Chassis Evolution

Here’s a cool example of the genius of the Polaris race team, and how they practiced continual improvement on all the factory race sleds.

In 1977, all the sleds are somewhat different and show signs of them experimenting with different ways to make them faster, better and stronger. But they also had to make them quick to manufacture, as they knew they would be building new sleds for every racer who wanted one for 1978.

Lately, I’ve seen evidence of what they did to give the trailing arms the support they need, and here is a great example.

Starting with Don Omdahl’s 250 (one of the two first IFS races sleds built at Polaris) we can see the support for the trailing arm and the bottom of the clutch guard is two pieces welded together.

On the 340 built in time for Eagle River in 1977 for Jim Bernat, we can see they added a curve to it, which adds strength both to the clutch guard and the trailing arm bolt.

On one of the last race sleds built in the shop, Jerry Bunke’s 440X built just in time for Eagle River in 1978, you can see that is now one piece that goes all the way around and is riveted to the tunnel for maximum strength with the least possible amount of material.

Pretty darn clever, and if I had to guess, I’d say this is the work of Arlyn Saage, who is a master of this kind of thing.

Don Omdahl's 1977 250.
First IFS sled, a 250 built for Don Omdahl. Note the weld up the middle holding the two pieces together. 
Jim Bernat's 1977 340
Jim Bernat’s 340 built in time for Eagle River in 1977, note it is now one piece with a bend to add strength. The plate to the right we believe was added by a racer in later years. 
Bunke's 1977 440X WC Machine
Bunke’s 440X built in time for Eagle River in 1978. Now it’s all one piece that goes all the way to the tunnel for support. 


The passion, triumph, dominance and tragedy of one of the most successful
efforts in motorsports: The Polaris Professional Race Team


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