[Don Swanburg]

I'm looking for ACCURATE speed readings @ 3000 rpm for the GL1800.

If I remember correctly, my 04 gave me 65 mph @ 3000 rpm after I calibrated the speedometer.

It was originally off by 10%. I installed an Ahlzman correction unit, which was factory preset for 10%. Confirmed the accuracy with roadside radar and being paced with a bike having GPS.

My 07 reads just about 70 mph @ 3000 rpm. That's around 7.5%.

I'm really looking for confirmation that it should be 65 mph @ 3000 mph after calibration.

Thanks
Don Swanburg

 

[GreenDragon]

My 03 is doing 67 @ 3000 RPM according to the Garmin.

 

[IR Harry]

Don - depends on your tire size. A new tire will read a little different than an old tire, and a 70 series rear will read way different. Mine is just under 75 at 3000, with a worn 70 series ME880.

Also depends on the accuracy of the tach. A lot has been said about speedometer error, but I have not seen any tachometer comparisons.

Quick way to figure it out is measure time between mileposts and calculate it - 60 MPH is 1 mile per minute and 88 feet per second.

Or the lazy way - GPS.

 

[joel3078]

Here is some food for thought for all you gps guys - me included. Why are we assuming that gps speed indicated is dead nuts on? Anyone here do 60mph consistently and do a stopwatch test for mile markers, paint stripes, etc? Who says the mile markers are really mounted at exactly 5280 feet. Lots of assumptions going on! Who was anal enough to actually check this out. I know somebody here fits the bill.

 

[KJ5IX]

Here is some food for thought for all you gps guys - me included. Why are we assuming that gps speed indicated is dead nuts on? Anyone here do 60mph consistently and do a stopwatch test for mile markers, paint stripes, etc? Who says the mile markers are really mounted at exactly 5280 feet. Lots of assumptions going on! Who was anal enough to actually check this out. I know somebody here fits the bill.

I didn't check it out as you described, but I do use an old GPS for Speed only. I have used it in several vehicles and a couple of aircraft, and when ATC makes initial contact they give heading and speed. It has Never been off on either.

I was stopped once for over 70 in a 55, as I finished the curve I saw him sitting there and glanced at the GPS 72.6 MPH OOPS. Of course the first thing the Trooper asked was "Do you have any idea how fast you were doing, and what the speed limit is here?" ( I did that for 16 years, a standard question ) I replied 72.6 give or take a 1/10th... He showed me the reading on his unit " 72.6 " That's Dead Nuts enough for me, No further Testing Required. I did manage to get the standard lecture on speed and because I had been a LEO for so long, and should Know better!! and a Warning Ticket. That was Kool, Warning Tickets don't cost nor go on the record, just had to be good for 6 mo's, and not get caught again.

Forgot: To keep it on topic, 3000 RPMs on my Trike is 73/74 Honda indicated.

 

[joel3078]

Oh ya on topic, same for me about 73mph on the speedo at 3000rpm - bike is an 06 wing. I should start my own parley board on when I'll get my 1st speeding ticket on the wing. Bike doesn't like doing 30 or 60. They want to go 20, 40, and 65-70. Speeding was not a problem on the old HD bike. :roll: I'm guessing the built in error on the speedo is just for that reason - a lil margin of error to keep the blue lights from going off behind ya.

 

[IrishGold]

According to Garmin their typical GPS has an accuracy of 0.05m/second steady state. 0.05m/sec ~= 0.1625ft/sec =~ 0.1mph. A GPS is one of the best indicators of accurate steady state speed that I am aware of.

In top gear my GW runs about 66MPH (true) at 3000RPM. My speedometer read about 7% high or about 70-71 at 3000RPM.

05 GL1800
Ride Safe and Often!

 

[Don Swanburg]

Thanks for the input.

I haven't found a GPS equipped bike to ride with and will just have to wait till spring.

Just thought I might be able to cheat a little while setting up my new bike, but there appears to be too many variables.

Thanks again
Don Swanburg.

 

[Ed Kruse]

joel3078,

I don't know about being anal but, I checked my speedo against the milemarkers on the road several time before getting a GPS. The results are the same!

I found the following on the web around the same time I was checking my Wing and agree with his numbers.

===============================================

I did this last year prior to installation of my yellowbox. This was on a GL1800A '02 (Silver, so you know it has to be right), with the stock Bridgestones at about 2000 miles of wear. Hasn't changed since the new Metzeler's were put on.
GPS Speedo TachX100 Error

50 54 22 1.080

55 59 24 1.073

60 64 27 1.067

65 69 29 1.062

70 75 31 1.071

75 80 33 1.067

80 85 36 1.063

1.069 AVG

 

[Silverback]

With a fresh Metzeler ME880 70 series on the back, I'm doing 72.4mph @ 3000rpm, as measured by my GPS.

 

[GW Wilkins]

My odometer and my gps say's 70 mph at 3,000 rpm

 

[All Boots No Saddle]

My 03 is doing 67 @ 3000 RPM according to the Garmin.

Same for my '02, so I used my Yellowbox to set my speedometer to that speed with new tires.

In the future, as the tires wear the indicated speed will stay the same at 3000 rpm, but the true speed will drop slightly.