Rail extension

[Cilius66]

I am going to extend my rail from 121" 144" with a kit from Hartman.

I was wondering if anybody has done this before, and what gearing they used?

Is there any issues when I extend my rail?

 

[Highmiler]

Rail extention kit

I have a 144 extention kit posted in the classifieds. Look it up and you'll see how it looks on an 03 proaction skid. I think the ideal gearing is 23/40, but opinions may vary on this. Hope this helps.

 

[LazyBastard]

23/40 is good gearing. If you overdrive, then 23/42.

In order to do this modification properly, you need to do more than just add on rail extensions and new drop brackets. You need to actually relocate the large upper wheels back by the same amount as you are extending the rails. If you do NOT, then as your suspension compresses, it will try to tighten the track out by over 3 inches.

Visualize it like this;
Your suspension is a parallelogram, as it folds up, the angles change, but the circumference remains the same. If you move the back wheels further back, then you have a trapezoid. This trapezoid is made up of the original parallelogram with a triangle added onto the back of it. As this triangle flattens out, the side between the lower rear wheels and the upper rear wheels will elongate while all the other sides remain the same, hence the circumference increases as the suspension compresses.

Now as long as you maintain a parallelogram by moving the upper wheels back, then the suspension will continue to function correctly.

 

[Cilius66]

I have read a post about the problem you mention LazyBastard, maybe a 136" extension is a better solution. But with a 1,5 inch track, will it handle deep snow almoust as good as a 144"?

 

[obr]

Cilius: I have all the parts you need. Tunnel extention and complete suspension for a 136"...you can have it for dirt cheap... It won't perform like a 144" will, but close enough I guess...Get some different skis too... I find Apex mountain ski's too work good in lots of snow, but in the spring they are more dangeruos than a 16 year-old on a turbo....So use the mtn ski's in the deep-snow conditions and the stock ski's or doo tunnel ski's on spring conditions...

 

[Cilius66]

Cilius: I have all the parts you need. Tunnel extention and complete suspension for a 136"

What do you mean with complete suspension?

 

[obr]

complete, or just the rails..I've just bought one that has the 136" Rails...I need atleast 144 on mine, so I'll part it out...

 

[rxrider]

Does the Hartman rail extensions take sliders all the way back, if not get the rails from obr or take a look at the rail extensions from www.tracksusa.com they are designed to take sliders on the extensions. You can still buy the Hartman tunnel extension.

 

[vtdownhiller]

I am buying an Ulmer Racing 144 kit with a 2 degree kick up in the rear of the rail for $270 with rail extensions & tunnel extension

 

[JFonseca]

let us know how the install works out

 

[vtdownhiller]

Ulmer made a mistake and do not carry this for the Warrior...back to square 1. I am thinking 144 Cobra and rail extension from track usa, and a tunnel extension from Hartman's

 

[sobfrogg]

I am in the processssss of installing the MPI Cross Country kit. Changes the 121 RX1 to a 144. Kit comes w/ Tunnel extension, Drop brackets, Hardware, Template( to move suspension back). Everything you need is in the kit. I am adding their 144 billit rails instead of rail extensions.

One of these days I will post some pics in the garage section when I get time. Its getting a bunch of stuff, more on that later.