| Author | Message | ||
     Xl1200r |
I know a bunch of people have been asking about this stuff, so I ran some numbers and put together these graphs to show the speeds in each gear. Enjoy:   | ||
| No_rice |
just ran them back to back yesterday. my 1125R does 40 mph in first gear at 6000 rpm. the new CR does 35 at 6000 rpm(you know, 5 miles on it and that whole break in thing!) | ||
| Edgydrifter |
Is this assuming the bike is being run in a vacuum, or are you factoring in drag? The thought of being able to run 100mph in 3rd comfortably below redline with three more gears on tap makes me irrationally happy. | ||
| Redscuell |
The math says that, @ 6,000 rpm the R is doing 38.6 mph (would read as 39),and the CR is doing 35.6 mph (would read as 36). Very close to No-rice's anecdotal evidence. Not bad for a humble spreadsheet. Interesting that with the XB's 65 tooth sprocket (I know they go on the wheel, I personally don't know if the XB sprocket is suited to the 1125r), @ same revs the speed is 41.6 mph. MORE interesting is that, with the 65T, 1st gear revs give up the same speeds as the 08 CBR1000RR, which is the superbike that I use as a benchmark; and the top (claimed) speed becomes the same as the CBR's, too. But without having to hit the mid-12,000's to do it. The two bikes have roughly equal torque but the Honda aces the Buell on HP; I would've thought that it would be torque that handles the launches, though?  | ||
| P_squared |
I know the R will do 100 in 3rd with room to spare. Here's to irrational happiness spreading everywhere.  | ||
| Rfischer |
Torque - or "twist" if you will - is indeed what accelerates the bike. It also, all else equal [weight, kinda; drag, available traction], is what wins races. Carol Shelby made that point over 40 years ago. Audi with their P1 diesel is making it again at LeMans, Sebring, and everywhere else the cars run. Interestingly, the Audis are significantly heavier that the gasoline-powered competition, and also have more aero-drag necessitated by larger cooling capacities, but, by optimizing weight distribution for improved handling, they dominate the class with their torque . An automotive version of Buell's "mass centralization" principles. Applied engineering, not bench or dyno racing. | ||
| Jaimec |
But isn't horsepower a measure of how QUICKLY that torque can be applied? | ||
| Rfischer |
Only loosely - it's really a mathematical formula based on torque. Which is why, regardless of engine type, size, or output, the torque and hp curves always intersect at 5250. | ||
| Pridayr |
The Priday Power Principle: More of Both... Better! R | ||
| Badlionsfan |
The 1125R will do 67 mph in first gear.  | ||
| Chevycummins |
And 92 mph in second. | ||
| Badlionsfan |
Thanks Chev, next time I'm out in BFE I won't hit 10.5 k in second, I'll go strait for 10.5 k in third. | ||
| Pizzaboy |
and 120 in 3rd! | ||
| Pridayr |
Damn. Now I'm probably gonna get arrested on the way home... <sigh> The things I do for you guys... Rob | ||
| Sheepaholic |
Does the rear drive(sprocket) off the CR most definitely not fit the 1125R? | ||
| Blazin_buell |
I know the R will do 100 in 3rd with room to spare Yes Phil, I was happy to see that as well while running 3rd all the way around ECR for the Inside Pass. By the end of the day I would let off between 115-120mph on the straights. Can you say practice late braking?? For the first time I was having to!!! | ||
| Drfudd |
I created this spreadsheet a while back, here it is again for reference. http://spreadsheets.google.com/pub?key=piMa420IFsf gb2gr2Irt5fg&gid=5 the SAE measured BHP = (Torque*rpm)/5252 hopefully the spreadsheets are self explanatory everything is calculated except for the green boxes, if you want me to add other bikes I can, takes 2 seconds. | ||
| No_rice |
Does the rear drive(sprocket) off the CR most definitely not fit the 1125R? it will most definatly bolt on to the wheel, but after that is where you run into a problem. the cr has a longer swingarm and a different belt. so even if you bolted a cr rear pulley on your r you would not have a belt} | ||
| Drfudd |
A lesson in physics. ok I feel I just gotta add some more, so if you like read on.... its all very simple if you understand and apply physics to everything. Power or BHP is the amount of work being done. Its the same as watts, just different units. the reason the /5252 is in the equation is to equate it to the estimated amount of work one real horse can do. rpm is the distance or speed at which that force is applied to. Torque is the amount of force being applied. in this case its rotational force which is force X 90degree distance to center of rotation. in order to calculate torque you need to take the amount of force from the explosion in the piston and using some fancy vector calculus you can calculate torque. the reason you have to use vector calculus is due to crank shaft, piston rod, etc geometry you have to. all it really is the same as hanging a weight off of a lever. Power is work, while torque is the force the engine rotates at. to compare it to electricity, power (BHP) is the same as watts. W=V*I volts is the same as torque or force times current or speed (distance). (don't read this sentence: speed is the second order integral of distance, acceleration is the second order integral of speed) The reason torque, HP and rpm info is listed for engine output is because we have transmissions and not fancy CVT's. The best engine in the world is useless unless the transmission can maximize the power output to the road. in other words if your gearing ratio isn't right. you won't be in the right RPM sweet spot for the acceleration you want. Acceleration is determined by Newtons famous formula: Force = Mass * Acceleration or Acceleration = Force / Mass. a simple equation but putting it to practice can be hell. you have more forces than just engine output, and in this case is not engine force, is the amount of force being applied to the road, remember torque is force times distance to center, T=F*D or F=T/D where torque is the amount of torque applied to the wheel and distance is the radius of the wheel. you also have force acting against you in the form of inertia, air drag, etc. which is very difficult to calculate, usually you have to use experimental results. HP numbers are only useful when RPM numbers are taken into account so you know where your power is being made a high HP high rpm engine makes all its power up high with a linear torque curve since above 5252 rpm its all Dependant on rpms to make power, a high HP low RPM engine has a flatter torque curve because below 5252 rpm you need lots of torque to make up the same HP number compared to a high HP high rpm inline 4. if we all had CVT's all we would care about is torque because we could rev the engine to the highest torque spot and continually vary the gear ratio to adjust power output to the wheels. hope this all makes sense. I'm an engineer I calculated all this crap in my spare time. | ||
| Smoke |
1125r- 138 in 4th at 10000rpm this morning. my backwoods straight isn't long enough to do 5th or 6th. tim | ||
| Jpfive |
Thanks for the lab work Smoke...  I concur. Fourth is your 1/4 mile gear. Jack | ||
| Xnr |
Theoretical top speed with a 24.5" diameter wheel and 10.5K rpm is 170 mph for the R and 157 mph for the CR. | ||
| Firemanjim |
There was a stock 1125 at Bonneville running in 160 range. | ||
| Chameleon |
I've had my stock 1125R up to 160mph several times. I've not gone faster due to running out of road. | ||
| Zac4mac |
Jim, that was ours. I work "parts" at High Country. The 1125R there was our demo bike. We are in process of putting a Uly front end on it for the Pikes peak run next year. I got permission to post about it, will have some pix soon. Zack | ||
| Duggram |
At Arroyo Seco Raceway I'm getting 123 at the rev limiter in 3rd. I can go into 4th but I'm just not ready to go that deep (2nd trackday). | ||
| Redscuell |
No_rice, how about bolting the XB rear sprocket and using the existing R belt -- would/could/should the idler pulley (I suppose it's called) fix this up (allowing use of the stock belt)? I hope. With the 65T XB pulley, 1st gear speeds on the R are identical to the Tuono's and CBR's with roughly equal torque, and top speed becomes equal to the latter without the high revs. Could be a good combo for those of us who don't value wheelies and do take long rides between cities (Sydney is ~8 hours from Melbourne, about equal to the San Diego to San Francisco ride). | ||
| Jammin_joules |
What swing arm?  | ||
| Chameleon |
2008 Buell 1125R goes 174 MPH in 6th gear on dyno. |
