| Author | Message | ||
     08uly |
Was a little bored this afternoon so I worked up this speed chart for the Ulysses showing engine RPM and the equivalent speed in MPH. Also threw in the shift points from the manual expressed in engine RPM. This is based on the stock 2008 tire making one revolution in 77 inches.  By request, using the XB9 Primary:  Enjoy! (Message edited by 08uly on November 14, 2007) | ||
| Treadmarks |
Sweeeet. Good job 08. | ||
| Diablobrian |
Very nice, and it should work for any XB12 assuming the tire's outside diameter is the same and they do not have the XB9 primary drive installed. | ||
| Random |
Wow...Just a "little" bored you say?? Great info though. Thanks. | ||
| Mainstreamer |
How does the XB9 primary affect these numbers? Could someone please post the conversion factor.... thanks | ||
| 08uly |
Sure, I'll post another chart for the XB9 Primary (1.676). It also will be affected based on differing tire travel. | ||
| Mikef5000 |
HAH! The manual says to shift to second at 1967 RPM? Sheesh! Talk about short shift! There'd be all of 2 seconds between letting the clutch out and pulling the clutch back in. | ||
| 08uly |
Added the XB9... See OP | ||
| Mike_dinger |
I must really be killing my engine because I have never followed that recommended shift table once! I may be on a road to engine failure because I don't ever ride that calmly. What fun would that be? I am constantly hitting the rev limiter. does anyone really follow these RPM/shift recommendations? | ||
| 08uly |
They are very conservative... Probably for the same reasons that the recommended break-in is also so conservative. I am curious if I ride "by the book" if that will improve my gas mileage. | ||
| Etennuly |
Any one get their Uly to go beyond 130 mph? Mine gets to about 128 or so and just kind of runs out. I think it is an ECM protecto thing. Or.....they don't want us out running the sportier bikes! | ||
| Mike_dinger |
I think it's to keep the engine from pooping itself. | ||
| Bertotti |
I'm in second till I'm at 40 or a bit better. If I have a long stretch of 40 I might shift to third depending on my mode and my location and where the cops are. I haven't gone 105 on the Uly. I can't afford to lose my license. | ||
| Jlnance |
I must really be killing my engine because I have never followed that recommended shift table once! I may be on a road to engine failure because I don't ever ride that calmly. I am convinced the recommended shift table is based on the need for the bike to pass EPA noise regs. The engine runs much better if you spin it up. I rarely use 5th gear anymore, even on the highway. I guess in theory the engine wears out faster if you rev it. At the same time, I've seen all sorts of Uly problems mentioned on this board, and not one of them has to do with a blown up engine. I think the much maligned "lump" is pretty tough. | ||
| Treadmarks |
Any one get their Uly to go beyond 130 mph? I tucked down behind my ZG shield as it was pulling hard past 125, still climbing. Not sure how far it went, as my eyes were glued to the road after that.  | ||
| Muppet |
Any one get their Uly to go beyond 130 mph? I've managed to get mine flat out a couple of times. Banging on the rev-limiter in top gear it was showing about 140 on the clock which equated to 132 on my Zumo GPS. Stock '06 bike running Michelin Pilot Road 2 tyres. Doesn't really fit in with either of your charts there 08uly? (Message edited by muppet on November 16, 2007) | ||
| 08uly |
Sounds to me like you are just about spot on with the numbers... You have to remember that this is just the pure math from the engine revs to a rotating tire. There are many other variables involved. The true distance of your tire/wheel travel, wind resistance, road conditions & grade, accuracy of gauges, etc. If you average your two gauges you get 136 mph so that puts you right in there at redline for the '06. If you're more curious, measure your tire travel for one rotation with you sitting on the bike. post or send that number and I'll see how your tire falls on the chart. Cheers! (Message edited by 08uly on November 16, 2007) | ||
| Blake |
Excellent point. A well-worn rear tire can reduce top speed by more than 3% (more than 4 mph if traveling near 140 mph). Then too at that speed there may even be some slight wheel spin, more like traction creep or tire slip, not actual spinning up and smoking. We can check the thrust at the contact patch to see if it seems like tire slip might be a factor. It's interesting to note that if you know the HP at the rear wheel coinciding with the engine speed at peak/terminal velocity of the bike on level ground, no wind, you can find the thrust force, which is equal to the aerodynamic drag, from the following: Thrust = Aerodynamic Drag = 375 * RWHP / Velocity in MPH The "375" is just the overall units conversions factor for HP and MPH where HP=550 FT*LB/s and MPH=5280/3600 FT/s (550/(5280/3600)=375) So for a 140 mph terminal velocity with a coinciding 90 RWHP, the aerodynamic drag force (equal to the thrust force at the tire contact patch) will be... Thrust = Aerodynamic Drag = 375*90HP/140MPH = 241 LBs More fun with numbers... With the rear tire's contact patch at a very convenient radius of about one foot from the rear axle, the torque at the rear axle is then... Torque = 241 LBs * 1 FT = 241 FT*LBs Divide that by the overall drive ratio between engine and rear wheel (57/38 * 1/1 * 65/27 = 3.611) to find the engine torque referenced to the rear wheel... Engine Torque = 241 FT*LBs / 3.611 = 66.7 FT*LBs Which for engine speed at/near 6,800 rpm sounds about right. The bike+rider total aerodynamic drag coefficient (Cda) can be found from... Cda = 391 * Aerodynamic Drag / (Velocity in MPH)2 For our case... Cda = 391 * 241 / 1402 = 6.5 Who needs a wind tunnel? ![: ]](http://www.badweatherbikers.com/buell/clipart/proud.gif) Geez David (08Uly), this is all your fault. I dig it!  | ||
| Etennuly |
Ow.  | ||
| Muppet |
Bike's in the shop at the moment 08uly, but I see what you mean about the numbers. I must admit to reading your chart quite hastily and seeing 143 as the top speed (missed the 06/07 - 08 references) and thinking, bugger - why is my bike a lot slower than that! I'll measure the rolling distance when I get her back, probably later next week. Blake, are you snowed in for the winter already?  | ||
| Bearly |
Interesting note that drag increases with the square of velocity. (evident in blake's formula). So the drag at 100mph is four times what it was at 50mpg on any given object. | ||
| Windrider |
08Uly, Thanks for posting this! Very nice info. Glad you were bored. | ||
| Mainstreamer |
Thanks 08uly, good information. I've been thinking about XB9 gearing for my Uly. Your charts were very helpful. Thanks again! | ||
| 08uly |
You're all welcome. Glad it's of use  |
