BRP (aka Can-Am) is not part of Bombardier Inc anymore(aka aircraft and transport). The parent company spun off BRP in 2003 by selling it to an investment group and family members.
My opinion is that you have to be very careful of using aluminum in off road. If the part is subjected to flex (as most off road parts are) it can be a BIG problem, as the fatigue life of aluminum is significantly shorter than steel. For example competition bicycles only have a 'life' of five years before they are junk...eg crack. Think of how long it takes to to fail a paper clip by bending it back in forth versus say a beer can.
The other factor is stiffness which is measured in modulus. Steel's modulus is 3x that of aluminum, but steel weighs 3x more than aluminum. Aluminum is also more expensive than steel. Sooo...what you end up with here is an aluminum part that has to be much bigger than it's steel counterpart to achieve the same strength with the same weigh. When you use more of a more expensive material, you end up with a more expensive product that may have a shorter life. Aluminum does have advantages in that you can cast it, forge it, extrude it with less expensive tooling into some creative parts that are strong and light.
But there is a reason that Trophy Truck frames are not made of aluminum and there is a reason why most desert and woods ATV racers with a straight axle rear suspension change their aluminum swingarms to chromoly.
My 2 pesos.
O really I didn’t know that about Bombaria and BRP.
Agree aluminum is tricky and takes some ingenuity to design to stiffness and fatigue, but that’s not always the load case. It’s all over most commercial and military aircraft, I know first hand these big giants can afford the design, manufacturing, testing such as fatigue tools the auto and powersports industry cannot. Aircraft AL is designed to 30 + year fatigue life, powersports less than third of that, biggest cost being corrosion not raw material, hence why composites are taking over. For one USAF example, we made the B2 bomber(flying wing) wing transfer box behind the cockpit out of AL that sees over a million lbs of transfer load, lots of flex, and high fatigue cycles.
I’ve followed the DS450 since its 2008 unveiling, we own a 08 DS450 and raced it in the upper national MX classes, my son has put it through a beating as many other pro bike/quad racers little to no issues. Hey, I also own a Cannondale bicycle for 15 years now no issues although I don’t compete. We have seen steel quad/bike frames have issues at the welds where knock down factors of mechanical properties apply. Often, the OEM puts welds at high stress/strain fatigue areas like arm attachments and joints. The XP900 trailing arm, the factory hand welds are so bad a knock down of 60% modulus would be a minimum, a huck fastener through al stronger. You could challenge it to a high speed 7075-T6 machined part if the billet size if not too large for greater stiffness and less fatigue, it may be stiff enough to eliminate the radius rods and prove a total cost reduction by part consolidation. XP900 front steel a-arm attach chassis has issues.
Although you raise some good points, comparing a paper clip to a beer can as fatigue analysis is very crude and misleading. Fatigue live is very dependant on such factors as type of applied load, geometry, alloy, temper, fabrication, temperature, as seen in MIL-Handbook-5 S-N curves, further defined by dynamic loading(as in reversing, compression then tension), average stress vs localized, etc) and mission, very difficult to predict the “actual” life of any material design in service in some cases impossible, although the al modulus is 1/3 steel. If you look at bending, tension, shear, compression , crack probagation, and some other properties depending on design loads and allowables, aluminum can show the design good and cost effective exceeding steels strength-to-weight.
We use a lot of cres steel and ti around aircraft engines since it takes the temp fatigue cycles. We investment cast it and titanium often for the same cost as aluminum and we extrude it readily. Currently I am struggling with machineing Nitronic 60 steel looking at aluminum for a cost reduction, so raw material is just a part of the producibilty cost especially in mass production.