Optimus Climb project ?

[Hawkster]

Ok , just pulled the SW volume 42 no. 1 from the mail box and I dial into the project Optimus Climb and see some really nice bling and than I flip one more page and there it is , both barrels cocked , smack dab right between the eyes , if I where a monkey's uncle .

The drivers , yes right there , the drivers and that lovely center extrovert beautifully scuffed up from walking the windows .

Some one please tell me why they insist on using a set up that walks the center windows tightening up the track so tight that it's a miracle the machine doesn't taco like a carnivore trap .

This set up is getting pretty close to ten years guys , wake up .

 

[icr]

Center extro is a gimmick. A tight track is beneficial on any mountain sled.

 

[richracer1]

Ok , just pulled the SW volume 42 no. 1 from the mail box and I dial into the project Optimus Climb and see some really nice bling and than I flip one more page and there it is , both barrels cocked , smack dab right between the eyes , if I where a monkey's uncle .

The drivers , yes right there , the drivers and that lovely center extrovert beautifully scuffed up from walking the windows .

Some one please tell me why they insist on using a set up that walks the center windows tightening up the track so tight that it's a miracle the machine doesn't taco like a carnivore trap .

This set up is getting pretty close to ten years guys , wake up .

That driver set up was made so people wouldn't have to trim their rails to fit normal extrovert drivers. I guess it's too much work to trim them.

 

[AKFULLTHROTTLE]

A tight track is beneficial on any mountain sled.

Why is this?????

 

[LPIdaho]

Why is this?????

parasitic drag

 

[AKFULLTHROTTLE]

parasitic drag

Is that not a type of air drag as skin-friction drag and form drag ?????

 

[icr]

Why is this?????

Keeps its shape and maintains proper angle of attack. A loose track gets thrown off the drivers forwards and down, worst case if you don't have a lot of clearance it can hit the bulkhead and rob speed or it just hits the snow vertically with a big bend in it creating lift instead of forward movement.

I had a picture of a turbo apex that illustrates this perfectly but can't find it.

 

[AKFULLTHROTTLE]

Keeps its shape and maintains proper angle of attack. A loose track gets thrown off the drivers forwards and down, worst case if you don't have a lot of clearance it can hit the bulkhead and rob speed or it just hits the snow vertically with a big bend in it creating lift instead of forward movement.

I had a picture of a turbo apex that illustrates this perfectly but can't find it.

Thanks! Always run my track loose as a tight track robs power (IMO) but a properly adjusted track would be good. I should probably tighten mine up a bit... ahaha

 

[icr]

Thanks! Always run my track as a tight track robs power (IMO) but a properly adjusted track would be good. I should probably tighten mine up a bit... ahaha

Too tight is just as bad as too loose, polaris' spec in the owner manual works well. Track tension affects rear skid performance and vis versa.

The only time a loose track is better is drag racing on hard surface.

 

[Hawkster]

So what your saying is that with all the money and work done to the Optimus they forgot one important thing , track tension ?

 

[mountainhorse]

tension dynamics

Why is this?????

Some thoughts from another post a while back.

Loose is NOT good... Not if you want your track to perform.

Heres my 2 cents. From experience and talking to some of the best in the industry including Camoplast and FTX.

The newer single ply tracks just do not tolerate looseness as much as the older 2 ply tracks did.

A loose track is MUCH more prone to stabbing.



From a previous post

Al, I've seen this argument before... I'll give my point of view here... [IMO]. I present this after talking to the people at Camoplast, and other respected people in the field like Jack Struthers.

An OVER-tightened track IS counter productive to performance as you say... not to pe confused with a Properly tightened track.

Since the weight of the sled presses the track against the hyfax (in use, compared to on the stand) the 'loosness' in a loose track has to happen some where... the track does balloon at the top unless the track is unloaded or catches some air.

As much as the track is pulled on the top by the driver, it is "pushed" past the hyfax on the bottom.

The physics of a track and tension / take-up are NOT the same as a chain drive under load. In a sled, the track is what transfers the power to the ground... not transferring power to something else that transfers the power (like in a motorcyle with the sprocket/tire being driven).

With a loose track... the tunnel side of the track cycles thru a herky-jerky motion of going from banjo-string tight to ballooning out as you run with the inherrent loading and undloading of the drivetrain that a sled goes thru in accelleration, dealing with terrain and braking... even more exagerated by the large amount of weight that you added with the studs on your semi-long track ripsaw.

As you point out a properly adjusted track DOES rely on the track being pulled past the rear ider. A looser track cant do this all the time and this is what causes the problems... the loosness in the track has to go somewhere... that somewhere ends up being the distortion of the track as it is crammed past the hyfax or gets tripped up in the drivetrain. This distortion of the track lays the paddles down and tilts the clips on edge which can also accellerate hyfax wear.

As the track leaves the driver, a loose track will get bunched up at the front of the rail... in that situation the rails must strip the loose track from the driver and Force the track down along the rail/hyfax... A loose track does not get "pulled" around the rear idler like a properly tensioned track does.

In this age of single ply tracks, seen mostly on the mountain sleds, the belting of the track is not a rigid as a multi ply track.. they are even more susceptible to this bunching-up of the track as it leaves the drivers.

When the track bunches up between the driver and rail.. this is where the 'stabbing' occurs.

The best analogy of the bunching up that I can think of of is kind of like watching a drag racing tire "wrinkle" as it launches... not a direct analogy... but something that shows the kind of hook-up that a sled with good traction is getting.

I run a 155" to 159" track, NO bogie wheels, standard Hyfax and Avid Drivers with trimmed rails. I run the Factory prescribed tension on the track. I have yet to stab a track or wear out a set of hyfax during the season but I do replace them long before they are needed at the beginning of each season.

I have also never smoked a bearing on a driveshaft, (caused by proper tension on a track) but I have replaced them as part of PM on sleds over 2500 miles to protect my ride time on the sled... none of the drive shaft bearings removed on the end or in the case have ever been worn out. I have had jackshaft bearings go on me though, but have since switched out to a greasable PTO side setup and hope for better results there.

IMO, if a loose track gave better performance... the factory race teams would be running that on the snowcrossers and oval track sleds. In this never ending game of trying to outdo each other, the factories would not leave something as easy to fix on the table...again IMO.

and my .02 on the track tension...I realize that grass/dirt is different than snow but in our years of testing with timing lights for grass drags, a snugger track was ALWAYS faster than a looser track. Didn't matter how much power , how much traction or how long the track was... it maintained its rotational shape better and et's dropped. Lots of great points made above about this subject.

curt

.

 

[geo]

And that's the reason why we still have that 10 yr old design lol.

Hawkster. If one POS extrovert driver shows all this "scrubing" why would you want another?

 

[mountainhorse]

To me... Those drivers have some... but not a rude amount of rubbing on the...

Probably happened on the first time out and then was remedied...

These single ply tracks have to be re-adjusted for tension every ride for the first 4-5 rides and checked at regular intervalshttp://www.snowest.com/forum/attachment.php?attachmentid=246981&stc=1&d=1420828386.

Those marks could have been from one time out.

I'd like to see what the roof of the tunnel looks like inside... especially with that 3-in track on there..

So what your saying is that with all the money and work done to the Optimus they forgot one important thing , track tension ?

 

[Hawkster]

The rail analogy is very convincing and it also shows how the tire balloons . If they are so set on using one extrovert maybe they should be setting the tension to one that is larger in diameter than the outside drivers . A win win besides keeping the track from climbing the windows they'd also improve in the flick ability with a pivoting center point . How's that for a pipe dream ?

There's just to much of a foot print for such a playable material to stay in it's manufactured form to not distort ?

 

[MotorMouth]

Here in the flat lands, tight is fast. Hard on stuff, but tight is fast. A buddy I help won 13' Haydays Lake Racer and also set the mph record at Am Snow Shootout in New York in 13'. He runs stock Cat drivers and small back wheels. 144" with 260 ish track h.p... I put Extros and big wheels on my trail sled; a Poo 858 with a gtxr 2867 and N2O. He said the extros and big wheels were not needed. He said to just "tighten up the track". You guys most likely don't see 140 mph in the deep snow, but the faster the track speed, the more efficient the track will rotate if it's tight. I would have to assume a 163" at 50 mph would be similar to our narrow 1" tall, 144" long trail sleds at 100 mph.. Glenn Hall who is a "John Force" equal in the small world of snowmobile drag racing, says to tighten the track to an extreme for best e.t. and mph results. I dont think he believes in extros due to a proven friction loss. I am just reporting things I have seen and heard from fast people east of the Missouri River.. The big h.p. asphalt sleds need a track so tight that the rails will wobble.

 

[LoudHandle]

Loose is never efficient nor fast.

Extro's are just a needless product propagated by the urban legend that "loose is fast" and provides an excuse for lazy people to neglect their maintenance.

Would you rather spend an evening with the hot, curvy 19 year old or her Grandma. Comfortably tight is so much better! Always!

Hope that helps

 

[Hawkster]

Ok , this is what I see from the conversations . The track has to be set up for asphalt , grass and water skipping tensions . I don't see where deep snow has any resemblance to those three .

Not all suspension are set up as tight as a Polaris when it comes to snow .

Some suspensions are set loose because they tighten as they follow threw .

A video of how that extrovert works in the suspension would be nice to show what it really does .

 

[Norway]

My pro had snow build up onthe center driver a couple of times, making the track climb on it and ratchet. Never seen that before.

Skin it this way; loose tracks need extros to prevent ratcheting..

Simple laws of physics will tell you that your loose track is bouncing of the tunnel ceiling (oh, and a quick look!).

 

[geo]

Not all suspension are set up as tight as a Polaris when it comes to snow .

Some suspensions are set loose because they tighten as they follow threw .

.[/QUOTE]

This is an important observation for your answer.

Cycle (on a stand and springless) a Pro and view the track tension change through it's travel.
Do it to a couple of other brands. Then ask yourself what to do with all the slack when the rear arm is bottomed or how tight you will allow when the front arm is bottomed.

Easy answer (not necessarily the best) is extroverts and extra slack. Why we have then today is way back it was easiest to add a longer track with bigger lugs by moving the suspension back and going to smaller drivers.
They actually came from flat oval racing where they did anything to lower the C of G including smaller drivers and 3" of suspension. With 1,000,000 studs they needed the extroverts even with a tight track to keep from ratcheting because there was simply not enough teeth on the track sprockets.



With extroverts you have to shorten the front of the rails to clear the teeth, as well as add a bit of upward curve to keep the tips away from track windows (antistabs provide a point of first contact to the track with out holes so they help the extrovert designs).

Picture the track in a WFO situation in deep snow with this set-up.
The drivers grab the track and tighten things up starting at the first rail contact at the front and pull up on the rear arm creating transfer. Squatting the rear suspention creates track slack and it is all in the area of the drivers and first rail contact.
This slack gets flung off the drivers as soon as possible because of centrifugal force reducing tooth contact. Only thing stopping it is the finite circumference (tension) of the track AND the snow you are driving into. The snow you are driving into pushes the slack in towards the rails creating an "s" bend. Too loose creates a HP robbing, attack angle killing and track stabbing bend.
After the slack finds it's way back onto the rails it is distributed in little manageable wobbles down the important front curve of the rails dampened by the snow pressure until tight from the pull of the drivers. No curve in the front , no help here. Too much slack and it takes longer, actually going into the flat of the rails until fully tensioned (the drag race part). Not good either.
Taking away rail lessens track support. Track support is flotation. Flotation is the reason for longer and longer tracks. A 163 adds about 4" of rail support (floatation) over a 155 and is noticeable.
If you cut 4" or more off the front of your rails what track length are you actually using.

All light weight mountain suspensions create slack in the track during movement.
The Pro rear suspension is positioned to give the tightest tension fully extended. Others require you to squat the sled to find this point but this is the point to take all the slack out of your track. Advantage with Poo's set-up for the mountains is whenever you are on the throttle in deep snow this arm is in the extended position. So why start here with extra slack.
The Pro introvert set-up allows rail tips long enough to almost touch the drive shaft. Rail support for the track starts there. 10 inches more rail support than some. This handles the "s" bend and the front curve handles the tension transition. No "s" bend equals better attack angle at all times. Gentle tension transition equals more HP transferred. More rail support equals more sled support equals more use of any length of track where it really counts (the on the snow part). Supporting a sled closer to the front (and C fo G) has a handling advantage in deep snow in off throttle-low throttle situations. Keeps the rear to front transfer in control and front feels lighter.

You're right IMO about comparing drag sled to mountain. It is much more important and difficult to eliminate big track tension changes on a mountain sled because of travel used by both arms and length of rail.
End result is the same though. More control of track circumference equals less HP loss through track.

 

[Hawkster]

That's pretty good , it's funny how everyone has different ideas that work but at the end of the day it comes out in the same wash . I thought Fast had a pretty good way of keeping tension by using a spring loaded idler , made sense for a mountain sled so you could run without rail idlers and not roast the hyfax .

The set up on my main ride is such that it requires 2 3/16 track sag in the center of the rail with regular drivers and I'm now running extroverts and didn't have to cut the rails but went with them so I don't stab the track .

I still think their center extrovert is a problem that has not been addressed because when it's set up tight enough to not climb the windows that when you let off the throttle it's like you all of a sudden have the four stroke braking affect.

If we ever get a good dump I've got access to an Axys and the way they have finally got that suspension to work might be a game changer .

Thanks Geo , gives a guy a better insight than someone trying to sell a product .