Speedometer Not Accurate - Are They All The Same?

[Trout]

The other thing I learned on the big trip this weekend is how far off my speedometer is. I suspected that it reads high, but wasn't sure how much. I rode along side my friend on his Sportster and he indicated 50 mph when mine was right at 55. That's 10%. I can't use his bike as a reference because he might be off too.

On 2 occasions, I checked the number of tenths over a 10 mile stretch. A perfect odometer should roll 100 clicks over 10 mile markers. I tried to be consistent and accurate, but I counted 104 clicks the first time and 105 clicks the second time. That's 4%-5% high. This is disappointing. Now I don't know really what my miles per gallon are... except that they are lower than calculated.

If the odometer is high by 5%, then is the needle reading 5% high also?

Are all Hayabusa's the same? Are they all high by the same amount?

Have you checked yours to know exactly how far off it is?

Is the error linear? In other words, does the error factor increase with speed or stay constant?

I don't necessarily want a GPS or a Speedo-Healer, but I would like a point of reference... in other words, if the needle says 70, I'd just like to know that I'm really going 66 or whatever.

[GsxrBots]

Mine is off by almost 10 percent as well. This past weekend on my trip with the GPS, 70mph actual turned into about 76 indicated...

I want a speedohealer, but at the same time, I guess, who cares ??? I dunno...

[SoCal Blur]

You might want to get a speedohealer or a speedoDRD (a lot less expensive), if not for the accurate mph, so that your odometer doesn't rack up miles faster than it should. My busa was off 8.3% with standard gearing. When I went to a 43 rear sprocket, it was off 15.3%. I like knowing how fast I'm really going and that my mpg is accurate as well. I have the speedohealer but probably would have gotten the speedoDRD had I known about it at the time.

[bigjack7679]

Mines is bone stock. I hae used to gps systems and at 75 on both gps bike was showing 74. So pretty dead on for me but rare

[black diamond busa]

Yeah I found out mine in about 10% off.

[kromdom]

also a happy Speed-o-healer (v4) user here

[jwcfbd]

Yeah I found out mine in about 10% off.

Same here when I had my 2000.

[Fastfrog007]

I thought they were all about 7% off from the factory, but Im about 7% off as a person, so mines dead accurate in my eyes

[t5stang91]

75 on the speedo is 70 on my bike, gen 1

[lankeeyankee]

Mine is calibrated -30% with a +3 rear sprocket, 220 speedo faceplate and the 9% factory error.

[Dennis]

I agree with about 7-10%. My gen-1 was not linear. The greater the speed, the greater the % error. I haven't checked the Gen-2 beyond normal cruising speed. Also, don't assume the speedo and odometer are off the same amount.

[fallenarch]

They are all off and don't even ask how far off they are above 100 mph! I have been riding by my GPS and never bothered to fix it until recently. It's interesting how accurate the speedo is not that I corrected (10% too). That means they want the speed to read high and NOW YOU RUINED IT WITH THIS POST

Wonder if we can get the ZX14R's to read higher.........

[02spool]

Gen 1 or 2 ?,
If gen 1 and you need sprockets sooner/later?,go to an 18 tooth front and you will be very accurate.
Your avatar suggests gen 2? so you are SOL. - speedohealer.
This applies to anyone else interested in getting the gen 1 on the money.This is also easier wear on the chain,having the bigger front sprocket.
As far as the rear sprocket, you will have to go up in teeth to get back to stock gearing.

[65svtfastback]

Just checked mine this weekend against my GPS. At 55 onthe GPS the speedo read 60, at 75 on the GPS the speedo was 83ish, and at 85 on the GPS it was showing 94-95 on the speedo...

[lil charlie]

Mine was off 8.3% but the spedohealer fixed it....and yes the milage is off to. Both are read from the same sensor so one cannot be off without the other being off too. A healer is the only way to make sure your speed, miles, and MPG are correct.

[dadofthree]

Mines is bone stock. I hae used to gps systems and at 75 on both gps bike was showing 74. So pretty dead on for me but rare

My Gen II is dead on at 70 MPH as checked by SCHP

[EarlyBird]

All my bikes where off and more so after I swapped gearing and changed tire heights. Corrected with a speedohealer (busa) and the speedodrd(Gsxr1k) and dead on from 25-100mph, until the tire wears down some then read 1 to 2 mph faster but rather be that then to slow and get a driving award!

[Trout]

Gen 1 or 2 ?, Your avatar suggests gen 2?

Mine's a Gen 1. My avatar is a caricature of a Gen 2, but I use it because it's blue like mine and it's way cool.

Just checked mine this weekend against my GPS. At 55 onthe GPS the speedo read 60, at 75 on the GPS the speedo was 83ish, and at 85 on the GPS it was showing 94-95 on the speedo...

Well, I did the math on your numbers and the difference is 109%, 110%, and 111% respectively. These numbers indicate that the error is not linear. I guess 10% is a good round figure.

I did some research on that SpeedoDRD. It looks like a good solution for $80.

[FloydV]

For me the question would be is the error linear. In other words is it 10% off at 30 and still 10% off at 160 mph. I've heard yes and no to the question. In the past the error was quoted as 5%.

When I ride fast I never look at the speedo anyway. The best I can manage is to keep the tach in my peripheral vision.

Floyd

[Dennis]

For me the question would be is the error linear. In other words is it 10% off at 30 and still 10% off at 160 mph. I've heard yes and no to the question. In the past the error was quoted as 5%.

When I ride fast I never look at the speedo anyway. The best I can manage is to keep the tach in my peripheral vision.

Floyd

No, it's not linear. Your GPS is the best way to prove it to yourself. I did this plus checked on a dyno.