RT Limited OEM Rear Shock- Making it Adjustable.

[h0gr1der]

Decided I wanted my rear shock to be adjustable. Not being a suspension guru, I took the simple route. Disclaimer; if you use this procedure you may have negative consequences up to and including death. My goal was to make my bike non-dependent on the air compressor system for 1 up riding.

First establish baseline. What is the OEM topping measurement, the free sag (unladen) and the sag (laden)? I’m pretty sure Can Am had their rear suspension designed well enough, so I decided to just work off their measurements.

OEM Setup with ±43 PSI in the air bag and OEM spring (appropriate for my weight plus my normal cargo) measurements to the floor. Topped 17.5”, Free Sag (unladen) 16.5”, Sag 15” (this is my normal ride height as maintained by the compressor). I know these numbers don’t come close to real suspension measurements; they were taken off the tip of the rear fender to the floor. Air compressor came on at 13”, bleed valve opened at 17”. The 15” rear ride height is right in the center of the span of the air leveling system. If you deviate from the OEM ride height set for your bike it will throw a C210A “Suspension Fault” code at you. Note these numbers are specific to my Spyder ( I have non OEM car tires), yours may be different.

Installed a 600 Lb/In Hyperco 9” free length spring on my sleeve setup. I used 9” only because it was real cheap on Ebay. Strongly suggest 8” as you won’t need spring compressors (you will need spring compressors to remove OEM spring). Started with 1” preload, that was too much. Reduced it to .75”, ride height was still a tad high. Ended up with about .625”. Bike rides like OEM air system is active, but can use zero air pressure (for my load and body weight). Preload adjusters are so far up in the bike, and room is so tight, you will need some kind of narrow, long reach preload adjuster to get to the adjusters. I made one that worked.

As proof of design, I rode single, using the preload to adjust the rear height level so that 5-7 PSI remaining in the air bag to keep it from pinching. Lower preload will add more air to the bag as the automatic leveling system seeks a height, higher will reduce the air bag pressure until the bike goes too high, resulting in the suspension fault code C210A. I then rode with about 170 Lbs on the pillion, and the airbag pumped up and stabilized at 35 PSI with that load. Upon riding with just me on board, the airbag returned to 5-7 PSI, and the air compressor and bleed valve never comes on.

Parts List:
1- 188A0600 Hyperco 600 Lb/In spring 8” long x 2.25” I.D. $70 on Ebay
2- 2280913A Coilover sleeve for 2.25 inch springs, 50mm shock body, 4.7 inch length, Elephant Racing, 1 needed, $40
3- 2280913B Coilover sleeve lower adjuster for 2.25 inch springs and 2280913A sleeve, Elephant Racing, 2 needed, $30 (each, $60 total)
4- Upgrade bolt from Fastenal, M10 x 140 10.9 or 12.9 grade for lower mount, 1 needed (Each $15).

Additional Disclaimer- This is a work in progress. I do not claim to be an expert at anything, and may change spring rates to suit me. Currently the setup rides smoothly and maintains a cushy ride which matches my level of spine damage. If it ever bottoms out I will go up in spring rate to test for comfort mainly, as sport riding is secondary to me. This post is for informational purposes only, do not put any of this into practice.


Elephant Racing sleeve and adjusters for 50mm Koni. RT Shock is about 47mm.


Elephant racing sleeve and adjusters for 50mm Koni. Note enlargement on the end. That has to go.


Enlargement removed.


Sleeve assembled. Use one adjuster glued and clamped in place as a foot for the spring perch. I put the cut end of the sleeve down.


Sleeve ready to install.


2 layers of 2” thin wall heat shrink will make up the slack between the 47mm shock and the 50mm sleeve.


Sleeve on shock with heat shrink.


You have to dress the end of the 2.25 I.D. spring down to fit the top retainer.


Finished product, ready to install. With the 9” long spring it had about .200” preload. Had to use spring compressors to install. 8” long spring won’t have this problem.

 

[BLUEKNIGHT911]

:clap::clap::clap::clap: I'd more icons but it take forever …. I think know how happy I am for you …..and the members here .... Bravo .……….. Mike hyea:

 

[h0gr1der]

It's all about reliability. By simply nullifying the weak links (air compressor and bleed valve), and modifying their function (lowering the required pressure to make them run less), I've killed one more source of a problem in the future. The 600 Lb/In spring is specific to my total running weight, if I ever sell the bike to a lightweight rider I'd have to retool the rear shock to a lower spring weight. But I don't intend to sell, I intend to run the wheels off this thing!

 

[Wahrsuul]

Very creative/inventive. Nice work.

 

[Mikey]

Very good job!!! I've been in the tinkering stage for doing some thing similar with my ride, but I am taking the compressor out of the pool all together, and just adjust the pressure in the bag by hand when I want to haul more weight! The bag will be like a overload, and I will get a shock that is rebuildable that I came adjust! That's some good work you have done, Keep us updated!:thumbup:

 

[h0gr1der]

Very good job!!! I've been in the tinkering stage for doing some thing similar with my ride, but I am taking the compressor out of the pool all together, and just adjust the pressure in the bag by hand when I want to haul more weight! The bag will be like a overload, and I will get a shock that is rebuildable that I came adjust! That's some good work you have done, Keep us updated!:thumbup:

Mr. Mikey,
If I remember correctly your air compressor failed and the OEM 340(?) Lb/In spring didn't have enough guts. This is exactly the type of fix you need. If I increase the preload by about 1/4" the air bag goes to zero. Mr. Aawen suggested keeping some air in the bag to prevent it from being damaged, and I did indeed find that there is a minimum spec on pressure noted in the manual, so I just set the preload so the automatic leveling system maintains that, but is available if I load more cargo or a person on board. So far it works exactly as I planned. I like that the air system goes dormant almost all the time as I ride solo mainly.

 

[KX5062]

EXCELLENT!!!!

You did just about what has been rattling around in my brain pan for years, but never put into action. I love it. :congrats:

 

[h0gr1der]

Which leads me to speculate- If the OEM setup uses ±43 PSI for me alone, exactly how high does it go for a two up scenario, and is it rated for that much pressure at constant use ( I know it's rated according to specs, but I mean really reliable in that use)? I'll bet simply by adding some more spring rate such as 500 Lb/In and lowering the pressure requirements on the air system, it would last longer.

You have to be careful about the point of no return on spring rate with the automatic leveling system. Say you went up to 700 or 800 Lb/In, but with the minimum preload to hold the upper spring retainer you may exceed your computers expected ride height, in which case you'd have the annoying suspension fault code all the time. I think I may get by with a 700 Lb/In, but the 600 is working for my weight right now.

 

[Mikey]

Mr. Mikey,
If I remember correctly your air compressor failed and the OEM 340(?) Lb/In spring didn't have enough guts. This is exactly the type of fix you need. If I increase the preload by about 1/4" the air bag goes to zero. Mr. Aawen suggested keeping some air in the bag to prevent it from being damaged, and I did indeed find that there is a minimum spec on pressure noted in the manual, so I just set the preload so the automatic leveling system maintains that, but is available if I load more cargo or a person on board. So far it works exactly as I planned. I like that the air system goes dormant almost all the time as I ride solo mainly.

Ya my compressor burnt out ad stopped, so all did was unhooked the dump valve and got that out of there, put a new line from my bag to the shrader valve, the shock is pretty shoot you have to bounce it like three times before you see and kind of damping going on, and with no air in the bag it on the frame two up!

 

[Mikey]

The bag has a 90 psi max on it. Two up with my wife and I, I put 70-80 in, works for us!

 

[KX5062]

Which leads me to speculate- If the OEM setup uses ±43 PSI for me alone, exactly how high does it go for a two up scenario, and is it rated for that much pressure at constant use ( I know it's rated according to specs, but I mean really reliable in that use)? I'll bet simply by adding some more spring rate such as 500 Lb/In and lowering the pressure requirements on the air system, it would last longer.

You have to be careful about the point of no return on spring rate with the automatic leveling system. Say you went up to 700 or 800 Lb/In, but with the minimum preload to hold the upper spring retainer you may exceed your computers expected ride height, in which case you'd have the annoying suspension fault code all the time. I think I may get by with a 700 Lb/In, but the 600 is working for my weight right now.

To add to the discussion: I think the air bag is designed as a spring helper and ride leveler, doing double duty. I think BRP did the air bag system as a way of keeping the ride plush over a range of carrying weights. Proven technology at a limited cost with the ability to upgrade to the LTD set up.

My thought was to completely eliminate the need of the air bag and potentially remove the bag itself. My main concern in doing that was making the ride overly harsh by being forced to over spring the shock in order to keep the ride height within proper perimeters. Which is why I never pursued it, but only kept it in the back of my mind in case the airbag failed.

 

[h0gr1der]

To add to the discussion: I think the air bag is designed as a spring helper and ride leveler, doing double duty. I think BRP did the air bag system as a way of keeping the ride plush over a range of carrying weights. Proven technology at a limited cost with the ability to upgrade to the LTD set up.

My thought was to completely eliminate the need of the air bag and potentially remove the bag itself. My main concern in doing that was making the ride overly harsh by being forced to over spring the shock in order to keep the ride height within proper perimeters. Which is why I never pursued it, but only kept it in the back of my mind in case the airbag failed.

Mr. KX5062,
Someone else suggested my 600 Lb/In spring rate would be too low, and the suspension would bottom out. I haven't found that to be the case with my ± 230 Lb person (with my equipment on) and the roughly 10-12 Lbs of cargo in the rear box. I can tell you for highway use, unless I told you it was spring only back there you wouldn't notice any difference. It hasn't bottomed out yet, and if it ever does I'll step up incrementally until it stops. I like the soft ride, it helps with all my broken stuff!

 

[h0gr1der]

Update on this rear shock modification. Today I took a wonderful crisp 2 up ride, 65°F and sunny (sorry to all the people that are snowbound). I loaded my rear pax at around 170 Lbs and allowed the air suspension to re-level the bike (±35 PSI in the rear bag with 2 passengers), then took off. This thing rides smoother than some cars. With the modifications I've done to this Spyder it is amazing how smooth it is. I didn't want to compromise ride comfort, but I did want to make the bike more stable and corner better, along with taxing the air system much less. Mission accomplished. With the 600 Lb/In spring in the rear, me and my passenger went over several large to very large bumps, no bottoming. Bike is smooth and due to the excellent Baja Ron swaybar it doesn't wallow, even 2 up. On the highway it's as smooth as silk, yet corners well. The only caveat I see is if a significantly smaller rider rides the bike without adjusting the preload lower it may hike the rear end up enough to throw the "Suspension Fault" code, which is only an annoyance, not a limp (as far as I can tell)

 

[PMK]

Did not recall or search for the info, did you test or find the original 1330 rear spring rate after testing?

 

[h0gr1der]

Did not recall or search for the info, did you test or find the original 1330 rear spring rate after testing?

I did not. I read several places it's in the 320-340 Lb/In range, but never confirmed that. Spacetiger offered some help, but I never heard back from him. He much be a infrequent visitor. I didn't even break down my OEM shock, but rather bough all new components for this build. I like the result, it definitely keeps the air compressor from running as much, and when it does run it's much less loaded.

 

[Rednaxs60]

I did not. I read several places it's in the 320-340 Lb/In range, but never confirmed that. Spacetiger offered some help, but I never heard back from him. He much be a infrequent visitor. I didn't even break down my OEM shock, but rather bough all new components for this build. I like the result, it definitely keeps the air compressor from running as much, and when it does run it's much less loaded.

Older thread but one near and dear to me. Good suspension however it is accomplished is a great upgrade. Any thoughts on your upgrade since you did it? Have looked for the parts you have mentioned, will be contacting Elephant Racing regarding what is available.

Have the M2 shocks coming this week - not as inventive as you. More expensive than your fix, but doing all three. The rear shock is coming with a 500 lb/in spring installed, but after reading spacetiger's posts and yours, had M2 send a 700 lb with the shocks. Intend to install the 700 lb/in spring before installing the new rear shock. Can use the 500 lb/in spring on the OEM shock as a just in case measure. I'm similar to yourself, 230 lbs with gear, ride two up quite often, and will be towing a trailer.

I agree with your wanting to minimize the ACS compressor for solo riding. My Goldwings, an ex-1800, ex-1500 and my retirement project an '85 GL1200 Limited Edition all have/had air ride systems. The only one that has auto ride leveling when riding is the 1200 Limited Edition. Once the air pressure is set for solo or two up riding the system auto levels on the fly, pretty good for an '85 bike.

The front shocks have 250 lb/in springs, but will monitor and determine if a stiffer spring rate is required.

Cheers