Race Sag

[Edmund Kean]

Further to my recent thread which asked other forum members about their preload setting in ESA equipped GSA's, I have detailed my findings in mm for "Race Sag".

Preload on 1 helmet: 83mm

Preload on 1 helmet + luggage: 71mm

As stated before fully kitted out I'm 14.5 stones approx. The bike just has a top box with a few bits (pair of gloves & lightweight rain suit) and had 3/4 full of fuel in tank.

I think the second figure (71mm) is nearer the mark; anyone know?

Ed

 

[Alan R]

Your figures are interesting but I feel that you may be over thinking this. There is little that you can do as far as I'm aware other than fitting after market suspension units such as Wilbers etc. Race settings and GSA in the same sentence seem to be something of an oxymoron, don't you think? Many of the riders on this forum have a far greater mass than you and seem to manage ok. Just ride, you'll be fine.
Alan R

 

[Edmund Kean]

Your figures are interesting but I feel that you may be over thinking this. There is little that you can do as far as I'm aware other than fitting after market suspension units such as Wilbers etc. Race settings and GSA in the same sentence seem to be something of an oxymoron, don't you think? Many of the riders on this forum have a far greater mass than you and seem to manage ok. Just ride, you'll be fine.
Alan R

Maybe I am overthinking; can't be blamed for thinking though, surely

Not much stops me riding so when I'm not riding I tend to think about bikes and riding; all okay on this forum hopefully, just curious

 

[Alan R]

Fair enough, and I agree that it's nice to think about and find out about your bike. I set rear suspension sag on my manually adjusted f800gs rear suspension. On my R1200 gs I don't/can't because the ESA only allows pre determined settings. Hence my comment that you may be over thinking in an area where you can't do anything anyway. I fitted Wilbers wesa to the 1200 which means that the settings are right for me at all times - all 20 stones of me.
Alan R

 

[Edmund Kean]

Fair enough, and I agree that it's nice to think about and find out about your bike. I set rear suspension sag on my manually adjusted f800gs rear suspension. On my R1200 gs I don't/can't because the ESA only allows pre determined settings. Hence my comment that you may be over thinking in an area where you can't do anything anyway. I fitted Wilbers wesa to the 1200 which means that the settings are right for me at all times - all 20 stones of me.
Alan R

So is your WESA bespoke for you?

 

[Alan R]

Yes, you tell them your weight and riding style, then either ride the bike to them or, as I did, tear the bike down and send the suspension units to them for fitting. They then send the units, your old springs and shocks back pretty much by return of post. A happy few hours rebuilding your bike and then a shake down run to discover that your bike has been transformed. If your bike is a keeper, then the financial outlay is worth it. If you change your bike after a few months as some people do, then not so much.
Alan R

 

[robb]

Further to my recent thread which asked other forum members about their preload setting in ESA equipped GSA's, I have detailed my findings in mm for "Race Sag".

Preload on 1 helmet: 83mm

Preload on 1 helmet + luggage: 71mm

As stated before fully kitted out I'm 14.5 stones approx. The bike just has a top box with a few bits (pair of gloves & lightweight rain suit) and had 3/4 full of fuel in tank.

I think the second figure (71mm) is nearer the mark; anyone know?

Ed

If you are going by the rule of thumb it should be around a third of the travel then 71 is about right for a GSA presuming you were sat on at the time

 

[Bendy toy]

The ESA ride height settings are not adjustable so all you can do is use the setting that feels best for your needs. Normal damping modes operate in the "One hat", "One hat plus luggage" and "Two hats" modes. The two off road settings soften the damping.

So jacking up the back end for quick steering and fast riding you need "Two hat" mode. Who said the Germans have no sense of humour.

 

[Edmund Kean]

There are some figures quoted on the link for suggested GS & GSA sag. Have a look if you're interested, it's up to you...

http://www.touratech-usa.com/Adventure/Blog/cAwZHo/How-To-Setting-Suspension-Sag

 

[Old Den]

Thought I may be able to help you understand what is happening from your earlier comments.
Firstly there is ESA 1 system fitted to early bikes. This purely has one spring and when you altered the setting to `one rider and luggage` this just raised the ride height to cope with the extra weight and the spring rate stops the same ( please note the term `spring preload ` does not change the spring rate and in my opinion it is a misunderstood term and would be better called `Ride height adjuster`).
Secondly there is ESA 2 system fitted to later bikes. This has effectively 2 springs. One the normal steel spring and a rubber. Please remember the steel spring rate will not change under compression provided it is a linear not progressive. The rubber bit by restricting the amount it swells under compression will change it`s spring rate(remember rubber donuts on Mini suspension?). So buy using the two together the spring rate can be changed. Just to clarify again (I`ll work in old money as I`m old) If you have a 10 inch long spring with a rate of 100lbs then it will take 100lbs to deflect it 1 inch,200lbs to deflect 2inch etc. If the spring is carrying 300lbs it will become 7 inch long. It will then take 50lb deflect it 1/2 inch.
Obviously the ideal situation would be to fit a higher rate spring to suit the extra weight carried but this is impractical so you raise the ride height to get the bike to sit correctly when loaded. Usually a little more to allow for the greater travel caused by the extra weight and stop it bottoming out. With the ESA2 there is a system that controls the rubber swell and hence changes the overall spring rate to allow for the extra load carried .
Now the problem occurs that if you find the bike handles better with the rear raised to `single rider+luggage` but no luggage you have effectively a higher rate spring which is not ideal .
I`ve also found that with the earlier 2013LC the front is better as the front geometry is changed when the rear is raised. Interestingly the later 2015 bike have a revised geometry/rake at the front and feel the same as the 2013 with the raised rear giving the change in rake (this is just my feed back).
The various ride modes affect the valve in the damper which controls both bump and rebound in one which is pretty basic these days.
The ESA2 is ok but lacks the adjustability but I`m sure some OE system will be along soon that gives that . For the moment the Ohlins ESA TTX system come pretty close but at £3000? a bit heavy for a standard new bike.
Hope this has helped ..........

 

[Edmund Kean]

Thought I may be able to help you understand what is happening from your earlier comments.
Firstly there is ESA 1 system fitted to early bikes. This purely has one spring and when you altered the setting to `one rider and luggage` this just raised the ride height to cope with the extra weight and the spring rate stops the same ( please note the term `spring preload ` does not change the spring rate and in my opinion it is a misunderstood term and would be better called `Ride height adjuster`).
Secondly there is ESA 2 system fitted to later bikes. This has effectively 2 springs. One the normal steel spring and a rubber. Please remember the steel spring rate will not change under compression provided it is a linear not progressive. The rubber bit by restricting the amount it swells under compression will change it`s spring rate(remember rubber donuts on Mini suspension?). So buy using the two together the spring rate can be changed. Just to clarify again (I`ll work in old money as I`m old) If you have a 10 inch long spring with a rate of 100lbs then it will take 100lbs to deflect it 1 inch,200lbs to deflect 2inch etc. If the spring is carrying 300lbs it will become 7 inch long. It will then take 50lb deflect it 1/2 inch.
Obviously the ideal situation would be to fit a higher rate spring to suit the extra weight carried but this is impractical so you raise the ride height to get the bike to sit correctly when loaded. Usually a little more to allow for the greater travel caused by the extra weight and stop it bottoming out. With the ESA2 there is a system that controls the rubber swell and hence changes the overall spring rate to allow for the extra load carried .
Now the problem occurs that if you find the bike handles better with the rear raised to `single rider+luggage` but no luggage you have effectively a higher rate spring which is not ideal .
I`ve also found that with the earlier 2013LC the front is better as the front geometry is changed when the rear is raised. Interestingly the later 2015 bike have a revised geometry/rake at the front and feel the same as the 2013 with the raised rear giving the change in rake (this is just my feed back).
The various ride modes affect the valve in the damper which controls both bump and rebound in one which is pretty basic these days.
The ESA2 is ok but lacks the adjustability but I`m sure some OE system will be along soon that gives that . For the moment the Ohlins ESA TTX system come pretty close but at £3000? a bit heavy for a standard new bike.
Hope this has helped ..........

Thanks for taking the time to detail you're understanding of the ESA systems. However at the risk of being lambasted for showing continued ignorance despite your lengthy input; are you saying that even though the sag measurement I have recorded with 1 Helmet & Luggage was closer to the 30% ratio to total suspension travel (220mm?), I would be better sticking to the 1 Helmet setting?

Thanks

 

[Fanum]

Does it feel right to you? ride it.
If not, adjust it, until it does feel right to you, then ride it

You can have that one F.O.C

 

[Bendy toy]

Does it feel right to you? ride it.
If not, adjust it, until it does feel right to you, then ride it

You can have that one F.O.C

Plus one.

All ride height adjustments will reduce the available wheel travel if the bike is loaded enough to return it to normal ride height. It's why the GSA has 220mm of wheel travel.
The only way to avoid that loss of travel is with a variable rate spring.
This can be done with air springs and some hydraulic systems.
HGVs often use air bag springs sometimes with separate dampers. These correct the ride height and stiffen the spring by pumping up the air pressure. They work best on short stroke systems.
Citroen hydropneumatic cars used compressed gas spheres and hydraulics to give on the fly suspension adjustment. When car sagged under load the system added hydraulic fluid to raise the ride height. This both extended the suspension struts and compressed gas in the spheres. Double benefit.
Powered hydraulics are quick reacting so would be fabulous on a bike. Not only would we get variable spring rate and ride height we could also adjust it on the fly to instantly lower the bike for a comfortable floor reach.