Originally Posted by dwayne
You use a thinner section when using steel, looks can be deceiving. Aluminum's strength to weight ratio is better than steel, but it strength to thickness ratio is shockingly poor compared to steel. You would also change the feel of the rear suspension, steel has more flex...I imagine there would be both good and bad things that come from a more rigid swingarm.
Again the KTM 950/990 would be a decent comparison for weight and use to a Dakar.
I suspect you wouldn't break most swingarms from modern bikes, but I can only imagine the headaches of trying to modify one (remember the bmw chain is on the "wrong" side). Take a look at which parts get modded (or not) on a tourtech rally bike as a baseline the for value of a high performance mod. I believe they use the stock swing arm.
pretty sure some of the husqvarna 2 strokes also have the chain on the wrong side. just an idea.