Why are twin tube shocks still made?

[ericwy]

I am a newbie when it comes to shocks, springs, and suspensions but my limited amount of reading leads me to
wonder why twin tube shocks are still common in the market place. By luck I stumbled into a set monotube design
shocks which I have been using on my TA for 10 to 15 years now (second set). Now that I started looking into the
actual design and function differences I am surprised the twin tube design is still marketed much less marketed as
a performance component. What am I missing?

[bret]

Great question. I think it comes down to cost of manufacturing. While there are more parts in a twin tube shock, most of them do not have to be "precision" parts, and can therefore be made in mass quantity relatively cheaply. By mass quantity, I'm talking about millions, not the few tens of thousands that most aftermarket companies make.
Another consideration is tooling. Precision parts require precision [$$$] tooling.
Another consideration is knowledge. Sometimes it is tough to get away from what you are used to, and are already vested in...even if there is clearly superior technology available.

By now it is no secret that I am a monotube fan. The larger piston size, along with the simple and efficient fluid path make it almost a no brainer for our customers. At this point we have changed over every RideTech shock to the monotube architecture.
We've been so impressed with the performance, and confident in the durability the last 4 years that starting on January 1st, 2013...every RideTech shock will now carry a 1,000,001 mile warranty.

You heard it here first.

[High Plains Mopars]

Well, not everyone is concerned with getting the best performance out of their components, so there will always be a market for value priced shocks, as well as anything else that simple does an adequate job.

I'd also add durablity to the list above. Twin tube designs by their nature can sustain more damage and still remain functional without compromising their action because of the double wall design. That means your average "don't give a flip" driver can heap abuse and neglect on them for as long as the seals hold up.

[bret]

I would agree that in theory the twin tube will withstand more external abuse due to the inner "working" tube being protected by the outer "reservoir" tube, BUT...1. the material thickness of the monotube [typically .090"-.134" wall] will deflect all the but most extreme external hazards. 2. any external abuse that would damage the heavier monotube wall would likely pierce the thinner twin tube material that is typically .030"-.060" wall.
There are some in dirt track racing who are conscious of this as dirt clods and rocks picked up during a race could hurt a monotube. This is less of a concern for us road going folk.
Also...monotubes are the overwhelming standard in offroad racing where external debris is a serious consideration...but even more of a consideration is the decreased operating temps and increased performance of the monotube design.

Here is a seat of the pants performance analogy... in a 2" OD twin tube shock the piston [which is where all the fluid flows through] is about 1" in diameter. The same diameter monotube piston is about 1.8" in diameter. That is 3.5x the effective area. Think of making 500 hp with a 307 cu.in engine versus a 500 cu.in. engine.

I agree totally about the lingering market for "value priced" products. Its hard for us to remember that many people [even hotrodders] do not know or care about the intimate details of shock performance. I can pontificate all I want, but I still have not figured out a way to give everyone a personal test drive so they can feel the difference. And there are differences between monotubes as well. There are as many ways to tune shocks as there is to tune EFI. Unlike EFI, however, your "buttometer" is the only relevant guide to success. While engineering data and experience is invaluable, we have found that when developing a tune for a particular shock it helps to have an enthusiastically tuned butt!

[High Plains Mopars]

I agree totally about the lingering market for "value priced" products. Its hard for us to remember that many people [even hotrodders] do not know or care about the intimate details of shock performance. I can pontificate all I want, but I still have not figured out a way to give everyone a personal test drive so they can feel the difference. And there are differences between monotubes as well. There are as many ways to tune shocks as there is to tune EFI. Unlike EFI, however, your "buttometer" is the only relevant guide to success. While engineering data and experience is invaluable, we have found that when developing a tune for a particular shock it helps to have an enthusiastically tuned butt!

I've often found success in explaining shock performace to "non believers" by using a camshaft analogy. A lot of guys know engines, not many know suspension. Much like a cam, shocks will determine the operating characteritics of the system, useful range, and has the ability to make all the individual components work well together. Like a bad cam choice, a bad shock choice may work within a narrow range, but a good choice will make everythng work well together over a much larger and more useful range.

[vintageracer]

Is it a proper statement to say:

"A good monotube shock can help or mask the poor performance of a bad suspension design/setup"?

[High Plains Mopars]

Perhaps, to a degree, depending on how it is used. It would help/mask a incorrect selection of components if not used in highly transitional driving, but would not help a bad design. Bad geometry is bad geometry regardless of how you control it. If all you do is off ramp racing and show cruising, you may not notice you have a bad selection of parts because yoru transitional activity is limited enough for the shock to control things. If you autocross, it would become obvious very quickly.

[bret]

Is it a proper statement to say:

"A good monotube shock can help or mask the poor performance of a bad suspension design/setup"?

In my OPINION...the most important items to make your car fast [at least in our world here] in order:

1. driver
2. tires
3. frontend alignment
4. frontend geometry
5. shocks
6. seats/harnesses
7. steering
8. brakes

Also, in my opinion, a GREAT anything will not be able to overcome a POOR anything. AND...there is no PERFECT anything. Everything is a compromise.

[exwestracer]

In my OPINION...the most important items to make your car fast [at least in our world here] in order:

1. driver
2. tires
3. frontend alignment
4. frontend geometry
5. shocks
6. seats/harnesses
7. steering
8. brakes

Also, in my opinion, a GREAT anything will not be able to overcome a POOR anything. AND...there is no PERFECT anything. Everything is a compromise.

HAHA... ^^^^THAT^^^^ needs to be a sticky all by itself!

[vintageracer]

In my OPINION...the most important items to make your car fast [at least in our world here] in order:

1. driver
2. tires
3. frontend alignment
4. frontend geometry
5. shocks
6. seats/harnesses
7. steering
8. brakes

Also, in my opinion, a GREAT anything will not be able to overcome a POOR anything. AND...there is no PERFECT anything. Everything is a compromise.


ALL very important!

Your mention "In Our World Here" Please describe your meaning of "Our World Here"?

Would your order of importance change for different PT activities such as autocross versus open track versus wheel to wheel road racing?

How would your order of importance change (if at all) for the 3 different types of track activities mentioned above?

[cornfedbill]

This is an interesting thread!

I have to agree with Bret. It's all a compromise and great shocks will not beat a better driver.

I used to work as an engineer designing shocks for OEM use. We made millions of shocks every year and sold to most large OEM's. We had two divisions, OEM and aftermarket. The OEM shocks were much better quality than the aftermarket parts, but still twin tubes.

The bottom line is cost. Twin tube shocks are just cheaper to mass produce.

Some could argue that the materials are not that much more expensive. But the cost to re-tool a legacy plant is more extremely expensive.

If you ask my opinion, I will just tell you that I bought Bilsteins for my ride.

[bret]

ALL very important!

Your mention "In Our World Here" Please describe your meaning of "Our World Here"?

Would your order of importance change for different PT activities such as autocross versus open track versus wheel to wheel road racing?

How would your order of importance change (if at all) for the 3 different types of track activities mentioned above?

Again, my opinion, but I consider "our world" to be turning corners with street cars, be it road course, autocross, or just spirited street driving down a deserted twisty backroad. "Real" hardcore autocross or road course racing, drag racing, top speed racing, or just cruising may shake up the order of importance somewhat, but the items listed are still relevant.
Road course, for example requires much more importance on brakes and shocks than autocross because of the higher speeds and longer event duration. Autocross may put more importance on driver finesse and frontend alignment. Drag racing seems to be all about horsepower and rear suspension, with not much significance placed on front suspension.

[vintageracer]

Bret,

Thanks for the excellent response and input!

[Rod]

In my OPINION...the most important items to make your car fast [at least in our world here] in order:

1. driver
2. tires
3. frontend alignment
4. frontend geometry
5. shocks
6. seats/harnesses
7. steering
8. brakes

Also, in my opinion, a GREAT anything will not be able to overcome a POOR anything. AND...there is no PERFECT anything. Everything is a compromise.

I think I will steal this for my website Bret if you dont mind, I have said the best part of the car is the driver for a while now, your list is in a great order