Triumphrat

natec · 06-12-2006, 11:10 AM

Mine's accurate(?!).

I did a quick 50mi loop Sunday from downtown up and around Sauvie Island. Passed a couple of those roadside trailer/camera/radar gun displays that tell you how fast you are going.

One of them I passed doing 25mph, the other one 45mph. The indicated speedo was on the money both times.

Based on other posts - this seems sorta uncommon, but I aint complainin.

Nate

dazco · 06-12-2006, 11:13 AM

I did that too. One time at 52 and it showed spot on. The other time at 43 and it showed off by 3 or 4 MPH. Who knows ! :???:

rwright · 06-12-2006, 05:30 PM

I've noticed the same thing. is that rumor that they run about 10% off or are we the exception?

nycthrux · 06-12-2006, 05:44 PM

those road sign radars are not all that accurate either. Also, I wouldn't be surprised if they cheated them up a bit to slow people down.....or not, just a thought.

larryshep · 06-12-2006, 07:09 PM

My 06 Bonny Black shows consistently 1mph slow at 50, 60 and 70 mph, checked various times over the life of the bike so far with bike mounted GPS (Garmin) Odometer is dead on with my auto on trips up to 20 miles. My previous Triumph twins, BA. SM's and 05 T100 were all 10% optimistic as to speed and the 05 T100 registered 10 % less milage than actually traveled. Perhaps Triumph has sorted the speedo gearing out on the 06's, or I am just lucky this time around.

Diego · 06-12-2006, 07:27 PM

> Based on other posts - this seems sorta uncommon

No, it's simply a question of perspective. Most of what you see on the Web follows the squeaky-wheel principal. There's no scientific correlation between the number of posts about some "issue" and the number of people actually experiencing it out of the whole owner base.

I've checked all my speedometers against a variety of radar sources, and all my Triumphs read no more than 1-2 miles higher than actual for speeds between 45 and 70 mph. (My H-D XL1200S was dead on the money. Of course, for the price, it should have been!)

There are variations, of course, so I have no doubt some folks' instruments read as much as 10% higher than reality. There are parts of the world where, if there are errors, by law they have to be on the high side, not the other direction! But I don't think it's as common as some believe.

I would never dream of basing my calibration on GPS, by the way. The algorithms for a GPS computing engine can be optimized for time or position, but not both simultaneously. Calculating velocity accurately requires both.

What should raise more eyebrows about GPS is the tendency to read a fixed number of mph different from the speedo indication. Remember all the posts from people who show "indicated 35, GPS 30, indicated 45, GPS 40" all the way up to 80 or 90 miles per hour? There's almost no way a speedometer, either electrical or mechanical, can be off by a fixed number of MPH! It will almost invariably be a percentage error, modified slightly by zero-set error and/or discrepancies in scale markings.

It generally takes a computer to be off by a constant offset.

Silverado57 · 06-12-2006, 09:36 PM

Nate, I checked my speedo the same way, it was right on too.

But I always ride 10% faster just to be sure. :-D

[ This message was edited by: Silverado57 on 2006-06-13 07:40 ]

mecscc · 06-12-2006, 11:53 PM

Well, that's scary. You are telling me that my trip back from Columbus running 75-80 acutually WAS 75-80!!

No wonder I was passing most everybody. I just thought they were all tired from a long work week!

Don't tell Sue! It will blow up my argument: "Well, honey, I was running an indicated 75, but my speedo reads about 10% high." I've been using that line for years.

Somebody KILL this thread!

Monte :-D :-D

FattRat · 06-13-2006, 09:18 AM

I suspected my speedo was off by about 7%.......
so I recently borrowed a buddy's hand-held GPS and went for a straight line ride at sea level for a reasonable distance. I found that on MY bike, with 3,000 miles on a front GT501:

an indicated 59 mph is actually 56 mph
an indicated 70 mph is actually 66 mph
an indicated 80 mph is actually 75 mph
and I presume to accurately guess'timate that an indicated 108/109 mph is "the ton".......

I have seen my figures match those freeway radars parked prior to construction zones, and I have seen some of those radars that were 'off'.

Panthermark · 06-13-2006, 10:16 AM

I know mine is wrong........I just don't know "how much" it's off.

The next time you are at a stop sign or red light, look at your speedo when you start moving forward. Mine speedo does not move until I really start picking up speed. I'm clearly going faster then 2 or 3 mph, but my speedo is still at 0 mph.