GEN II, our home built snowbike project

About 60-65% compared to a retail price of a Timbersled kit. A lot of man hours it put in to this, and its fun! All new parts. You could probably build it alot cheaper with used snowmobile parts, no powdercoating, used track and shocks, and so on....
The cost is'nt the thing that drives us to make a home built track kit.
The design, building and developement is fun.
For those of you who firstly prefer to ride than build, buy the Timbersled.

The turbo kit was about 50% of retail price Boondockers and I think we have a kit that works as good or even better. No short corner was put in the developement of this kit. Power and delivery is pretty spot on. Right now we dont need more power and that feels good :face-icon-small-win

As you know, building a prototype things doesn't go as planned.
As we go we see some minor improvements.
Front shock mount was not as strong as required.


No problem, back to the drawing board :face-icon-small-win
New design that spreads the load on to two shafts.

The kit works awesomely well! Wery pleased of how the suspension works.



Still some improvements and modifications to be made as predicted:face-icon-small-ton
Previously our design had dual bearings closest to the chaincase on the jackshaft. The theory was that two bearings would have double strength that would improve the longevity of the bearings. Unfortunately, that did'nt work as planned. Our tests showed that all load went to only one bearing and the other showed a lot of wear.
We have redesigned the housing to utilize a single 6305 bearing. A C3 rated bearing with wider tolerances will hopefully handle misallignements better.

The skid is rebuilt for short track. We have installed a 3050 mm backcountry X2 track with 51mm lugs for spring conditions in the Mountains. It will be interesting to feel the difference between LT :face-icon-small-win



Got some issues on the last ride when the upper shaft to the rear shock was bent quite dramatically. We could ride the next day so it was'nt an urgent fix but must of course hade to be improved. We suspected that this could occur with aluminum shaft but worth a test. Instead a 22mm 2541 steel shaft was installed, which will have a high yield strength quality and considered to be strong enoguh.

Lower shock bracket proved to be too narrow. Chafed against the lower end of the damper rod as the bogie flexes laterally at the front. Beveled the inside of the brackets so it does not happen again.

CATSLEDMAN1 said:

Never did resolve this issue with your clamping sprockets as it required too much reengineering to fit up with metric.

Click to expand...

We have moved away from clamping the sprockets.
It works but they were too hard to disasemble.
As they are tightened firmly on the chaft, it was a pain in the a$$ to break off the taperlock.
Rebuilt all chafts with regular keyways.

You might be right Raveous, bottoming limiters may be necessary.
Our theory is that the shocks comes from a sled front suspension. These suspensions usually doesnt have bottoming limiter. The shock takes the load all the way to in the end position.
I think these Fox have built in rubber damper or I'm wrong. Either way, Fox is quite progressive and bottoming is unusual with the right air pressure preload.

My longest horse run so far, 167 kilometers. From Vuoggatjålme to Sulitelma Glacier and back. Worked fairly well and quite fun trail riding. Problems with hyfax overheating, they where completely worn out. Strange as it mostly wasnt icy or hardpack, rather fairly fresh powder on top. Ice sratchers or better quality of hyfax is perhaps the solution. The new 121"short track cogged over (maybe swenglinsh) pretty much. Gonna try to move back front lower shock mount that it stretches the track more.
If this doesnt help maybe nonslip drivers is the solution. Due to the high roll resistance because of hyfax overheating, 10 liter of extra fuel didnt take me all the way. Borrowed another 2 liters to take me home.




New nonslip drivers has arrived.
Machined and milled a new drive shaft adapted for nonslip drivers. Hexagonal part comes in a different place compared to internal operating wheels.



After Easter ride overheating problems on hyfax i thought I should test fit ice scratchers on the ski. Have no idea if it works. There is risk that it becomes heavy controlled or tend to strive go straight ahead.


Maybe not the neatest design or construction but well worth a test. Not much time spent on these....
Putting scratchers on the rails, theres a risk are that they may get tangeled in the track when sidehilling on hard snow?



Scratchers in up position.

After some testing I've concluded that the scratchers doesn't work.
Must figure out a new solution.

Our final trip to the Swedish Mountains May 9 th

Using our custom made snowbike hauler.


Filmed using the new Quadrocopter, a DJI Phantom 2 with Zenmuse 3D gimbal. Not the best resolution, something wrong in settings between Gopro and editing app. Must learn more. Will be amazing shots next season!

We try to find simpler solutions to most of the parts for the construction of our next track kit.
Our goal is to make it quicker and easier to build.

Here is an example:
Our frst ski mount was previously made of a one piece of shaped and welded aluminum, more like a reproduction of Timbersleds.


The next refined mount needed no bending or welding.
Just 8 mm aluminum watecut side panels.


However, the ski spinle required a lot of milling.


Here is our latest solution where no ski spindle is required. Just some spacers and sleeves.
All parts are water cut of 8 mm aluminum and bolted together.

Here are all the drawings we made ​​for construction of our GEN II snow bike kit.
Maybe it can help those who want to build their own snow bike.

Unfortunately, all the drawings are in Swedish. Did'nt really have time to translate them. Hope you can still understand what the drawings show and the locations of all parts. Google translate can be a tool for that ;-)
Maybe the pictures in this thread can be helpful

Click on this link to dropbox http://www.dropbox.com/sh/1hglezhmoz...B0V20LzHa?dl=0

Cutting files for different materials and thicknesses can be found in the folder DWG-files
We take no responsibility for either drawings or construction ...; -)

I'd like to point out that current suspension geometry works best for Long track.
We are working on a different geometry for those who prefer short track.

We are currenly working on an update to our GEN II build.
The kit works great but as always some small refinements every year.
Here are our thougts so far:
- Move the drive shaft 30 mm forward and 20 mm upwards
- Suspension will be moved the same amount as the drive shaft.
- Changed suspension mounting points
- New shocks with other lengths and stroke.
- New tunnel panels will be required, new design.

We want to lower the ride height as much as possible. Moreover, the rear part of the suspension was previouly slightly too high.

These changes will decrease the ski pressure slightly, enhanced suspension performance and lower ride height.

To know what is required, we have made a simple wooden mockup.
Then we can easily see what happens when design changes are made.



Gen II has a reinforcing rim on the chain case. This solution has worked very well, it makes the kit very strong and rigid.

Manifacturing the rim with bending, machining, drilling and tapping is way too much work. Having a enclosed cover for the chaincase may not be necesary? Motor chain's exposed in the open, right?

Testing out a simpler solution to stiffen the tunnel in a new way that is much easier to manufacture.
This particular prototype will be mounted on our first build as a testbed for future designs. In the picture it's temporary mounted. The idea is that a 8 mm cover spaced with aluminum spacers and bolted in several places should reinforce the structure.
The chaincase cover will be open and just a proection from the chain.

We have worked hard in the 2015 reworked Gen II snow bike kit. In fact now its called GEN 2.5 ;-)
Finally, it's completed!
Can't wait or snow!

Our focus of the improvements have been on the suspension and reduce weight. Also fix some minor design flaws.
Notice that we have manufactured our own bogie rails.
Tunnel panels has a new slimmer design.
The drive shaft is moved forward 30 mm and up 20 mm.
New shocks. Fox float 3 with new length and stroke.


A new slider in the rear arm with ballbearings instead of teflon.


Here a comparison between new and old panel.
Reworked suspenson atatchment points. The whole suspenson package is moved 30 mm forward.
Drive chaft is also moved 30 mm forward and 20 mm upward.


During disasembly we saw that one of the tubes was broken.

Made a new tube with a 2 mm wallthickness and also a reinforcement.
All powdercoated.


Production of fork camps.
Start with water jet cut blanks

48 mm core drilling. Impressive fine cut and tight tolerances. Fits tightly around the fork legs very well.

Chamfering th edges for a nice look.

Using a router mounted under an old saw-bench.
The bit has a 10mm ball bearing.

Remains is to drill and countersink and last of all cut apart the clamps into halves.

Mill the first plane out of the outer diameter of allen bolt, 13 mm.
Then drill 8 mm holes.




Cutting the clamps in a band saw.


Since these clamps are more slender than previous hydralic clamps, now we can also mount the fork guards.



Some construction photos from the production of bogie rails. The reason we have chosen to make our own is to get the right length, the right angle , closer to the drive chaft as possible. In addition, we were able to adapt them to the new design of the sliding function. Last but not least, it is fun to do something of their own!

Made a drawing on the basis of our previous wooden mockup.
The idea was to get a high profile but with large lightening holes.
Had an idea of cutting out a text but it proved to increase the weight too much.

The rails are cut out of 8 mm aluminum.


Here you see the recess for the bal bearig trolley that will runs inside.

Milling a 4 mm wide and 15 mm deep groove in the underside of the 8 mm-rail


4 mm aluminumT-profile is only available as 40 mm. Cut it down to 25x14 in a resaw with carbide blade.



Rounding at the front of the rail, the T-profile is cut equally spaced so rounding is acceptable.

T-profile is inserted into the groove and drilled for pop rivets.



Done!


Here is a picture from our previous slide function. A plastic liner of Teflon-like material ran in the groove. Turned out to work out poorly with the combination of aluminum. The wear was greater than estimated. With ball bearings, we hope that the wear is non-existent. In addition, it rolls easily.