stewartb
Expert
Here's a question for discussion. If the new front ends, which are far better performers anything we ever had in the past, are more susceptible to suffering failures, where should that failure occur? What if the spindle was sacrificial? How'd you like to clip a deadfall branch hiding in the snow and have the spindle come apart at 50 or 60 mph? I don't prefer that option myself. What else could take the hits? The A arms? If the A arm was sacrificial in any way I don't think any owner would be happy. Serious accidents would be occurring because of the sacrificial part. What else is there? It seems we're seeing a few "sub frames" bend while allowing the rider to return to the trailer. Bent but intact. That's pretty cool. Getting back is a good thing. Not being injured by a sacrificial part leaving the sled at a bad time is pretty cool, too. Are these sub frame "failures" statistically important? Is the entire fleet flawed?
Maybe we should give up A arm suspension performance benefits and return to pogo struts. Or trailing arms. How many of you would line up for that? Is durability more important than performance? How much performance are you willing to give up to gain more durability?
Any comments?
Maybe we should give up A arm suspension performance benefits and return to pogo struts. Or trailing arms. How many of you would line up for that? Is durability more important than performance? How much performance are you willing to give up to gain more durability?
Any comments?
theCATman
TY 4 Stroke Master
I posted this statement in another thread, but I feel it may get seen more & pondered more here.
The '09s have got extra gussets & a relaxed angle on the spindle right?!?! This is supposed to help the possible durability issues of the '08s vs '09s along with better handling, right?!?!
Now, either we have alot of half-truth stories going on here on just how the impact happened, or there is a "magic" angle that some people have had the $hitty luck of hitting and viola!!! , bent parts.
I for one think it's a 80/20 crap shoot on how it happened. 80% being the half truths and 20% being the magic angle of impact. There must be something about a certain angle that can & will transfer the energy to the frame & not be absorbed by the shocks. However, is this just an FX Nytro problem, hardly!!
I witnessed an older trailing arm sled fold its trailing arm up like an accordion. The operator of the sled had the bars turned 1/2 way to the left crossing a road (slow speed, maybe 10 -15 mph) & when he struck the snowbank on the other side it crumpled the arm instantly without him even losing grip on the bars. SOUND FAMILIAR?
This being said, I have owned and ridden (sometimes beaten) many trailing arm sleds & never once bent an arm a little, let alone fold one into a "V". I'm sure there are many, many others that suffered this demise on his/her trailing arm design sled. I don't recall an outcry for revolt or a town square lynching about trailing arm design. They too had their weakness, but only in certain circumstances. This goes to show the angle of impact plays a huge part of possible damage.
The '09s have got extra gussets & a relaxed angle on the spindle right?!?! This is supposed to help the possible durability issues of the '08s vs '09s along with better handling, right?!?!
Now, either we have alot of half-truth stories going on here on just how the impact happened, or there is a "magic" angle that some people have had the $hitty luck of hitting and viola!!! , bent parts.
I for one think it's a 80/20 crap shoot on how it happened. 80% being the half truths and 20% being the magic angle of impact. There must be something about a certain angle that can & will transfer the energy to the frame & not be absorbed by the shocks. However, is this just an FX Nytro problem, hardly!!
I witnessed an older trailing arm sled fold its trailing arm up like an accordion. The operator of the sled had the bars turned 1/2 way to the left crossing a road (slow speed, maybe 10 -15 mph) & when he struck the snowbank on the other side it crumpled the arm instantly without him even losing grip on the bars. SOUND FAMILIAR?
This being said, I have owned and ridden (sometimes beaten) many trailing arm sleds & never once bent an arm a little, let alone fold one into a "V". I'm sure there are many, many others that suffered this demise on his/her trailing arm design sled. I don't recall an outcry for revolt or a town square lynching about trailing arm design. They too had their weakness, but only in certain circumstances. This goes to show the angle of impact plays a huge part of possible damage.
nytrose
Pro
the Crown rests your Honour..
the subframe should be stout, and the a-arms should be the sacrificial parts. easier and cheaper to replace.
on the doos when the nuns were taking the abuse (still are) some guys were drilling a hole in the back of the a arm giving it a relief area so to speak to persued the arm to fail before the nun. alot cheaper to fix.
now big hits, it doesnt matter... usually everything including the nun/subframe will bend. but light hits, and normal "bumps" shouldnt effect the whole frame AND suspension. my trailing arm suspensions (doo and yamaha) never ever had this much of a problem.
we really need a fix. i have been to the dealer, talked till i am blue. said the rsa was going to come to my house to review both my sleds. never materialized. found a good dealer out of state while on vacation to help with my cause and a new subframe is on its way.
ski
on the doos when the nuns were taking the abuse (still are) some guys were drilling a hole in the back of the a arm giving it a relief area so to speak to persued the arm to fail before the nun. alot cheaper to fix.
now big hits, it doesnt matter... usually everything including the nun/subframe will bend. but light hits, and normal "bumps" shouldnt effect the whole frame AND suspension. my trailing arm suspensions (doo and yamaha) never ever had this much of a problem.
we really need a fix. i have been to the dealer, talked till i am blue. said the rsa was going to come to my house to review both my sleds. never materialized. found a good dealer out of state while on vacation to help with my cause and a new subframe is on its way.
ski
arteeex
TY 4 Stroke Master
StewartB – Perhaps the flaw in the argument presented may be the implication that only the sub-frames are bending. This certainly was not true in my case. On my sled the right spindle, spindle bolt, upper a-arm and rear lower a-arm bolt were bent by the impact. The energy to cause this damage was applied at or near the ski bolt on the right side while I had the bars turned hard left. The feedback to me was minimal. However, I would suggest that the two bent 8mm bolts are the best indicators of how significant the impact was to the system, regardless of how it felt to me. And, I actually find this a bit reassuring.
In engineering terms the sub-frame is an anisotropic structure. This means it responds differently depending on the direction of the applied load. For example, the same load (force) applied from the front may impose a deflection much less than the same load applied in another direction. From what I have seen the torsional and lateral stiffness of the sub-frame appears much lower than the same properties in the axial direction. This isn’t uncommon or even necessarily inappropriate in this application but may be central to the issue. The gusseting in the new sub-frames should help increase the lateral stiffness but probably won’t improve the torsional stiffness significantly. One other point, after I removed my sub-frame I noted several holes in the tubing used for securing the body panels – these holes act as stress risers and I think this is bad, bad, bad.
In terms of sacrificial components this is not a new concept, nor does the failure of the component need to be catastrophic to serve its purpose. It would be reasonable to expect that the spindle, a-arms and sub-frame to be designed to provide progressively increasing load capacity and yield strengths as you move inward toward the sub-frame. These are not mutually exclusive properties. It is possible to have it both ways in this case.
Certainly the expectation for the survivability of the sub-frame and suspension is different for an impact at 10 MPH than it is for one at 60 MPH. (It’s also important to note the energy of a 60 MPH impact is 360 times greater than one at 10 MPH.) But what seems to be case here is the discrepancy between the loads the sub-frame and suspension can support head-on versus from the side.
I would agree that this is not a Nytro-specific problem. It is completely possible that an impact of identical energy would have totaled any other sled. Still, I would rather not be out $900 and counting to replace the bent parts.
In engineering terms the sub-frame is an anisotropic structure. This means it responds differently depending on the direction of the applied load. For example, the same load (force) applied from the front may impose a deflection much less than the same load applied in another direction. From what I have seen the torsional and lateral stiffness of the sub-frame appears much lower than the same properties in the axial direction. This isn’t uncommon or even necessarily inappropriate in this application but may be central to the issue. The gusseting in the new sub-frames should help increase the lateral stiffness but probably won’t improve the torsional stiffness significantly. One other point, after I removed my sub-frame I noted several holes in the tubing used for securing the body panels – these holes act as stress risers and I think this is bad, bad, bad.
In terms of sacrificial components this is not a new concept, nor does the failure of the component need to be catastrophic to serve its purpose. It would be reasonable to expect that the spindle, a-arms and sub-frame to be designed to provide progressively increasing load capacity and yield strengths as you move inward toward the sub-frame. These are not mutually exclusive properties. It is possible to have it both ways in this case.
Certainly the expectation for the survivability of the sub-frame and suspension is different for an impact at 10 MPH than it is for one at 60 MPH. (It’s also important to note the energy of a 60 MPH impact is 360 times greater than one at 10 MPH.) But what seems to be case here is the discrepancy between the loads the sub-frame and suspension can support head-on versus from the side.
I would agree that this is not a Nytro-specific problem. It is completely possible that an impact of identical energy would have totaled any other sled. Still, I would rather not be out $900 and counting to replace the bent parts.
stewartb
Expert
Good response. Thoughtful and informative. Thanks.
I've bent a few sleds in my time. Several in fact. Mostly Polaris sleds. Trailing arm sleds. The bending of the sled in most cases saved the breaking of the pilot. That's a worthwhile feature. In a couple of cases I wish the machines had bent more and me less. Manufacturers will make more parts. There's only one of me. Your description of how many parts bent with such little impact to you supports my conclusion. Maybe the problem is that you aren't getting adequately punished for your actions.
I always marvel at how I can rocket up the river at 85 or 90, hitting bumps and swells, never worrying about the reliability of the fragile structures that are supporting my activity. I think the engineers that make these sleds are right on top of things.
I've bent a few sleds in my time. Several in fact. Mostly Polaris sleds. Trailing arm sleds. The bending of the sled in most cases saved the breaking of the pilot. That's a worthwhile feature. In a couple of cases I wish the machines had bent more and me less. Manufacturers will make more parts. There's only one of me. Your description of how many parts bent with such little impact to you supports my conclusion. Maybe the problem is that you aren't getting adequately punished for your actions.
I always marvel at how I can rocket up the river at 85 or 90, hitting bumps and swells, never worrying about the reliability of the fragile structures that are supporting my activity. I think the engineers that make these sleds are right on top of things.
The jury is still out on my 09 SE. But I'm starting to think what rrxx-1 said. Does anyone think their 09 may be off from the factory? I'll wait till I hear more about the 09's before I give my final word. See (bent lower a arm.)
Well the court has ajourned. I have bent my sub frame. I found a picture I took when I brought my sled home. The arm is centered when new now it's not. I'm going to still ride it the way it is. and find out where it bent. I will post pictures later.
devil
Extreme
bent mine last year, straightened it, welded in reinforcements, first ride out this year and i smacked it pretty hard on a climb/sidehill on the same side that was bent last year. bent it to the point that the spring was touching the upper arm. straightened it with a couple cables and trucks, didn't bend it again that weekend even after a few rough bumps.
i'm just going to accept that bending it will be a fact of life and i will just straighten it when required.
i'm just going to accept that bending it will be a fact of life and i will just straighten it when required.
My 2 cents is when you see the notice your shocks are not centered in the a-arms, it isn't your subframe that is bent, it that your a-arms twisted a little. Now that being said, can someone look at a sled in the showroom and double check if the shocks come centered in the a-arms? I'd think that they would but mine sure aren't.
devil
Extreme
looked closer today, can't see any bends in the control arms (which i also reinforced last year) but the subframe is visibly bent. i will have to look closer at where exactly once all the snow and ice melts off
2008 Nytro RTX
TY 4 Stroke God
my 08 is not bent as of yet (Knock on wood)
TurboMatt
Pro
I bent my '08 last winter. Had it replaced under warrenty. This last summer, I removed the subframe, reinforced it the way the '09 frames looked and put it back together. I have about 500 miles on the sled this winter already and I have already bent it again.
This sled is not taking any serious hits. I am being very careful as I cringe everytime I hit any kind of small jolt.
I am now chosing the option that I will just bend it back into shape each time I bend it again and live with it. I just used a 6' long piece of 2" round tubing as a pry bar and bend it back.
Its actually sickening how easy it bends back into shape.
IMHO there is something wrong here. But I guess it doesn't matter what me as the cunsumer thinks.
This sled is not taking any serious hits. I am being very careful as I cringe everytime I hit any kind of small jolt.
I am now chosing the option that I will just bend it back into shape each time I bend it again and live with it. I just used a 6' long piece of 2" round tubing as a pry bar and bend it back.
Its actually sickening how easy it bends back into shape.
IMHO there is something wrong here. But I guess it doesn't matter what me as the cunsumer thinks.
Be thankful you don't own a Cat. A friend of mine works for a Cat dealer and had a 08 F8 in that hit a small tree. (the sled actually ran over it.) bent and or broke the welds on the a-arms and bent the sub frame or bulk head what ever they have. At least we just bend sub frames. My 09 SE only had 200 miles on it when it bent.
Skinner
Newbie
The dealer is checking with Yamaha on mine. He said the right side is 10mm back, visually it is noticeable but I havent noticed any change in handleing. So I didnt vote yet.