PRESS RELEASE
Over the past month there has been great interest in the EZ RYDE rear suspension. Internet and direct inquires have increased significantly. Customers have been asking many of the same questions. This release is intended to provide answers to these questions. It is also intended to acquaint new customers with the product and efforts that have gone into it.
First, who is Great Lakes Sound & Vibration (GLSV) and how did they get involved in the suspension business? GLSV is an engineering consulting firm that was formed in 1996. The company has executed, and are currently performing, an array of shock, noise and vibration engineering design/consulting contracts. Projects span many industries, including the snowmobile industry. It is also worth noting that two GLSV engineers own separate OEM snowmobile dealerships. Staff members have been and are sponsored by OEM’s to race in snow cross and ice oval events. All of this is combined with a great interest in snowmobiling. This passion goes right to the top of the company. In fact, our president logs 3000+ miles every season.
Design of any suspension requires a vast knowledge in the area of dynamics, shock, vibration, and isolation. This was right in our “wheel house” as we have and are continuing to execute an array of similar projects. As avid snowmobiler’s, we came to realize that the rear suspension could be much improved. Simply put, it was a natural extension to combine our interest in snowmobiling, knowledge, technical capabilities, and manufacturing experience.
At the onset there were a number of design points there were not negotiable, or left to chance. These include weight, traction, ride performance, maneuverability, handling, durability, simplicity, and ease of tuning. Objectives were met by using solid engineering practices, tools, and measures. The process began by creating dynamic models of the suspension. Models were used to understand phenomena that contribute to superior ride, weight transfer, traction, and maneuverability. Furthermore, they yielded initial shock angles, shock locations, spring rates, and damping characteristics.
The next step was to create finite element analysis (FEA) models. Initial loads were acquired from dynamic models. Load case evolved via experimental measures and known sacrificial components. The picture below show an eyelet that is strain gauged. This eyelet was installed on shock calibrated, and run in a test sled. Loads were directly measured. In other cases, GLSV used components with know load to yield points. Components were modified until yield was not observed. Field loads were then easy to determine. GLSV is continually updating both load cases and models. GLSV have built a shock dynamometer, and acquired a spring tester to assist with loads generation, durability, and modeling inputs.
Eyelet used to measure loads
GLSV Shock Dynamometer
GLSV Spring Tester
A number of people have stated “It looks heavy”. The arm is made from aluminum. Extensive FEA was used to minimize weight without sacrificing durability. Analyses also included extensive fatigue life predictions. These predictions were based upon hill climb type events. At the end of the day, the arm has a big cross section that gives it a “beefy” look. However, it is light and durability was not left to chance. Weight reduction will range from ~15 to 30 Lbs depending upon application.
Another hot topic is Float Shocks. Our suspension is built using FOX ZERO PRO shocks. This choice was based upon desired spring characteristics and shock travel. It is important to understand what a characteristic rate curve is for an air spring is and how it compares to coils. So here it is……..Air springs are not new and equations for restoring force are well known. Basically an air shock is nothing more that a volume of air under pressure. As the volume is reduced the air inside is compressed. This causes the internal pressure to rise (PSI or Lbs per Square Inch). An increased restoring force is created as the pressure rises. This is due to the fact that the restoring area, or area that the air pushes against, remains the same. That phenomenon is generally understood. However, what many people to not realize is that the force increases in a non liner fashion. Here’s how that works. The figure directly below shows what happens to the internal pressure as a typical air shock goes through 6” of travel. Equations in that figure show that pressure (and resulting force) is not linear, i.e. they grow rapidly near the end. This is due to the fact that volume is a cubed function. This might appear to be a good thing. However, one must also consider shock angle relative to suspension position.
EZ RYDE engineers have built models that chart suspension vertical restoring force. The models take geometry into consideration. The result, a coil over configuration out performs an air shock.
There is one other important factor. Our rear shocks are required to have ~6” of travel and an extended length of ~16.5”. Float shocks use an internal spring that is used to achieve the desired initial rate. This spring is ~1 to1.5”. Furthermore, float internals are a bit longer. As a result, Float shocks generally yield about 4” of stroke. The equivalent compressed length of a Float would be about 12.5”. This creates a situation where the suspension does not collapse as far. Therefore, you would ride high and loose travel. You could maintain travel by using a longer Float. However, this would push the rear bumper up way beyond a typical height; it still wouldn’t compress to the full up position. EZ RYDE engineers have purposefully selected a coil over for this application. TI springs will be available, if ordered before 10/09/06, and will cost $675.00. The set will consist of 4 TI springs and will shave 2 - 2.5 Lbs.
The front of the EZ RYDE suspension has generated much discussion. Many people have expressed concern over the apparent lack of support. This issue is best address by stating that the front has evolved a great deal via analysis and real world testing. Last winter we booked a combined 15,000 miles. The skid was raced on the RMSHA circuit by some of the best racers. It survived Jackson Hole where some stock suspensions failed. Clearly, it is different. However, one must consider that addition support would come in the form of a front arm. At that point, the design would be slaved with the same compromises that are inherent in existing designs.
How does it work in deep snow? The slot located in the skid rail is commonly mistaken as a coupling device. This patented technology allows the lower skid to translate in an aft direction. What does this do? Under any displacement, due to acceleration or bump absorption, the skid moves back. This reduces the track angle and applies additional track to the ground. In deep snow this gives you a shallower track angle when you need it (under acceleration). It keeps your front end down. It keeps your rear end from dancing side to side in the big bumps. Lastly, it keeps you flat when jumping or pounding up a rutted mountain pass or trail.
Now to simplicity…… It was intended and is an integral part of the design. We have spent numerous hours evaluating and working on stock suspensions. In addition, we have spent many hours at local dealerships and have witnessed people’s complete confusion over how their stock skid works. EZ RYDE is simple for the average rider to setup and tune. Furthermore, changes are quick and easy. Front and rear shocks can be removed without pulling the suspension. Front and rear springs can be changed without pulling either shock. In fact, here at EZ RYDE we commonly do it without releasing the track tension. This is important as the rear shock uses a cross over that many people may what to “play” with. The rear shock comes with a CD adjust reservoir. It is mounted so that adjustment can be made without going under the sled. I will guarantee you that this is the easiest suspension to install and tune. I couldn’t say that for some of our prototypes. However, we continually focused on our objectives and improved the design until they were met. We are very proud of how simple the suspension has become. More importantly, we are delighted that it didn’t create any compromises
Some people have referred to our skid as a Beta version. It is far from that. In fact, it has been in development for ~ 5 to 6 years. We also believe that the level of engineering in this design exceeds that of most out there.
We hope that this clears the air a bit and that many of you now have the answers you are looking for. We want satisfied customers as we plan on being in the business for many-many years to come. We are currently seeking interested dealers and racers. We want satisfied customers. We will do our best to answer your questions and concerns. Please feel free to contact us via the following.
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