| Author | Message | ||
     Growl |
I am not a speed demon, really pretty mellow, but on Sunday I found myself on a straight country road with no-one in front or behind for miles... the fastest I had ever clocked any motorcycle - according to them lying cheating speedometers - was 95 on a Harley big twin and 95 on an Ironhead Sporty - and 90 on a humble little Honda 360 - so I knew this was the opportunity to "break a ton"... The Uly reached 105 on the speedo without fuss and the handling felt secure... and the visceral effect told me that I was going faster than on any bike before. But, how fast was I really going? 95? How high do I need to register to really break the ton? | ||
| Panhead_dan |
Buell and HD speedos are generally fairly accurate compared with the big 4. | ||
| Crusty |
I just look at the Tach and double the number. i.e., 3500 RPM = 70 MPH, 4000 RPM = 80 MPH, 5000 RPM = 100 MPH. I might be a little off on the true speed, but not by much. | ||
| Johnnylunchbox |
My 06 Uly speedo generally reads 4-5 MPH less than my GPS. | ||
| Gotj |
"My 06 Uly speedo generally reads 4-5 MPH less than my GPS." I found the same thing for the 60-75 mph range. It's likely a bigger differential at 100 mph. I haven't checked there yet. I'll post if I get some more data. | ||
| Danger_dave |
>>The Uly reached 105 on the speedo , how fast was I really going? << 105. | ||
| Thunderbox |
I would say they are pretty accurate. I got a ticket for 173 kph (108mph) and my speedo was just about right there. I am going to take the radar out and test it soon but I am a little hessitant after my ticket. I have to be really careful but i will let you know. | ||
| Ejc |
My GPS indicates a speed 3 mph less than the speedo. My rpm/speed ratios are the same as Crusty's,( depending on windage of course). | ||
| Terrible1one3 |
By law the speedo's have to be within 5% of actual mileage. So at 100 Mph you from a legal standpoint are going anywhere between 95 and 105 Mph. Correct me if I am wrong. | ||
| Zenfrogmaster |
While there is some tolerance for speedometer error in the regulations, I believe it's only on the optimistic side. In other words, if it reads 65, you can't be going any faster than that, although your actual speed can be less. Come to think of it, that may be to avoid lawsuits. "But it said I was doing 30 when I went into that turn!" My tuber seems to be 5% optimistic at all speeds, but that also depends a bit on tires. | ||
| Gotj |
I take my GPS speed as "accurate" and my speedometer speed as "indicated". So I wish there were a way to disable the maximum speed readout on my 2610 or at least have it max out at 35 mph. | ||
| Froggy |
Last time i tried to gather data for this, i was doing 130 on the speedometer, my GPS said 123, and then my short windshield flew off. I think that was the sign that i should back off.  | ||
| Gotj |
Froggy, You're a daring man. Your observation is consistent with the 4 mph differential at about 65 mph. So it looks like to do a "real" ton, you have to go about 105 on the on the speedo. I don't really get Danger_dave's response though. I guess if the speedo said 170, he'd say "170"? | ||
| New12r |
My 12R's top speed was 140, gear/rpm limited. at the rev limiter in 5th it read 150ish. Did not look long. | ||
| Froggy |
I couldn't get anymore out of mine, I'm guessing the aerodynamics are to blame. I got it to 130 and she just said that's it, i was doing it for about 20 seconds before the shield flew off. I was running with only the top case on my bike, so i don't know how fast i could of gone with no bags. I tried it again recently on a highway instead of a town, and got it to about the same speed again  Oh yea, don't turn your head at that speed, my neck is still recovering. | ||
| M2nc |
My buddy's mom got a new car. She got pulled over for running 75mph in a 35mph. She told the officer that she was paying attention to her speed and she knows she was only going 35mph. She was pointing at the speedometer as she told the officer that she was looking at the speedometer the whole time and she knows exactly how fast she was going. The officer asked her if that was the gauge she was looking at and she said yes. He chuckles and says, "ma'am, that's the tachometer." True story. So, if my Uly indicates 130mph, I was going 130? I do know about that, but my RPMs match Crusty's. | ||
| Growl |
Thanks - all - for the input. Crusty, the tip about watching the tach is totally logical but I overlooked it - Thanks | ||
| Gotj |
Crusty's tip is fine if you accept your speedo reading as accurate. As many here have noted, there is about a 4 mph-low reading compared to GPS at about 65-70 mph. Or maybe that's not an issue for you or Crusty. The thread started as a discussion of how fast your speedo had to read to be doing a "true" ton. | ||
| Sanchez |
My speedo reads faster than I'm actually going. It got further off when I put on new tires. From the factory, it read 80 when the GPS said 77. Now the GPS reads 75 when the speedo reads 80. There was a thread a while back about GPS vs speedo readings, and it seems to vary from bike to bike. IIRC, more read a bit fast than a bit slow, but none were off by much, so 105 on the speedo is probably very close to 100 mph in reality. | ||
| Az_m2 |
I think Crusty's point is that regardless of what the speedo says, you can get a good idea of speed by looking at your RPMs. In 5th gear, 4k is 80mph. My speedo shows higher than that. 5k should get you 100. | ||
| Bearly |
My speedo reads one mph more than my gps with mid life perelli's (Message edited by Bearly on August 30, 2007) | ||
| Gotj |
Bearly, How fast were you going? Most times that makes a difference in the differential. | ||
| Bearly |
Oh, I have that Zumo mounted most of the time I'm on the bike, so it's at most cruising speeds between 60 and 80. | ||
| Crusty |
Gotj; My speedo is about 5 MPH optimistic between 60-80 MPH. My 1998 S3-T, my 2000 M2 and my Uly were geared the same. If my tach says 4,000 RPM, I'm traveling pretty damn close to 80 MPH, no matter what my speedo might say. I've checked this several times with those roadside radar units that give your speed. If you don't trust your speedometer, or don't know its margin of error, and want to go 100 MPH, then put the bike in fifth gear and run it up to 5,000 RPM. You'll be close enough. |
