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So there seems to be a pretty general consensus that the TW speedo indicates just a little faster than the actual speed as reported by GPS, radar gun, etc. Often times people will report "indicated" speed vs. "actual" speed, and the indicated always seems to be a bit faster. How much faster? By my calculations based on various reports and my own findings on my bike, about 10% (68 indiciated, 62 actual via GPS)

Since the speedo and odometer are the same gauge cluster and pull data from the same sensor on the front wheel, this must mean the mileage recorded by the odometer is off by +10% as well right? May not sound like much, but that would mean a bike with 10000 "indicated" miles really only has 9000 actual miles on it.

Whatcha guys think? Am I wrong in any of my assumptions here? Obviously not a huge concern or anything.... just food for thought
 

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I think you may be right, it would be putting on more miles if the speedo indicates a higher MPH.

I switched to a lager front tire (Kenda K270 4.5-18) and now the speedo and GPS show identical speeds, right on the $$.
 

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Now, I may be incorrect here but I think the odometer and speedometer may be calibrated slightly differently. I remember reading about this on a ZRX forum and they were saying that the speedometer is regulated to be off on purpose so as to not have you going past what's indicated but the odometer was correct.

Once again, this was all speculation and I don't remember seeing any documents backing it up. If you really wanted to test it, you can also use a GPS that records distance traveled and compare it to the odometer/trip.
 

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I never had the original tire on when I bought the bike, but with the MT 43 it is close that I never tried to figure out how far off it was.

On the WR the speedo was off by 7% on purpose, while the odometer was pretty much accurate and these were read from the output shaft.
I put a 12 o'clock speedo healer on the bike and when I changed gearing I would adjust the speedo, which screwed up the odometer. Speedo was accurate, but odometer was low.

Same is true of the Wee, but it is an electronic pickup off the front wheel and rear(?). Speedo is 7% faster, but odometer is out by a little. 12 o'clock also sells a speedo healer for it.

Slight thread highjack, why do the manufactures do this? v=d/t the distance recorded is accurate, the clock on the bike is accurate so someone had to adjust the speed output from the formula.
 

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Both of my TW's are off. The only exception is with my 2005 TW when I had the 5.10x18 Shinko 244 mounted similar to what 1911Garand mentions. However, the 05 now has a 4.60x18 and the speedo is off again. There will be a few of us whose speedo's read correctly but I'm guess the majority of us experience some sort of "offness".

What I want to know is why in the morning is my speedometer 2 miles per hour off from my GPS (62 indicated is 60 actual) and in the afternoon it changes from 2 mph off to 4 mph off (64 indicated is now 60 actual). Has something changed in the speedometer or in the GPS? This isn't just a one time fluke but has happened many times.
 

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The biggest problem is with the 87's.. is the incorrect speedo ;)

If the 87's speedo was correct we wouldn't have all this controversy. It would be obvious beyond a reasonable doubt that no other year would even be close to an 87...



Both of my TW's are off. The only exception is with my 2005 TW when I had the 5.10x18 Shinko 244 mounted similar to what 1911Garand mentions. However, the 05 now has a 4.60x18 and the speedo is off again. There will be a few of us whose speedo's read correctly but I'm guess the majority of us experience some sort of "offness".

What I want to know is why in the morning is my speedometer 2 miles per hour off from my GPS (62 indicated is 60 actual) and in the afternoon it changes from 2 mph off to 4 mph off (64 indicated is now 60 actual). Has something changed in the speedometer or in the GPS? This isn't just a one time fluke but has happened many times.
 

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"Old model" bikes would have an allowance for an indicated speed of up to +10% actual speed. Modern technology has reduced that differential, but the TW remains a 30 year old design, and they haven't changed the parts they use for the speedo - so +6% to +8% is to be expected.

Even tread depth will have an effect on this - so they allow for that in how the speedo will read
 

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read very carefuloly what I wrote. I made no such claim (that an 87 was faster) ;)

Au Contraire, mon ami.......if the '87 speedometer were not off by SO much...as compared to the '88 - '16 bikes...then it would show that the '87 is not really a faster bike, but...just a lowly TW200 like all its' brother and sister TW200s out there. :D

And...Admiral, I will take a wild stab at this and say the difference between your morning readings versus youtr afternoon readings may have more to do with the circumference of the heated up front tire, than it does with the speedometer changing between morning and afternoon. With the afternoon warmth, and that front tire heating up, it could gain in circumference of the tire.
 

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Wouldn't the greater circumference lower the apparent speed?
 

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Wouldn't the greater circumference lower the apparent speed?
Not if the rider had a large head circumference...

Gear, Tire?
 
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