Why Spyders need VSS

[spyderCodes]

I think I have an idea of how the various parts of the VSS (Vehicle Stability System) work, but I really didn't know why it was so important on the Spyder.
Almost every on line explanation of how the VSS worked had wording to the effect of "due to the inherent instability of the configuration ...".
What made it inherently unstable?
And what does that mean?

I have only a bare understanding of vehicle handling terms like oversteer and und understeer.
I tend to just think about something else when those terms start flying around.

But back to the question of what is unstable about the Spyder's configuration?
I called an old friend of mine. Paul who lives in California and sets up suspensions for race cars and even has done a bit of consulting with Bosch, though NOT on the Spyder's system.

Knowing my limitations, he explained it to me this way.
The two wheels in the front with their wide stance are much, much more sticky to the road than the single wheel in the back.
Sticky to the road must be one of those technical terms.

Because of this, the rear wheel tends to want to pivot around the two anchored front wheels when given half a chance.
The big wide rear tire helps, but it would take a massively wide one to compensate completely.
That's why VSS is a must.
It intervenes and makes sure the rear wheel stays where it should in relation to the front.

The modern electronic wizardry of VSS takes an inherently unstable configuration and makes it stable.

The explanation could get loads more complicated but that seems to make sense to me.

 

[BajaRon]

I think I have an idea of how the various parts of the VSS (Vehicle Stability System) work, but I really didn't know why it was so important on the Spyder.
Almost every on line explanation of how the VSS worked had wording to the effect of "due to the inherent instability of the configuration ...".
What made it inherently unstable?
And what does that mean?

I have only a bare understanding of vehicle handling terms like oversteer and und understeer.
I tend to just think about something else when those terms start flying around.

But back to the question of what is unstable about the Spyder's configuration?
I called an old friend of mine. Paul who lives in California and sets up suspensions for race cars and even has done a bit of consulting with Bosch, though NOT on the Spyder's system.

Knowing my limitations, he explained it to me this way.
The two wheels in the front with their wide stance are much, much more sticky to the road than the single wheel in the back.
Sticky to the road must be one of those technical terms.

The big wide rear tire helps, but it would take a massively wide one to compensate completely.
Because of this, the rear wheel tends to want to pivot around the two anchored front wheels when given half a chance.
That's why VSS is a must.
It intervenes and makes sure the rear wheel stays where it should in relation to the front.
The explanation could get loads more complicated but that seems to make sense to me.

As you say, the 'inherent instability' is due to the unequal traction and stance between the front of the vehicle and the rear. Though unequal traction exists in virtually every vehicle, it is pronounced in a 3 wheeled configuration. This coupled with the unequal stance (wide in front and narrow in back), makes for some interesting consequences. For instance, how many vehicles have you ridden which can relatively easily lift 1 wheel off the ground? Other than doing a wheelie on 2 wheels, probably not many.

The main issue with the Spyder occurs when you break traction. This will usually happen in a turn or curve which means you will begin to slide sideways. What happens then is the problem as traction is usually recovered. But on the Spyder it tends to be very abrupt and sudden. The BRP test pilots I spoke with who had ridden prototype Spyders with the VSS turned off said the rider ends up being a lawn dart. Meaning the rider is ejected when traction is regained. I don't think I need to tell you how detrimental to your longevity this could be.

So, the VSS is specifically designed, (and may I say, works extremely well) to prevent this initial loss of traction thus preventing the unwanted consequences. Those who have disconnected or defeated the VSS need to ride VERY CAREFULLY!

 

[Brian Kay]

Cool...lawn darts were so much fun. The unfortunate part is, when you are holding onto handlebars, one thrown off tends to keep hands planted and cannot overcome the force and therefore your hands are kept close to your body and you do a "header" into the lawn, pavement, whatever. Classic example is Christopher Reeve...ouch.

 

[Bob Denman]

Roger,
Thanks for an explanation that is so simple: even I can keep it all straight! :clap: :2thumbs:
Back in 2010: I met a fellow who said that he worked for the firm that developed the front suspension system. It took CUBIC dollars to get it close to what they wanted; but it took Bosch and their V.S.S, to bring the machine to market!

 

[Peter Aawen]

The interesting thing is.... that as time progresses & everyone concerned gets more 'skilled'(??) with these Spyders & the VSS, it's becoming clear (to riders & more importantly, also to BRP & the Bosch VSS developers) that the Spyder is much more drivable than they originally thought/ever dreamt, & it's obvious that while the VSS is an important & necessary feature, it doesn't need to be as quite as restrictive & intrusive as was originally thought & implemented.

That's meant there have been a number of 'enhancements' along the way to how much the VSS let's the rider get away with & how it interacts as the Spyder & various models have developed; the F3 in particular has seen a couple of stages of 'greater relaxation' for the Nanny/VSS, & it sounds like the 2017 Daytona release is going to take that even further with the introduction of a 'Sports' mode!! Now all I need is for that VSS program to be made available as a retro-fit for my 2013 RT! :thumbup:

 

[PrairieSpyder]

Two-wheelers also have a problem if the rear wheel out-runs the front. Or, I should say, the rider has a problem. This happens when the rider hits the front brake too hard in relation to the rear brake, and it can be deadly.

That may be a reason our Spyders have linked brake controls.

 

[Chupaca]

Thanks....

gotta say I can live with that...:thumbup: I have had the odd run in with the VSS and with it's ultimate wisdom it let my over zelotness slide...:bowdown:

 

[Bob Denman]

 

[wanderingman]

Wanting more oversteer

ds

The interesting thing is.... that as time progresses & everyone concerned gets more 'skilled'(??) with these Spyders & the VSS, it's becoming clear (to riders & more importantly, also to BRP & the Bosch VSS developers) that the Spyder is much more drivable than they originally thought/ever dreamt, & it's obvious that while the VSS is an important & necessary feature, it doesn't need to be as quite as restrictive & intrusive as was originally thought & implemented.

That's meant there have been a number of 'enhancements' along the way to how much the VSS let's the rider get away with & how it interacts as the Spyder & various models have developed; the F3 in particular has seen a couple of stages of 'greater relaxation' for the Nanny/VSS, & it sounds like the 2017 Daytona release is going to take that even further with the introduction of a 'Sports' mode!! Now all I need is for that VSS program to be made available as a retro-fit for my 2013 RT! :thumbup:

The thought of the VSS from the F3 is interesting. I have enjoyed cars with a lot of oversteer. the problem of comparing the Spyder RT with the F3 with looser VSS standards, is that the RT has a much higher CG than the F3. Basically this means it would be much easier to be spit off the RT than the F3. ( become a lawn dart) Comparing it to an oversteering car is even worse due to the seat belts in a car, making the driver much more secure. The thought is appealing. The reality could be scary. Remember us newbies haven't had the experience to "get more skilled", and as I see 18 year olds on 150 + horsepower 2 wheelers going down the road, I am well aware, if the ability to do what you refer to is available, not only the skilled will do it.

 

[wanderingman]

Agree

VSS

gotta say I can live with that...:thumbup: I have had the odd run in with the VSS and with it's ultimate wisdom it let my over zelotness slide...:bowdown:

Chupaca, I like your thinking. I am too much inexperienced to have yet experienced the VSS taking over. The fact is I would love to be able to get the rear end to hang way out dirt tracker style. But the reality is that if the VSS works correctly it may keep me around to become one the oldest Spyder riders alive. An old aviation axiom says, "there are old pilots and bold pilots, but no old bold pilots". I believe this same may be true for motorcyclists.

 

[spyderCodes]

The VSS has other uses besides keeping the Spyder stable in turns.

I hit a massive puddle about 6 inches deep while going 70mph. I felt the VSS applying brakes in such a way as to keep the Spyder going in the direction of the bars.
I don't recommend trying something like that on purpose.

Had it not intervened I probably would have been in for an interesting next couple of months recuperating.

 

[Dan McNally]

At 68, I am all for features that help me to not out ride my capabilities. :thumbup:

I'm not the man I used to be, :banghead: and I heal a LOT slower, now! nojoke

 

[Deer Slayer]

Morgan?

I ponder how the 3 wheel Morgan got down the road all these years. VSS = Canadian Lawer.
:riding:

 

[BajaRon]

Though there is some inherent instability with the reverse trike design Spyder. Compared to a conventional trike the Spyder is much more stable.

 

[robmorg]

THAT was a GREAT video! Thanks. :thumbup:

 

[cognaccruiser]

As suggested by others, we/I don't bounce like I used to and healing is too lengthy a process now. I don't mind in the least that the VSS might kick in should gravity loose its grip on our Spyder.
Saw it work when we hit interstate covered with hail going to 2015 Spyderfest. Happily we were already going slowly.
I have no desire to turn the system off or relax it even though I don't push the envelope much any more. If the speed I'm going feels like fun to me and yet doesn't activate VSS, all the better.

Gary