MPS- Mechanical Power Steering
See Video Below for Deltabox Installation
MPS- Mechanical Power Steering
See Video Below for Deltabox Installation
Ever since the introduction of Electronic Power Steering many Yamaha riders have grown to have a real appreciation for the technology. With the newer Viper and Sidewinder sleds on the market many are looking to upgrade, but they are reluctant to give up the power steering as Yamaha has not incorporated the technology into these sleds. MPS is the solution for those wanting an easier steering Viper or Sidewinder.
New for the 18-19 season we have now expanded the MPS concept to the pre EPS deltabox chassis sleds. So, if you have an RX-1, RS Venture, Rage, Vector, Attak or Apex that does not have power steering there is now a kit available. This kit utilizes a bolt on linkage arm and pre bent tie rod ends just as the procross kit does. To keep costs down we were able to utilize the stock tie rod ends, and opted to utilize good used tie rods as supplies last for the kit. Installation procedure is similar to the procross kit. We will have updated instructions up as soon as possible.
FX Nytro Kit will be here soon too!
Deltabox Kit
Procross Kit
Reduces steering effort via mechanical
advantage
MPS utilizes mechanical advantage principles to reduce the input effort required at the handlebars to turn the skis. The greater the distance from a pivot point the greater the leverage. Each of the 3 tie rod connection holes in the MPS arm is located farther from the pivot point of the spindle which translates to less force required at the handlebars.
Minimizes trail feedback to
handlebars
The change in mechanical ratio provided by MPS makes it easier for handlebars to turn the skis, but harder for skis to turn the handlebars. If a force on the trail tries to turn the skis the ratio change provides resistance and reduces the force felt at handlebars.
Offsets the heavy ski pressure =
heavy steering set up dilemma
When a sled pushes in a turn and doesn't hold a line skis typically need more ski pressure. The easiest way to achieve this is to soften up the pre-load on the center shock of the rear suspension and tighten up limiter straps. The downside to adding more weight to the skis is harder steering. MPS will allow for the use of heavy ski pressure and aggressive ski and skag combos without hard steering.
Adjustable with 3 levels of steering assist
The MPS arms were designed with 3 tie rod mounting point holes. Each of these 3 holes provides easier steering over the stock tie rod mounting position. These 3 holes were placed on a radial center line which means operators can switch between the 3 settings on the trail with minimal change to the ski alignment. Overall length of tie rods with ball joints will slightly vary from sled to sled, so the radial diameter the holes are located on may not always be 100% correct for all sleds, but it will be very close. Once you find the setting that works best it is suggested that you double check your ski alignment.
Utilizes formed tie rods to ensure there
is no tie rod binding on chassis
MPS moves the tie round mounting points rearward on the spindle. With a straight tie rod, we experienced binding in the bulkhead opening as the suspension and tie rods moved through their available range of motion. Our solution to this was forming the tie rods to provide adequate clearance. Bent tie rods have been used with success for years on many aftermarket spindle and a arm relocate kits.
Hardware utilizes cotter pin locking
to ensure that the kit remains in place
Yamaha engineers were always very meticulous to assembly detail on the Japan built sleds. Prior to the Viper and Sidewinder sleds all steering component fasteners contained drilled bolts and cotter pins to ensure they could not come undone. We opted to uphold this standard on our fasteners as well.
Installation requires no alterations
to existing sled components
The kit was designed to be a bolt on kit for even those with limited mechanic skills. There is no fabricating involved to install the kit and disassembly of the sled for the installation is minimal. Detailed installation instructions with photos are available at the link posted on top of the page.
Does it really work?
Mechanical advantage is a proven principle, so we knew the concept would work. The concern was whether small incremental changes to the tie rod connection point would generate a noticeable difference to the rider. After creating the first prototype our initial testing was field riding around home. The difference in steering effort was immediately noticeable. Eager to take testing to the next stage my father and I took a trip to Old Forge Ny for groomed trail testing. We had the whole trail system to ourselves that afternoon and rode nearly 100 miles. We mapped out a tight twisty trail loop in the woods and just ran it over and over again testing different settings and jumping back and forth between my Sidewinder and an EPS Apex. When I ran the loop aggressively with no MPS I had a death grip on the bars maneuvering the Sidewinder through the turns. With MPS set for easiest steering, I could essentially just let the handlebars float in my hands! After the trail testing we were 100% convinced MPS was worth pursuing.
For reference, my Sidewinder had curve skis with 6" Bergstrom triple points, center shock preload at 1/4", and limiter straps on the second loosest setting.
So What's the Catch?
MPS maintains the factory handlebar range of motion so when improving the mechanical advantage at the handlebars, the trade off is a reduced output range of motion at the ski. In simple terms, the turning radius will not be as tight. When trail riding, the increased turning radius has no effect and is not a concern. You will notice the loss of turning radius doing slow speed maneuvers in parking lots or when trying to make a u-turn on the trail. Reverse quickly makes up for this.
Retail for Pro Cross kit ( Viper & Sidewinder)…$380
Retail for Delta Box kit (Pre EPS Apex, Vector, Venture, Rage, Attak & RS Venture)… $250
