posted July 26, 2006 09:29 AM
TRUTH OR BS? I spoke to a guy yesterday in a parking lot, who has a 2005 stock CBR 600. He said he had it up to 275km/hr.... Is he bullshitting, or can a cbr do that? I have a 2004 zx10 with akro system on and at 250 km/hr it seemed as if there wasn't too much left to go... Is this normal for my bike, or should it be faster? ( not that I need more....) Just curious
posted July 26, 2006 09:52 AM
275 indicated mebbe. If it's geared for top end it could do it but more than likely it's geared for acceleration in some way and the speedo hasn't been corrected.
posted July 26, 2006 11:20 AM
That is 171mph/275kph No it cannot do that. It wouldn't have to do with gearing either, unless you added about 20hp. Bikes are not that aerodynamic for there size, so for a bike to increase its speed from 150mph/240kph to 165mph/264kph it would take about 20% more power. 105hp 600cc bikes reach there maximum velocity at about 153mph.
posted July 26, 2006 11:28 AM
oh very well could be, not disputing that at all, all I'm saying that's what my speedo said, and I'm pretty sure the guy with the CBR is just going by what his said too......
posted July 26, 2006 12:20 PM
So my 250km/hr on the zx, might not be 250 then either? So what is the best way to see the difference between indicated speed and real speed...except testing it with a cops radar gun....
posted July 26, 2006 07:04 PM
well my 02 zx6r i had top speed of 168mph and I was tucked in tight for like 3-4 seconds held it w/ no more to go. My 06 ZX10R had to 189mph and I was tucked in tight and held for 3-4 seconds hopin to see 190 but didn't. both stock bikes too.
posted July 27, 2006 05:52 AM
275 is 171.875 mph not likely... with a tail wind I suppose possible.. ask him to do a two way run lol...I don't believe a stock 600 would average 171 in a two way run anyways..down hill slope and tailwind gives ya mor top end but still.. bit of a stretch to say he can do 171+ on average..
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Salsa1
posted July 27, 2006 12:14 PM
168 mph on a gps or radar gun? Or are you just adding another worthless speedometer report after we all just said the speedo doesn't give you an accurate read. Last time I was on the freeway a CHP officer gave me a ticket. I shit a brick because I was indicated at 105. But the officer said he radar and paced me at 91mph. That how far some of these speedos are off.
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posted July 29, 2006 06:02 AM
I havent seen a sportbike speedo that was within 5% of accurate speed yet, unless correct with a speedo healer, or some other type of corrective device. Hell even my nomad is 5 mph off at 60mph. At 60 MPh, the GPS says 55 mph....
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posted July 29, 2006 03:38 PM
That bike would'nt do 275km/hr even if you threw it out of a plane.........................
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posted August 02, 2006 06:03 PM
HDL, my Aprilia is accurate to + - 1kmh reads off the rear wheel assembly and is supposed to be the most accurate bike speedo made and I can vouch for this as on a correctly calibrated Dyno the bugger is pretty well spot on the money.
My 10R well thats another story on the same Dyno 299 is actually 273kmh with a kit ECU on the race bike it see's about 328kmh with 18/42 gearing and does it scream!
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posted August 05, 2006 08:41 PM
Cheaper than GPS and radar, there are some highways that have speedometer test markers. They are signs that are spaced 1 mile apart. Usually there is a warning sign before the first marker telling you that they are coming up. And there are typically 5 miles of signs, so you have plenty of opportunity to time yourself. The onboard lap timer makes this really easy to do if you can hold a constant speed over several miles. For instance, if you can maintain 60 mph indicated, your lap time for each marker should be exactly 1 minute. If your speed varies slightly, try to make it vary equally above and below your target speed (so your average is as close to your target as possible). For instance, if your lap timer registers 57 s for a mile, then you're really going 3600s / 57s ~= 63.2 mph. If your timer registers 1:04, you're really going 3600s / 64s~ = 56.3 mph.
The problem is that there are two ways your speedometer can be off. It can be off by a constant offset (such as always reading +5 mph), or it can be off by a constant factor (say, it inflates the speed by 5%), or both. The latter problem causes higher speeds to be overstated more and is guaranteed to occur when changing the wheel/tire size (and I'd be willing to bet that the tire changes shape at higher speeds in a way that affects accuracy). So to see what kind of error your speedo has, you need to take at least two samples at different speeds (three or more is much better). And the more widely different the speeds, the better. Most interstate highways have mile markers which might be useful for calibration, but I'm not really sure how accurate they are. However, I'm sure if you were to take a large number of samples over a variety of lengths of highway, the average will tend towards the true value.
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posted July 26, 2006 09:29 AM
Just curious
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