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ESA
Electronic Suspension Adjustment
ESA
Rider Guide
DDC
Dynamic Damping Control 
Öhlins
Electronic Adjustable Shock Absorber System

ESA (Electronic Suspension Adjustment)

An overview of what BMW ESA is, how it works, problems and aftermarket suppliers

Author: Hari Ahluwalia Feb 2012

ESA (Electronic Suspension Adjustment) makes almost immediate suspension adjustments without tools even while riding. It is operated using a thumb button on the left handlebar.

This manually-operated electronic control is an exciting first step forward into a future that leads to semi-active suspension such as DDC and ultimately to fully active suspension.

esa_button_2008.jpg

About ESA

ESA makes suspension settings simple to understand and quick and easy to change. ESA:
  • is an option on many BMW models in most markets
  • displays the current settings on the info flatscreen
  • is easy to use - just press the ESA button
  • is very intuitive - you only need to be shown how to use it once
  • makes it possible while riding to adjust suspension in two ways:
    • Preload - can be adjusted while stationary with the engine idling such as while at traffic lights. *
    • Damping - can be adjusted while riding.

    * Important note
    Unlike damping, preload adjusts the spring that carries the weight of the bike plus the rider and any passengers or luggage. ESA uses a small electric motor that is capable of changing the preload when the spring is unloaded. Using ESA to change the preload while the bike is heavily laden or in cold weather, risks burns out the ESA motor. Some owners on email lists complain that their ESA "froze" when they tried to change the preload while waiting at traffic lights with their wife and luggage on the back.

    An owner who wishes to reduce the risk of burning out the ESA motor can do the following.

    • Solo: before pushing the ESA button to change preload, put both feet down and take your weight off the suspension (that is stand up). You can feel the adjustment being made. Don't sit down again until the adjustment is complete and the display stops flashing.
    • With a passenger: don't use ESA to change preload while the bike is laden with a passenger or heavy luggage. Adjust preload to suit before loading. If you do want to adjust it again, wait for a suitable stop and do it while the passenger is off and the bike is unloaded.

    This ability to make dynamic changes while on a ride is very useful in a number of situations, for example as follows.

    1. Changed road conditions - after riding on soft settings along smooth tarmac, when the road becomes twistier switch to harder settings for faster responses and more precise handling.
    2. Previous knowledge - an experienced rider who already knows how suspension influences the feel of his bike, might decide while riding that he'd like to make a change such as increase damping. ESA allows him to make that change immediately without stopping.
    3. Changed weather conditions - when it starts raining, switch to softer settings. When the road dries, switch back.
    4. Carrying a passenger mid-ride - switch to harder settings.

Finally, ESA simplifies suspension set up in 3 ways.

First is the obvious, no fiddling with tools anymore.

Second, ESA de-mystifies proper suspension set up for the average rider. It is no longer a black art practiced only by gurus who have studied it for years or raced.

The biggest factor that makes setting up traditional suspension difficult is that you can't feel what the front suspension is doing separate from what the rear is doing. It would be great if you only felt the front through the bars and the rear through the seat! Then by feel you'd know to adjust the front and not the rear or vice versa. But the two suspension units are completely interlinked and the bike behaves as one so feel has to be interpreted and that only comes with experience. I have to admit that on more than one occasion over the years with traditional multi-adjustable shocks I got "lost" and had to return all adjusters, front and rear, to base settings and start again from scratch.

By contrast, all ESA settings are pre-programmed with damping choices that are always appropriate for the selected preload. And its settings of front and rear suspension are balanced to work together. ESA reduces set up to two steps with simple choices and prevents you choosing settings that conflict with each other.

Third, ESA offers suck-it-and-see changes in real-time, an easy and powerful way to learn. This speeds up and improves learning how suspension settings affect bike feel.

Without ESA, you have to stop, get off, break out the tools, make one suspension adjustment, pack away, get back on and ride again before you can feel the effect of your change. And to do this effectively you have to do this over and over again in a systematic manner.

After a while you learn what suspension changes do to the feel of the bike. So with that experience you use your black art magic (that is work backwards from bike feel). That way you decide not only that a suspension change is needed but also which adjustment is necessary and whether it needs an increase or decrease.

ESA's virtually instantaneous feedback creates a wonderfully simple tool for learning how suspension affects bike feel. Not only does it cut out the drudgery and make it much easier and faster, it's also more fun! So a rider who does not yet know what effect increasing damping has on bike feel, learns with ESA quickly and easily from the immediate feedback after making the change.

  • If it does not improve the feel of the bike, go back and try adjusting it the other way instead.
  • If it improves the feel of the bike, good. If it's possible try increasing it again. But when the feel gets worse stop and go back.

But ESA cannot prevent rider error - it's still possible to choose the wrong settings for a given situation!

And of course ESA does have some disadvantages beyond the obvious of having to pay extra for it.

  • It increases weight although most of the increase is in sprung rather than unsprung weight.
  • It increases complexity - more things to wear out and go wrong.
  • There is no manual adjustment of its base settings. So if you are significantly lighter or heavier than the 80kg average rider weight BMW used to set up the suspension, you might have problems finding settings that you are happy with.
  • The pre-programmed settings can't be altered to fine tune. (This is an advantage for some!).
  • The stock ESA shocks are non-serviceable nor rebuildable. This can be addressed by buying quality shocks from an aftermarket supplier. However, the electrical and control parts on the shock are not available separately. If anything fails, the whole shock has to be replaced.

Background

ESA was developed by WP suspension for BMW.

  • ESA: originally launched for model year 2004 on the K 1200 series. It has:
    • 9 possible choices
    • front adjustment: only rebound
    • rear adjustments: preload, rebound and compression
    • a maximum range of preload adjustment of 10mm.

  • ESA II: launched for model year 2008 on the K 1300 series and features the same 9 choices as ESA. The differences are:
    • both extremes of damping (Sport and Comfort) have been extended to offer a wider range of settings compared with ESA
    • a new preload adjustment mechanism also affects rear spring rate for the first time.

  • Enduro ESA: launched at same time as ESA II on the 2008 model year R1200GS, it has the same 9 road settings. The difference is that Enduro ESA offers an additional 6 choices specifically for off-road.

    The suspension changes required for off-road riding are extreme compared to anything on-road. Even the difference between suspension set up for touring and a track day is not so wide. Riding a bike off-road with suspension set up for the road is challenging, everything is too soft and handling is imprecise. Similarly, riding a bike on the road with suspension properly set up for off-road has major disadvantages such as very hard suspension and higher seat height.

    So, Enduro ESA has a wider range of suspension adjustments than ESA to deal with both on-road as well as off-road.

    • The range of all Enduro ESA adjustments are extended further at one extreme - "hard".
    • In addition, the maximum range of preload adjustment is doubled compared to ESA from 10 to 20mm.
    • The adjustments also include preload/spring rate on the front for the first time (but only for off-road choices).

    The Enduro ESA adjustments are:

    • front:
      • on-road: only rebound
      • off-road: preload/spring rate and rebound
    • rear: preload/spring rate, rebound and compression.

Market Take Up
From my experience, the average rider does not understand traditional suspension and the controls on their own bike and rarely if ever adjusts them. Typically with a burst of enthusiasm when they first get their bike, they'll read the manual and set it up once themselves or else ask a friend who knows about suspension. But once it's set, that's pretty much it and they don't touch it again.

The first thing that started to make a difference was remote preload adjusters for the rear suspension. For the first time many riders learnt that by quickly and easily adjusting it before taking a passenger, bike handling improve while riding.

When ESA was launched, the Press mostly liked it but they did not have to pay for it nor live with it day-to-day. Initially owners weren't so enthusiastic. But the second generation ESA II/Enduro ESA saw a definite increase in take-up as the real-world usefulness of ESA improved.

Now, the feedback from riders who have ESA but who previously rarely adjusted their suspension is almost universally positive. ESA works well and is worth its added cost and complexity because the suspension changes are immediately noticeable.

For the first time they understand not only what all their suspension adjustments are but also what effect they have on their bike. Consequently they use ESA regularly to make suspension adjustments and they feel the benefit of those changes.

Other manufacturers now offer their own systems with similar functionality, always a good sign of market acceptance. So it seems likely that electronic suspension adjustment is here to stay in some form or other.


How ESA Works

Basically, you use the ESA button on the handlebar to tell the ESA ECU what setting you want. The ESA ECU displays that setting on the info flatscreen and looks up the corresponding values in its preprogrammed table of settings. It then sends commands to the appropriate electric motors on the front and rear suspension units. In turn these electric motors operate hydraulic activators that make the actual suspension adjustment.

enduro_esa_front_shock_GS12A.jpg
The Enduro ESA front shock.

  • An electric motor at the top adjusts preload/spring rate.
  • A small step motor at the bottom adjusts rebound damping.

    enduro_esa_rear_shock_2008.jpg
    The Enduro ESA rear shock.

    • An electric motor at the top adjusts preload/spring rate.
    • A small step motor at the bottom adjusts rebound damping.
    • A second step motor at the top adjusts compression damping.

    The following diagram shows an exploded view of the internal components of the original ESA rear shock.

    • The preload adjustment mechanism is shown at the top. The potentiometer has programmed presets for each preload position. It controls the electric motor with gears that adjusts the preload. The maximum range is 10mm for ESA or 20mm for Enduro ESA.
    • The step motor that adjusts compression damping is at the top.
    • The step motor that adjusts rebound damping is at the bottom.

    esa_rear_shock_exploded.jpg
    Exploded view of the components in the original ESA rear shock.
    At the top are the motors to adjust preload and compression damping.
    The step motor at the bottom adjusts rebound damping.

    The mechanism to adjust damping is simple. Essentially each click you would make with a screwdriver on a traditional shock corresponds to a step for the ESA step motor.

    ESA II uses the same layout as ESA but features an upgraded mechanism that not only adjusts preload but at the same time spring rate as well. BMW produced the following diagram for the launch of ESA II to try and explain. But I have read several articles that use this diagram but they differed in detail! If you are interested you can look them up yourself on the web.

    However the basic point is that ESA II has a "spring" made of two parts.

    1. The usual spiral steel spring.
    2. An elastic bush that sits on top of the steel spring. The bush is made of "Elastogran" a polyurethane material used in car suspensions. The bush behaves like a spring, compressing when force is exerted on it and then springing back into shape.

    Together, these two springs form one combined spring. The combined spring has spring characteristics that depend on the spring characteristics of both springs. Change the characteristics of one of the individual springs and that of the combined spring also changes.

    bmw_esa_2_2.jpg
    ESA II has an elastic bush made of Elastogran that sits on top of a steel spring.

    • Inside the elastic bush is a moveable sleeve.
    • Moving the sleeve down increases both spring preload and spring rate.
    • Moving the sleeve up has the opposite effects.

    Inside the elastic bush is a moveable sleeve. The sleeve is precisely moved by ESA II to preprogrammed positions, one for each preload setting. Cleverly, when the sleeve moves it changes the spring characteristics of the elastic bush.

    Move the collar down and the elastic bush becomes:

    • shorter which increases preload and
    • stiffer which increases its spring rate.
    Consequently, both the preload and spring rate of the combined spring are increased. Move the collar up and the opposite happens.

    Altering the spring rate is a neat trick that before ESA was only possible by dismantling and physically changing the spring.


    Problems and Ownership FAQs

    In this section, I have tried to review the numbers and types of ESA problems reported on various web forums and discussion groups. This helps to build up a picture of how ESA is actually working out in practice.

    The following owner quotes summarize the feedback on ESA from most riders nicely.

    "When I first heard about the ESA, I honestly thought it was just a frill until I took a test drive. I rode about 50 miles and constantly changed the settings on it and the difference was quite noticeable so I bit the bullet and ordered it on mine."

    "I've come to really enjoy the ESA. It seems like the only drawback is the cost of replacement if one of the shocks goes out. If I did it over again, I'd still get ESA."

    "I really like the convenience of being able to change the suspension settings while riding."

    Of course I have to point out that all I am reporting here are my subjective view of trends from which I've tried to reach some guidelines which you may or may not find helpful. There is no guarantee that if you were to purchase a bike with ESA shocks your experience would be the same.

    Problems
    The original ESA seems to had a few teething problems. The major one was "freezing" at 2 helmets (Rider with passenger preload). No further changes could be made to preload but damping was usually unaffected. Dealers fixed this by a software upgrade or if it happened again, possibly replacement shocks. In fact initially there seems to have been a lot of warranty work and many shocks were replaced. This is typical when launching any new technology.

    In response there seems to have been an upgrade to ESA with a different motor. Certainly fewer problems seem to have been reported since the ESA upgrade. I'm not sure exactly when the upgrade occured but approximately a year after the original launch.

    This trend of few reported problems continued with ESA II/Enduro ESA. By comparison with the original ESA few problems seem to have been reported.

    ESA or not: New Bike
    In some markets ESA is standard and no longer an option. This tells you that the manufacturer has confidence not just in the technology but also that buyers find it useful. In that respect ESA is similar to ABS.

    But for buyers where ESA is an option the following seems to apply.

    Everyone appreciates the ease and convenience of ESA, whether they are experienced with suspension or not.

    • Given the price of the new bike, ESA is an affordable option for most. So rather than price, the ones who decide against ESA tend to be those who know about suspension already. Typically they'd prefer to spend the money on aftermarket shocks.
    • The rest seem to go for ESA as it has become a common choice now. For the riders who aren't in the habit of adjusting their suspension, it makes suspension adjustment understandable and simple and quick to make. The rest go for its convenience and being able to adjust it on a ride.

    In general it seems that for buyers of new bikes, ESA is robust and unlikely to cause problems until the shocks wear out. ESA is an easy choice if you intend to sell before the manufacturer's warranty ends.

    Note that a bike bought:

    • with ESA can have it de-activated by a dealer for example to fit non-ESA shocks
    • without ESA can not be retrofitted with ESA.

    But of course individual faults are always possible and can never be ruled out.

    ESA or not: Used Bike
    In general it seems that for those buying second hand who expect to sell before c. 30k km (20k miles), ESA is unlikely to cause problems.

    Obviously as with any other component, buying used is more of a gamble than buying new especially if out of warranty. Individual faults are more likely and mostly dependent on how the the first owner treated the bike. The lower the mileage and the better the condition, the lower the risk of problems. But again problems can occur at any time on any bike.

    Replacing ESA Shocks
    But what is certain whether you buy new or used, if you keep the bike long enough eventually the stock ESA shocks will wear out. It's always difficult to say how long a shock will last but wear replacements seem generally to be made from c. 30k km (20k miles) onwards. A lot depends on usage and loading for example how hard the bike was ridden and how often it carried a passenger and luggage. Because the shocks wear out over a long period, the owner often doesn't notice the drop off in suspension performance. But when oil starts leaking out, it's obvious that something needs to be done.

    Your options include the following.

    1. Replacement ESA shocks - very expensive.

    2. Rebuild your existing ESA shocks - impossible for all but the exceptional few.
      A few owners with expert knowledge and access to the appropriate tools have managed to rebuild theirs but that is rare. A very few specialist suppliers can rebuild and fit new valves that ease future maintenance. Perhaps a market segment will open up especially given the price of stock replacements but for now such specialists are rare. Your best chance of finding one is to ask on established GS lists and forums.

    3. Fit aftermarket replacement ESA shocks.
      But if they use the ESA electrical components from your shocks, see the following note.

    4. Fit non-electronic replacements, either stock or aftermarket.
      This is certainly cheaper than fitting ESA replacements but obviously you lose the convenience of ESA.
      Note however that simply disconnecting the leads to the ESA motors creates faults although nothing is visible on the flat screen info panel. In fact, a single communication fault for the rear and a single communication fault for the front, depending on which one you remove.
      The fault does show and can be cleared on either the:

      Your dealer can disable the ESA function electronically.

    Note that the ESA electrical components are not available separately. Neither is the preload/spring rate change mechanism that will also wear out at some point. Since the ESA upgrade they do seem to be quite reliable and probably will last longer than the shock absorber. But if the electrical components fail for any reason to replace them you'll have to buy a complete new stock shock.

    And finally to answer a common question, no unfortunately you can't just fit the ESA electrical components on a standard set of shocks! However you can buy replacement shocks with electrical adjustment such from WP Suspension.


    Aftermarket Suppliers

    Several aftermarket suspension suppliers offer replacements for the stock ESA shocks. Typically replacement shocks use higher quality components than stock shocks and are rebuildable, serviceable and customizable to your own requirements/specifications.

    The details provided here are for info only to provide an overview. If you are interested to know more, don't rely on this - instead check for the latest up to date information with your own retailers.

    WP Suspension
    developed ESA for BMW and have EDS (Electronic Damping System) II replacement shocks
    • Specifically for any R1200GS without ESA
    • Includes their own WP controller that fits under the seat.

    wp_eds_shocks.jpg

    Wilbers
    offer WESA (Wilbers ESA).

    • Send them your ESA shocks and they "marry" the electronic units from your shocks with their own replacement quality shocks
    • Operated by stock BMW ESA controls
    • Specifically for Enduro ESA
    • Only available with orange-colored springs!

    Works Performance in California
    offer quality replacment shocks for ESA

    • Send them your ESA shocks and they "marry" the electronic units from your shocks with their own replacement quality shocks
    • Operated by stock BMW ESA controls
    • ESA only, not yet ESA II nor Enduro ESA
    works_performance_esa_front_800x346.jpg
    works_performance_esa_rear_800x506.jpg

    Race Tech
    offer quality replacment shocks for ESA
    • Send them your ESA shocks and they convert your shocks with their own Gold Valve Conversion kit
    • Operated by stock BMW ESA controls
    • ESA only for R1200RT, not yet ESA II nor Enduro ESA
    race_tech_esa_shocks.jpg

    Öhlins

    Hyperpro
    Address another aspect of ESA - its pre-programmed settings that can't be altered to fine tune. (Some consider this simplification an advantage!)

    The Hyperpro ESA adjuster is an electronic controller that sits under the seat and allows you to remap the ESA settings. Hyperpro claim it is plug and play and that when unplugged, all settings return to standard.


    Ducati Multistrada S

    See also: Ducati Multistrada 1200S 'DES' Suspension for more detailed articles.

    Ducati Multistrada S models also feature electronic adjustment of suspension called Ducati Electronic Suspension (DES). The differences to BMW's ESA include the following.

    BMW ESA Ducati DES
    Development partner: WP Suspension Ohlins
    Front adjustments: preload and rebound damping compression and rebound damping
    Rear adjustments: preload, compression and rebound damping preload, compression and rebound damping
    Adjustments while riding: damping only all
    Suspension modes: 3: rider only
    rider with luggage or
    rider and passenger
    4: rider only
    rider with luggage
    rider and passenger or
    rider and passenger with luggage
    Personalized adjustments: standard settings cannot be changed independent mode allows riders to set their own personal settings

    Probably the biggest difference is that changing the Multistrada's engine mode (Sport, Touring, Urban or Enduro) automatically adjusts the DES mode to suit. (It also affects Dynamic Traction Control (DTC), Ride by Wire (RbW) throttle response and engine power). This automatic integration of more and more electronic systems seems to be the future for both bikes and cars. Expect to see some similar integration on the follow on model to the R1200GS.

    Copyright Hari Ahluwalia / www.motorcycleinfo.co.uk

     

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