Off Trail Mike
Gone Riding!
So I've been VERY slowly (nearly 2 years now)... working on putting a whole new front end on my Nytro...everything from bars to skis.... to see how much I could reduce steering effort while maintaining handling thru the powder. A big thanks goes out to those true builders Nikolai, Kennyspec, and Sportsterdanne for the inspiration. I took something learned from all your builds to get this one done...so many many thanks....
I still don't have a ton of seat time ... thanks to those latin twins El Nino and La Nina...the snow here absolutely sucks, but what I can say is that it is drastically better....and with a month or two of winter remaining, I hope to test it with a bunch more riders and another Nytro MTX if I can find one!!!...
The WHY is simple. I loved my 153 Mtx pared down to 565RTR but was unhappy with how much rider fatigue came with it. Handling with the Skinz front end was very good when you were starting a ride cause you could muscle the steering, but after 4 or 5 hours when your shoulders were shot, you simply made mistakes or wouldn't try things you would normally be able to do.
So way back, I decided on a mini build..
Wish List
===========
1. Narrower. I was gunning for a stance between 36 and 37 and settled on 36.75 for a bunch or reasons. And yes, the 2016 Viper MTX is now at 36 ...so I guess the industry is heading narrower too.
2. Spindles Forward. IMO, Skinz nailed it by pushing the spindles ahead, but how they got to 4.5" forward and the need to be out that far is not for me. I basically settled on 3" to match CR Racing's front end .. a proven combo with the narrower stance.
3. Direct steering. This was the biggy....No more linkages from the steering post to the skis. It adds weight, friction and geometry issues. Gone..
4. Steeper steering post angle. As all of us with the OFT relocate can say....Anything here helps. I want steeper than the OFT, and I landed at 56 degrees which is slightly better than the XM!!. I can actually steepen it quite a bit more by using the upper OFT relocate mount, but decided against in for this first round.
5. EASIER STEERING. Regardless of center shock/limiter strap position it is one of the worst sleds to turn out there. The Viper, Renegade 1200 and Proclimb 1100 all have it beat in spades.
Here's a shot of the completed front end using Summit XM spindles and custom fabricated a-arms. The upper a-arm is a heavily modified 42" doo arm, the bottom uses the doo ball joint forging which I salvaged from a few wrecked a-arms.
At the last minute, I decided to invert the doo forgings to gain ground clearance and make my shock mount shorter. That decision caused me a lot of grief with clearance for my steering rods, but ultimately I gained enough room to make it work...aka ducked a bullet.
It's hard to see, but I've mounted the forward upper A-Arm ahead of the stock Nytro location. Doing this allowed me to use a modified skid00 upper a-arm and gave me lots of room for my shocks. Because the upper doo a-arms use 3/4" tubing I didn't have to cut the plastics much either.
What Direct steering looks like in a relatively stock Nytro subframe! It's hard to see but the lower steering post bearing mount is attached to the subframe using the front A-Arm bolts. There was a ton of CAD work in this build to get everything to fit with minimal bump steer. I'm just under 1.2mm of bump steer thru it's entire stroke!!
Amazing Goop is truly amazing!!! The aluminum pieces are also held by the lower front A-arm bolt so it's not going anywhere....
What Direct steering looks like under the hood.....thank god for K&N Filters!!!. ECU is mounted to the frame on the left and Relays are mounted parallel to the engine just behind ECU.
Had to slot the upper holes of the stock radiator mount just a bit so there was enough room for the steering post. PC5 got a new home too! Much easier access than my last mount.
After the first ride, I was curious to see how much ice/snow build up accumulated around the steering post/ball joint area. I have the GNR braces on my XM, and I find they cause the steering to get sticky from time to time. With Mountaintech's full length skid plate, I was worried I'd have the same issue, but looks much better.
Despite adding insulation to the housing in an attempt to reduce dripping, I still have ice buildup under the A-arms which was a problem with the Skinz front end too, so I cut up another Yoga block (closed cell foam) and jammed in under the a-arms. Foam is much lighter than ice LOL.
Had to use some grease to jam the back one in!!
The completed sled finally on the snow!!
Still lot's to do. I need to seal up around the upper a-arm mount as there is snow getting in there, and lighten up some of my pieces to drop a few more pounds, but for the next month or so it'll be fun just getting some seat time.
OTM
I still don't have a ton of seat time ... thanks to those latin twins El Nino and La Nina...the snow here absolutely sucks, but what I can say is that it is drastically better....and with a month or two of winter remaining, I hope to test it with a bunch more riders and another Nytro MTX if I can find one!!!...
The WHY is simple. I loved my 153 Mtx pared down to 565RTR but was unhappy with how much rider fatigue came with it. Handling with the Skinz front end was very good when you were starting a ride cause you could muscle the steering, but after 4 or 5 hours when your shoulders were shot, you simply made mistakes or wouldn't try things you would normally be able to do.
So way back, I decided on a mini build..
Wish List
===========
1. Narrower. I was gunning for a stance between 36 and 37 and settled on 36.75 for a bunch or reasons. And yes, the 2016 Viper MTX is now at 36 ...so I guess the industry is heading narrower too.
2. Spindles Forward. IMO, Skinz nailed it by pushing the spindles ahead, but how they got to 4.5" forward and the need to be out that far is not for me. I basically settled on 3" to match CR Racing's front end .. a proven combo with the narrower stance.
3. Direct steering. This was the biggy....No more linkages from the steering post to the skis. It adds weight, friction and geometry issues. Gone..
4. Steeper steering post angle. As all of us with the OFT relocate can say....Anything here helps. I want steeper than the OFT, and I landed at 56 degrees which is slightly better than the XM!!. I can actually steepen it quite a bit more by using the upper OFT relocate mount, but decided against in for this first round.
5. EASIER STEERING. Regardless of center shock/limiter strap position it is one of the worst sleds to turn out there. The Viper, Renegade 1200 and Proclimb 1100 all have it beat in spades.
Here's a shot of the completed front end using Summit XM spindles and custom fabricated a-arms. The upper a-arm is a heavily modified 42" doo arm, the bottom uses the doo ball joint forging which I salvaged from a few wrecked a-arms.
At the last minute, I decided to invert the doo forgings to gain ground clearance and make my shock mount shorter. That decision caused me a lot of grief with clearance for my steering rods, but ultimately I gained enough room to make it work...aka ducked a bullet.
It's hard to see, but I've mounted the forward upper A-Arm ahead of the stock Nytro location. Doing this allowed me to use a modified skid00 upper a-arm and gave me lots of room for my shocks. Because the upper doo a-arms use 3/4" tubing I didn't have to cut the plastics much either.
What Direct steering looks like in a relatively stock Nytro subframe! It's hard to see but the lower steering post bearing mount is attached to the subframe using the front A-Arm bolts. There was a ton of CAD work in this build to get everything to fit with minimal bump steer. I'm just under 1.2mm of bump steer thru it's entire stroke!!
Amazing Goop is truly amazing!!! The aluminum pieces are also held by the lower front A-arm bolt so it's not going anywhere....
What Direct steering looks like under the hood.....thank god for K&N Filters!!!. ECU is mounted to the frame on the left and Relays are mounted parallel to the engine just behind ECU.
Had to slot the upper holes of the stock radiator mount just a bit so there was enough room for the steering post. PC5 got a new home too! Much easier access than my last mount.
After the first ride, I was curious to see how much ice/snow build up accumulated around the steering post/ball joint area. I have the GNR braces on my XM, and I find they cause the steering to get sticky from time to time. With Mountaintech's full length skid plate, I was worried I'd have the same issue, but looks much better.
Despite adding insulation to the housing in an attempt to reduce dripping, I still have ice buildup under the A-arms which was a problem with the Skinz front end too, so I cut up another Yoga block (closed cell foam) and jammed in under the a-arms. Foam is much lighter than ice LOL.
Had to use some grease to jam the back one in!!
The completed sled finally on the snow!!
Still lot's to do. I need to seal up around the upper a-arm mount as there is snow getting in there, and lighten up some of my pieces to drop a few more pounds, but for the next month or so it'll be fun just getting some seat time.
OTM
Sportsterdanne
TY 4 Stroke Guru
Nice mod !
Deeppow16
TY 4 Stroke Master
- Joined
- Oct 19, 2015
- Messages
- 1,159
- Age
- 29
- Location
- Montrose, Minnesota
- Country
- USA
- Snowmobile
- 2016 Arctic Cat M8000
2009 Yamaha Nytro MTX (Totaled)
2002 Polaris 600 XCSP (Sold)
1999 Ski-doo Formula 500 (Totaled)
Just the other day I was thinking about how hard it would be to put a ski-doo front end on my nytro. I'm glad I saw your post and gave me a little insight on it. Looks like a great build.
Nikolai
TY 4 Stroke God
So awesome.
kennyspec
Expert
Looks awesome!!
kennyspec
Expert
Updates?
Off Trail Mike
Gone Riding!
Yeah....we have no snow!!!!! LOL
I haven't seen anything like it in my lifetime. Maybe 6" in my back yard versus 4 feet by now....so no real riding time yet.
I'm hoping to get out in the next week or so as it looks like we might actually get some a couple of old fashioned snow storms later this week so I can finally test it in something deeper than and inch!!! Hoping to test agianst XM and another Nytro to really compare.
Gotta post some pictures of spindles tho.. Learned a lot about why Nytro's don't steer so easily.
otm
I haven't seen anything like it in my lifetime. Maybe 6" in my back yard versus 4 feet by now....so no real riding time yet.
I'm hoping to get out in the next week or so as it looks like we might actually get some a couple of old fashioned snow storms later this week so I can finally test it in something deeper than and inch!!! Hoping to test agianst XM and another Nytro to really compare.
Gotta post some pictures of spindles tho.. Learned a lot about why Nytro's don't steer so easily.
otm
kennyspec
Expert
I'm interested to hear your results.
ViperTurboPete
TY 4 Stroke Master
- Joined
- Mar 25, 2005
- Messages
- 1,068
- Age
- 57
- Location
- Sudbury, Ontario
- Country
- Canada
- Snowmobile
- 2015 Viper XTX LE MPI Turbo
2022 Expedition Extreme 850
The talent on this forum never ceases to amaze!
Off Trail Mike
Gone Riding!
Still waiting for snow here to do more testing but looks like this week we are going to get a fair bit.
While waiting I thought I'd upload a few pictures to compare spindles....which I think is one of the reasons why the Nytro has heavy steering and why I switched to the Doo spindle.
In some regards, the spindle is the heart of the steering system and some interesting and strange things happened along the way with Yami Nytro spindles that have always made me suspect they were covering some basic front suspension design flaws.
In the pictures below, the black Nytro spindle is from a 2008 and the silver one is from a 2011 (but I think they made the spindle change in MY2009 tho). If you line up the two a-arms, you can see that after 2008, Yami moved the ski bolt back...relative to the ball joint centerline....more than 1/2".
Here's the after 2009 spindle....pretty easy to see the offset here
Here's the 2008 spindle......almost no offset.
The why is easy. Moving the ski bolt back improves high speed stability and centering. The down side of this "choice" is ...... the more you rake your caster, the more steering effort it takes. The further you move the ski bolt away from the ball joint centerline....the more steering effort it takes. For anyone who has ridden a chopper, which takes the idea of caster to an extreme... knows what this feels like .. you are literally lifting the weight of the bike on each turn.
And the other big problem is that the OEM's and the aftermarket have been increasing caster angles from 18-20 degrees to 24-27 degrees because it makes mountain sleds sidehill and handle in the powder much better..... but those offset spindles with higher caster angles really increases steering effort.
So here's a pic of the Ski-Doo spindle. Pretty sure I could have used the poo spindle too but doo had the advantage of getting my steering post where I could do direct steering.
You can see that the ski bolt lines up with the a-arm ball joints pretty well. There offset is maybe 3mm. I've seen the Arctic Cat spindle and the offset is minimal as well.
The reason why Cat/Doo/Poo all stayed with minimal offset is that it makes the sled more playful and if you have a well designed suspension, you can still have OK high speed stablity without the need to offset....Like comparing a slalom ski to a Downhill ski...if that make sense.
So Yami.... maybe you should have kept the 2008 spindle on the MTX and put the newer one on the boulevard cruisers. It would have been fun to compare!
OTM
While waiting I thought I'd upload a few pictures to compare spindles....which I think is one of the reasons why the Nytro has heavy steering and why I switched to the Doo spindle.
In some regards, the spindle is the heart of the steering system and some interesting and strange things happened along the way with Yami Nytro spindles that have always made me suspect they were covering some basic front suspension design flaws.
In the pictures below, the black Nytro spindle is from a 2008 and the silver one is from a 2011 (but I think they made the spindle change in MY2009 tho). If you line up the two a-arms, you can see that after 2008, Yami moved the ski bolt back...relative to the ball joint centerline....more than 1/2".
Here's the after 2009 spindle....pretty easy to see the offset here
Here's the 2008 spindle......almost no offset.
The why is easy. Moving the ski bolt back improves high speed stability and centering. The down side of this "choice" is ...... the more you rake your caster, the more steering effort it takes. The further you move the ski bolt away from the ball joint centerline....the more steering effort it takes. For anyone who has ridden a chopper, which takes the idea of caster to an extreme... knows what this feels like .. you are literally lifting the weight of the bike on each turn.
And the other big problem is that the OEM's and the aftermarket have been increasing caster angles from 18-20 degrees to 24-27 degrees because it makes mountain sleds sidehill and handle in the powder much better..... but those offset spindles with higher caster angles really increases steering effort.
So here's a pic of the Ski-Doo spindle. Pretty sure I could have used the poo spindle too but doo had the advantage of getting my steering post where I could do direct steering.
You can see that the ski bolt lines up with the a-arm ball joints pretty well. There offset is maybe 3mm. I've seen the Arctic Cat spindle and the offset is minimal as well.
The reason why Cat/Doo/Poo all stayed with minimal offset is that it makes the sled more playful and if you have a well designed suspension, you can still have OK high speed stablity without the need to offset....Like comparing a slalom ski to a Downhill ski...if that make sense.
So Yami.... maybe you should have kept the 2008 spindle on the MTX and put the newer one on the boulevard cruisers. It would have been fun to compare!
OTM
Nikolai
TY 4 Stroke God
Really good information, thanks for posting.
Nugget_the_Nytro
Newbie
Ok I am apparently a little dense. Are you saying the 08 spindles perform better?
If yes then are you saying the 08 spindles are better for side hilling or high speed stability?
You lost me with the slalom and downhill ski analogy. And I'm a former ski racer. Ha!
I know this is good info and I have learned a lot from your (otm's) posts over the years. So thanks for being patient in advance
If yes then are you saying the 08 spindles are better for side hilling or high speed stability?
You lost me with the slalom and downhill ski analogy. And I'm a former ski racer. Ha!
I know this is good info and I have learned a lot from your (otm's) posts over the years. So thanks for being patient in advance
Off Trail Mike
Gone Riding!
Nugget....not dense....I suck at explaining.
The 2009 spindles gave the Nytro more high speed stability because the offset axle uses some of the weight of the sled to keep the skis tracking straight. That's why Yamaha made the change.....people complained about the 08 darting and lifting the inside ski, which the offset definitely helped in 2009 and newer sleds. The price you paid for that stability was more steering effort.
On side hilling, the Nytro was never the RMK ....we all know that....but seemed to get much better with the a-arms moved forward 3 or 4 inches and increasing caster from 22 to 25+ degrees (skinz, barcode, mountaintech all added caster), but doing so with 09+ spindles increased steering effort even more. Nothing they could have done about this problem.....It's what came with the sled!!! It's in this situation the 08's should work better.
Figured someone would call me out on my ski analogy....LOL....What I was trying to say is a Downhill ski is built more for high speed stability and less for cornering...but it still corners very well. A slalom ski is meant to turn on a dime...and turn a lot... but has a tendency to wander nervously if you point them straight down the hill. Yamaha decided in 09 we needed downhill skis more than slalom and that's what we got. I think had they done their homework, they could have left the 08 spindles on the mountain sleds to make them more maneuverable and easier on the shoulders and put the new spindles on the turbo lake rockets
OTM
The 2009 spindles gave the Nytro more high speed stability because the offset axle uses some of the weight of the sled to keep the skis tracking straight. That's why Yamaha made the change.....people complained about the 08 darting and lifting the inside ski, which the offset definitely helped in 2009 and newer sleds. The price you paid for that stability was more steering effort.
On side hilling, the Nytro was never the RMK ....we all know that....but seemed to get much better with the a-arms moved forward 3 or 4 inches and increasing caster from 22 to 25+ degrees (skinz, barcode, mountaintech all added caster), but doing so with 09+ spindles increased steering effort even more. Nothing they could have done about this problem.....It's what came with the sled!!! It's in this situation the 08's should work better.
Figured someone would call me out on my ski analogy....LOL....What I was trying to say is a Downhill ski is built more for high speed stability and less for cornering...but it still corners very well. A slalom ski is meant to turn on a dime...and turn a lot... but has a tendency to wander nervously if you point them straight down the hill. Yamaha decided in 09 we needed downhill skis more than slalom and that's what we got. I think had they done their homework, they could have left the 08 spindles on the mountain sleds to make them more maneuverable and easier on the shoulders and put the new spindles on the turbo lake rockets
OTM
Nugget_the_Nytro
Newbie
Thanks OTM. I'm following now. Good news for my setup as I still got the 08 front end but I'm thinking of putting a mountain tech front end on this summer. So I like what you are saying.
On a side note Im still rocking my arctic cat skid you helped me with a few years ago on the float thread (back when my username was NUKNUK)It's still doing great especially with the turbo kit I put on last year and the new CE 2.5 track it got this year.
Thanks for the info and inspiration! Your steering setup looks badass!
On a side note Im still rocking my arctic cat skid you helped me with a few years ago on the float thread (back when my username was NUKNUK)It's still doing great especially with the turbo kit I put on last year and the new CE 2.5 track it got this year.
Thanks for the info and inspiration! Your steering setup looks badass!
whitewheels
Pro
Very intresting thread. Nice work! 
