Reason for rear suspension change?
I have always wondered why Buell moved away from the underslung suspension, to me that system made way more sense. Also should have made for a system with way more adjustability, wouldn't it have?
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Answer selected by mudsocks at 4 weeks ago.
Understand that the under slung suspension on the steel tube frame bikes was a smart packaging solution.
Buell chose an arbitrary lean angle capability, I'm sure he did the math, but then built a simple jig to hold the engine to fit the desired ground clearance. The Sportster engine is wide down low, clutch etc. , so it had to be raised very high by street bike standards to get that lean angle capability.
If that was the Only factor in play, then the bike would have looked much like a huge motocross bike. Very high center of gravity, enough ground clearance to slide a case of beer underneath, etc. But both vertical center of gravity and mass centralization front to rear were considered.
Porche once had a great advertisement for their front engine, rear drive cars to explain why they arranged the mass as they did. A dumbbell vs. A ball. With the mass in the middle instead of the ends, it takes less energy to rotate.
So Buell, having an empty triangular space under the engine, lowered the high center of gravity, AND pulled mass normally far from the middle ( mufflers & shocks ) into the low, central, space to improve handling by reducing the energy needed to rotate the motorcycle in yaw. Plus reduce the top heavy aspect that raising the engine created.
Simple and obvious in retrospect, but brilliant and patented innovations at the time.
How smart is shown by how many of the competition copied the under engine muffler idea.
why the shock wasn't under the engine on the later bikes is a bit more complex. Please correct me if I am in error!
One factor is noise regulations made a bigger muffler necessary. The relocated shock is still as centrally located as fits, and is a smaller, more conventional ( easier to source ) shock. Where the tube frame bikes used a reverse ( pull apart instead of compress ) action shock. ( hard to get aftermarket replacement )
Hope that answers your question.
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Understand that the under slung suspension on the steel tube frame bikes was a smart packaging solution.
Buell chose an arbitrary lean angle capability, I'm sure he did the math, but then built a simple jig to hold the engine to fit the desired ground clearance. The Sportster engine is wide down low, clutch etc. , so it had to be raised very high by street bike standards to get that lean angle capability.
If that was the Only factor in play, then the bike would have looked much like a huge motocross bike. Very high center of gravity, enough ground clearance to slide a case of beer underneath, etc. But both vertical center of gravity and mass centralization front to rear were considered.
Porche once had a great advertisement for their front engine, rear drive cars to explain why they arranged the mass as they did. A dumbbell vs. A ball. With the mass in the middle instead of the ends, it takes less energy to rotate.
So Buell, having an empty triangular space under the engine, lowered the high center of gravity, AND pulled mass normally far from the middle ( mufflers & shocks ) into the low, central, space to improve handling by reducing the energy needed to rotate the motorcycle in yaw. Plus reduce the top heavy aspect that raising the engine created.
Simple and obvious in retrospect, but brilliant and patented innovations at the time.
How smart is shown by how many of the competition copied the under engine muffler idea.
why the shock wasn't under the engine on the later bikes is a bit more complex. Please correct me if I am in error!
One factor is noise regulations made a bigger muffler necessary. The relocated shock is still as centrally located as fits, and is a smaller, more conventional ( easier to source ) shock. Where the tube frame bikes used a reverse ( pull apart instead of compress ) action shock. ( hard to get aftermarket replacement )
Hope that answers your question.
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