I searched for "speedometer error" and only found this thread

The thread states the speedometer error is about 3 mph. Or at 100 the bike is actually doing 97, or 43 doing 40. Does anyone have any more recent info on this for 2012+ ZX-14Rs?

It seems like when I'm going 70 in my truck I'm passing people pretty steadily on a 60 mph 4 lane divided highway. However, when I'm on the Ninja doing 70 it's like I keep pace with the semis. In my truck, I'm pretty quickly closing and passing them. If I do 75 it seems about like my truck, but still a little slower. I know my trucks speedo is pretty accurate from prior speeding tickets (like doing 83, I got a ticket for 83 in a 65).

I have the exact same feeling, that my bike is a little slower than indicated. I will be interested to see what people weigh in and say, but every bike could be different too.

I thought it was more like +7%. The faster you go, the greater the discrepency in mph that is indicated. Pretty accurate at low speed, though. Get a Bonneville PRO or Speedohealer VH-4.

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Do you have a gps you can take for a ride? That's a very easy way to check for accuracy.

*update* Sorry I just read the thread you posted, so I guess you heard about using a gps.

* Last updated by: wfozx14 on 7/31/2014 @ 8:34 PM *

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This discussion is very "tire diameter" dependent.

Fresh rubber, diametrically, is vastly different than a tire nearing the end of its service life.

Hence the inaccuracy of your speedo-meter. The manufacturer, for liability reasons, must err on the side of caution.

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I have the exact same feeling, that my bike is a little slower than indicated.

Glad..in a way I'm not the only one!

Do you have a gps... Get a Bonneville PRO or Speedohealer VH-4

Yes, I've heard of the GPS method (and no it doesn't bother me you posted about it). I have a smartphone capable of GPS but not setup. I've not read any test comparing the methods (GPS vs. specialized devices) but I'm guessing because of how satellites work it's not as accurate. As far as buying a specialized device, if I could avoid it I would prefer to!

7%

This is pretty much what i remember when I had my old bike, although it seems the speedometers were pretty accurate until above legal speeds. I remember most bikes that indicated say 150 will really doing around 143. On my VF1000, at highway speeds it seemed pretty accurate.

Tire diameter dependent

Bike is new, 1360 miles, all stock. It's seemed like this since the first time I rode it to work with probably less than 100 miles on it. During break-in (1st 1000) I was keeping the engine speeds varying so it was difficult to really tell if my perception of seeming slow at speed was accurate. Now that it's broke in, I just maintain consistent speed/rpm and what I perceived early on is definitely true.

I'm guessing because of how satellites work it's not as accurate. As far as buying a specialized device, if I could avoid it I would prefer to!

If you can maintain a steady speed for 15 seconds, that aught to be plenty of time for satelites to pinpoint your speed. A new SpeedoHealer or Bonneville will cost you about 250. The SH is easy to install. The Bonneville requires one wire to be cut but other than that, just as easy as a SH. The Boneville also disables the top speed limiter. The SH can disable the TSL as well but then it will not show the correct speed. Neither of the two will automatically compensate for tire wear. You would have to recalibrate for tire wear and for that, a gps would be best.

If you use a 190/55 rear tire, that will put your speedo just about dead on. My busas old 190/50 is down to the tread and I can tell the speedo is displaying a higher speed than it should. Even in town, I get passed by a lot of cars.

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Lol. Gauging speed by flow of traffic is kinda hard. I do roughly about 500 + miles a week commuting a week. I can do 70 as indicated on spedo and get passed by semi trucks or keep pace with then. Cars are flashing by. Lol. I roll up to 80 im passing semi's and keeping pace with cars. Roll up to 90 and im passing semis and cars at a steady pace.
I've went by those chp little radar wagons the setup on the side of the road and my spedo has been pretty accurate as to what the read. Wwithin 1-3 mph at up to 60 mph. Going a lot faster than that down one deserted street it failed to read anything. Idk. Ive also passed the chp standing out with rifle radar gun and they hqve failed t get a reading on me. Maybe areo on the bike idk. Ive also checked speed with gps on my phone only seemed to be 2-4 mph difference with and without 10 inch stretch

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I conducted my own test using video today. I cruised 3 miles at 70mph on the interstate. Bike is '13 ZX-14R bone stock. Here was my findings:

1 - 26:24.10
S - 25:30.47
00:53.63 - 67.12 mph
2 - 27:18.53
1 - 26:24.10
00:54.43 - 66.14 mph
3 - 28:11.73
2 - 27:18.53
00:53.20 - 67.66 mph
66.97 avg = 3 mph error

You are correct...3mph overshoot.Good thing about this is though...at 150...it's NOT like 5-7% off...like the gen 1's.It remains consistent throughout the speedo range.Nice when ya think yer over...but actually a couple lower...70 means 67...great on radar;)

Seems weird ... wouldn't this mean that at a speedometer indicated speed of 140 our actual speed would be 134? (-6 mph)

If not, I don't think a Speedo Healer could correct our speedometers(?) ... since the Speedo Healer works by means of entering a correction factor percentage that's applied equally over the speedometer's entire range.

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I'm not sure. Grn's saying for G2 14s it's always +3, instead of being a percentage. This is great. I'm going to try to get an 85 mph test in just for kicks and giggles.

Sounds good Vic. I look forward to the results so we can know

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"If not, I don't think a Speedo Healer could correct our speedometers(?)"...Healtech doesn't make one for the 14R...I called and asked.Gen 1's...yup..all day long.

If not, I don't think a Speedo Healer could correct our speedometers(?) ... since the Speedo Healer works by means of entering a correction factor percentage that's applied equally over the speedometer's entire range.

I have the SHv4 on my Gen1. I used the setting calculated on the HealTech site for my tire size, gearing and bike model. Seems to be very accurate but I have not checked with my GPS yet. I wonder if the correction is perfect across the range of mph? The speed sensor is reading the crankshaft, not the wheel. There must be some calcing going on between the speedsensor and the ECU. The % of speedo error might not always be the same at every speed. Close enough for me.

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yeah but does it matter if you pass a LEO going 180 and he only writes you p for 177? :)

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Here's my 85 mph test results - '13 ZX-14R stock

1 - 5:56.27
S - 5:12.62
43.65 - 82.47

2 - 6:40.21
1 - 5:56.27
43.94 - 81.92

Looks like 3 mph to me!

I thought for sure your 85mph test would show a bigger difference. Oh well, I've been wrong before. Good test.

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I feel better about it now. I generally like to do 10 over, never really get 2nd glances from LE. Now I know how to really judge the speed of the bike. I'd like to do a 40 mph test don't think it would be safe on the interstate and there's no lower speed roads marked around here. I'm fairly confident in the 14R-3-mph-theory though after these two test.

IMO would be nice if they'd just do away with speedo-error, or make it configurable.