For Those With Aftermarket Lowering Links and ESA

[marcparnes]

Just a heads-up if you have a bike equipped with ESA and have lowered your bike by installing a lowering link like Soupy's or Brock. The bike will ride better if you reset the rear suspension travel sensor.

Here is what it is and why it is important: If you look along side the rear shock on the left side you will see a link that goes from the swingarm to a sensor mounted to the frame. This travel sensor keeps track of the swingarm's position and speed of movement and then relays that information in realtime to the suspension program. From this data the program adjusts the shock's damping. As an example, lets say you are accelerating hard out of a corner. This will cause the rear end to "squat" changing the bike's geometry which can cause it to steer wide. In order to control the amount of "squat" the sensor tells the program that the rear end is coming down fast and its position so the program can respond by increasing the compression damping in order to slow down the "squat". There are all kinds of scenarios where the program responds to the speed in which the swingarm moves as well as it's relative position. When you lower the rear of the bike you aren't changing the swingarm's speed in response to a bump but you are changing its relative position under load by the amount you lowered the bike. This will result in bogus information being relayed to the program which effects how it reacts. Fortunately this is very easy to correct.

Lets say that you lowered the bike by 25 mm at the rear as well as the front. Since all you did was to move the fork tubes up 25 mm in the triple clamp you didn't change anything at the front as far as the program knows. In other words, with the bike on the center stand and the fork fully extended the top of stroke is the same as it was originally. This is not the case with the rear. Since you lowered the frame of the bike relative to the axle by 25 mm then when the bike is on the center stand and the shock is fully extended the program thinks the axle is actually under compression by 25 mm. This error is maintained as the swingarm moves through its stroke. We need to correct this so the program knows where the top of the stroke is so it can react properly to swingarm position.

There are two ways to do this: take it to the dealer and ask him to reset the travel sensor or you can do it yourself as I have using a GS-911 tool. I don't have my GS-911 hooked up at the moment but under suspension there is a function which re-calibrates the travel sensor. This is done with the suspension unloaded and teaches the program where the top of stroke is. I did this to my lowered bike yesterday and it rode and cornered noticeably better today 

Marc

[LAMBO281]

Ok wow good info, mine was lowered 10mm but rides perfect, guessing this will make it ride even better? Is it easy for bmw to reset? A quick plug in and reset button?

[MattR]

Good post 

[Bree]

    Ha Ha This forum is a never ending font of useful information. Don't you just love it..  

[marcparnes]

Originally Posted by LAMBO281

Ok wow good info, mine was lowered 10mm but rides perfect, guessing this will make it ride even better? Is it easy for bmw to reset? A quick plug in and reset button?

Yep, all they do is plug the bike into their computer, but the bike on its side or center stand and push a button or two. Very simple.

Marc

[cj125]

Interesting.....I had mine fitted by the dealer when I picked it up new in Nov last year. I wander if they have carried out this resetting....guess the only way to know is to ask! Is there any way to check / verify it?

[marcparnes]

Originally Posted by cj125

Interesting.....I had mine fitted by the dealer when I picked it up new in Nov last year. I wander if they have carried out this resetting....guess the only way to know is to ask! Is there any way to check / verify it?

Not without plugging it into the dealer's computer or a GS-911.

Marc