Vehicle Stability System - Any Way to Make it Less Sensitive?

[NancysToy]

Heck, I didn't need a test to tell that the nanny kicks in sooner with a passenger. I can't push curves and turns at all when my wife is riding. However, I am pretty sure she is keeping me from hurting myself......


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That has less to do with the nanny settings than it does with the passenger. The passenger on a Spyder is less tuned in with the machine, hence the grab-bars. They are pretty much thrown around back there, to some extent. That changes the center of gravity and the Spyder's response in turns. The passenger weight also changes the weight distribution, increases the body roll, and works the suspension harder. All contribute to more difficult cornering...whether or not the nanny gets involved.

 

[BajaRon]

That has less to do with the nanny settings than it does with the passenger. The passenger on a Spyder is less tuned in with the machine, hence the grab-bars. They are pretty much thrown around back there, to some extent. That changes the center of gravity and the Spyder's response in turns. The passenger weight also changes the weight distribution, increases the body roll, and works the suspension harder. All contribute to more difficult cornering...whether or not the nanny gets involved.

All true. Weight distribution can be as important, if not more important than the amount of weight. The best place for weight on our Spyder is low to the ground between the front wheels. The higher the weight, and the further the weight from the front wheels, the greater the negative impact on handling.

So really, the worst possible addition of weight for a Spyder is a passenger. A passenger is located high and a long way from the front wheels. The Nanny attempts to compensate for this critical addition with a more stringent setting activated by a switch under the seat.

 

[sledmaster]

Be Thankful for VSS

Tell ya' what, we should all be very thankful for the VSS system as it is about the only way the Spyder was made possible. I was able to ride early prototypes that did not have the VSS and, when cornering hard on a test track, you could get the inside front wheel to come up off the pavement pretty much at will and it was up to you (and only you) to lay it back down. So while we can ask for ways to make the VSS less apt to kick in, ultimately I am very thankful for this technology.

Seems like each and every Spyder I ride it acts just a little bit differently, but as many have said you can learn how to work with it and use it to your advantage. I can tell you it kicks in far easier on my ST-S than it does the original GS models, but when it does kick in it is less intrusive. The single biggest thing I can do to keep it happy is to lean further into the corners with my body, like riding a snowmobile. And just like this keeps the inside ski down on a sled, it helps to keep the inside wheel down on a Spyder.

This is why BajaRon's anti-sway bar works so well, it reduces the body roll that the VSS senses and helps to keep the nanny from kicking in. And, this is why better shocks also help, again to reduce body roll and better control the vehicle mass and keep it within the established parameters of the VSS system.

 

[Bob Denman]

Maybe I notice because I'm just such a sensitive guy!

And good looking too! :2thumbs:

 

[stewartj239]

The passenger seat switch changes the response of the VSS, namely the traction control, and it also changes the braking bias. Either would likely cause VSS intervention sooner or stronger without a passenger. The ABS response could also be adversely affected.

Thanks for the confirmation. When my wife and I are touring, it never kicks in because I don't push it. However, when I zip tied it and went out by myself, it was literally 2X more sensitive. It was very noticeable.

 

[stewartj239]

So while we can ask for ways to make the VSS less apt to kick in, ultimately I am very thankful for this technology.

I agree. I truly believe that it is a necessary safety feature, but the way it is tuned is way too aggressive.

 

[Bob Denman]

Nanny ain't nothing, when compared to "The Missus"! :shocked:
nojoke

 

[sledmaster]

VSS is actually a culmination of three systems, the ABS braking, the TCS traction control and the SCS stability control. The notes I took when the system was explained to me say there are six sensors being monitored by the VSS. We have three wheel sensors, a lateral yaw sensor, a steering angle sensor and an engine torque sensor. Based on the input of these six sensors that are being monitored 25 times per second, engine power can be reduced and each of the three wheels can have the brakes applied independently.

Having ridden units without VSS I think you might be surprised at how the vehicle worked without it. Maybe not. The VSS is kicking in because it knows what kind of forces it takes to get a wheel off the ground. During product development there would have been all kinds of data acquisition equipment on the units and they measured time and time again what it took to get the vehicle out of sorts. If it kicks in, it is because you are rapidly approaching that moment of truth. The lateral yaw sensor might be the one we are most concerned with. I’m not sure if the programming is monitoring the rate of change, but I suspect it does.

So while we might believe the nanny is kicking in too early at times, it might not be. It just might know what the impending outcome would be, otherwise. Considering I got yelled at railing around corners on a test track lifting the inside front tire on a unit without VSS, I am not surprised at how sensitive the nanny is. It is there for a very good reason, to keep us out of trouble. If you crank on the handlebars and the throttle at the same time when sitting at a stop sign you will find out in a hurry what happens. This is not a suggestion, just an observation!

 

[Bob Denman]

Thank you for a very clear and concise explanation! :thumbup:
And some very interesting background on how Nanny came to be what she is! :clap:

 

[NancysToy]

VSS is actually a culmination of three systems, the ABS braking, the TCS traction control and the SCS stability control. The notes I took when the system was explained to me say there are six sensors being monitored by the VSS. We have three wheel sensors, a lateral yaw sensor, a steering angle sensor and an engine torque sensor. Based on the input of these six sensors that are being monitored 25 times per second, engine power can be reduced and each of the three wheels can have the brakes applied independently.
and the throttle at the same time when sitting at a stop sign you will find out in a hurry what happens. This is not a suggestion, just an observation!

Correction...it's a steering torque sensor. The steering angle and steering torque are compared and the VSS makes corrections using the brakes to try to maintain the intended steering line if necessary.

 

[sledmaster]

Thank you for the correction professor. pps: I was working off of notes from over six years ago, but when you think about it that is far more logical!

Edit: I looked back through my notes and can confirm it is a steering torque sensor, not an engine torque sensor, as one of the sensors used by the stability control. This should be the same steering torque sensor used for the DPS dynamic power steering. The DPS system uses it, along with the steering angle sensor and speed sensor, to maintain the same steering force at all speeds by applying variable power assist.

I had also noted the Spyder was fitted with four different ECUs on board, communicating via a CAN bus. Professor probably already knows this, but I thought it was cool!

Other items of interest includes specs for the original 990 Rotax, rated at 106 HP @8,500 RPM and 77 ft-lbs of torque at 6,250 RPM.

These notes were taken on January 11, 2007 when we were introduced to the P3 prototypes. At that time, BRP indicated the Spyder had been a concept ten years previous (which would have been 1997) and they had prototypes 7 years previous (which would have been 2000). This is consistent with my first ride opportunity in 2001.

 

[Sny]

Couple things:

I had swapped seats on my ST and somehow a bolt wound up lodged in the passenger sensor and jammed it in the "on" position. Man did that suck. Later I swapped seats again and noticed it. I had no idea what I had done

If you want the nanny to go away (you don't... trust me) move both the front speed sensors to the rear wheel so all three sensors are together on the same wheel. The nanny will think the world has ended and go out to lunch.

But if you do: baaaad things happen.

 

[Bob Denman]

77084[/ATTACH] baaaad things happen.

Wow! :shocked: That one moved quite a bit... How long did it take to knit back together?? :yikes:

Moving the spped sensors is an option...
My Grampa Denman also used to tell me that you've always got the option to hit yourself in the head with a hammer...
Just because you CAN do something, doesn't mean that you should! :thumbup:

 

[sledmaster]

Additional Info

I looked back through my notes and can confirm it is a steering torque sensor, not an engine torque sensor, as one of the sensors used by the stability control. This should be the same steering torque sensor used for the DPS dynamic power steering. The DPS system uses it, along with the steering angle sensor and speed sensor, to maintain the same steering force at all speeds by applying variable power assist.

I had also noted the Spyder was fitted with four different ECUs on board, communicating via a CAN bus. Professor probably already knows this, but I thought it was cool!

Other items of interest includes specs for the original 990 Rotax, rated at 106 HP @8,500 RPM and 77 ft-lbs of torque at 6,250 RPM.

These notes were taken on January 11, 2007 when we were introduced to the P3 prototypes. At that time, BRP indicated the Spyder had been a concept ten years previous (which would have been 1997) and they had prototypes 7 years previous (which would have been 2000). This is consistent with my first ride opportunity in 2001.

 

[Bob Denman]

:thumbup: :clap: Thanks!

 

[Barlock]

I want to thank everyone involved in this discussion. I had no idea about any of those things you discussed here, and now (I think) I learned quite a bit. AlthoughI must admit I haven't (yet) experienced my Spyder's nanny kicking in (Isn't it a good thing?):dontknow:

 

[Bob Denman]

If nanny kicks in; you may have been tickling the Dragon's tail, so she saved your butt...
I would say that's pretty good! :thumbup:

 

[HuckFin]

I want to thank everyone involved in this discussion. I had no idea about any of those things you discussed here, and now (I think) I learned quite a bit. AlthoughI must admit I haven't (yet) experienced my Spyder's nanny kicking in (Isn't it a good thing?):dontknow:

As far as I'm concerned its a good thing. Anyway awhile back in this same thread I posted that the rear wheel on my RS-S broke loose going twice the recommended speed limit around a corner with out the nanny kicking in. Well... last week I decided to try it again, only this time 5 mph slower, but this time about half way through the corner my throttle went away. The only thing different this time, besides going slower was me not leaning as hard (the first time I was half off the seat) Still haven't felt nanny applying the brakes....Yet..

 

[Sny]

Wow! :shocked: That one moved quite a bit... How long did it take to knit back together?? :yikes:

Moving the spped sensors is an option...
My Grampa Denman also used to tell me that you've always got the option to hit yourself in the head with a hammer...
Just because you CAN do something, doesn't mean that you should! :thumbup:

16 weeks give or take... probably another year before it "felt right" putting any real force behind it.

 

[stewartj239]

Although I must admit I haven't (yet) experienced my Spyder's nanny kicking in (Isn't it a good thing?):dontknow:

If you are at or past your limits when the nanny kicks in, then yes, it is a good thing. But there are plenty of riders out there who can push the Spyder beyond what the nanny will allow and that is the frustrating part. I've said it before, you can scrape the pegs on a GoldWing, so there is no reason why the Spyder can't be pushed to it's limits as well, but the nanny won't allow it. It is WAY too conservative. Obviously, lawyers were involved when Can-Am determined what the default threshold would be. I can only imagine the shock and dismay of the engineers who designed this thing when they found out.