Öhlins Rear Suspension Explanation・OHLINS Monoshock / Twin Shock Summary

For more than 40 years, Ohlins has reigned as the top suspension brand essential for major races around the world, including motoGP. The brilliant track record of the brand proves that its performance is top-notch, and it is well-known as the brand that is the first choice when replacing suspension. However, there are so many products in the lineup that many people may not understand what is going on when there are multiple products that fit their bikes. Since these parts are quite expensive, you may want to ask yourself, "What kind of product lineup do I have to start with? What is the difference between different product lines? What are the differences in the product lineup? We have summarized the Ohlins product lineup in an easy-to-understand manner. By looking at the part numbers, you will be able to understand "What kind of functionality does the product have? You will be able to understand "What kind of functionality does the product have? *Ohlins has a part number that combines numbers and alphabets called "type symbols". [/color] [/color] [/color] [/color [/color] [/color

What is Ohlins?

Öhlins is a prestigious suspension brand that is gaining recognition not only in top category races around the world, but also in amateur racing and recently in 4-wheel racing. It is based in Sweden, a Scandinavian country that has produced many rally drivers, and perhaps the Scandinavian national character (?) of "flying over rough and slippery roads" is the secret behind its excellent performance. The company was founded in 1978. The company was founded in 1978, but it was not until the mid-1980s that it became well known in Japan. At that time, there were almost no magazine articles on world championship motocross, and moreover, there was no way to know what kind of suspension was installed on the champion machines. However, the situation changed drastically when pictures of the suspension installed on the cars of leading teams in motoGP (WGP at that time) began to appear in the market. The performance of Ohlins suspensions quickly made them a major name, and they became an indispensable suspension brand for high-performance custom vehicles. In the early 1990s, Ohlins yellow springs were already admired and coveted. In a short period of time, the brand grew from an emerging brand to a coveted brand, all because of its performance.

What are the advantages of replacing them?

It is a very expensive item, and it is a part that requires a great deal of determination to purchase. Although you hear a lot about its "goodness," you may be very curious as to what exactly makes it so good. First, you need to know the typical characteristics.

High quality

High quality is convincing to anyone who holds it in their hands. This is not just a simple matter of beautiful surface finish, but also includes, for example, the fact that if you purchase three sets, all three sets will perform exactly the same. ...... It means that not only the superficial appearance is of course of high quality, but also the quality of the contents, which are not visible, is always maintained at the highest level. If you think that because they are machines, they must all be the same, you are mistaken, and in fact, this is a difficult task. Also, this kind of quality does not show up in catalog specifications. It is not the same as saying that the more clicks in the damper adjustment, the higher the quality, or some such superficial thing. Öhlins does not cut corners if it is necessary for performance, even if it does not show up in the specs.

High Precision

Nowadays, there are many suspension brands that boast of high precision, but this is simply due to the improved precision of machine tools. However, Öhlins has been boasting of its outstanding precision since the days when the precision of other companies was still lax, and even with the same high precision, Öhlins has a long and distinguished history. Our experience in "high precision" is extraordinary. The high accuracy can be experienced immediately by anyone who rides the car. For example, if you push in the damper rod with the spring removed, the internal gas pressure will push the damper rod back into place. Up to this point, the stock product, other company's product, and Ohlins are all the same. However, the Öhlins damper rod always fully extends every time, whereas the genuine product does not fully return to its original position due to various sliding resistances, the time of return is different every time, and the position at which the extension stops is different every time. Moreover, the time from full bending to full extension is the same every time. This is a proof of high precision (high quality) with little sliding resistance.

Wide adjustment range

The damping adjuster has a large number of clicks, and if it is a stepless adjustment, the adjustable range is wide. Other brands claiming multi-step adjustment may have little change in characteristics at the beginning and end of the steps, but Öhlins does not have this problem. If it says "20 steps" on the dial, it will change by 20 steps. Even if the dial itself has more than 30 clicks, if the adjustable range is 20 steps, it says "20 steps". The range of adjustment is so wide that it cannot be compared with the stock suspension, and the amount of change from the weakest to the strongest is impressive.

Fine adjustment range

The number of steps is important, but the range of change per step is also important. Although the manufacturer does not say so, Öhlins has a narrow range of one step. Moreover, because of its high quality and high precision, it is wonderful that the narrow width of one step can be felt as a change. This is also a part that is not shown in the catalog specs, but it is extremely important when you actually start setting up the car. The image below shows how it looks like.

Durability.

Because of its high quality and high precision, there is no tight rubbing or unnecessary rattling. Therefore, wear of each part is minimal, and the durability is high to begin with. Moreover, as is common practice for high-end suspensions, overhaul is possible, so even if parts wear out, they can be replaced part by part. You can use it for a long time. It was almost 30 years ago when I first purchased Ohlins, but it is still in use. As expected, the spongy dust cover next to the bearing at the mounting point and the bump stop rubber are cracked, but both can be restored in the next overhaul. At this rate, it will almost certainly last a lifetime.

Functional Beauty

The fusion of function, precision, quality, and durability obtained from actual battle has resulted in a functional beauty that cannot be imitated by other companies' products. There is a beauty of form that has been achieved by thoroughly eliminating waste and focusing solely on performance. There are no superfluous decorations at all. Even the shapes of the smallest accessory parts have meaning.

Can you really feel it?

When considering the purchase of an expensive suspension system, the question is, "Will I really be able to feel the performance with my own arms? Will I be able to feel the performance that is worth the high price? This is the most common concern when considering the purchase of an expensive suspension system. We assure you that "Anyone can experience it ". The smooth and smooth movement produced by the low friction can be felt almost from the moment you start driving. You will be surprised at how smoothly the suspension moves even when you just raise the vehicle to put it on the side stand. This is not because the springs are soft or the dampers are weak. The overwhelming lack of sliding resistance allows the suspension to smoothly follow even the slightest change in load, and the damping is effective even when the suspension moves slowly, allowing the vehicle to settle down smoothly. Compared to the genuine parts, the cost of the parts is overwhelmingly high, and the smoothness of the movement is impressive. You can feel that this is what correct suspension movement means.

Explanation of each part's function and features

Piston Diameter

Öhlins offers four types of damper pistons with different diameters, from a minimum of 36mm to a maximum of 46mm. So what happens when the damper diameters are different? The larger the piston diameter, the larger the shim diameter of the damper can be. Also, for the same amount of stroke, the amount of oil to be moved can be increased. As a result, larger-diameter pistons are more adaptable to fine-tuned settings. However, there are many cases where large-diameter pistons cannot be used due to the structure of the vehicle (two-piston suspension vehicles in particular have many restrictions), which is why small-diameter pistons are also available. The smaller diameter piston is more severe, but that is Öhlins. The performance is not inferior just because it is a two-piston shock.

About the reservoir tank

When the suspension is retracted, the damper rod is inserted into the body. The oil must be released somewhere to cover the volume of the damper rod (since it is not possible to compress the liquid, the damper cannot be shrunk otherwise). Therefore, Öhlins has a gas chamber to absorb the volume of oil from the damper rod. This gas chamber is called a reservoir tank. Even a damper that does not appear to have a reservoir tank at first glance has a gas chamber inside the damper. However, the gas chamber built into the damper has a limited capacity. This is why we developed the separate reservoir tank type. There are two types of reservoir tanks: one is rigidly connected to the damper body, and the other is completely independent of the damper body by means of a hydraulic hose. Theoretically, the closer the tank is to the damper body, the better, but sometimes it is not possible to integrate the tank into the damper body due to the body structure. Many people prefer this separate type because it is more mechanical, and many people go out of their way to choose the separate type for its appearance. The difference in performance between the integrated type and the separate type can be seen at ......, but probably not felt by almost everyone.

About pressure side (comp side) adjustment

This is the damper adjustment mechanism for the compression side. Compression side = COMP side = COMP side, all mean the same thing. This is an adjustment of the damper to prevent the suspension from entering too far in a large gap, so it is different from the original function of the damper, which is to control the extension, and is not intended to be very effective. However, if adjusted properly, it can prevent unnecessary contraction only at exceptionally large gaps that appear during driving. In some grades, the damper can be adjusted separately for "low speed" and "high speed" in more detail. Low speed and high speed refer to the piston speed of the damper, not to the speed of the bike itself. Therefore, it is not correct to say "I am a leisurely touring rider, so I will only need the low speed side. It is easy to understand that the low speed side is for when the suspension moves slowly on smooth road surfaces, and the high speed side is for when the suspension is moving briskly on rough road surfaces. The more steps there are, the finer each step is, the better.

About the rebound side (ten side) adjustment

This is the damper adjustment mechanism for the extension side. Tension side = Tension side = TEN side, all mean the same thing. Öhlins calls it "rebound side" for simplicity. This is the part that adjusts the original function of the damper, preventing the suspension from swinging back too much after it has contracted at the gap. The more steps there are, the finer each step is.

About Preload Adjustment

Öhlins dampers have a stepless adjustment. You turn the screw on the outer circumference of the body to shorten or loosen the spring. Basically, once the pre-load is set, it will not change unless the body dimensions change or the riding style is changed. However, this is only for racing. We, ordinary riders, carry camping equipment or ride in tandem, so we have to change the pre-load quite often. To use a simple analogy, when you tandem, the light axis of the headlight turns up, doesn't it? In such cases, preload can be applied to return the vehicle to its original position. Preload is a device that adjusts the vehicle height when the weight on the spring changes, thereby returning the vehicle to its original posture. Preload gives pressure to the spring, so the part where the spring is positioned must be touched to adjust it, but the suspension of a motorcycle is often located deep inside, making it difficult to work with. To make such work easier, some models have a hydraulically adjustable preload and a control dial on the outside. This is recommended for those who tend to change the load on the rear of the bike, such as single rider, tandem, touring, and camping .......

About Ride Height Adjustment

This is mainly located at the bottom of the damper and changes the overall length of the damper by turning a screw. On models with a ride height adjustment mechanism, it is possible to adjust the body posture without changing the spring rate and preload settings, in case the ride height exceeds the target range after selecting the correct spring rate and correct preload. For models without a ride height adjustment mechanism, either the spring rate or preload must be compromised in order to achieve the correct ride height.

What is single-tube or mono-tube?

This term describes the internal structure of the damper. As the name suggests, a single tube has one tube inside the damper, while a twin tube has two tubes inside the damper. The advantage of the single-tube is that the piston diameter can be enlarged to the very limit of the damper. The larger piston makes it easier to achieve the effect of damping adjustment even with small movements. The twin-tube system has another smaller-diameter tube inside the main damper to circulate damper oil between the inner and outer tubes. Since the oil circulates, the oil pressure difference is less likely to occur in the damper, and cavitation (bubbles generated by rapid depressurization) is less likely to occur when the damper piston moves at high speed. The current Öhlins has a unique structure called "TTX " which is a further development of the normal twin-tube.

What is TTX?

TTX is Öhlins' unique mechanism, which is basically a twin-tube system. However, whereas the twin-tube system used by other companies has oil passages in the damper pistons and damping is adjusted with shims, the Öhlins twin-tube (=TTX) has no damping adjustment mechanism in the damper pistons. The piston only pushes oil out of the damper purely as a piston, and a completely independent adjustment mechanism is installed in the circulatory passage of the pushed oil. The advantage is that the compression side and the rebound side can be controlled completely independently. With dampers other than the TTX, adjusting either the compression or rebound side always affects the other side, but the TTX has completely independent oil flow paths and completely independent rebound/rebound adjustment mechanisms, so adjustment of the rebound side does not affect adjustment of the compression side. Also, cavitation (bubbles generated by rapid decompression) caused by rapid decompression is less likely to occur on the low-pressure side of the damper, which is separated by the piston, as in the past, so the gas pressure that gives pressure to the damper oil can be set lower to prevent cavitation. When gas pressure is lowered, oil does not leak even if the oil seal is loosened to prevent oil leakage, thus eliminating the need to use oil seals with large sliding resistance. As a result, smooth operation with low friction is possible. The figure below is a conceptual diagram, but only the compression side is shown because of its complexity (in reality, there is another route on the extension side that is identical to this one). You can see that there is no damping adjustment mechanism on the piston.

Explanation of Symbols

As mentioned at the beginning, Öhlins has a part number called "type symbol" which is a combination of numbers and letters. The meanings of the symbols and numbers are as follows!

Cylinder type

S: Cylinder construction is single tube T: Cylinder construction is twin tube (TTX)

Piston diameter

36: Uses a piston with a diameter of 36 mm 39: Uses a piston with a diameter of 39 mm 44: Uses a piston with a diameter of 44 mm 46: Uses a piston with a diameter of 46 mm

Shock absorber shape and internal structure

E: Type without a free piston in the cylinder D: Type with a free piston built into the cylinder P: Piggybacked (body-integrated) reservoir tank installed H: Reservoir tank connected by a hose K: Chrome-plated design

Various adjustment mechanisms installed

C1: Compression damping force adjustment C2: Compression damping force independently adjustable at low and high speed C4: Compression damping force adjustment electronically controlled R1: Rebound (rebound) damping force adjustment R4: Rebound (rebound) damping force adjustment electronically controlled SS: Spring preload, with separate hydraulic adjuster mechanism (hose type) S1: Spring preload electronically controlled B: Spring preload, with built-in hydraulic adjuster adjustment L: With ride height adjustment function

Examples of Symbols

In the case of Type：T36PR1C1LS, T → twin tube 36 → Φ36mm piston P → piggyback type reservoir tank R1 → with rebound damping force adjustment C1 → with compression damping force adjustment L → with car height adjustment S → with separate hydraulic pre-load adjuster Once you know it, it is really easy to understand!

Monoshock Lineup

Single Rear Shock Absorber "TTX GP

The pinnacle of Öhlins monoshock (single suspension)! It has a structure directly derived from motoGP, and is the ultimate achievement of replacement suspension that exists in the world. Anything more than this and it becomes an electronically controlled variable semi-active damper, not the kind of thing that can be replaced later. If the vehicle body is controlled purely by physical and mechanical control, there is nothing beyond this. The TTX GP has a new shape of the damping force adjustment needle, which is the "keystone" of a damper, and it offers the finest and most precise adjustment Öhlins has ever achieved. Isn't it inferior to electronically controlled suspensions? You may wonder, "But actually, it is not so. The reason why electronic suspension is used in production cars is "to respond to all kinds of situations," and it is simply an attempt to automatically adjust damping from circuit driving on flat road surfaces to large gaps such as going over bumps. If such extreme situations are ignored, it can be said that the main application is easier to set up without electronic control. In fact, serious circuit racers do not use electronic suspension (because they do not want the damping characteristics to change against the rider's will). In other words, the same quality suspension used in the highest level of racing can be purchased for as little as 200,000 yen. In a sense, it is even cheap.

Single Rear Shock Absorber "TTX RT

This lineup was introduced in 2014 and corresponds to the entry model of the TTX series, which is based on the "TTX36 MarkII" below and incorporates elements of the "TTX GP" above. The "RT" stands for "Road & Track". In other words, this model is designed for a wide range of situations, including racing use on circuits as well as on public roads. The term "entry model" may give the impression of a crude, low-priced version, but this is not the case. The biggest factor in keeping the price low is that it is not equipped with a hydraulic preload adjuster. However, those who do not need to change the preload frequently, for example, those who specialize only in driving on certain circuits or those who always drive with the same equipment weight, will not have a big problem because they do not need to change the preload frequently. The shape of the adjustment needle inside the damping force adjustment mechanism is different from that used in the TTX GP (the same one used in the TTX36 MarkII shown below), but the concept of the TTX mechanism is the same, so the advantage of completely separate rebound and compression for reliable adjustment remains the same. The weak point is that the lineup of compatible models is small, but if you drive a compatible model, you are lucky!

Single Rear Shock Absorber "TTX36MarkII

This is the successor model of the "TTX36" which was introduced as an innovative rear shock. (*The previous TTX36 is no longer available on Webike.) It is a new generation TTX rear shock, reborn under the name of "Mark II" with evolved damping force adjustment mechanism that allows complete separation of rebound and compression, which is the concept of TTX mechanism, to ensure reliable adjustment. The number of adjustment levels has been increased from 20 to 25, and the rigidity of each part has been improved to maintain high road-following performance even under heavy load for a long period of time. Almost all models have a threaded hole for mounting a stroke sensor in the end eye (the part where the damper rod attaches to the car body), which gives a glimpse of how these models are designed to be used in full-scale races. This is a super high performance damper for racing, but of course it can also be used on public roads. You can fully benefit from the latest damper structure, TTX.

Single Rear Shock Absorber "S46

Öhlins was the mainstay of the TTX until the introduction of the TTX. This is the "S46" series. The model has evolved little by little depending on the year, but the current lineup has an aluminum body. (Older models had a steel body.) It has reached the point of perfection as a so-called rear shock, and has reached a level where it cannot evolve any further. There are no parts that could be better (......), and there are no parts that need to be modified for installation due to the vehicle-specific design. Also, because of the familiar "single tube and multi-stage stacked valve" damper configuration that has been used for many years, the vast amount of setting data from the past 40 years can be utilized as experience, so excellent initial settings can be made for each car model. We have a great initial setting[/color] for each car model. The setting of the multi-stage stacked valves in particular is so good that almost everyone will not feel the need for resetting. Just by adjusting the damping adjustment dial, the car can be driven on ordinary public roads, such as city driving, mountain passes, and touring, as well as in full-scale races where the car can compete for victory. This is impossible if the product is simply well made. Basically, unless the settings of the internal structure, which cannot be adjusted by the purchaser, are perfect, there will be something impossible to do. But Öhlins is indeed the best! It is obvious from the impressions that almost all of the purchasers have realized the excellence of the product just by installing it!

Twin Shock Lineup

Twin Shock Absorber "S36

The original Ohlins! This is the traditional twin suspension that led Öhlins to be founded and became a legend through its success in the races. At that time, monoshock (single suspension) had not yet appeared, and motorcycle suspension = 2 suspensions. Therefore, mastering the two suspension was absolutely necessary to win races. And as a result of continuous friendly competition since the establishment of the company, Öhlins twin shocks have reached almost the ultimate realm. It is difficult to evolve further due to the mounting position of the suspension, and it is all about how to improve the basic performance, but we have reached a level where it is no longer difficult to go any further. The feature of this shock absorber is that all the basics have been firmly and surely fixed. Like the single rear shock absorber "S46" mentioned above, the "single tube and multi-stage stacked valve" configuration is the standard configuration for high-performance shocks, and is the same as other top-quality products from other manufacturers. However, as with our single shocks, our experience in setting up these shocks is incomparable. The reason why these shocks are not general-purpose products, but are available exclusively for each car model, is because the settings of the multi-stage stacked valves are different for each car model, and the optimum damping characteristics are set for each car model. The damping characteristics other than those that can be adjusted with a dial are set perfectly for each car model, and this is the value of Ohlins that no other company can imitate. The simple design is resistant to breakdowns and damage, and of course, each part is fully adjustable. The design concept is to make it fully disassembled, which is completely different from the non-disassembled factory suspension, and it is possible to recover the performance as good as new by overhauling. The upper and lower mounting parts are directly supported by bearings without rubber bushings (spherical bearing support), a large-capacity reservoir tank prevents heat leakage, and a wide range of settings is provided: 30 steps on the rebound side and 20 steps on the compression side. The preload adjusting nut is also unique, with an original single nut type adjuster instead of the usual double nut type. Even a slight turn of the preload adjuster, or a single click of the dial, is enough to feel the ultra-high-precision processing in your hand.

Rear Shock Absorber "Legend Twin

Based on the "S36" twin shock absorber above, this model has been modified to suit older cars and classic chassis. The internal structure is the same as the regular twin shocks, so performance is exactly the same. The only difference is in appearance! In addition to the Öhlins yellow spring color, the Legend Twin is also available with black springs for those who prefer a more stock-like appearance. In the past, Öhlins twin shocks had a steel body and black springs. Although the body material has been changed to the latest aluminum body, those who want to ride the famous cars of the past with the atmosphere of those days will appreciate the black spring specification very much. The pressure side damping adjustment dial is also made of black resin, just as it was back then, making it ideal for those who want to ride the latest twin shocks with as much of the original look as possible! Although it looks like the original, the inside is the same as the latest "S36" twin shocks, which have been redesigned with the latest technology, so when installed, the shocks will give you a wonderful movement that does not look like an old car.

In other words, Ohlins is recommended for the following people!

Long ago, Ohlins had a steel body (this is the oldest Ohlins I own). They were expensive suspensions, but to be honest, they didn't look like much. However, the current lineup, with a few exceptions, all have high quality aluminum bodies and rust-resistant chrome plating, giving them a very high quality look that is well worth the price. And although they are certainly expensive, their performance has always been top-notch, so anyone who installs them can easily experience the benefits. Even if you don't know anything about suspension settings, you will be able to experience the excellent movement. Moreover, it is so obedient that you can feel "something has changed" as soon as you turn the adjustment dial, so there is no need to worry even if you have tried suspension setting with the stock suspension but did not understand it well. Öhlins can be used for a long time after overhaul, and always give you a moist feeling every time you ride, so it is not an expensive investment. If you have a bike that you plan to ride for the rest of your life, or even if you have a favorite bike that you don't plan to change for a while, Ohlins is highly recommended.

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