| Author | Message | |||
     Jad2 |
Can someone check my math here? I have been a member for only a couple of months and have probably seen about 3 different discussions about top speed. So during the 3 hurricanes that I've had go over my house in the last 2 moths and meeting the rev limiter in 5th gear (on a track), I gave it some thought. It seems to me that our bikes or neither aero nor HP bound, but mechanically. By that I mean that the bike obviously is got the aerodynamics and HP to reach Max engine RPM. So if top speed is what you are looking for you either have to go beyond the Rev limiter or change your drive ratios. OK, so that may have been obvious to all of you, but this is my first bike and I'm slowly catching up. With that in mind I created the following spreadsheet.
Like I said at the beginning let me know if this logic makes sense. | |||
| Jad2 |
This one has the numbers for an R1 and R6
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| R1DynaSquid |
Well if I had excel on my computer I could check it out. | |||
| Rockbiter1 |
The math looks sound (though I would have used more than two decimal places for pi, but thats just me, heh) Very good job coding that excel doc. I put in the info for my FXD...if i put in a screaming eagle ignition, allowing me to rev to 6200 prm, it would top out at (theoreticly) 140.46 beating all the bikes except the R1  Granted, the other bikes will reach top speed a hell of a lot quicker than i will, but i'll get them in the long haul MUAHAHAHAHAHA | |||
| Ingemar |
Greg, You want it in a different format? I can try and convert it for you. | |||
| Rockbiter1 |
ARGH>..somebody shoot me. I'm in Pre-Algebra in college. I'm TRYING to figure out the real gear ratios and mechanical top end for the Blast, and my brain just imploded. The manual for the 2000 Blast is fubar (imho) on the gear ratio numbers. Anyone done the math already, and can copy/paste the info? I'm coming up with 93.77 mph(using Jad's excel document), which is less than discussed July 15 2003 (96.1mph)...and I don't know where the discrepancy is. Which theoretical top end is correct? 93.77 or 96.1? and what is the true rev limit? 6500? And of the rev limit is 6500, and the moon is in decline, and i've been awake far too long, then scott's brain go bye bye. Proof:  | |||
| Ingemar |
Cool. Math looks good to me. My speedo showed me 216 Kmh (135 Mph) once, meaning the speedo would be less than 4% off. Thanx man! | |||
| Jad2 |
Here it is in HTML format for those without Excel.
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| Jad2 |
I guess my HTM upload did not work. Anybody knows how to do it? For those without Excel you can use this formula: 1) Max clutch RPM = Rev Limiter RPM/Primary reduction ratio 2) Rear wheel diameter = 2*3.14*Radius of rear wheel (Measured while the bike is off the stand from the floor to the axle) 3) Max wheel RPM = Max clutch rpm/Gear ratio/Final reduction ratio 4) Max inches per Min = Rear wheel diameter * Max wheel RPM 5) Max MPH = Max inches per minute*60 minutes/63360(inches in a mile) xb12 1) 4533.333 = 6800RPM/1.500 2) 75.36 = 2*3.14*12inches 3) 1,883.396 = 4533.333/1 (5th gear ratio on an XB12)/2.407 4) 141,932.70 = 75.36*1883.396 5) 134.41 = 141,932.70*60/63360 | |||
| Xb9er |
Very interesting post. Thanks for the information. The calculations make sense to me. Mike. | |||
| Anonymous |
<http://office.microsoft.com/downloads/2000/xlviewer.aspx> Nice little functional .xls viewer. Dump M$ and go to: http://www.openoffice.org/ It works and works well -- price is right too. Greg | |||
| Bigdaddy |
The anon tag was brain fart. OOops. Greg | |||
| 1320 |
Here is a simple solution http://www.rbracing-rsr.com/gearspeed.html |
Maximum Speed 
Top Speed