with dampers which would make any more than a single adjustable out of your league. My advice to you is to get a single adjustable shock of decent quality, set it then forget it. Properly adjusting compression and rebound individually isn't easy.

[JRouche]

Unless if you are paying $800+ for a shock, each adjustment will change both compression and rebound, even if the manufacturer states only one is changed. What happens is say one click adds 10% to rebound, but also happens to add maybe 5% to compression.

Wow, really? 800 each. I bought some shockwaves for 800 a pair and thats with an air spring and double adjustable shocks. They look surprising close to varishocks too so I wouldnt be surprised if they were.

I just couldnt imagine paying 3200 buck for a set of shocks. Really?? Anyone paying that much here?? Where is that money tree, I am gonna change jobs from being retired to a gardener :) JR

[Twentyover]

Wow, really? 800 each. I bought some shockwaves for 800 a pair and thats with an air spring and double adjustable shocks. They look surprising close to varishocks too so I wouldnt be surprised if they were.

I just couldnt imagine paying 3200 buck for a set of shocks. Really?? Anyone paying that much here?? Where is that money tree, I am gonna change jobs from being retired to a gardener :) JR



Penske motorcycle shocks are $1200-1600 each. They do come with a spring.

Yes, they contain essentially the same parts as a $10 pep boy shock, but are 4 way adjustable (adjustable for low speed, high speed (shock speeed, speed of linear compression and extension) dampening in jounce and rebound)

But where the $10 shock is put to gether by a piece of automated assembly equipment in a dark greasy factory from whatever parts the previous machine spat out, the Penske is assembled by nubile beauties to custom specification (yours) from precision parts fabricated to close tolerances in well lit clean rooms accented with the light aroma of smoldering incense.

Or something like that

[Rhino]

...They look surprising close to varishocks too so I wouldnt be surprised if they were...

As far as I know, they are Varishocks as of this moment. I've been told they're varishock components that ridetech builds and dynos in house. It doesn't really matter in regards to the rebound/compression/both discussion, but I figured I would let you know.

[High Plains Mopars]

I'm going to be a bit blunt here, but it sounds like you aren't very familiar with dampers which would make any more than a single adjustable out of your league. My advice to you is to get a single adjustable shock of decent quality, set it then forget it. Properly adjusting compression and rebound individually isn't easy.


Very observant and very close to the truth. My experience with shocks has all been in highly restricted, stock type racing classes that did not allow adjustable capability. If we needed more or less control, we swapped the whole shock, which got expensive fast and became a limiting factor since the budget was tight and we had to sometimes compromise on the best set up in order to buy tires or gas instead of another shock.

So on my street car 'd rather pay more up front for more capability that I can grow in to than swap shocks every few years. My car will not only see street duty but will also be doing an occasional autocross and and regular Nasa HPDE. So yes, my initial choice was a very good, high quality single adjustable unit that may last me a long time before I get tuned in enough to the set up to get double adjustables. I doubt I'll just set it and forget it since in addition to those activities, I also hit the drag strip once or twice a year, hence the whole idea behind adjustables.

So, knowing the above and referencing a single adjustable unit, would you lean more towards a rebound or compression adjustment? I can see merits of both, but like you said, lots of margin for error in there if I head off in the wrong direction with a double adjustable unit. Before making the purchase, I probably will also call the manufacturer to talk about where I am at with my wheel rates and intended applications to see if an off the shelf valving will work or if I need to get something custom set up.

[High Plains Mopars]

Feel free to give a call for more info on the Varishocks. We`ve been using and selling them for quite a while now so we know them very well.

I haven`t used the Strange shocks but as a rule nothing violates the old standby that you get what you pay for, ;)

Mark SC&C

Exactly my concern. Hence this line of questioning. I'll plan on giving you a call in the coming months about them. Other build activities are going on at the moment, so if shocks are one of the last parts that go on, that is okay with me.

[Bryce]

i bought AFCO T2 double adjustable for $660 for both and that included the springs. i searched/waited for a good deal and found it. Im very happy with the performance.

i think a compression adjustable shock would help more as it will allow for how the initial bump will be controlled.

[silver69camaro]

I probably will also call the manufacturer to talk about where I am at with my wheel rates and intended applications to see if an off the shelf valving will work or if I need to get something custom set up.

That's what you need to do. Get a rebound adjustable shock with a matched valve to your application. If they're any good, it should be near spot on with maybe one click either way. But honestly, the people who really can do that charge a fair amount for a shock. Like I was saying before, $800 per unit will get you in the market for a high quality shock...and that's entry-level field. Some are $2500 each, but obviously you aren't looking for that.

Personally, I'd get a mid level Koni if you want something nice. Double adjustable is still going to cost you, but they have a good quality valve and a choice of valve specs. Cost is around $650 each. A Penske 8300 would be a step up from that.

[High Plains Mopars]

So you recommend a rebound adjustable rather than compression adjustable. Why is that?

[Bryce]

to rephrase what has been said, almost all single adjustable shocks change both rebound and compression at the same time. a few companies give you the choice, one of them is AFCO. Maybe give them a call and see what they reccommend.

Or step up to a good quality DA like Matt was saying.

I think the quality of the AFCOs i bought are great. They are not a Penske but a close second. I may never be able to tell the difference between the two shocks since my driving skills are not on a professional level. But i bough the best within my budget and do not regret my descision.

[[email protected]]

My 2 cents: If you're going to go with a single adjustable, go with the rebound. Think of it this way: your shocks work in tandem with your springs. When you hit something, the spring compresses and soaks up that energy; while the shock does do its part in controlling the compression, the biggest effort is made during rebound and controlling the rate at which that spring releases the energy. (Your typical 'stock' non-adjustable shocks have more rebound than compression for just this reason.) Yes, compression adjustability is great and can be a huge benefit especially when paired with rebound adjustment, but if you're going to stick with single adjustables you'll get way more of what it sounds like you're looking for by adjusting rebound-only and having more tunability over how that spring releases rather than adjusting compression-only.

[silver69camaro]

I think the quality of the AFCOs i bought are great. They are not a Penske but a close second.

AFCO does make good shocks, as well as Strange, Alston, etc. BUT, these are low-end shocks in the real-world. I'm a bit of a shock snob, I know the benefits of a good quality shock:

1. Definitive & repeatable adjustments
2. Linear adjustments
3. No adjustment crosstalk (where a rebound adjustment affects comp)
4. Proper valving
5. Fade-free

Good, high quality shocks can be purchased from:
1. Ohlins
2. Sachs
3. Bilstien
4. Penske
5. Koni

Again, I'm a shock snob. I know these shocks are starting at $650 and up to $2000 each, which is why I recommend Koni and Penske for their entry level "budget" quality shock ($650 for Koni, $825 for Penske). There is a difference, and they aren't for everybody. If you don't know how to properly adjust a shock, don't bother. If you only plan on lap days maybe three times a year, don't bother. Most people find the valving too stiff for street use anyway, but I think it's important for people to realize there is a whole world of shocks out there rather than what you see in the Pro-Touring world.

Amber's comments are right on.