Questions Regarding Rear Suspestion System

[Old Crow]

I don't quite understand what the rear suspension system is actually supposed to do, based on what I've read here. The indicator on the dash shows adjustment from "hard" to 'soft", but comments here seem to indicate it adjusts to maintain the correct ride height based on rider/passenger loading.

Although I never hear the compressor running the system appears to be working. With me on the seat, in gear, engine running the "soft" setting reads about 30 PSI when checked with a gauge on the valve under the seat. After adjusting to "hard", the pressure has risen to 50+ PSI, so obviously the compressor is working as it should.

The load on the suspension is the same in both cases since it's me on the seat both times, so what is that change in pressure doing if the ride height remains constant? Need some education here. 2013 RT-S.

Thanks,
Bob

[Woodaddict]

new here with 2015 RT-LTD. the adjustment from soft to hard is NOT automatic. you choose what kind of ride you want, pushing up or down to adjust

[Bob Denman]

There is a strut mounted between the shock and the swingarm...

ACS Strut.jpg
It is actually there to monitor your ride height. As the load on the bike changes; this system will automatically adjust the air pressure in the shock reservoir to maintain a constant ride height.
By using the terms "Soft to Hard": you are actually referring to lowering the ride height, or raising it. ("Soft" meaning less air in the reservoir, and a lower ride height...)

[KX5062]

I don't quite understand what the rear suspension system is actually supposed to do, based on what I've read here. The indicator on the dash shows adjustment from "hard" to 'soft", but comments here seem to indicate it adjusts to maintain the correct ride height based on rider/passenger loading.

Although I never hear the compressor running the system appears to be working. With me on the seat, in gear, engine running the "soft" setting reads about 30 PSI when checked with a gauge on the valve under the seat. After adjusting to "hard", the pressure has risen to 50+ PSI, so obviously the compressor is working as it should.

The load on the suspension is the same in both cases since it's me on the seat both times, so what is that change in pressure doing if the ride height remains constant? Need some education here. 2013 RT-S.

Thanks,
Bob

The rear suspension on the Spyder uses a conventional motorcycle style shock, in that it uses a coil spring surrounding a single shock absorber. What the ride height and settings are referring to is the Spyder uses an air bag, like on some cars and trucks. The air bag is a supplemental suspension component, in that the air in the bag is adjustable to accommodate different weight loads. More air pressure the higher the rear of the bike is lifted and the firmer the ride, and vice versa. On the base RT there is no compression and the air pressure must be set manually.

HTH

[Old Crow]

There is a strut mounted between the shock and the swingarm...

ACS Strut.jpg
It is actually there to monitor your ride height. As the load on the bike changes; this system will automatically adjust the air pressure in the shock reservoir to maintain a constant ride height.
By using the terms "Soft to Hard": you are actually referring to lowering the ride height, or raising it. ("Soft" meaning less air in the reservoir, and a lower ride height...)

So if I understand correctly, for any given weight load, you can vary the ride height by adjusting the pressure up or down on the air bag. Is there an optimum height we should be trying to achieve? One that would require different pressures for different loads on the seat?

Bob

[JayBros]

I'm probably all wet on this, but your operator's manual says the same things as mine (pg 24, 58-59 in yours). Nowhere does the manual address ride height but talks about softer and stiffer settings. I translate these terms to increasing or decreasing the chance of the shock bottoming out with different weight loads, sort of like an independent preload of the shock. I keep my setting on maximum stiffness just because I like a stiff ride. I also don't notice any difference in ride height with me solo or my wife aboard with me although I've never seen a need to measure it.

[Old Crow]

I'm probably all wet on this, but your operator's manual says the same things as mine (pg 24, 58-59 in yours). Nowhere does the manual address ride height but talks about softer and stiffer settings. I translate these terms to increasing or decreasing the chance of the shock bottoming out with different weight loads, sort of like an independent preload of the shock. I keep my setting on maximum stiffness just because I like a stiff ride. I also don't notice any difference in ride height with me solo or my wife aboard with me although I've never seen a need to measure it.

That is my understanding as well, and I always adjust to a stiffer setting when riding two up with my wife. That said, there have been numerous posts talking about ride height and that the system adjusts to maintain a given height. Just trying to get some clarification.

Bob

[Bob Denman]

So if I understand correctly, for any given weight load, you can vary the ride height by adjusting the pressure up or down on the air bag. Is there an optimum height we should be trying to achieve? One that would require different pressures for different loads on the seat?

Bob

Actually: the answer is "No"...
ASSUMING that you are happy with how your headlights are aimed: just leave it alone, and everything will be peachy-keen.

Your ride height will remain consistent regardless of the load on the bike. Consider the ACS as a road-going version of trim-tabs on an boat.

[KX5062]

So if I understand correctly, for any given weight load, you can vary the ride height by adjusting the pressure up or down on the air bag. Is there an optimum height we should be trying to achieve? One that would require different pressures for different loads on the seat?

Bob

You can adjust the ride height via the air bag, but I don't think there is an ideal ride height per se. (You take all of the air out and you'll see what happens, which is it will be bottomed out.)

The manual list air pressure as referenced by weight, so if you're concerned I suppose you could measure the ride height with the appropriate air pressure and weights to get base lines.

[Devious56]

Actually, the five positions setable but the firmness switch only sets the system within the limits set by the BUDDS. When I first got my RTL I was putting air in my air bag every time I went for a ride. Thru trial and error, I decided that I liked 60 pounds in the air bag and would set it as such. The next day (or so it seemed) when I would go for a ride, the air bag would have 45 pounds in it and I would put 60 in for my ride. Little did I know, or understand, that the system was bleeding the pressure off as the BUDDS was set to 45 pounds max. When I had the rear tire replaced, I mentioned this to the technician (Kenny Butler) and he explained what was happening. He also said that he could reset the limits set in BUDDS, which he did. And now, the center position on the switch sets the air bag at 60 pounds, and I can let a little are out or add a little using the setting of the switch.

That seems confusing when I read it back, I hope you can understand what I tried to say.

[KX5062]

45lbs of air pressure as a maximum doesn't make sense. IIRC, the BRP recommendations for air pressure starts at about that figure as a minimum and ends up around 100 lbs. Again, IIRC, for most solo riders of any 'Merican type weight figures it should be set at 60 lbs and two up is usually starting around 75 lbs of air. (Going from memory, since I don't have the tables at my finger tips right now.)