Installation and Review: SKINZ Protective Gear Concept A-Arms

christopher

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Lets start at the begining.

Nytros doing what Nytros aren't supposed to
http://www.snowestonline.com/forum/showthread.php?t=263165

You WILL want to read that thread to see the PHOTOS of the sled in action.

Skinz Concept Front Suspension Video
http://www.snowestonline.com/forum/showthread.php?t=271737



March 20th, 2011.

A "certain company" contacted me a few weeks ago about a whole new prototype suspension they had been working on for the Yamaha Nytro, 2008-2012 editions.

Over the course of this winter they had built up a couple test mules and wanted to know if I would be interested in taking them out for a ride and offering some feedback as a fairly typical "Intermediate" rider, not as a hard core hill climber or well seasoned veteran with many years of back country experience. The plan was to meet up at the West Yellowstone Expo and spend a couple hours test riding.

Well, weather being what it was, they got nailed and delayed and we were not able to hook up. Fast forward to Friday last. The company and several of their employees traveled from West Yellowstone to Alpine Wyoming to participate in a 3 day "Next Level Riding Clinic" with Dan Adams. I had tried to call them on Thursday but the company cell phone was out of service, so knowing they were in the class, we just drove up to Alpine hoping for the best and arrived just in time to join in on the morning warmup before they left for the day's ride. What I thought was going to be a 1-2 hour ride, turned into a full day with group while they were in class with Dan.

(Just a side note here. I was VERY impressed with the operation that Dan Adams had put together up there. Its not very often that you get a free peek into someone else's classroom when your not a student. But Dan was gracious and allowed my son and I to tag along for the whole day's course and ride, and I liked everything I saw. If your seriously interested in improving your technical riding skills, I would heartily endorse his class. This is not a RIDE WITH ME clinic, this is an actual course of instruction designed to make you a better, more competent rider. I plan on returning for the full class)


So, what did we have to play with.
2 normally aspirated late model Yamaha Nytros.
Both running this new prototype suspension, but with subtle differences.

The "Black" sled is SCMURS ride and the "Green" sled was the shop's own test mule.

While the two sleds were similar, they rode as different as day and night.
The primary difference between the two test sleds was the ride height and the A-Arm Width.

Black Sled = Higher Ride height and narrower Arms.
Green Sled = Lower Ride height and wider arms.

It should be noted that the green sled also had a new prototype "Freestyle" seat that took you down to only 2 inches off the tunnel! The center of gravity on this sled is as LOW as you can go!!


Most of the day I rode SCMURS Black sled and my son rode the green sled. Had I understood how HUGE the differences were, I would have traded with him sooner.

Sadly, the bone stock Nyto is not know as one of the best handling snowmobiles being offered right now. In fact, it has some really significant downsides.

They dive, they are unpredictable, they dart and seem to go wherever they want on the trail. From what I can tell, the 2008 were the worst. However, I LOVE the Nytro for many other reasons. With a little bit of work and effort this sled can be "transformed" into a very sweet ride. While it is not likely the Nytro will ever become an M or a Pro, riding this new prototype shows it can be extremely close.

So, what exactly have they done?

This front end moves the spindles forward 4.5" and increases the caster angle to about what the Pro and the M are running.

They also narrowed it a little and are running the EVOL shocks.

They feel the Nytro front end is positioned in the wrong place which affects the balance points and the manners on the trail.

They found (as did we) DRAMATIC improvements in the sled's abilities and predictability.

The Yamaha factory made improvements after 2008 model, but they didn't think Yamaha went nearly far enough. Their thought was that pushing the skis further out in front of the sled (ala Arctic Cat) deals with the nose diving and the big time unpredictable nature. The new front end drops about 6 pounds and they also built a tee top steering post that drops another pound.



Riding impressions.

Some of you may recall that I installed a set of GEN III skis on my sled this year, with the most noticeable effect being that it was "easier" to turn the skis when at a dead stop. Not a huge thing, but it was very apparent to me, and made it easier to change direction of the ski when stopped AND when moving very slowly...

The first thing I noticed about the test sled, which had the OEM skis on it, was how EASY it was to turn on the trail.

My personal #1 gripe about the Nytro is the horrible trail manners. Like it or not, I have to spend a good portion of my weekend on trails getting to my favorite playgrounds. And piloting the Nytro on trails is a PAIN IN THE BUTT. Even with the OFT Steering Relocator kit, it still takes a LOT of energy to ride this sled around tight turns at speed and keep it going where YOU want it to and not where it wants to.

This new front end suspension reduces the amount of physical effort required to control the sled by a HUGE amount. While I "thought" the difference was big, I didn't fully appreciate it till I took my sled out and rode it on Saturday. The difference is DRAMATIC! It is MUCH less fatiguing to ride and require a whole lot less upper body input to steer.


The 2nd thing I discovered was how much easier it was to roll over and get up on an edge. I could lean this sled over, step OFF the running boards, and walk the sled through a tight turn without having to exert myself! The chance in the suspension geometry has resulted in a sled that is MUCH more willing to roll over and do what you ask of it without having to FORCE it. My 162SE is a PAIN IN THE BUTT to get over. It will do it, but there is no grace or finesse to it, its not "elegant" in the least degree.

The new sled is just the opposite, it was ready and WILLING to roll over any time I asked it to! It should be noted that my side hilling abilities are VERY LIMITED at this point in my sledding experience. That said, I did things on this sled I have never been able to do on mine! With no small amount of encouragement I found myself doing things I wouldn't have even attempted with my sled. Its manners are Vastly improved over the stock sled.


As a general rule, if you improve the trail manners you sacrifice the off trail performance, and vice-a-versa.
So far as I was able to tell in 4-5 hours of riding, this is NOT the case. they seem to have nailed a winning combination that makes the sled behave better in both ON and OFF trail riding.

If they take this into production this summer, then it WILL be on my sled next Winter!


Some comments on the Green Sled.
This is what they were calling the "Freestyle Sled".
It had a very low center of gravity with a slightly wider ski stance.
If I understood it correctly they changed the center shock air pressure quite a bit Thursday night to see what differnce it would make.
With my limited experience, this was the single worst handling sled I have ever ridden in my life. I swear this sled wanted me OFF it's seat. It darted and turned and tried to buck me off every chance it got on the trail riding back. Apparently the difference in performance from Thursday to Friday that resulted from that mid shock pressure change was way beyond their expectation. The previous riders reported that this sled handled like a race car on the trail. that it rode like it was on rails. And for me it was just the opposite, it took everything I could to keep it pointed straight ahead and not diving off the side of the mountain into the river down below.

I simply wouldn't have believed that just changing the air pressure in one shock could so drastically alter the behavior of a sled!


==================

Shortly after my test ride I placed my order for a set of these "Concept A-Arms". Those A-arms arrived a few weeks ago and today I got started on the installation at long last.
 

christopher

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The long awaited box arrives!




The Concept A-Arms come with a single page of instructions.
Installation is NOT complicated and should be doable in just a couple hours time.



Everything was well wrapped, just as every other shipment from Skinz has been.


YES.
I ordered everything in YAMAHA BLUE as a custom order.

You will notice in this photo that one of the lower A-Arms has part of the bushing chipped off. I can not account for this. The box looks clean and the packing was good, but this peice was broken when I took it out of the box. I have NOT yet contacted SKINZ about this.
 

christopher

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The stock OEM setup on my 2010 Nytro SE.




Looking down on the symmetrical orientation of the OEM A-Arms.



Side Shot.
 

christopher

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Step 1.
Remove hood & side panels. Remove front bumper along with plastic nose piece. Remove Shocks. Remove plastic clip fasteners and bolts from lower left and right side plastic shroud pieces to allow enough movement to access A-Arms bolts.

All of this was previously done on my sled as I am in the middle of a "Moding Summer"...


Step 2.
Remove bolts from spindle as shown. Keep all hardware as it will be used again. (Note: Spacer busing in the lower A-Arm outer heim joint will not be reused). Remove steering rods from machine. It is not necessary to remove heim joint towards center of machine steering rode as the new rod can be threaded into place.




This bolt was on TIGHT!


Thought I was going to strip it before I got it off.
Then I realized that the HEIM JOINT was an OPPOSITE rotation.
RIGHTY LOOSE, LEFTY TIGHT.




Again.
This one was on TIGHT.











And the Spindle is off the Sled.
 

christopher

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I tried hard to get photos of removing the steering arm from the Heim join in the center of the sled. But I just could not get any proper lighting in there because my supercharger was blocking everything.

NOTE.
Hindsight is such an awesome thing.

I SHOULD HAVE INSTALLED THIS BEFORE I INSTALLED THE SUPERCHARGER.
It would have been MUCH EASIER to reach all of the internal Nuts!


Removing the external Heim Joint from the end of the steering rod.
Once again, reverse rotation. RIGHY-LOOSE.




The silver OEM Arm, The BLACK SPG Arm.



OEM arm weighs in at 7.3 ounces.


SPG Arm weighs in at 12.1 for a net Gain of +5 ounces.
 

christopher

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Step #3.
Remove bolts fastening the upper and lower A-Arms. Remove two bolts from the bottom and one long bolt in the upper arm. (Note: the nut in the upper a-arm is fixed in the sub frame. You only have to unscrew the bolt from the front). Upper and Lower A-Arms can be removed.








The upper bolt comes out pretty easily.
 

christopher

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SIDE-BY-SIDE COMPARISON of UPPER A-ARMS.








This shows the real offset of the new Concept A-Arms compared to the OEM.
From Center to Center there is a 3.75 inch change relative to the mounting point!



OEM Lower A-Arm weighs in at 49.4 ounces.


SPG Concept A-Arm weighs in at 37.2 Ounces.
For a Net LOSS of -12 ounces!
 

christopher

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While the Uperer A-Arms were relatively easy, the lower A-Arms were much more of a challenge to me because I did NOT have easy access to the nuts closest to the engine!



This lower rear Nut/Bolt combo was the hardest.
Finally removed the sterring boot and was able to get a socket in there and stop the nut from rotating on me.


The lower A-Arms obviously carry the majority of the sled's weight, as they were torqued on MUCH tighter than the uppers.


The front bolts were on very tight.


Finally broke down and got out the Air Gun.


One it was loose, I had to pound it out with a hammer


The rear one was MUCH harder.
 

christopher

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SIDE BY SIDE COMPARISON OF LOWER A-ARMS.

OEM Arm on Left.
SPG Arm on Right.









Center to center on Lower A-Arm shows a 3.5" forward offset.



OEM Lower arm weighs in at a WHOPPING 85.4 ounces.



SPG Lower arm weighs in at ONLY 57.6 ounces.


Net savings = -28 ounces!


TOTAL SUSPENSION WEIGHT SAVINGS =
+5, +5, -12, -12, -28, -28 = -70 ounces.
 
Last edited:

christopher

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Step #4.

Place new A-Arms in place and install upper and lower bots just as they came out. Apply small amount of Red Loctite and tighten all hardware. Do not forget to install aluminum bushings. New Bushings have already been installed in A-Arms.

Inserting old OEM bushing into new lower A-Arm,


Lower arms slid right into place


A dab of red Locktite on the nuts.


And in they go!
 

acutah

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The lower inside nut can be easily accessed by popping out the plastic rivets on the plastic shroud that surrounds the a-arms. That way you do not have to drill and replace the rivets on the rubber boot. By pulling the shroud down you will have ample room to r&r the lower inside bolt.
 

christopher

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Thats exactly what I found as well.
Just took me a while to get there.
Started out by trying HARD to wiggle that wrench into place before i said to heck with that and started undoing more plastic.

Still, with no supercharger, it would have been so much easier to reach down in to that heim joint from above!
 

TRUEBLUEMAX

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It would of been nice if this kit came with new aluminum bushings. I found a couple that are damaged and need replaced.
Yeah I had to get a couple of bushings too but that was because I had a little run in with a rock last year.

I have my subframe out to do mine and decided to make the chore of getting the bolts out easier for next time, so I welded the nuts to the subframe as the ones on the upper arms are. I also made it so both bolts go into the center so nothing has to be removed to take out the lower arm. Hoping there will be no reason for the arms to have to come back out but rocks just like to hide right under the snow waiting for me to come and find them.
 

christopher

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FX Nytro/Phazer Oilite Front End Bushing Kit:
  • Replaces all the front end bushings in the front end of your 2007 and newer Yamaha 4-stroke!
  • Fits 2007-2012 Phazer/Venture and 2008-2012 FX Nytro models!
  • Kit Includes:
    -4 upper a-arm bushings
    -8 lower a-arm bushings
  • 2007-2009 Phazer $75
  • 2008 FX Nytro $75
  • 2009 FX Nytro $86

***Click on image for larger picture***​
 

Jager Bomb 243

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Nice job so far...BTW what type of skid plate do you have? Is it roest racing? I was just wondering cuz i saw the 2 bolts coming up in the center of the subframe and that would sold the icing and bowing issues of the plastic GYTR skid plate.
 

bigecb

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Nice job so far...BTW what type of skid plate do you have? Is it roest racing? I was just wondering cuz i saw the 2 bolts coming up in the center of the subframe and that would sold the icing and bowing issues of the plastic GYTR skid plate.
Pretty sure that is a Roest skid plate... looks just like mine does...
 
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