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Posted: Sun May 21, 2006 4:45 am
by KarateChick
Sevulturus wrote:
PS, most bike speedos are out by a minimum of 10%
I've also read a few notes from various riders who have said the same thing about the speedos on their bikes, but being out by 10% up or 10% down. Which way ? And anyone here find that with your ride?
* Edit to ask if the 10% is up or down
Re: Speed
Posted: Sun May 21, 2006 10:40 am
by FreeRide
YellowWing wrote:FreeRide wrote:Has anyone experienced the sensation of riding along @60mph and it seems more like 40mph or is the speedo not accurate? What gives?
If you rode a Goldwing, your statement about the speedo's would be accurate. The Goldwing speedo is out by about 10%. Reading higher than what you're actually going. This was the result of putting a 60 series tire on the rear, which is OEM. Apparently, if you replace the rear with a 70 series (which I just did this week) it corrects the speedo issue. I am giving this 70 series a try for this tire change. Probably on the next one, I will be going back to the 60 series. I am not content on the handling of my Wing, now with the 70 series. Really enjoyed it with the 60 series.
Cheers!
My bike tires are: Bridgestone Exedra-Front size-100/90 19 inch
back tire-140/90 15 inch. Does this have any effect for the speed discrepancies?
Posted: Sun May 21, 2006 2:35 pm
by Kal
Pretty much all speedo's are out by up to 10% plus or minus. British Traffic Police have to have the speedo's of their cars calibrated everytime they take them out otherwise legally its not considered an accurate enough device to 'pace' a speeder with.
As our poster has had the sensation of going slower than his speedo is showing on two different bikes I'd suggest that it is more likely to be his perception of speed that is off.
If it is bugging you find a mechanic with a 'rolling road' setup and have your speedo calibrated, then take it out.
Posted: Sun May 21, 2006 3:50 pm
by dieziege
Or just calibrate it yourself. They still have mile markers in most of California, and if we still have'em, you probably still have'em too. Hold a steady speed on the speedo, measure the time between markers... 3600/seconds=actual speed... e.g. 50 seconds=72, 65 seconds=55.38, etc. If you were holding 60 but took 65 seconds, your speedo is 5 high at 55.
Helps if you have a stopwatch I guess.
Posted: Sun May 21, 2006 4:33 pm
by camthepyro
Ok, so how do you adjust the speedo after you find out how much it's off by?
Posted: Sun May 21, 2006 8:17 pm
by FreeRide
Yep,it could be just my perception of speed and yes we still have mile markers here in OK. I bought a clock for my bike w/second hand and will try that. Thanks for all the input!
Posted: Mon May 22, 2006 2:57 am
by dieziege
you don't adjust it... it adjusts you....
Posted: Mon May 22, 2006 3:58 am
by camthepyro
Oh, I see what you're saying.
Posted: Mon May 22, 2006 5:26 am
by yoda731
Another way to get an estimate of your speed is to use a handheld GPS unit. Strap it on the gas tank, and select the display option that shows current speed (most of them do at this point). As long as you are getting a decent reading (accurate to within 15 feet or less, I'd say) then you will get an accurate speed reading as well, once you are cruising at a steady speed.
I'll post more about other GPS-motorcycle uses soon. We just got a new unit (Garmin eTrex Legend Cx) with some "games" on it which *might* be useful for practicing low-speed maneuvers (in a big empty area/parking lot, of course...).
Posted: Mon May 22, 2006 5:38 am
by dieziege
re: GPSes... make sure you are on level ground, or make two opposing passes (drive down the road one way, then turn around and drive down it the other way)... many of the low-end GPSes calculate speed in two dimensions but you travel in three... which means if you are going up or down a hill your "gps" speed will be lower than your "cop" speed.