E-Bay Spitfire with rubber conversion track

JDT · Post by **JDT** » Sun Jan 20, 2008 7:33 pm

Mr. BoaSki ( sorry but I can't find your name )

Those look very nice. Did you cut them from UHMW or Delrin?

What were are dealing with os a driver of very small diameter for this application.
I am unsure if the external drive will work for that. Any thoughts?

Thanks for the pic post.

Todd

JoeRainville · Post by **JoeRainville** » Sun Jan 20, 2008 8:01 pm

Hi Todd,

The drivers Ernie has listed are regular 8 tooth 2.52" pitch 1" round shaft sprockets. These are about 20.16" in circ. and has a 6.41" diameter. These were used on vintage Scorpion sleds.

The Deere sprocket was 7 tooth std. on the Spit and Snow, with an 8 tooth on the Sprintfire, but with a 2" pitch for 14" or 16" circ and a 4.45" or 5.09" diameter respectively. The Scopion sprocket is almost 2" taller.

To have a 2.52" pitch close to the desired 4.45" diameter, it would need to have only 6 teeth, resulting in a 15.12" circ and a 4.81" diameter.

If I made a custom 3.29" pitch sprockets, we could use 4.5 teeth since Deere put a sprocket tooth on each side of the track drive lug. This would yeild a circ. of 14.08" and a diameter of 4.71" or nearly the 7 tooth 2" pitch sprocket size. A full 5 tooth sprocket with a 3.29 pitch would end up with a 5.24" diamter, very close to the 8 tooth factory sprocket.

There is a solution to this problem, but I don't think it will be cheap or easy...

-Rainville

boaski · Post by **boaski** » Sun Jan 20, 2008 8:44 pm

I'd have to look, but I think I used some black UHMW. I really like the durability of UHMW, but I think it has a low UV resistance rating. I had a few problems with the Snowbug last winter & haven't had much snow this winter so I don't have a real good feel for how it'll hold up in this application. I did some research on having drivers made from polyurethane but ran into roadblocks as far as getting the drivers cast.

mwking · Post by **mwking** » Sun Jan 20, 2008 11:34 pm

JDT mentioned that the track on the E-Bay Spitfire looked like a Skidoo track and Liquifire 4/6 said he had a Spitfire with a Skidoo track conversion that was not successful. That got me thinking so I had a look at the Kimpex catelogue and there is an Agressor track that is 1.97" pitch, 15" wide and 114 inches long. Only being 2" shorter is great, if the suspension could be modified the tension adjustment would allow for the shorter length. With the pitch being so close to 2" it would seem that the gearing would be very close to stock with the right drivers. I don't have the other dimensions of this track so I don't know what suspension modifications would be needed. This track seems to ge a very common Skidoo track and has been used on the following sleds:

64-70 Alpine
70-71 Blizzard
78-81 Blizzard 5500
82-94 Blizzard MX9500, 9700
78-83 Citation 300/4500
65-67 Chalet
82-84 Citation SS
91-96 Elan 250
73-74 Elite
85-89 Flormula MX, Plus, SP & SS
70-74 Olympique
65-78 Olympique (Bogies)
60-64 R &RD models
76 RV250
76-78 RV 340
84-88 Safari 477
84-86 Safari 377
89 Safari Saga
89-92 Safari Scout
69-71 SS, TNT (Bogies)
87-89 Stratos, Voyageur
73-78 TNT
71-73 Valmont

Anyone able to get some measurements or even get a good look at the track to determine what the Skidoo drivers are like or what kind of drivers would be needed?

Liquifire84 · Post by **Liquifire84** » Mon Jan 21, 2008 12:14 am

Not to add to the tension here but I have seen one conversion kit done with a mercury rubber track. The guy added a couple of spacers that were manufacted up that looked like a thick washer to all points along the suspension. They also came with new drivers. I did ride this machine and it worked almost as good I one would have expected a new full rubber track would be. It did slow it some but not to much. But it was a 30 degree day when rode it also. just my 2ct.

Brice

basketdators · Post by **basketdators** » Mon Jan 21, 2008 1:35 am

My 77' Skidoo RV track is about 1/2" thick, not sure what the new ones would be like. I would say we would be getting into "too thick" again if they're the same.
Bill

JDT · Post by **JDT** » Mon Jan 21, 2008 1:47 am

Mr. Boa Ski ... yes, UHMW is not a good choice if UV resistance is an issue. But as long as you keep your sled upright it will not be exposed to UV light and therefore should last many years.

Todd

JDT · Post by **JDT** » Mon Jan 21, 2008 1:55 am

mwKing.... The JD's run 12" center-to-center on the slides. The Skidoo runs approx 9".
So yes a lot of work would be required to modify the JD suspension to use this track. That is why I think it would be best to also use the doo suspension.

Todd

JDT · Post by **JDT** » Mon Jan 21, 2008 1:57 am

Bill does your RV use internal or external drivers?
Is the 1/2" thick rubber track OEM or aftermarket?
Thanks, Todd

JDT · Post by **JDT** » Mon Jan 21, 2008 2:05 am

Brice... That Merc track was internal drive without windows? And he ran the Spit slide system on it?
Todd

JDT · Post by **JDT** » Mon Jan 21, 2008 2:18 am

Hi Joe,
I am aware of the application of the sprocket listed on e-bay.

My point was that this is a new driver not NOS. Erine told me he has these made for him.

The idea is that whoever is making these could make them for our Deere's. He is selling tham at about the same price as other commom drivers.

It appears from my reseearch that of all the sleds listed by mwKing some have internal drive and some have external drive.

So the next problem we have is I can't find an aftermarket driver that is around 5" od with 2" or 1.97" pitch.

Are you aware of any, either internal or external drive??

Todd

JoeRainville · Post by **JoeRainville** » Mon Jan 21, 2008 2:18 pm

Hi Todd,

My guess is that Ernie had a "short run" of the sprockets make by PPD or the original molder on the original tools. Mold charges, even for one made out of aluminum is hugely expensive.

There are plenty of 2.0 Pitch drive sprockets made for the Polaris DD sleds. I have seen them as small as 5 tooth (they weren't even round, looked more like a pentigon!) up to 8 teeth. Polaris also used a hex shaft, but I am not sure of the daimeter.

I think most of early Ski-Doo's quoted above used "ex-volute" or external drivers through the track windows. They don't make small diameter sprockets for them either.

Just my take, but the path of least reistance could be one of these choices:

1) Polaris or Ski-Doo track swap, change all the center distances, or use a Polaris Ski-Doo suspension. (my least favorite idea)
2) Make new drivers for the LF 3.29 track, leave everything else stock. (My favorite idea)
3) Find who the heck molded the orginal belting, and if the tools aren't trashed, beg them for a short run of the 3 belts required to assemble a new track. Get a bulk rate on the cleats, by an air rivit gun and hire a teenager kid to assemble tracks. (most unlikey to actually happen)

JRC, Jerome, Rich, etc, any idea's on tracking down the OEM belting vendor? I came up at a dead end years ago chasing down Rockland/Arivin-Meritor for the 79 TF tracks...

-Rainville

B)

That Girl Racing · Post by **That Girl Racing** » Mon Jan 21, 2008 3:06 pm

The belting was done by Dayco. They made the belts for the Wahl cleated tracks up until about 10 years ago. Joe here is my opinion. I think the Polaris drivers and track is the simplest. I don't know how a 3.29 on that small of a driver will work. Spacing out the suspension is not that hard. Anyway you look at it, it is hardly cost effiecient. Like I said , it has been tried before. Peter

Horicon Joe · Post by **Horicon Joe** » Mon Jan 21, 2008 3:06 pm

Chuck picked up this sled for me this weekend. I will be meeting him at Waconia to see it in person for the first time. The owner claimed that the suspension was not modified or the drivers to install it. I will let you know for sure what the story is when I get it but looking at the pictures it appears that the holes in the tunnel have not been moved.
Chuck said the track is all rubber and looks brand new.

Joe

Horicon Joe · Post by **Horicon Joe** » Mon Jan 21, 2008 3:07 pm

I believe the Sprint and Spit tracks are interchangeable?