ACS Suspension Adjustment Question

[robmorg]

I converted from 2 to 3 wheels last fall when I purchased my local dealer owner's personal demo 2013 RT Limited. (No loss to him - he's now riding a 2014 model with the larger engine. ) I've now got almost 1000 miles on my new Spyder and am now leaning properly into turns and no longer over-steering, etc. I'm loving it!

But, I am confused about how the ACS suspension actually works. I've read the manual but it does not seem clear. I understand that the ACS system automatically adjusts the suspension height for the load, and that you can use the buttons to change the automatic settings. I also understand that pushing the top (forward) button stiffens the ride and the bar on the screen goes up. Conversely, pushing the lower (rearward) button softens the ride and makes the indicator bar goes down.

What I do not understand is what is actually happening when the buttons gets pushed. It would seem intuitive that pushing the top button would add more air to make the ride stiffer and pushing the bottom button let's some air out to make it softer. Is that right, or do I have it backwards?

If I'm correct, then why does the manual (page 59) say that the top position on the screen (stiffest setting) is the "Lowest" riding position and bottom position on the screen (softest setting) is the "Highest" riding position? That is counter-intuitive. Wouldn't adding more air make the suspension stiffer by raising it, not lowering it?

Could someone please tell me what I'm missing here. :banghead:

Thanks,
Rob

 

[NZSpyderRyder]

My guess

My guess for what it's worth, by taking air out and lowering the suspension you will actually stiffen the suspension up as there won't be as much air to cushion the ride. when you add air you soften the ride as you have a larger volume of air to cushion the ride, think about fluffing your pillow up to make it softer and more comfortable.

Like I say just my guess as I don't have this system on my spyder.

 

[Bob Denman]

The air pressure that the system generates for all of this is pretty much irrelevant; it'll use whatever it needs to maintain a certain ride height... :2thumbs:
That's why you'll always hear bikes bleeding off air OR pumping it up when they first fire up...:thumbup:

 

[robmorg]

The longer suspension travel means a softer ryde.
That means the suspension will try to maintain a higher height by adding air to the system if you choose soft.

A shorter suspension travel means a stiffer ryde.
The system will remove air to lower the height if you choose stiff.

The settings between soft and stiff are just variations on the theme.

Thanks, guys, for your input.

Roger, First, thanks for the Spyder Codes app. What nice "Father's Day gift".

What you said above sort of makes sense, but it is NOT what actually happens on the bike. Also what happens to the ride height is exactly the opposite of the way it is shown in the manual. I just went out and tested the system by placing a board across the back seat and then measuring the distance from the garage floor to the board with a yard stick at various suspension settings. Here's the result:

When you press the "Stiffen" button Z(the one that shows the spring compressed on the icon), the compressor runs, pumping air into the shock, and raises the back of the bike. Alternately when you press the "Soften" button (the one that shows the spring not compressed) you can hear air being released in increments and the bike will lower in steps as you keep pushing that button. You can actually feel it lowering as you sit on it. The range of ride height, between the top and bottom of the gage on the display, is 3/4 of an inch while sitting on the bike. (If there is no one sitting on the bike, the system works the same, but with less travel in the ride height.)

In other words, when the bar indicator is at the top of the bar graph on the display (in the stiffest position) the shock has the most air. As you press the soften button, air is released from the shock and the bike goes down. This observation is the opposite of what you just said, AND also the exact opposite of what is printed on the "ride height diagram" that is shown on page 59 in the owner's manual.
So now, after observing the system in action, I am still confused. :gaah:

 

[Magdave]

On my RT the chart under the seat indicates the more weight you carry the more air it needs to maintain the height. Lower height softer ride so lower air = the same. Just like the old days when we put air shocks on our cars to raise the rear more air made the suspension stiffer not softer.

 

[robmorg]

On my RT the chart under the seat indicates the more weight you carry the more air it needs to maintain the height. Lower height softer ride so lower air = the same. Just like the old days when we put air shocks on our cars to raise the rear more air made the suspension stiffer not softer.

Yep. It was the placard under the seat on the non-ACS RT that got me wondering about this. On my Limited, I have the ACS automatic adjustment system, but I've just confirmed (with a ride on some bumpy roads) that it works exactly the way you just said. You push the "Soft" button, air is released from the shock, the ride height lowers, and the ride gets softer.

Thanks, Dave.

 

[robmorg]

hmmmmm
so much for that bit of guessing.
honestly if it is the opposite I don’t (obviously) understand it either.

Roger,

Don't feel bad - neither does the guy who wrote the RT owners manual. :shocked:

I've just come back from a long afternoon ride, and I was careful to include some fairly bumpy back roads so I could test which way makes the ride softer. So, here are the combined results, of my "garage ride height test" and my "bumpy road test"....

Push the "Hard Button", the indicator on the display rises, air gets pumped into the air spring, the back of the Spyder rises, and the ride gets more harsh.

Push the "Soft Button", the indicator on the display lowers, air is released form the air spring, the back of the Spyder lowers, and the ride gets more soft.

As for ride height, that is completely the opposite of the chart on page 59 of the 2013 RT owners manual. But at least now, we know exactly how it works (and what the Owner's Manual SHOULD say).

Thanks for your help.
Rob

---

Update... Since this thread was first posted, I have received a copy of the shop manual which clarifies things a little. (See the picture and text below from the shop manual.) The Spyder does NOT have an air shock, as I originally thought. It has a conventional shock with a pre-load spring, PLUS an airbag (which BRP calls an "air spring"). It is the air bag that raises and lowers the bike against the swing arm. However, the resulting principles and conclusions are the same as originally posted.

ACS AIR SPRING
ACS Air Spring Location
The ACS air spring is located on the swing arm in
front of the shock absorber.

SOME PARTS REMOVED FOR CLARITY PURPOSE
1. ACS air spring

 

[Bob Denman]

I HATE to throw another issue on the pile for you... :shocked:
By pumping it up and down; you also are affecting the aiming of the headlights... :yikes:
You can use the ACS as a "Quick & Dirty" way to re-aim your headlights in a pinch! :thumbup:

 

[robmorg]

I HATE to throw another issue on the pile for you... :shocked:
By pumping it up and down; you also are affecting the aiming of the headlights... :yikes:
You can use the ACS as a "Quick & Dirty" way to re-aim your headlights in a pinch! :thumbup:

Bob,

Yep, 3/4" movement in the back will definitely re-aim the headlights. That's the travel distance I measured between the lowest and highest setting while the bike was static in my garage.

Hope you are enjoying your new 2014 Limited with the new engine. I'm sure you probably have posted your impressions of the differences here by now. If you don't mind, please throw me a link to that thread. I'd like to read it. (Yeah, I know I could search for it. Just feeling lazy today.) pps:

 

[Bob Denman]

http://www.spyderlovers.com/forums/showthread.php?65533-The-More-That-I-ride-This-Thing

I think that this is it... :thumbup:

 

[Questions]

Ok so does Raising the back (making shock stiffer) cause the nose to sag at all? And alternately lowering the rear (making shock softer / removing air) Tip the nose up? I have been riding back roads (bumpy ones) in the Stiffer setting on the "assumption" that the nose of the bike is higher or at least LESS PRONE to bottoming out.

My 14 RT limited does not seem to like bumpy roads and the Bumpskid I bought, I am confident has paid for itself many times now. I have been wondering if I should try adding air.:dontknow:

 

[robmorg]

Ok so does Raising the back (making shock stiffer) cause the nose to sag at all? And alternately lowering the rear (making shock softer / removing air) Tip the nose up? I have been riding back roads (bumpy ones) in the Stiffer setting on the "assumption" that the nose of the bike is higher or at least LESS PRONE to bottoming out.

My 14 RT limited does not seem to like bumpy roads and the Bumpskid I bought, I am confident has paid for itself many times now. I have been wondering if I should try adding air.:dontknow:

First, I should point out that the RT does NOT have an air shock as I assumed when this thread was originally posted. It has a conventional shock with a coil spring AND an airbag that sits in front of it. However, the principles discussed earlier in this thread are unchanged. See correction here to the post above (along with a diagram of the system).

Now, to answer your question... Your assumption is correct, although the up and down movement of the front tip of the Spyder would be very slight. The entire movement at the rear passenger seat, between the two extremes, is only 3/4 of an inch, as I discovered with actual measurements. The swivel point would be at the front axle, so the actual movement of the front end of the Spyder would be very minimal. Although, as Bob points out above, the movement is enough alter the headlight focus point (which is way out in front of the bike). Also keep in mind that as you ride, the "air spring" is continually adjusting a small amount as dictated by the ride height sensor.

As you add air, the front tip of the bike would lower very slightly, since it is in front of the pivot point. (Remember that the "ride height chart" in the owners manual (and the shop manual) are both wrong, as adding air to the bag does indeed raise the back end. Don't know if this was corrected in the 2014 manual.) Again however, the movement at the front tip would be extremely slight - probably not enough to have much of an effect with regard to your question. On my 2013 RT, I do not have any problem at all with the front tip touching the road on bumps, but I could not offer any input as to the 2014. The front suspension would be a little different between these two models.

 

[Questions]

Good info. From what I can tell the 2014 manual has the same. Confusing info.


Sent from my iPhone using Tapatalk

 

[Marker]

On my 2010 RT-S when you are at the top setting the air bag is full of air so the ride is stiffer. It only makes sense because the air bag is stopping the shock from being able to ride up and down with ease hence a stiff ride.
When the re is less air in the air bag the shock can move farther up and down on its stroke and you get a softer ride.

I had the ACS sensor fail and the bag became completely inflated and stayed that way ,very stiff ride and trhe back of the trike was a way up in the air. I also have had a shrader valve fail and the opposite happened the air bag could not hold air ,the ride was soft and rough. Thank goodness for warranty.