Extra preload needed

[CPJS]

Bike '17 euro4 TE Low chassis
Supension set in Auto Road Dynamic, I Weigh about 12 stone full kitted.

My problem is I am running out of ground clearence on the right hand side of the bike. The centre stand and brake pedal touch down.
The suspension is working properly and wasn't a problem till I put on Pirelli Scorpion Trails, they have given me the confidence to lean the bike more than ever before, I am not off the edge of the tyre, so there is more to go if there wasn't metal in the way.

Setting the preload to Max is too extreme as it lifts the bike way too much, on the previous bike I could go to 1 plus luggage.

I was wondering if there was a mechanical means of raising the ride height as on a good quality shock or changing the preload parameters, I wouldn't mind if the preload starting point was a little higher.

I don't want a std GS as I only have a 28" inside leg.
I don't want to change the shocks as I will be taking out extended warranty in March.

 

[tanneman]

RH side, because you have a better view through the bend when driving in RHD countries. Changing the shocks to Wilbers or Tractive suspension I very much doubt will influence your extended warranty on the rest of the bike plus the upgraded units can be rebuild, not replaced as is the current set up. As for changing the preload, yes you can. Just get yourself down to Revsracing (Wilbers Agent) having previously informed them of your (accurate) weight all dressed up ready to go, what type of riding you do, where you ride and how often you take a pillion etc. The fine gentlemen will order and fit a spring to increase the preload of the shock.

Or a much cheaper way is to go on a diet.

No charge: http://www.revsracing.co.uk/aboutus.htm

BTW the tyre is not the reason. It is because you have been riding all season. Try from scratch next year after winter and see where you go.

 

[fred_jb]

Stating the obvious I know, but sounds like you either lean it less or get a bike with greater ground clearance for the seat height you need.

 

[wessie]

I am no expert but it sounds like you need to move your body weight more i.e. hang off more so you lower the centre of gravity that enables you to keep the bike more upright for a given corner

 

[roamer]

You wont get to the edge of the tyre ,
my standard gs lc decked out and still had app 10 mm left at the edge,
not sure how esa works but trying a luggage setting might add pre load,
The good news is you have confidence to get to this point,
as your bike is lower, creating less rider sag or adopting a hang off to stand it up may help,
it is a bit of a rave swapping suspension on the lc especially fronts,

 

[fred_jb]

I believe the lowered chassis GS has proportionately stiffer suspension so is not going to sag more for a given load, and also at maximum compression will be no lower than the standard bike. Also while the uncompressed suspension is 20 mm shorter on the lowered bike, at a typical rider sag of 33% the difference is only about 13 mm, and will be significantly less under further compression due to hard cornering. That is not to say that the lowered bike won't touch a bit sooner, but under extreme cornering loads I don't think there will be as much difference as people might imagine.

 

[CPJS]

I believe the lowered chassis GS has proportionately stiffer suspension so is not going to sag more for a given load, and also at maximum compression will be no lower than the standard bike. Also while the uncompressed suspension is 20 mm shorter on the lowered bike, at a typical rider sag of 33% the difference is only about 13 mm, and will be significantly less under further compression due to hard cornering. That is not to say that the lowered bike won't touch a bit sooner, but under extreme cornering loads I don't think there will be as much difference as people might imagine.

This may be true, the problem is that I cannot add a bit more preload, it is all or nothing as with my weight the Auto setting it is the same as Min. If I put it in Max it puts me right up on tiptoes and is making it too hard on the rear suspension. I am looking more to raise the ride height generally as opposed to firming up the spring rate.

 

[fred_jb]

I also have the lowered chassis bike. I weigh nearer 15 st all kitted up and my bike doesn't sag unduly, and the AUTO setting is higher than MIN and lower than MAX. This as it should be as AUTO is designed to keep the bike at the pre-determined ideal ride height, which mine does, and still does even when I add a pillion and luggage. Perhaps your bike has a problem?

 

[tanneman]

I am looking more to raise the ride height generally as opposed to firming up the spring rate.

The only way you are going to do that with an adjustable length shock. These are not available for the GS as far as I know.

In order to keep the ride height higher or correct for your weight is to get the sag correct. 2 ways of doing this, adjust preload or change the spring to suit the weight. Last one is the preferred method. You do not suffer from stiffer suspension as the rate at which the spring compresses is the same, it just takes more force to compress it the same amount as a lesser rated spring.

I don't know if you have the correct bike for your inside seam but with me at a measly 31'' I guess I have no problem on GSA, even adjusted to max preload. Maybe you should move the thread to the suspension section where the gurus hang out or give revsracing or rallyraid a call with your query. I doubt you will get a satisfactory answer in this forum or you are on the wrong bike. Have you tried a low seat on a standard GS? Have you tried any other bike because the 1200R (which is kinda like a lowered GS) decks out easily and for me to do that I have to hoon a bit? Time for a rethink on the kind of bike you want to hoon around on.

 

[fred_jb]

In order to keep the ride height higher or correct for your weight is to get the sag correct. 2 ways of doing this, adjust preload or change the spring to suit the weight. Last one is the preferred method. You do not suffer from stiffer suspension as the rate at which the spring compresses is the same, it just takes more force to compress it the same amount as a lesser rated spring.

Not sure you meant what you seemed to be saying there.

Adding preload does not change the spring rate (for a linear spring) and therefore the spring does not get stiffer as a result of adding preload, even though many people refer to adding preload as "stiffening up the suspension" whereas in fact it is just changing the ride height. It still needs the same amount of force per mm of compression.

On the other hand if you fit a higher rate spring, requiring more force to compress it a given distance than the original, then you are actually stiffening the suspension.

If your weight causes excessive sag, requiring a lot of preload adjustment to get a sensible ride height, then it would be preferable to fit a stiffer spring.

Current ESA systems can auto-adjust preload, but they cannot change spring rate. I believe that some older ESA systems, used on K1200/1300, actually had a way to change spring rate. These had a spring consisting of two parts, metal and rubber, and the effective rate of the rubber component could be changed by moving a metal sleeve that constrained its compression.

 

[CPJS]

Thanks for the replies, I would say the GS Low Chasis is the right bike for me, I have never been able to flat foot any bike I have owned during 40 years of riding (road track and dirt). The GS is the nearest, my heels are still an inch off the ground, I don't want a higher bike as I do a lot of 2up as well during my average of 9,000mls a year and have given up balancing on tiptoe whilst the wife climbs on board.
I will give revs racing a call and see what they suggest.
As for the tyres, PST II, the best feeling tyre I have ever ridden on, they give massive confidence hence my problem now. On this GS i have had ANK III, Road smartIII, PR4 and RTec 01 for me these PST II are the best and suit the GS really well.

 

[tanneman]

Leave the bike on the sidestand when the pillion mounts the bike. Easiest and most secure way of doing it.

 

[fred_jb]

Leave the bike on the sidestand when the pillion mounts the bike. Easiest and most secure way of doing it.

Except if you do that you have to haul more weight upright to get it off the stand and vertical (not that I'm saying my better half is excessively weighty - she might read this!) There can also be a problem with this when the last ride was solo, as in this case the preload is left set appropriate to solo use from the last outing, so if I don't retract the stand before she gets on it gets trapped in the forward position by the extra sag this allows. This is because the AUTO preload setting does not change the preload to suit the extra weight and get the ride height back up to normal until after you start riding.

 

[CPJS]

Leave the bike on the sidestand when the pillion mounts the bike. Easiest and most secure way of doing it.

I don't have a problem with the low GS its all the previous bikes that had me on tip toe.

 

[Deleted account 191119001]

Just go back to A3,s and your problem is fixed way cheaper.........

 

[CPJS]

I also have the lowered chassis bike. I weigh nearer 15 st all kitted up and my bike doesn't sag unduly, and the AUTO setting is higher than MIN and lower than MAX. This as it should be as AUTO is designed to keep the bike at the pre-determined ideal ride height, which mine does, and still does even when I add a pillion and luggage. Perhaps your bike has a problem?

The suspension works ok, the preload adjusts if I load the bike up, just my weight alone is not enough to activate extra preload.

 

[roamer]

It will be interesting to see how you get on at revs,
The great thing is you are confident to get to the limit of ground clearance,
This issue may end up being being something to accept as a limitation,

 

[Deleted account 191119001]

The suspension works ok, the preload adjusts if I load the bike up, just my weight alone is not enough to activate extra preload.

BMW suspension is normally setup for 80kg riders, so roughly in your weight, so all is good there, although this is not a tyre thread you obviously know some tyres are not as rounded off as others hence you can get lower with your Pirellis.

 

[fred_jb]

I think part of the problem is that people may not appreciate that the latest auto preload setting system works in a very different way to the previous adjustment.

Previously the bike was effectively blind to load induced suspension sag, so you had to tell the bike what was going on by manually selecting the most appropriate of the three settings - either "solo", "solo with luggage", or "with pillion passenger and luggage". These were all factory set to suit average rider, pillion and luggage weights so would not give a totally accurate ride height setting if your situation did not conform to those averages - for example if you were much heavier than average, then the solo setting might allow excessive sag. There was no feedback to tell the system if you had selected the best setting for your situation, and only three fixed levels of preload, so no way to fine tune it.

However, people could "game" the old system by deliberately choosing the "wrong" setting in order to increase preload, for example when riding solo you might select solo with luggage, either to compensate for being heavier than BMW's average figure, or to get a higher ride height and greater ground clearance than recommended, albeit the latter would deviate from BMW's ideal setup which would have implications not just for ground clearance, but also steering angle, etc.

The latest system is completely different in that the bike can now detect how much the suspension has compressed, from which it can deduce exactly what the actual load on the bike is. In AUTO mode it will then adjust by the exact amount required to compensate for the actual load and put the bike at what BMW have predetermined to be the optimum ride height, but note that this adjustment only happens when the bike is moving so you won't immediately see a response to any change in load while stationary. A key difference here is that rather than having just three predetermined levels of preload, none if which may be exactly right for the actual load, the preload is now completely variable in AUTO mode so the system can automatically set preload to exactly to what the actual load requires.

It is a bit misleading that there are still three settings MIN, AUTO, and MAX as some seem to think these correspond with the old "solo", "solo with luggage", or "with pillion passenger and luggage" settings. This is not really the case. The system is really intended to be used in AUTO in order to get the same BMW determined optimum ride height for all allowable loads. The MAX and MIN settings seem to be only there to meet rare special case conditions, and are seemingly not intended to be routinely used, as they literally raise the bike to its maximum possible ride height or lower it to the minimum possible, regardless of what the load is.

The further implication of this, as the OP has found, is that you cannot now "game" the system to get just a bit more ride height than BMW thinks is optimum because the three manually selected load settings are gone, meaning that you cannot now deliberately choose the "wrong" one. In AUTO mode the ride height is now always as near as the bike can get it to the BMW determined optimum setting, regardless of load variations. Your only other choices are MAX and MIN preload which are not really suitable for normal riding.

Personally, I think the latest system is a big improvement because the preload is now much more accurately tailored to the actual load, which I think is particularly beneficial when carrying a pillion and luggage, making the handling surprisingly good compared to that when riding solo. It does remove some element of rider control over preload setting, but as you only had three choices before, probably none of which were exactly right for your situation, then I don't see that as a big loss.

 

[the woodster]

I think part of the problem is that people may not appreciate that the latest auto preload setting system works in a very different way to the previous adjustment.

Previously the bike was effectively blind to load induced suspension sag, so you had to tell the bike what was going on by manually selecting the most appropriate of the three settings - either "solo", "solo with luggage", or "with pillion passenger and luggage". These were all factory set to suit average rider, pillion and luggage weights so would not give a totally accurate ride height setting if your situation did not conform to those averages - for example if you were much heavier than average, then the solo setting might allow excessive sag. There was no feedback to tell the system if you had selected the best setting for your situation, and only three fixed levels of preload, so no way to fine tune it.

However, people could "game" the old system by deliberately choosing the "wrong" setting in order to increase preload, for example when riding solo you might select solo with luggage, either to compensate for being heavier than BMW's average figure, or to get a higher ride height and greater ground clearance than recommended, albeit the latter would deviate from BMW's ideal setup which would have implications not just for ground clearance, but also steering angle, etc.

The latest system is completely different in that the bike can now detect how much the suspension has compressed, from which it can deduce exactly what the actual load on the bike is. In AUTO mode it will then adjust by the exact amount required to compensate for the actual load and put the bike at what BMW have predetermined to be the optimum ride height, but note that this adjustment only happens when the bike is moving so you won't immediately see a response to any change in load while stationary. A key difference here is that rather than having just three predetermined levels of preload, none if which may be exactly right for the actual load, the preload is now completely variable in AUTO mode so the system can automatically set preload to exactly to what the actual load requires.

It is a bit misleading that there are still three settings MIN, AUTO, and MAX as some seem to think these correspond with the old "solo", "solo with luggage", or "with pillion passenger and luggage" settings. This is not really the case. The system is really intended to be used in AUTO in order to get the same BMW determined optimum ride height for all allowable loads. The MAX and MIN settings seem to be only there to meet rare special case conditions, and are seemingly not intended to be routinely used, as they literally raise the bike to its maximum possible ride height or lower it to the minimum possible, regardless of what the load is.

The further implication of this, as the OP has found, is that you cannot now "game" the system to get just a bit more ride height than BMW thinks is optimum because the three manually selected load settings are gone, meaning that you cannot now deliberately choose the "wrong" one. In AUTO mode the ride height is now always as near as the bike can get it to the BMW determined optimum setting, regardless of load variations. Your only other choices are MAX and MIN preload which are not really suitable for normal riding.

Personally, I think the latest system is a big improvement because the preload is now much more accurately tailored to the actual load, which I think is particularly beneficial when carrying a pillion and luggage, making the handling surprisingly good compared to that when riding solo. It does remove some element of rider control over preload setting, but as you only had three choices before, probably none of which were exactly right for your situation, then I don't see that as a big loss.

Well explained, and most importantly, spot on.