Suspension

[Rednaxs60]

Suspension is one of the most important aspects of a vehicle operation, regardless of what the vehicle is. The main purpose of suspension is to keep the tires firmly planted on the road while at the same time providing a good ride and ride performance. To all but a few, this is something that we accept from an OEM, and for the majority it is an aspect of vehicle operation that, if possible, can be made better with aftermarket additions the better.

I posted on another thread, "Bit of a Shock", my understanding of how a shock works: https://www.spyderlovers.com/forums/showthread.php?141435-Bit-of-a-shock-!!

Good banter on whether I am right/wrong, but we all have our understanding of this issue, much like tires, oil and such.

One issue that was mentioned was the stored energy in a compressed spring. Agree with this premise; however, to utilize this stored energy you must allow the spring to release back to the original length. Not doing this you now have a new delta with the same spring rate, and less travel. This is why spring preload is for ride height and sag. Once you have the ride height and sag set, should not have to adjust again unless you increase or decrease the riding weight such as having a passenger, and/or adding luggage. Excessive preload does limit suspension travel, and as mentioned, does impact on ride quality - more harsh. This is why preload should be kept to a minimum when adjusting for height and sag.

Had to get an understanding of the air system on the Spyder. It is very similar to a 1500 Goldwing that has a non-air shock for normal operation such as ride quality and performance. It has an air shock to adjust ride height when a passenger and/or luggage is put on the bike. The Spyder has a rear shock for normal operation, and an air bladder to adjust the ride height to compensate for the added weight.

In this case without using the air bladder, the premise that there is stored energy in the shock spring from the compression of the shock spring is correct. What will happen as you ride the stored energy will try to return the shock spring to its original length possibly making for a rough ride. Good possibility of the bike bottoming out because of this. To compensate for this, an air bladder is used to adjust the ride height to remove the compression on the shock spring so that the shock spring is at or as close as possible to the ride height before any additional weight has been added. This is supposed to give the same ride quality and performance, or very close.

Add to this a system that monitors and adjusts the ride height continuously. This is not a new concept for a motorcycle. I have this system on my '85 Honda Goldwing Limited Edition.

It was mentioned that damping, compression or rebound, can be a nightmare if not correct, BTDT. The benefit is that you can adjust the rebound and if you have it, the compression function, to suit the way you ride and what you expect from the suspension. How fast or slow the shock returns to the set ride height influences the ride quality and performance.

The issue with suspension, and the want to upgrade it to suit your requirements is that it is not inexpensive. There are many aftermarket products that you can purchase at a reasonable price. As long as these products meet your requirements, money well spent.

Didn't want to hijack the other thread so I started this one. Thanks for reading. Cheers

 

[Rednaxs60]

M2 shocks should be here this week for install. Still searching for information on suspension setup and have found some older threads with good information.

From 2014 - 2010 RT-S shock upgrade: https://www.spyderlovers.com/forums...grade&highlight=rear+shock+spring+replacement
From 2013 - 2012 RT-S SE5: Front Suspension: https://www.spyderlovers.com/forums/showthread.php?60792-2012-RT-S-SE5-Front-Suspension
From 2014 - 2012 RT-S SE5: Rear Suspension: https://www.spyderlovers.com/forums/showthread.php?61674-2012-RT-S-SE5-Rear-Suspension-(shock)
From 2013 - RT Weight Distribution: https://www.spyderlovers.com/forums/showthread.php?60434-RT-Weight-distribution
From 2019 - RT Limited OEM Rear Shock - Making it adjustable: https://www.spyderlovers.com/forums...ng-it-Adjustable&highlight=suspension+upgrade

Will update thread as more informative threads are found. Nice to have a consolidated list.

Cheers

 

[Rednaxs60]

Have installed the M2 shocks on my Spyder, and immediately noticed a significant improvement in ride quality and performance. The M2 shocks came with a recommended spring rate setting, and very good install and setup instructions. I asked for a 700 lb/in rate spring be included in the shipment for the rear shock which was installed on the rear shock before the rear shock was installed. The 700 lb/in spring replaced the 525 lb/in spring that was shipped with the rear shock. Front shocks have a 250 lb/in spring installed.

When you setup the suspension, the aim is to minimize front shock preload, and rear air shock use, and achieve the ride quality and performance that you expected. Preload front/rear should not exceed 1 cm - industry standard.

The preload is set at 2.2 cm to give the Spyder a ground clearance of 4.25". This ground clearance is measured at a point 2" on the centre frame 2" in front of the imaginary line between the wheels similar to when an alignment is done. This gives the Spyder a ground clearance IAW the OEM service manual of 110 mm just under the engine with approximately 210 pounds of weight on the seat.

The 2.2 cm of preload on the front shocks indicates that the spring rate is too soft even at 250 lb/in. I have no empirical data to support what spring rate is required, but suffice it to say IMHO that a spring rate of 350/400 lb/in would not be excessive. I submit that most shock manufacturers will rely on its clients, or sponsored clients to provide information on the ride quality and performance of its product based on the clients riding profile. My riding profile and expectations are different from another rider; however, a rider with a similar riding profile to myself that can be classified as "close and in the ballpark" would probably be sold a similar setup with the same spring rate(s) that I am using. After this it's a matter of fine tuning the setup after install.

The 700 lb/in rear shock spring is good for solo and two up riding. The air shock has approximately 8 PSI in it for solo riding using the lowest ACS setting, and adequately compensates for two up riding on the second lowest ACS setting. Only heard the ACS compressor come on once while riding two up. The rear suspension shock setup is with no preload.

This 700 lb/in spring rate is quite stiff compared to the OEM shock spring rate. This being the case, is it too stiff? My opinion of this 700 lb/in spring is that it is on the cusp of being too stiff. A 600/650 lb/in spring rate would probably be optimal, but I do intend to tour and tow a trailer so the 700 lb/in spring is the spring rate I believe to be what is needed for my riding profile.

When the spring rate is not adequate to do what it is intended to do, and you have rebound damping, and possibly compression damping, you may have the tendency to use these damping adjustments to compensate for the weaker spring rate. In actuality you are not. What you are doing is adjusting these settings to minimize spring compression and increase the rebound of the spring back to the ride height. When you use the damping setting(s) to compensate for a weaker spring than required, you are changing the ride quality and performance of the Spyder.

This is a time issue. When you restrict the oil flow on compression, you change how fast the shock will compress, and have a very firm ride. Gives the illusion that the shock spring is adequately sized for the riding profile. At the same time you stiffen the rebound adjustment so the shock spring quickly returns to the set ride height, again giving the illusion that the shock spring is adequately sized for the application. When you do this the ride quality suffers, is more firm and harsh, and very uncomfortable. I was going down this rabbit hole, but realized that what I needed to do was change the shock spring(s). I had already made up my mind that different shock spring(s) were required, but it's easy to think there may be an easier way to fix the problem, ergo the rabbit hole syndrome. Having worked through this rabbit hole syndrome, I reverted back to Plan A - different shock springs. I then adjusted the shock rebound damping settings to give me a good ride quality, but reduced lean/roll performance. Now for new shock spring(s).

Getting the suspension setup and tuning for your riding application is not a black art, but it does take time and a good amount of resolve. Changing springs to get the desired results when you don't have a readily available supply of different springs to choose from is a disincentive. The time required to change shock springs, and the resulting road test(s) and time required to do a good evaluation of the change keeps a lot of us from going down the suspension upgrade road.

The cost involved further aggravates the situation. When you spend some $1500.00 USD on a set of 3 shocks for the Spyder, you tend to want it to be the plug and play solution, and when it isn't there are a couple of things you can do. Enter into a discussion/way ahead with the manufacturer - if the manufacturer will entertain this option, and if not - tell the world that your experience has been less than stellar. My preference is to convince the manufacturer that it is in both our interests to rectify the situation to a satisfactory end.

Another way ahead resulting from the research you may do regarding a suspension upgrade is to modify what you have to get a better ride quality and performance from your Spyder. You can buy and install stiffer springs, but without having the ability to do a preload adjustment this can be problematic. You want to be able to adjust the preload of the new spring(s) to achieve the desired ride height/ground clearance. There are aftermarket coil over spring sleeve kits available that can make the shock adjustable.

You can change the shock for one that has preload, and compression and/or rebound damping capabilities. The issue with these shocks is that these are not inexpensive.

I have been browsing the internet for inexpensive options to purchasing an aftermarket set of ready made shocks. Living in Canada and buying the components that would allow me to do a DIY suspension upgrade is actually cost prohibitive. Exchange, taxes, duty, no warranty or technical assistance makes a DIY suspension upgrade a non-starter. I do not mind doing the work required to properly setup and tune the Spyder suspension, but it is in conjunction with the manufacturer. I do not mind sharing with the manufacturer what the difference is with any change I do as long as I am able to articulate it correctly in a quantifiable manner.

There is one last issue for this post and that is the collateral "damage" resulting from the suspension upgrade. This is not "damage" in the usual sense, but what on board systems need to be looked at and calibrated to accommodate the new suspension settings. I had to calibrate the ACC system with the B.U.D.S. software. The ACS system was not working and there was no air pressure in the system regardless of what I tried. Reda the section on the ACC system in the service manual, and determined that the calibration was probably incorrect for the suspension upgrade. Once the ACC system was recalibrated and the new numbers read into the onboard computer, all was well.

Enough for now. As usual, this post is JMHO, and layman thoughts on an interesting topic. Not a suspension specialist, but I do like to keep the gray matter of the brain engaged.

Cheers

 

[BertRemington]

I have a binder full of rednaxs60's (and PMK's) posts and PMs. Thanks guys.

 

[Rednaxs60]

There has been a lot of chatter on various threads regarding suspension, especially the front suspension of the Spyder. This is a very expensive topic as the Can-AM family is a very small market, if it wasn't expensive everyone would dive in and go for a complete suspension upgrade. The reality is that the Can-Am fraternity is a frugal bunch as is the motorcycling world, and wants the best bang for their buck, understandable.

Tires are a good source of information, and discussion. Not an expensive upgrade, but can make a considerable difference. Radial construction is the same regardless of manufacturer, the difference is the quality of the material used in various "plys". A $130.00 dollar tire regardless of the manufacturer is going to have similar material quality. There are only so many manufacturers of material for tires, similar to batteries, and household appliances to mention a couple. The more premium the tire, the better the "ply" material, an d you expect better tire performance. Going straight and level with sweeping curves doesn't tax the tire that much. More robust riding does and this is where the differences in tire quality comes into play.

The tire must now resist roll/lean of the Ryker/Spyder, and the better quality tire should do this better than an inexpensive tire. A Spyder RT LE with a higher centre of gravity, more weight to be compensated for. A Spyder F3 roll/lean is quite different from the RT and as such, changes the dynamics of the tire even if it is the same tire.

One way to change the roll/lean characteristic of the tire used is to find one with a 2 ply sidewall. I submit this will be difficult, and probably not possible. Another way is to minimize the aspect ratio to minimize sidewall height. This would entail using a larger diameter rim. The car industry has done exactly this. Low profile tires, larger diameter rims, less roll/lean and with this an increase in cost of the tire using less material, go figure.

Next is the stabilizing/sway bar. Definitely a plus in the performance aspect of the Can-Am family. You expect more from a more robust stabilization/sway bar. This is also dependent on the material used in the stabilization/sway bar manufacturing. Stabilization/sway bars can be the same size but the design characteristics can be substantially different, and because of this, affect the performance of the Can-Am you are riding.

A good quality, properly sized stabilization/sway bar can mitigate the roll/lean, and corner/curve dive of the Ryker/Spyder you are riding, but not it all. If this was possible would not need shock assemblies to assist.

The next and last issue is the shock assemblies front/rear.

These shock assemblies come from the factory designed to give the best ride and performance for the general ridership that is expected to buy these machines, and for a predetermined timeframe. I mention this because nothing lasts forever. I renewed the shock assemblies on my 2011 KIA Soul after some 125K Kms on the recommendation of the local tire shop. I was informed by this shop that the shock assemblies on my car are generally ready for replacement after this many Kms. I had a discussion with a second shop, and the information was confirmed to be an industry standard. Did I have to renew, no, but weak/soft shock assemblies can be the reason for collateral damage to the hard parts of the suspension system such as bearings, ball joints and such.

An OEM does not just put random parts on its equipment. To some of us, the rationale escapes us, but suffice it to say that we must understand this, but don't necessarily have to agree with it. If the OEM did do a better job with the suspension components and other aspects of its product, there would be no need for an aftermarket industry.

Tires we understand and the price point is generally one that we will accept, more premium the tire, better ride quality and performance, and it's in the budget range. An aftermarket sway bar is an inexpensive upgrade and can meet the expectations of a good majority of riders, no need to do more. The last batch of riders will include a shock assembly upgrade front/rear, but this is an expensive proposition.

I have posted on other threads regarding the benefits of a shock assembly upgrade. Suspension is a system where each component has a specific function that cannot be replaced by one of the other components, but when all the suspension components are sized for the respective rider profile and requirements, the result is quite nice.

The aftermarket shock assembly sector relies on feedback from clients regarding what is delivered. This information has to be specific, and quantitative so that it can be used to better support our ridership.

A suspension component upgrade/renewal can change the ride quality and performance such that the owner is satisfied with the change, and no more action is required. When this does not happen, more research/work is required.

Other suspension issues can be because of the steering geometry, such as the Ackerman effect. Formula racing, pro go karting and even the snowmobiling world deal with this on a regular basis. I am not an expert on this effect, but suffice it to say, it is where the inside wheel is angled more than the outside wheel to get the vehicle around a sharp corner/curve. The Can-Am Ryker/Spyder is dependent on this effect, but there is no adjustment available to fine tune it to your riding profile/requirements. I've thought about what can be done to offset this Ackerman effect, and the only change I can envision is making sure that wheels are properly aligned.

Just a few more thoughts on this subject, and JMHO.

 

[PMK]

Rednaxs60, interesting read. Often overlooked when determining setups, whether tires, tire pressures, dampers, spring rates, anti roll bars, Ackerman, rear suspension squat or anti- squat, and so many other parameters, it is not about how good the consumer public responds and offer input.

More correctly, in my opinion, the best setups are derived from a quality base platform that a knowledgable test rider and technical team supporting him can optimize the setup.

Ackerman angles can be altered with minimal effort but will require alignment after each change and the nulling of the steering angle and torque sensors.

My experience working on performance suspension components typically finds buy quality stuff from top tier suspension companies. I avoid second tier and lesser companies, simply too many surprises when you get inside the shocks.

 

[Rednaxs60]

PMK - thanks for the comment, and couldn't agree more. Lots to consider. I was philosophizing regarding this issue. The two wheeled industry has the same issues, especially with motorcycles that do not fit any mold such as my '85 Goldwing Limited Edition. The suspension on this bike can be better, but getting there is not an easy task.

The best setups are achieved with a knowledgeable test rider, but in this small market, not very economical so the aftermarket manufacturers have to rely on the general population. Cost benefit ratio has to be in the OEM's favour for anything to happen. If we had Can-Am Ryker/Spyder competition racing, this could be different.

Suffice it to say that in the short time I've had my Spyder, the onus for any meaningful suspension change for the better seems to rest entirely on the owner. Need to put together a plan based on information available, what the requirements/expectations are, what you are capable of doing, and what the budget is. May not be perfect, but it seems to be the best that is available at this time.

I would like a better road map to get to the results I would like, but there isn't one available. I read and digest a lot of information, some from non-related industries to get a sense of where I want to go, what needs correcting in my opinion, and what is the best way to achieve this. I try to isolate the issue in question, and realistically identify a possible solution that makes sense to me. Once I get to this point, I have a decision to make, is the cost benefit of another change in my favour or not, simple yes/no answer.

I understand why many do not tackle this issue, not only from a monetary perspective, but from an understanding perspective. There's a lot to consider, and learn.

I have one more issue related to this and that is the stabilization/swat bar that is installed on my Spyder. I was told it is a BajaRon sway bar installed when the PO bought this Spyder. I mentioned in my main thread on what I have done to my Spyder that the bar bushings were loose, and that the bar was flopping around not doing the job it was designed for. I tightened the bushings IAW the BajaRon installation instructions and there was a difference, but not as much as I would have expected from the threads I had read. This has led me to think if there is a possibility that the PO removed the upgraded bar and reinstalled the OEM bar. Shouldn't have had to tighten the bar bushings. Will be looking into this, nothing would surprise me.

Cheers

 

[PMK]

Rednaxs60, while I hope you have the anti swaybar on it you desire, anything is possible.

Regarding Spyders in general, in my opinion, they are a novelty vehicle of sorts. Use them as designed, within reason of increasing performance and handling. The frame and suspension components are all mild steel. The earlier designs have very little design engineering to increase chassis stiffness, but the F3 added bracing bars and a stiffened rear arm. A flexy chassis is only so good, and believing that adding much superior dampers and springs to a noodle will make it a racer, is fantasy. Also, the Can Am engineers wisely limited the engines power output. As a general rule, lower power output makes lesser chassis and suspension components adequate. Take a poorly designed or flexy chassis, increase the power and poor handling traits will surface.

Your comment in regards to cost effectiveness in suspension mods is very valid. After talking with Ohlins, it was apparent at the time they had no intentions to build Spyder dampers. The other three top tier companies only had Fox that offered components, and this was via BRP accessories. Showa and KYB had nothing.

While I despise dealing with Fox, those shocks proved to be very good and reasonably priced. I was expecting a need to go inside them and revalve them myself. To my surprise, they were very good out of the box.

I get it that so many folks want to have pinnacle handling on their Spyder. It can be i proved, but truthfully, until a frame and suspension components is made from better materials, or the frame is correctly stiffened, the limits will be met early on.

Consider this...if the Spyder were truly performance based, the front suspension would have been delivered where an alignment can reset not only toe in, but also caster and camber.

All the best getting your machine sorted out. Ours does just fine within its limits.

 

[Rednaxs60]

Thanks for the reply.

I'm leaning towards a proper front shock spring rate that will have the preload at 1 cm or less. If I can achieve this, I think the suspension issue with my Spyder will probably be closed. I have never expected the Spyder to be a formula racer, but I do expect it to be a comfortable ride that I don't fight with at any time. Do hate hanging out the side on an off ramp, aggravated when riding two up, but it's one of the compromises I will probably accept. The M2 shocks are a good investment and do a very good job of improving the Spyder ride quality and performance.

It's the same with the rear shock, bottoming out and hitting on the hard parts is not a good time. Will be trialing a 600 lb/in rear shock spring rate in the future. The 700 lb/in rear shock spring rate is firm when riding solo, but good when two up. The 600 lb/in spring will soften the solo riding but still give good two up ride quality.

Most of what I do is to improve the ride quality when riding two up. If I can minimize the roll/lean of the Spyder two up so that Sonya feels better about the ride, I'm quite conservative when riding two up, and she notices the difference, money and work to achieve this is well spent. We spend a lot of our time riding on the Spyder, I keep the Goldwing for my enjoyment and every now and then go out two up - Sonya still enjoys riding on it.

Still have the alignment issue so that the handlebars are in the proper position.

Other than the suspension exercise, all I've done is the maintenance required. Since my intention is to keep this Spyder for a while, doing everything up front so I can enjoy the fruits of my labour.

It has been a good exercise in learning about the Spyder.

Cheers

 

[Mikey]

opcorn:opcorn:

 

[PMK]

Rednaxs60, regarding Spyder suspension setup, forget everything typical about setting up moto suspension. There is no need to measure free length, sag and race sag. A Spyder front suspension is not moto suspension and because of this could even be dangerous to use sag as a means of setup.

The Spyder front is more like a SxS or formula car. Actually with the long suspension arms and street use, closer to the formula car. Knowing this you might consider reading about chassis setup for those vehicles. The easiest way is based on suspension angles, not sag.

My experience setting up motorcycles using sag knows it can be a valid method. Primarily though, based on the riders weight as a large percentage of the total weight, sag numbers truly are important for determining correct spring rates first, and then thereafter used to obtain repeatable turning setup. Repeatable in that since race bikes use a sliding rear dropout, and the wheel is slid as needed for chain adjustment, this change in length alters the leverage into the spring. Repeatable sag dimension retains the steering feel a rider expects and ensures the same reactions induced by the chain for squat / anti squat.

A Spyder with rear air ride, automatically controlled, retains repeatable rear sag.

On race bikes, once the fork spring rate and air volume are correct for proper fork response, testing determines the relationship of where the forks might be positioned in the triple clamps. However, since sliding the forks up or down can alter the trail dimension, each change may require revisiting rear sag.

Tuning a Spyder is far more like dialing in suspension on a car than a motorcycle. Because of this, make it easy on yourself. Set the front spring preload, with you on the machine, with the lower arms at 0.0 degrees, and adjust from there. Remember too, as front suspension compresses, negative camber is induced. With chassis roll / lean, you might strive for the negative camber on the outside tire to come close to zero while cornering. Having the outside tire go to positive camber will reduce mechanical grip.

So many setup and dynamic parameters, all while dealing with a noodle of a frame and swingarm. A noodle that is an uncontrolled spring that winds and unwinds without predictability.

 

[Rednaxs60]

Mikey - hope that is Costco Kirkland brand popcorn, better than Orville Redenbacher IMO.

PMK - thanks for the info. Will do some reading on this.

I had already decided on a plan of action based on the information in the OEM service manual. The ground clearance is to be 110 mm directly under the engine, and there is the ACS calibration as well. To achieve the 110 mm under the engine its a balance between the preload front/rear, and with myself sitting on the Spyder. The OEM service manual wants approximately 210 lbs on the bike for ACS calibration - I weigh in at 220 lbs, so I'm estimating that what I want is to set the preload front/rear and with me on the Spyder, slide the 110 mm block under the frame without forcing it, with the preload on the front/rear shock assemblies at no more than 1 cm and 0 psi in the air shock.

Having mentioned the above, your suggestion front first ensuring the lower arms are for all intents and purposes level, is a good starting point. Will do this in concert with the above.

Reminds me of my days as Engineering Officer of HMCS IROQUOIS, gas turbine frigate after it had undergone a mid life refit. New Integrated Machinery Control System that had a terrible operating manual. My staff and I rewrote the manual, corrected the errors and omissions, submitted for approval and republication. Did this based on operating experience. Bit more involved than this subject, but the same principle applies, not a lot of information available to use, so its on with the test and trial, determine what needs to be looked at or left alone, make necessary changes, test and trial, repeat as necessary until the desired result is achieved. Keep good records of what is done and what works. I caveat this by mentioning that the work on the Spyder is generally done when the weather is not cooperating. Better to be riding than to be wrenching during good weather.

Once this is done, reset the ACS if required using B.U.D.S.

Will report back on this. Cheers

 

[PMK]

Rednaxs60, like your manual for the gas turbine installation, consider the same for the Spyder...toss it to the side.

Consider the words you posted. You will try and achieve 110mm ride height at the center of the vehicle. Unfortunately doing that will not allow you to have any valid datum point since raising any corner can make a change or more correctly, you can have total imbalance and attain 110mm.

Search online or in the library for a book or articles on suspension setup for race cars. Use the chapters regarding double wishbone suspension setup as a basis.

The rear of the Spyder simply follows along. Yes spring performance is important, but has a minimal reaction regarding front handling traits. It is all about the suspension arm angles, balancing front corner weights, and using that as the datum to build from.

Find a median setting for the rear. Start with the front lower arms at zero degrees. Ride and evaluate. Adjust the lower arms in say 1/2 degree positive increments, ride and evaluate. If the front clearance is adequate, adjust the arms in negative increments. At a point nearing optimum for you, your tires, your roads, your weight and payload, the front outer tires tread will ideally find the best grip with least steering input effort.

With the front determined, then you can experiment with the rear to achieve the desired 110mm clearance. That change should have minimal, effect on the front. Possibly a slight amount, but if you have set the rear to give 110mm with the front arms at zero as a starting point, the change will be small.

 

[Rednaxs60]

Very interesting. Have some readings to take, and hopefully in the next month, life does get in the way, have a go at the setup. Putting new rings in my '85 Goldwing, these arrived today. Should have it buttoned up and in by end next week. Like to have at least one of these on the road.

Will definitely be having some good reading. Have to change out the front shock springs, start with 300 lb/in. Need to get to a lesser preload setting, otherwise just using up good front end travel. Agree with the need to establish a datum for the front suspension.

Will report back.

 

[Rednaxs60]

PMK - This is a very interesting topic depending on how far down the rabbit hole one wants to go. Found this article: http://www.formula1-dictionary.net/set_up_mechanical.html and it branches off into the various aspects of suspension setup. This article starts with "tires" and provides a lot of information and links to other pages that relate to tires. I got the impression that tires can get a bad rap not because of the tire, but because of the suspension setup. I'm going to use this web site to start understanding what you have mentioned to me, and possibly come up with a game plan/way ahead.

I did have a look at the lower a-frames on the front of my Spyder regarding to your 0.0 degrees. For my Spyder to meet this, I'm estimating that the front trunk road clearance will probably drop at least 1/2". Depending on where you take your road clearance measurement(s), this could be problematic. My read of the site I've posted for a formula one car, street cars are also mentioned and compared, would indicate to me that reducing the road clearance would require a stiffer front shock spring rate to keep the front end from contacting the road, or the bump you had to negotiate.

I'm of the opinion that a stiffer spring rate with a well designed shock to control the shock spring oscillation, does not necessarily mean that the ride quality will suffer. Having mentioned this, still looking at a front shock spring rate increase to reduce the preload and achieve the same road clearance.

I am going to take some front trunk and frame road clearance measurements, and possibly do some preload changes then road test. The front trunk is lower than the frame. This will be a good exercise for those days when mother nature does not cooperate and provide good riding weather.

Regardless of what I do or don't, following up on this subject will not be for naught, quite interesting.

 

[PMK]

Rednaxs60, after reading your last post, I kindly offer up that you should not overthink your setup.

A golden rule of suspension tuning is that the best setup is merely the best compromise of many factors.

Saying that, without worry of ground clearance being reduced, use care and test various settings. Possibly the 0.0 setting may give the best handling, maybe not. So if clearance is a primary concern, possibly a compromise elsewhere is required.

Testing, on the same road sections, various setups will give insight. As for swapping springs, no doubt a viable tuning parameter. However, you may find that once the angle you desire is found, then, tuning springs becomes an option, along with controlling chassis roll via the swaybar.

For that matter, you could find the oem chassis untrue, and the swaybar induces an input towards one side, requiring adjustment of the link rods to null the chassis lean.

If you are running stock shocks without adjustable preload, dialing in the settings is more involved. Adjustable preload allows easy changes away from the datum setting, and result can be experienced very quickly with minimal effort.

Expect too, increasing spring rate and roll stiffness has the possibility to reduce grip. Finding the balance between spring rate, preload and ride height becomes its own set of best compromises when the damper lengths are not adjustable. Explaining further, you may find the best setup for the A arms, and the best setup for spring rate and preload (offering initial and final spring force), but with no means to alter the shocks length, a compromise is met between the parameters.

If the shock assemblies lower eyelet could be tuned for length, the compromise might be a non issue. Altering the frame / damper mounting points will alter suspension geometry back to the beginning and require sorting everything from step 1 again.

As you are aware, altering preload does not alter spring rate, HOWEVER, altering preload will change spring force initial and final, which increase or decrease the springs stored energy.

When shopping for springs, pay attention to using quality springs if available. Many suspension companies often rebadge spring manufacturers as their own springs. Your expected rates and dimensions may limit the selection, but sticking with companies such as Eibach, Hyper, or other high end spring manufacturers is important. Also, if serious about attaining maximum performance, have both springs tested and verify the actual rates are close. Many manufacturers have a plus or minus 10% of labeled rate as the tolerance. Getting a 10 plus and a 10 minus on two springs is a 20% error which may be difficult to tune through.

In the end, remember, this is a simple toy with a noodle of a chassis. Chasing perfection, or simply perfection is merely a word...

 

[Rednaxs60]

PMK - thanks for the kind words and encouragement. Can say that I am not overthinking this issue for the Spyder, similar to my wanting to upgrade the suspension setup on my '85 Goldwing limited Edition. Rear shocks are easy, just about any manufacturer can accommodate my requirement(s) - have a set of Hagon shocks with the RAP. The front forks are a different kettle of fish, and theses forks are very flexible.

My Goldwing is my long term retirement project. Would like to get a '69 Mopar and rebuild it, but space limitations are the biggest concern, so I am happily keeping myself occupied with it and the Spyder.

I have installed M2 shocks all round so I have a good shock assembly to adjust. M2 uses Eibach springs, and I'm in discussions with Marcus as well.

I have a road route that I use to road test my changes to ensure as much as possible consistency/repeatability.

This exercise reminds me of the days back in the '60s when my father had 10 stock cars operating out of his garage. Lots of thoughts on what to do, used some very questionable autos for the local stock car circuit. Many evenings were spent welding stiffeners, roll cages, building/repairing engines, modifying rims - cut/insert spacers/weld and use, and changing the suspension for the short track. Tires back then looked a bit odd, tread was narrow, but the rim was wide. I shudder sometimes because of what we did to cars that are now commanding a premium price.

Having mentioned all this, these more detailed exercises have always interested me, working on an ECU replacement for my '85 Goldwing. If the ECU fails, the bike becomes a boat anchor so to speak. Using the Speeduino project as the basis for this exercise.

Everything I do is deliberate and to sometimes test the waters, but foremost is that what I do cannot affect the reliability, or ability to ride. I know enough to leave certain aspects alone.

Will get more done to the Spyder regarding this issue once I have my '85 Goldwing back on the road - had rebuilt the engine, but it still smoked on start. The machine shop I worked with did not like the rings I provided - these guys have a gut feel about products - so a new set of Hastings piston rings has been installed. My '85 has been down the west coast - two up, 'all through the interior of BC - solo and two up. Lots of road miles in her before it retires.

Always something. Cheers.

 

[Rednaxs60]

Still digging into the suspension setup for the Spyder. It's an illusive animal, but I will get to the bottom of it so to speak, or a reasonable facsimile that will allow me to achieve the result(s) I am looking for.

Looking into snowmobile suspension setups because a snowmobile is similar in configuration to a Spyder, and there is a lot of information on the web regarding suspension setup. This post is for general information, and for those of you who want to be adventurous, more information to ponder as you go forward, or if you are talking to an aftermarket suspension specialist you will have a bit more knowledge to sift through the minutia to formulate an informed decision.

Accelerated Technologies in Ontario has an excellent video on snowmobile suspension regarding dual rate coil over spring dual rate spring setup. This is the video: https://www.youtube.com/watch?v=-MIU0hqb8MA Here is a more technical read regarding coil over shock springs, and dual rate spring setup: https://shocktherapyst.com/the-truth-about-dual-rate-springs/

There are 3 types of coil over shock springs that you can use. A single spring with a pre-set spring rate, a progressive spring with a spring rate that goes from soft to firm, and a dual rate spring system.

Straight rate springs are primarily used in the aftermarket shock assembly world. Self-explanatory, the M2 front shocks I have, have a coil over spring installed with a spring rate of 250 lb/in - same spring wind spacing over the length of the spring, and the spring rate should be relatively constant over the length of the spring.

A progressive coil over spring has a tighter coil wind at one end than the other. This type of spring has the advantage, not necessarily better, over a straight rate spring in that the spring moves and provides a very plush ride when riding on roads, but will stiffen as the weight transfer - roll/lean - continues to the outside of the turn/corner/curve. The softer section of the progressive shock spring - tighter windings - compress and "bind" against each other stopping further movement. The remainder of the shock spring now takes up the slack, and the shock spring compresses at a stiffer rate, further reducing roll/lean. The downside to a progressive rate spring IMHO is that the change from a spring rate that gives a soft/plush compliant ride to the stiffer spring rate is less controlled than that of a dual rate spring setup, and having the manufacturer provide the spring rate details may be difficult to get.

Dual rate springs for the Can-Am world is a good compromise between the two coil over shock spring setups mentioned above, and IMO, does deserve consideration by those who are looking at their suspension setups.

The dual rate spring setup uses a tender spring and main spring. Under normal riding on roadways where you are floating along enjoying the ride, sweeping corners/curves and such, the shock spring assembly allows for a soft/plush compliant ride that is very comfortable – the tender and main springs operate as a single unit. It is when you are cornering aggressively, using cloverleaf off ramps, traffic circles and such that this dual spring setup is beneficial.

The tender spring can be mounted at the bottom or top of the spring installation, and is separated from the main spring by a spring divider. This spring divider moves up and down on the shock as the spring assembly moves. A cross over ring – the key to this system, is generally threaded onto the shock, and is installed at a point that will limit the compression of the tender spring to that what is wanted/needed before the main spring takes over.

For example, if you have 5 inches of suspension travel, and one inch is taken up by the weight of the machine, rider and normally carried luggage, you may want to use a cross over ring that allows a maximum compression of the tender spring to say 1 inch. Once this is done, the main spring takes over and the suspension acts as if there was only a straight rate spring of whatever rate the main spring is rated at.

Preload for all three of these spring assembly setups is identical. Preload is to set ride/road clearance height.

Depending on the damping setup of the shock assembly that you use will depend on how the shocks are setup for ride quality and performance. It was suggested in one video that you start at the minimum softest damping setting and adjust from there.

An understanding of how springs interact when used in a spring assembly has to be considered. I do not get into the why this is because someone a long time ago came up with the equations that are universally used, and as such, no need to second guess the author. If someone develops a better equation, then I’ll revisit what I do.

Let’s use an 8 inch 200 lb/in shock coil over spring as the example for all the math.

Using two 8 inch 200 lb/in springs in a spring assembly that now becomes a 16 inch spring assembly, the spring rate is now a 100 lb/in spring rate.

The basic math for this is: (200X200)/(200+200) = 100 lb/in

To get a 200 lb/in spring rate by stacking two 8 inch springs would require you to use two 400 lb/in springs.

Conversely, taking an 8-inch 200 lb/in spring, cut it in half, it is now a 400 in/lb spring rate. Cut the 4 inch piece in half again, gets you a 2 inch 800 lb/in spring.

Stacking shock springs is not always convenient, especially in the Can-AM world. Finding springs of various spring rate(s) and lengths to accommodate the requirement is a challenge especially if you are doing the upgrade yourself.

What is it I would want if I were to use a dual rate shock spring system? I’d want a soft/plush compliant ride on the roads, good rough road absorption, and give the Mrs a comfortable ride. The secondary issue is to minimize roll/lean in corners, curves, cloverleaf off ramps and such.

There are several different methods to achieve this in a dual rate spring assembly. You need a cross over ring, different models are available, that is installed on the shock body, or up against the shock preload adjuster. There is a spring divider installed between the two springs that floats up and down the shock body. When enough force is exerted on the shock assembly and the top spring is compressed sufficiently that the spring divider and the cross over ring, or the spring divider and preload collar meet, the top spring is no longer being compressed and used. The remainder of the suspension compression is absorbed by the lower spring at the lower spring initial spring rate, not the combined spring rate.

If we use a tender spring with a spring rate of 400 lb/in combined with a main spring with a spring rate of 200 lb/in, we have a combined spring rate of approximately 133 lb/in. In the example above, the force towards the outside of the corner/curve compresses the combined spring assembly to a point that the spring divider and cross over ring meet and the top spring is no longer used. The suspension compression now has to deal with the 200 lb/in main spring, stiffening the suspension and minimizing roll/lean that is being realized.

You can use a dual rate spring assembly to fine tune/tailor your suspension requirements. Say you have a shock assembly designed to give you a 5 inch suspension travel. You use 1 inch of this travel for the weight of your Spyder, rider, and normal luggage/cargo. You then determine that you are willing to use 1 inch of the remaining 4 inches of suspension travel to accommodate the first requirement of a soft/plush compliant ride leaving 3 inches of suspension travel for your more aggressive riding style in the twisties.

You decide that the tender spring is a 2 inch long 400 lb/in spring rate and the main spring is a 6 inch 300 lb/in spring. This gives you an effective combined spring rate of 171 lb/in. This should give a soft/plush compliant ride. You have installed a cross over ring and spring divider that will limit the compression of the top tender spring to a travel of 1 inch that once this is reached, the tender spring is no longer being used. The main/lower spring with a spring rate of 300 lb/in is now being used and the effective resistance to the roll/lean being encountered is now 300 lb/in almost double the combined spring assembly rate.

The rating of the combined spring assembly has to be sufficient to allow for a correct preload setting.

This is an iterative process. The snowmobile world has delved into the dual spring rate application for suspension tuning and has a good understanding of what has to be done and how to achieve it. The video I mention at the start of this post has a good comparison between 2 identical machines and the rider requirements, a father and son difference.

The benefit(s) of the dual rate spring assembly should be obvious from the above, that is if I have articulated the concept(s) correctly. All 3 shock assembly spring systems have benefits and limitations. The intent of this post is to discuss the different options I have found and researched. The values for spring rates, spring lengths, and shock assembly travel are for example purposes only, and may or may not be useable.

I am not an expert, but I do enjoy finding out and learning about different options. This post is my understanding of the dual spring rate assembly.

If you have read this far, and have not fallen asleep, I thank you. Until my next post.

 

[PMK]

Regarding spring rates, they are determined at a predetermined amount of compression. Progressive springs are determined at a minimum of two predetermined amounts of compression.

In order for a spring to have constant rate, whether straight or progressive wound, and this includes springs stacked as dual or even triple spring setups, there must be no, or any end conditioning must not be a factor of the installed spring. This can sometimes be very difficult if not impossible to accomplish.

It is also a consideration that the greater the spring force change during suspension or the more extreme the SLR, the more difficult it becomes to accurately valve the the damping.

 

[Rednaxs60]

Been a while since I visited this thread. Lots going on and more things to do. The shocks in question are from M2.

Have installed the 300 lb/in front shock springs with a 1 cm preload at the bench. Installed these and also changed the rear shock spring from a 7" long 700 lb/in shock spring to a 6" long 600 lb/in shock spring.

Calibrated the ACS system, but think it needs another look see.

My research into this type of front suspension, and the comments to my posts, has always indicated that this is a change and trial situation, probably more than most people want to invest in.

Having mentioned this, had a good road trip/test today - two-up. Initial thoughts, and "feel" and it is a "feel" that I am looking for, are quite good.

The preload change is approximately 1.5 cm. The preload with the 250 lb/in shock spring installed was approxiamtely 2.5 cm. The preload for the 300 lb/in shock spring is 1 cm. The front trunk road clearance is the same.

The roll/lean on road corners/curves was much more flat than with the 250 lb/in springs supplied with the M2 shocks. Can get caught out going wide if I relaxed too much, coming back is always a treat.

I kept the same damping settings to make the comparison. The front suspension is more firmly planted, and when a roll/lean is felt and the Spyder straightens up, the return to level riding is much more smooth. This could be becasue the 300 lb/in shock spring does not compress as much as the 250 lb/in shock spring.

The return to level riding with the 250 lb/in shock springs installed was more abrupt, quicker - could have been the damping settings, but my focus has been mainly on shock spring rates up to now.

The roll/lean on cloverleaf off ramps, I have two favourites, was significantly improved. I was able to corner at the posted recommended speed. I gained 10 KPH on these corners riding two-up, without having to hang out the side. Small lean angle was required, but not like before.

I have adjusted the shock damping so it is a bit softer. This will be my focus for the next while.

If I am going to make another shock spring change, it will be to a shock spring rate of 325 lb/in. Was thinking of a shock spring rate of 350 lb/in, but think this might be too much.

For those of you who have been following this thread, I do not have OCD. I just enjoy doing things like this. Learn a lot and have fun in the process.

More to follow.