Suspension tightening

[Pletch]

My RT, with ESA, has about 22k on the original shocks. I know that replacing the shocks is the ideal way to get the best performance, but what about adjusting the pre-load on the facotry set-up? I know that the ESA adjsuts the pre-load through any of the 9 different positions or settings, but is it possible to stiffen the base setting, there by increasing the pre-load across all of the settings?

 

No to answer the obvious question, I am a bit of a big guy, 6'4" and 230 pounds, so when riding two up, its a bit soft in the twisties, regardless of the ESA setting.

 

pletch

[dirtrider]

Morning Pletch

 

I think you might be confusing preload with shock dampening?

 

The preload and rebound dampening are separate but both controlled by the ESA.

The preload are the settings depicted by the helmet/luggage symbols on the computer screen and the rebound dampening is depicted by comfort, normal or sport.

 

The preload is basically setting spring length therefore load/height and the dampening is basically controlling the shocks resistance to rebound return.

 

What are you looking to do with your suspension? With your weight + passenger and luggage you probably need all the spring preload you can get. If that isn’t enough you might need a little higher rate rear spring. As you increase the spring preload you will need more shock dampening to control it.

 

 

 

[Jerry Duke]

dirtrider, your answer brought up a question.

Can you adjust the preload settings on an ESA bike to reflect you and your passengers weight rather than what the factory determined them to be?

I've heard most BMW's come from the factory set for a 170 rider. Are the ESA settings set for the same weight?

[Firefight911]

In suspension you must be able to understand the difference in set up from pre load to spring rate.

All the pre load in the world is irrelevant if the weight the spring is being asked to support exceeds its rated capacity.

Modern day BMWs are provided with a spring rate that accommodates an approximately 185 lb. rider. If the rider is 230 lbs. for example, then pre load will not solve the poor handling characteristic. You would need a spring rate suitable for the job being asked of it to optimize the handling.

Cranking in more pre load only band aids the issue.

Do not confuse this with the provided ESA settings of helmet, helmet/luggage, and helmet/helmet. This is pre-load and if the rate spring in place is inadequate to start it will remain inadequate as you load the bike with passenger and or cargo.

And, as has been stated, more rate will require a move up on the amount of damping required.

This is one of the short comings of the ESA as provided. It does not allow for custom tailoring from the manufacturer. There are aftermarket companies that can take your ESA and set it up for your requirements. They will re-spring and re-configure the damping internals to your requirements.

And, of course, once all the above is provided and correct the spring will still need to be set up to its base settings. These are all derived objectively with measurements. After the objective portion is complete then, and only then, can the subjective portion begin; i.e., firmer ride, more damping, softer ride, less damping, etc.

Hope this muddies the water.

[dirtrider]

Afternoon Jerry

 

On the ESA bikes you only have/had the preload settings the ESA gives you. I would imagine if more was needed the spring could be shimmed a little but no way that I know of to go less as the movable collar is all the way up at minimum ESA setting. You have to be careful here as spring RATE alone means nothing without also having the proper spring LOAD. Rate is ONLY the rate or amount of force increase per a unit of movement. On the other hand a proper spring load rating is useless without having the proper spring rate. For heavy riders/passengers the spring LOAD would need to increased as well as the spring rate.

 

 

I have no idea what the stock weight setting is. I have my doubts that even BMW knows exactly where they are as the bikes leave the assembly line as I’m sure they don’t measure or check each and every spring. As far as ESA spring preload goes, early on that used to be somewhat calabrateable (sp) but the newer ones seem to not be.

 

Also, from what I have seen/felt the rebound dampening is all over the board on new ESA bikes.

My personal hexhead RT had so much rebound dampening when new that I never moved it off the comfort setting, on the other hand my friends hexhead bike bought about the same time as mine was loose as a goose even on the normal or sport setting. No way to hold exact tolerances as built in a production situation so I would imagine the delta is pretty large across a weeks or months builds.

 

 

[Indy Dave]

I've heard most BMW's come from the factory set for a 170 rider. Are the ESA settings set for the same weight?

 

I've inquired to the BMWNA consumer advocate about this and his response was that he had no information on the specific weight range of the settings. That information has to be somewhere, but I'm guessing he (and BMW) had bigger fish to fry.

[Firefight911]

One variance from the ESA to the ESA-II systems is the addition of a spring rubber (they call it an elastomer) in the ESA-II.

 

This elastomer somewhat fools the spring in to thinking it has a higher spring rate when the elastomer is wedged between the spring coils. best way to think about this is in NASCAR (yes, I said it) when they add or remove the spring rubbers the effective rate of the spring is being changed.

 

Essentially, as the spring compresses with the elastomer in place the spring can not compress as freely as it could in the absence of the elastomer. This increases rate as it is adding resistive force to movement.

 

Increasing pre-load is not the same as above. As I am not a great articulator of these I offer the below link to help better understand what is going on;

 

LINKY

 

There ya go, more mud.

[Firefight911]

I've heard most BMW's come from the factory set for a 170 rider. Are the ESA settings set for the same weight?

 

I've inquired to the BMWNA consumer advocate about this and his response was that he had no information on the specific weight range of the settings. That information has to be somewhere, but I'm guessing he (and BMW) had bigger fish to fry.

 

A simple look in the owner's manual will provide the answer.

[markgoodrich]

What about the widget Hyperpro announced a year or so ago, and started advertising in the MOA magazine, which allows adjustment of the ESA system to a rider's personal preferences. I presume it changes preload/rebound "set points." Or you can buy my ESA shocks, cheap. I think they have about 18,000 miles on them.

 

http://www.ascycles.com/detail.aspx?ID=119797

[dirtrider]

Evening Mark

 

 

I’m not familiar with that interface box but it would still be limited by the range of the stock ESA shock actuators. Even then after all that money invested you still end up with stock shocks and springs with no compression control.

 

I guess for that kind of money ($900.00) I would put it towards a good set of shocks and springs. (something more adjustable and rebulidable)

 

 

[Firefight911]

Complete waste of money, IMO.

[markgoodrich]

Evening Mark

 

 

I’m not familiar with that interface box but it would still be limited by the range of the stock ESA shock actuators. Even then after all that money invested you still end up with stock shocks and springs with no compression control.

 

I guess for that kind of money ($900.00) I would put it towards a good set of shocks and springs. (something more adjustable and rebulidable)

 

 

Agreed, I mentioned it because of what the OP requested.

[I812]

I think a bigger spring would help. Just thinking back to older shocks. The stock spring is rated for a certain weight range. What that is I don't know. Going to a higher rated spring would help, I would think.

[Swag]

Race Tech will rebuild, revalve, and put new spring on the stock ESA. I just took my in to get it done,they will be doing all that and removing and installing for $979.78.

http://www.racetech.com/page.aspx?id=97&menuid=125

[Pletch]

I just went cross eyed

[BerndM]

Has anyone seen any guidelines for what would be considered "normal" SAG on the 05 series of RT?

I would think that this MAY be a reasonably good indicator of shocks going or gone bad.

Regards

Bernd

 

 

[Hall Vince]

With rider 35mm is about right.

I found on mine 30mm made the bike a bit to twitchy on the steering.

I weight around 85 Kilos with bike gear and carry both panniers and about 5 kilos of kitchen sink around with me all the time.

 

Excessive sag would indicate not enough pre-load or a weak spring. I don't think I've ever heard of a weak spring being reported.

 

Incorrect spring weight for the load carried yes, but not heard of one becoming weak.

 

Usually fading damping is what kills off a shock.

 

I've Wilbers fitted

 

hth

\v/