kennyspec
Expert
Thanks mike, all the 4130 came from aircraft spruce Canada they have the cheapest prices. What are a a arms for? A Nytro I assume? What diameter/thickness were you going to be using?
When my drivers are installed the tip of the anti ratchet is just even with the bottom of the frame tubes. So I guess they are about as low as I want without them sticking out the bottom of the chassis.
When my drivers are installed the tip of the anti ratchet is just even with the bottom of the frame tubes. So I guess they are about as low as I want without them sticking out the bottom of the chassis.
kennyspec
Expert
Quick skid mockup
Off Trail Mike
Gone Riding!
Nice Pipe bender.....think I've seen that one before!!
Your drivers and suspension setup look good to me. I wouldn't worry too much about absolute ground clearance. More is better, but approach angle trumps everything, so make sure the track follows the tipped up section of the rails and smoothly into your drivers.
I'm putting a complete new front end on the Nytro. Modded subframe with direct steering (no intermediate link), a much steeper steering post angle, 37" ski width and a 3 inch forward layout. I'm really hunting a drastic improvement in steering effort, a "ride all day" front end if you want to call it that so we'll see how it turns out. For tubing, I'm using DOM (drawn over mandrel) tubing for all the prototypes. 1" x 0.83" lowers and 0.75" x 0.083" uppers but will drop to 1" x 0.065 if I end up using 4130. DOM is a CR1026 steel, so medium strength, easily weldable.
The more I think of it, the more I think A-Arms should be expendable, meaning you don't want to damage your sub frame or that beautiful tubbie frame because your super strong a-arms stayed intact after an impact.
OTM
Your drivers and suspension setup look good to me. I wouldn't worry too much about absolute ground clearance. More is better, but approach angle trumps everything, so make sure the track follows the tipped up section of the rails and smoothly into your drivers.
I'm putting a complete new front end on the Nytro. Modded subframe with direct steering (no intermediate link), a much steeper steering post angle, 37" ski width and a 3 inch forward layout. I'm really hunting a drastic improvement in steering effort, a "ride all day" front end if you want to call it that so we'll see how it turns out. For tubing, I'm using DOM (drawn over mandrel) tubing for all the prototypes. 1" x 0.83" lowers and 0.75" x 0.083" uppers but will drop to 1" x 0.065 if I end up using 4130. DOM is a CR1026 steel, so medium strength, easily weldable.
The more I think of it, the more I think A-Arms should be expendable, meaning you don't want to damage your sub frame or that beautiful tubbie frame because your super strong a-arms stayed intact after an impact.
OTM
kennyspec
Expert
pipe bender is a JD2 model 3. its a awesome bender. OTM do you have a bender yourself? is DOM really that much cheaper than chromo? If you dont have access to a bender id be more than happy to bend your DOM in my bender and then ship them over to you. if you are going to be fabbing with a lot of tube you should look into bend tech. its a awesome program, it has really helped me with this build.
In the pic above it looks like my skid is moved back a fair amount more than it needs to be, it probably is because I just threw it in there for a quick pic. I think the way to position it is with a straight edge on the bottom of the tipped up part of the front of the rails and have that angle end up at the tangent of the drivers.
When I first hacked up my nytro I also thought of making a direct drive steering system to get a more vertical steering post, but instead I just used a post from a fusion with a universal joint in it. when I was looking at the steering I don't think that making it direct will make it any harder to steer. It seems as if all the linkages are 1:1 (the distances from the input tie rod to the center of the intermediate link is the same as the output tie rod to the center of the link). for my wifes nytro I moved the tie rod a little closer to the center of the steering post to make the steering less sensitive. the bars now needed to be turned more degrees for the same amount of ski movement. It made a huge improvement with the darty twitching feeling. I think for your direct drive system you should consider moving the ski tie rods closer to the steering post as well. it may require turning the bars further to get the same ski movement but the first thing I notice when riding my nytro with the pro rmk steering is how much more you have to turn the handlebars.
In the pic above it looks like my skid is moved back a fair amount more than it needs to be, it probably is because I just threw it in there for a quick pic. I think the way to position it is with a straight edge on the bottom of the tipped up part of the front of the rails and have that angle end up at the tangent of the drivers.
When I first hacked up my nytro I also thought of making a direct drive steering system to get a more vertical steering post, but instead I just used a post from a fusion with a universal joint in it. when I was looking at the steering I don't think that making it direct will make it any harder to steer. It seems as if all the linkages are 1:1 (the distances from the input tie rod to the center of the intermediate link is the same as the output tie rod to the center of the link). for my wifes nytro I moved the tie rod a little closer to the center of the steering post to make the steering less sensitive. the bars now needed to be turned more degrees for the same amount of ski movement. It made a huge improvement with the darty twitching feeling. I think for your direct drive system you should consider moving the ski tie rods closer to the steering post as well. it may require turning the bars further to get the same ski movement but the first thing I notice when riding my nytro with the pro rmk steering is how much more you have to turn the handlebars.
Off Trail Mike
Gone Riding!
Just picked up the same JD2 bender a month ago. It's a tough little unit. On the DOM vs CrMoly, I don't think price is much different, but I prefer my a-arms to fold rather than destroying my subframe, thus using a slightly weaker steel.
On setting up track, yeah a straight line from tip up to tangent is the way to go, and set your adjuster straps in the stock position when you do it. The bigger question I struggled with in my AC skid in Nytro was where do you install the skid relative to your tunnel/frame/ski position? It's all a compromise, and on mine I positioned both my front mounts and rear brackets so that my rear bumper was slightly higher than the stock MTX which is about the same height as my XM.
Steering pivots, I'm totally with you. I was watching a video of Rasmussen's sled setup and the first thing I realized was the amount of handlebar rotation it took to go from center to full lock on one side. I started to realize that when I'm normally riding backcountry and banking, I don't use a ton of steering input, so adding a bit more "turn" on the bars to ease up on the arms seems like a good idea. And as you said, it's easy to adjust this by changing the distance from pivot to heim joint on your steering post.
The direct steer for me is to drop weight, steepen steering post, and allow for more "adjustment" of linkages since I am using different spindles.
Where are you planning to put the Turbo?
On setting up track, yeah a straight line from tip up to tangent is the way to go, and set your adjuster straps in the stock position when you do it. The bigger question I struggled with in my AC skid in Nytro was where do you install the skid relative to your tunnel/frame/ski position? It's all a compromise, and on mine I positioned both my front mounts and rear brackets so that my rear bumper was slightly higher than the stock MTX which is about the same height as my XM.
Steering pivots, I'm totally with you. I was watching a video of Rasmussen's sled setup and the first thing I realized was the amount of handlebar rotation it took to go from center to full lock on one side. I started to realize that when I'm normally riding backcountry and banking, I don't use a ton of steering input, so adding a bit more "turn" on the bars to ease up on the arms seems like a good idea. And as you said, it's easy to adjust this by changing the distance from pivot to heim joint on your steering post.
The direct steer for me is to drop weight, steepen steering post, and allow for more "adjustment" of linkages since I am using different spindles.
Where are you planning to put the Turbo?
kennyspec
Expert
Good info OTM, the turbo will be located right behind the engine. Debating on using a gt2860 or going down to a smaller gt25 series. I am not looking for huge power, id rather have the quick spool. Planning on running 5psi to start. should be ok on the stock engine I hope???? elevation is sea level. I will be fabbing an aluminum fuel tank.
Are your a arms drawn up in cad?? if so do you mind sending me the file? k_tataryn@Hotmail dot com.
More work done on the sled today, I had to redo my front tubes that were connecting the bulkhead to the tube frame. I pulled the bulkhead 2" closer to the engine. The clutch now sits more in the cutout area of the pro plastics. this is something that both sportsterddanne and I had troubles with our nytro/pro conversion.
I also added a 20* swing to the upper bars that tie in the pro bulkhead. Shitty part is that after I get the engine fully mounted I will have to cut one of the upper bars out and make it removeable to get the engine out. I seen that coming as I was building, but there wasn't any way to avoid it.
pic of my PTO side rear engine mount. It is a bit ugly but clutch alignment turned out perfect!!!!
Are your a arms drawn up in cad?? if so do you mind sending me the file? k_tataryn@Hotmail dot com.
More work done on the sled today, I had to redo my front tubes that were connecting the bulkhead to the tube frame. I pulled the bulkhead 2" closer to the engine. The clutch now sits more in the cutout area of the pro plastics. this is something that both sportsterddanne and I had troubles with our nytro/pro conversion.
I also added a 20* swing to the upper bars that tie in the pro bulkhead. Shitty part is that after I get the engine fully mounted I will have to cut one of the upper bars out and make it removeable to get the engine out. I seen that coming as I was building, but there wasn't any way to avoid it.
pic of my PTO side rear engine mount. It is a bit ugly but clutch alignment turned out perfect!!!!
Sportsterdanne
TY 4 Stroke Guru
Nice work !
I have so many ideas of how i would build a sled chassi from scratch... gimme more time and money..
Since even the Pro RMK:s are getting better handling with forward A-arms do you think its a good idea to move the Bulkhead back ?
I have so many ideas of how i would build a sled chassi from scratch... gimme more time and money..
Since even the Pro RMK:s are getting better handling with forward A-arms do you think its a good idea to move the Bulkhead back ?
Off Trail Mike
Gone Riding!
Kennyspec
I'm still working thru the steering geometry on CAD so no arm design yet. It's a tougher job than I thought, especially getting the steering post right. One small change effects everything else. Will get it you once I get there.
OTM
I'm still working thru the steering geometry on CAD so no arm design yet. It's a tougher job than I thought, especially getting the steering post right. One small change effects everything else. Will get it you once I get there.
OTM
kennyspec
Expert
Danne I only moved the bulkhead 2" forward from where it was on my Nytro. This should still leave me 3" forward to where the Nytro skis would of been. Why do you think moving the a arms/ski forward improves handling? Most of the time on a climb the skis are in the air anyway.
OTM sounds good. I would be interested to draw them in bendtech for you, could print off and send you all the coping templates and bend locations for your bender.
OTM sounds good. I would be interested to draw them in bendtech for you, could print off and send you all the coping templates and bend locations for your bender.
kennyspec
Expert
got a couple more tubes built. First is a PTO side tube that will tie in the front engine mount
same thing for the MAG side
and a tube connecting those two that the mounts will be welded to
I also made this poor mans dust collector lol. I am surprised at how well it works to remove the dust from in the shop.
same thing for the MAG side
and a tube connecting those two that the mounts will be welded to
I also made this poor mans dust collector lol. I am surprised at how well it works to remove the dust from in the shop.
Nikolai
TY 4 Stroke God
Sick build.
Mike, I'm looking forward to seeing what you come up with for a steering/a-arm setup.
Mike, I'm looking forward to seeing what you come up with for a steering/a-arm setup.
edge_232
Expert
- Joined
- Jan 15, 2014
- Messages
- 254
- Age
- 50
- Location
- Madison WI
- Country
- USA
- Snowmobile
- 2011 Nytro MTX slowly being modded
2005 IQR Trail Converted
Very nice work on the sled & dust collector! LOL
kennyspec
Expert
I got myself a killer deal on a brand new power commander V PTI and a wideband 2 and the new on board pod 300 screen.
my question on it is everyone is mounting the MAP sensor from the powercommander in the intercooler/chargepipe. but then it wouldn't read vacuum. can the powercommander map sensor be hooked up into one of the vac lines so it would read vac/boost as well?
my question on it is everyone is mounting the MAP sensor from the powercommander in the intercooler/chargepipe. but then it wouldn't read vacuum. can the powercommander map sensor be hooked up into one of the vac lines so it would read vac/boost as well?
Sportsterdanne
TY 4 Stroke Guru
Most builds and factory kits with it have it installed on the chargepipe/intercooler since its mainly used for adding fuel during boost, it could possibly se a pressure spike during release of throttle and add fuel at that time.
kennyspec
Expert
I will be running a quality TIAL BOV so I don't see how it would create a pressure spike during the throttle release. I want to be able to tune the whole map range vac and boost. I think for now I will try to tee it into the two existing map sensors so it should see vac and boost. If it doesn't work I can easily tig it on to the chargepipe/intercooler.
Similar threads
