At the risk of being labeled as solely looking at acceleration numbers...
I did fairly well in Physics 231 and 232 (B and A respectively) in college so this one sort of baffles me.
Cycle World has a write up of the revised for 2013 Yamaha FJR. The engine has not been touched from it's introduction in 2002. CW claims the exact HP and torque as test results from previous years. The new model weighs 30 pounds MORE than the 2010 model that MCN tested (3.3 seconds to 60 MPH). The only changes to the drive train are modified throttle bodies and modified exhaust...both only slightly. The new bike has throttle by wire and different fuel mapping. Also stiffer springs in the suspension.
So how does this new model get to 60 mph 0.5 seconds quicker? The bike looks more aerodynamic but that doesn't come into play at 60mph. 2.8 seconds to 60 with the same HP, same chassis, and more weight?
Could the fuel mapping make that much difference? The springs? And that is super fast for a 673 pound bike. Maybe it's a typo...
Miles By Motorcycle
established 11 years ago
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Ahh yes, the physics of speed 
First off, 0-60 is probably not the best view of power and acceleration for a motorcycle because most have such a higher power to weight ration than cars there are little tiny things coming into play that can make results less meaningful. Looking at 1/4-mile times and trap speeds are a better indicator (higher trap speed at the end is a sign of higher horsepower, higher at the 100ft is of traction). A huge factor is knowing if both bikes being compared were able to hit 60 in 1st or 2nd gear and at what point did the shift occur and with what method. Assuming two bikes using the same gearing, rider, and shift points even with compensation for standard temp and pressure the variables get persnickety at these minuscule time differences. Basically everything is impactful...including things that we may not think about, like: viscosity changes in the fluids in the driveline; overall rear tire diameter changes because of brand/mdel/size change, altering final drive ratio; the shape and delivery of power within the rev range; materials and condition of the clutch; materials and condition of the brakes (any drag will come into play); suspension geometry and setup (this is actually huge as it effects directly the ability to transfer power to the rear). Then their are the operator components. Big ones include skill at launch, throttle and clutch control, experience level and feel. Then come environmentals including: track surface; surface and air temp; humidity; composition of the launch surface; direction of wind; etc.
The changes that were described are major in terms of power delivery. The fly-by-wire combined with throttle body changes are probably creating much more clean power pulses, smoothing out delivery. Also, the mapping change and throttle bodies likely impact the low and mid, important for good launches. The suspension change can increase the mechanical traction available to the rear tire, again providing a stronger launch.
My guess is that it is making up the time in the first 1sec to 2 secs of the run, where weight isn't much of a factor but the ability to deliver a strong launch and faster transition to full throttle is.
First off, 0-60 is probably not the best view of power and acceleration for a motorcycle because most have such a higher power to weight ration than cars there are little tiny things coming into play that can make results less meaningful. Looking at 1/4-mile times and trap speeds are a better indicator (higher trap speed at the end is a sign of higher horsepower, higher at the 100ft is of traction). A huge factor is knowing if both bikes being compared were able to hit 60 in 1st or 2nd gear and at what point did the shift occur and with what method. Assuming two bikes using the same gearing, rider, and shift points even with compensation for standard temp and pressure the variables get persnickety at these minuscule time differences. Basically everything is impactful...including things that we may not think about, like: viscosity changes in the fluids in the driveline; overall rear tire diameter changes because of brand/mdel/size change, altering final drive ratio; the shape and delivery of power within the rev range; materials and condition of the clutch; materials and condition of the brakes (any drag will come into play); suspension geometry and setup (this is actually huge as it effects directly the ability to transfer power to the rear). Then their are the operator components. Big ones include skill at launch, throttle and clutch control, experience level and feel. Then come environmentals including: track surface; surface and air temp; humidity; composition of the launch surface; direction of wind; etc.The changes that were described are major in terms of power delivery. The fly-by-wire combined with throttle body changes are probably creating much more clean power pulses, smoothing out delivery. Also, the mapping change and throttle bodies likely impact the low and mid, important for good launches. The suspension change can increase the mechanical traction available to the rear tire, again providing a stronger launch.
My guess is that it is making up the time in the first 1sec to 2 secs of the run, where weight isn't much of a factor but the ability to deliver a strong launch and faster transition to full throttle is.
BTW, the times are perfectly within margin using 0-60 calculators. This one is surprisingly accurate:
0 to 60 Calculator 0-60
0 to 60 Calculator - Calculate what time your car can do 0 to 60 mph in.
http://www.autosnout.com/0-60-Calcu...
Rob listed out everything I was going to say and then some.
Hmmm. Weight of the rider is clearly a factor ... I was also going to say that human often human beings, even at upper end of consistency, do vary even day to day and of all the factors the rider probably has the largest effect.
Hmmm. Weight of the rider is clearly a factor ... I was also going to say that human often human beings, even at upper end of consistency, do vary even day to day and of all the factors the rider probably has the largest effect.
I'm gonna have to go with the revised (improved) fuel mapping. All of those other factors are minor. If additive, yes they could affect significant change in results but chances are some are contributing and others are detracting. The HP and torque peaks have not changed so WHERE the HP and more importantly the torque are in the rev range has probably changed (flattened curves). The transmission has not changed either so no consequence there.
It will be interesting to see the results when MCN does a full test. I'll be checking the new FJR out at the show on Sat. In the pictures I don't care for the styling though.
It will be interesting to see the results when MCN does a full test. I'll be checking the new FJR out at the show on Sat. In the pictures I don't care for the styling though.
