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adouglas · June 29th, 2015, 02:22 PM

Yeah, I realize it's apples to oranges to a degree. But I couldn't find anything published for a 40-80 mph roll-on.

Here's why I'm still skeptical. Literbikes make huge torque and power, even at relatively low RPM. My 750 pulls like a freakin' freight train no matter what gear I'm in.

According to a Sport Rider dyno chart I found at http://www.sportrider.com/sites/spor...000rr-dyno.jpg, ticking over at just 5000 rpm (sounds reasonable for engine speed at 60 mph in 6th gear to me), a BMW S1000RR is making about SIXTY ft-lb of torque.

With that much torque, if it can't get a 20 mph speed increase in two seconds, seems unreasonable that it'd be able to get double that in two seconds even in a lower gear. Three seconds? Maybe. Four? Sure. But not two.

Just a feeling based on my own butt dyno. I have no data to back it up, but I do ride a mid-heavyweight sportbike so I'm not speculating in a total vacuum.

Edit... on my commute home tonight I noticed that my bike is running at about 4500-4700 rpm in 6th gear at 60 mph. So my guesstimate above is a little high. Underlying thoughts still apply IMHO.

June 29th, 2015, 02:22 PM	#69
adouglas Cat herder Name: Gort Location: A secret lair which, being secret, has an undisclosed location Join Date: May 2009 Motorcycle(s): Aprilia RS660 Posts: A lot. Blog Entries: 6 MOTM - Jul '18, Nov '16, Aug '14, May '13	Yeah, I realize it's apples to oranges to a degree. But I couldn't find anything published for a 40-80 mph roll-on. Here's why I'm still skeptical. Literbikes make huge torque and power, even at relatively low RPM. My 750 pulls like a freakin' freight train no matter what gear I'm in. According to a Sport Rider dyno chart I found at http://www.sportrider.com/sites/spor...000rr-dyno.jpg, ticking over at just 5000 rpm (sounds reasonable for engine speed at 60 mph in 6th gear to me), a BMW S1000RR is making about SIXTY ft-lb of torque. With that much torque, if it can't get a 20 mph speed increase in two seconds, seems unreasonable that it'd be able to get double that in two seconds even in a lower gear. Three seconds? Maybe. Four? Sure. But not two. Just a feeling based on my own butt dyno. I have no data to back it up, but I do ride a mid-heavyweight sportbike so I'm not speculating in a total vacuum. Edit... on my commute home tonight I noticed that my bike is running at about 4500-4700 rpm in 6th gear at 60 mph. So my guesstimate above is a little high. Underlying thoughts still apply IMHO. __________________________________________________ I am NOT an adrenaline junkie, I'm a skill junkie. - csmith12 Nam et ipsa scientia potestas est. Heri historia. Cras mysterium. Hodie donum est. Carpe diem. Last futzed with by adouglas; June 29th, 2015 at 06:37 PM.