It was nice of the local cops to help calibrate my speedo - The 1947 - Present Chevrolet & GMC Truck Message Board Network

willyCJ · 03-25-2009, 09:47 PM

I decided it was a nice sunny day to take the truck out for a spin. I was pretty sure the speedo gear wasn't right, but now its confirmed.

So the local cops set up one of the big "Your speed is XYZ" trailers by the local high school, my speedo says 45 and their machine says 31. I'm guessing theirs is more accurate.

And it also means I wasn't doing 70 in a 40 earlier

I like sunny days

69halfton · 03-25-2009, 09:49 PM

well, when its that far ahead, you know your never gunna get a speeding ticket

thats not a speedo, its a dream-meter! (how fast you IWSH you were going :lol)

willyCJ · 03-25-2009, 10:29 PM

It makes my ego feel pretty good when I think I'm doing 70. Although with 4 corner drums, I'm not sure I want to be doing 70 right now...

Although I will laugh if a cop ever asks me "how fast were you doing?" and I respond about 20 faster than he clocked me at...

68 short step · 03-25-2009, 11:13 PM

side note, if you go by one of those bad boys at over 100MPH they will just blink '00'.......or so ive heard

72BlckButy · 03-26-2009, 08:13 AM

Quote:

Originally Posted by 68 short step

side note, if you go by one of those bad boys at over 100MPH they will just blink '00'.......or so ive heard

Woody · 03-26-2009, 08:39 AM

On my '68, i was driving down the Interstate and a guy in a Olds Cutlass with digital gauges. I could see his speed from the drivers seat of the truck. Yea I know his speedo could have been off but it did show me I was reading about 3-4 mph slow.

lowriden58 · 03-26-2009, 11:51 AM

GPS works pretty good too

mrein3 · 03-26-2009, 12:11 PM

Quote:

Originally Posted by 69halfton

thats not a speedo, its a dream-meter! (how fast you IWSH you were going :lol)

Kinda like a Ranger bass boat. All those guys in Rangers claim they have 75 mph boats yet I pass them all the time in my Triton with the GPS reading in the 60s

Quote:

Originally Posted by lowriden58

GPS works pretty good too

Actually I recommend a GPS to calibrate your speedo. Even with some of the errors from the ionosphere and the quality of the unit most of us can afford, from a relative point of view they are at least as good as the cop's speed gun.

**americanmusc1e** · 03-26-2009, 12:33 PM

HAHA i checked my speedo with one of those radar signs too, but mine was 5mph over

tcb-1 · 03-26-2009, 12:38 PM

I won't say when, I won't say where, but I can confirm the blinking "00" when you pass a portable speed check at over the century mark.

and I can't confirm it happened twice, just to see it again.........

shhhhhh, it's our secret.

Critter · 03-26-2009, 12:54 PM

I have had pleanty of cops be so kind as too actually flag me down and give me a little paper "ticket" that tells me exactly what my speedometer should be reading. I have even taken this paper to the court room and had it confirmed that I was actually going as fast as they said.

Seriously though, the handheld GPS works great in my opinion. Assuming that a speedo unit is physically working properly (aka not gummed up or something) but simply off in accuracy, they will be off by a %, not a set amount. I have heard way too many guys say "my speedo says 70 when I am actually going 60 so it is 10mph off." In reality, it is about 15% fast. Anyway, the GPS allows you to take reading at 30mph, 55mph, 70mph, etc and get an idea of the % variance. The trailers work nice also though.

old Chevy guy · 03-26-2009, 03:03 PM

If you check your odometer on a measured mile ,like you see places along the hiway,you figure how many 10ths its off + or - and figure 10% for every 10th. So that means every 10th eqauls 1 mile off for every 10 miles of speed on your speedometer 1mph at 10,2at 20 ,3 at 30 and so on. If you have less than 1 mile on you odometer in a measured mile your speedo is slow,and if it reads more than a mile it reads to fast. Hope you got all that there may be a quiz latter.LOL

03-25-2009, 09:47 PM	#1
willyCJ Registered User Join Date: Mar 2009 Location: Lafayette, IN Posts: 37	It was nice of the local cops to help calibrate my speedo I decided it was a nice sunny day to take the truck out for a spin. I was pretty sure the speedo gear wasn't right, but now its confirmed. So the local cops set up one of the big "Your speed is XYZ" trailers by the local high school, my speedo says 45 and their machine says 31. I'm guessing theirs is more accurate. And it also means I wasn't doing 70 in a 40 earlier I like sunny days __________________ 1970 Shortbed C10 Parts I need: Headlight Switch, Headlight retainers, Bezels (found, thanks jc) wiper arms, wiper switch (found, thanks jc) Carpet (blue/black preferred) about half the e-brake cables (for a shortbed truck)

03-25-2009, 09:49 PM	#2
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: It was nice of the local cops to help calibrate my speedo well, when its that far ahead, you know your never gunna get a speeding ticket thats not a speedo, its a dream-meter! (how fast you IWSH you were going :lol) __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men.

03-25-2009, 10:29 PM	#3
willyCJ Registered User Join Date: Mar 2009 Location: Lafayette, IN Posts: 37	Re: It was nice of the local cops to help calibrate my speedo It makes my ego feel pretty good when I think I'm doing 70. Although with 4 corner drums, I'm not sure I want to be doing 70 right now... Although I will laugh if a cop ever asks me "how fast were you doing?" and I respond about 20 faster than he clocked me at... __________________ 1970 Shortbed C10 Parts I need: Headlight Switch, Headlight retainers, Bezels (found, thanks jc) wiper arms, wiper switch (found, thanks jc) Carpet (blue/black preferred) about half the e-brake cables (for a shortbed truck)

03-25-2009, 11:13 PM	#4
68 short step Senior Member Join Date: Aug 2005 Location: tulsa OK Posts: 3,070	Re: It was nice of the local cops to help calibrate my speedo side note, if you go by one of those bad boys at over 100MPH they will just blink '00'.......or so ive heard

03-26-2009, 08:39 AM	#6
Woody Registered User Join Date: Feb 2000 Location: Georgetown, KY, USA Posts: 631	Re: It was nice of the local cops to help calibrate my speedo On my '68, i was driving down the Interstate and a guy in a Olds Cutlass with digital gauges. I could see his speed from the drivers seat of the truck. Yea I know his speedo could have been off but it did show me I was reading about 3-4 mph slow.

03-26-2009, 11:51 AM	#7
lowriden58 Registered User Join Date: Jan 2008 Location: Chesapeake Beach, MD Posts: 812	Re: It was nice of the local cops to help calibrate my speedo GPS works pretty good too __________________ 71 cheyenne lwb 300rwhp best 1/4 time so far 12.8 @103 http://i195.photobucket.com/albums/z...en58/001-2.jpg

03-26-2009, 12:33 PM	#9
americanmusc1e Senior Member Join Date: Jan 2009 Location: Austin, TX Posts: 1,079	Re: It was nice of the local cops to help calibrate my speedo HAHA i checked my speedo with one of those radar signs too, but mine was 5mph over __________________ -- Josh Instagram: @americanmusc1e OLD SKOOL-- 1970 C10. 454/Th400/3.07 posi Build Thread FARM TRUCK----1949 Chevrolet 3800 Power Wagon Hauler Build Thread 1999 4wd OBS Tahoe - daily. DM me if you can't see photos i posted

03-26-2009, 12:38 PM	#10
tcb-1 Nothing to see here..... Join Date: Jun 2007 Location: Shawnee, KS Posts: 4,625	Re: It was nice of the local cops to help calibrate my speedo I won't say when, I won't say where, but I can confirm the blinking "00" when you pass a portable speed check at over the century mark. and I can't confirm it happened twice, just to see it again......... shhhhhh, it's our secret. __________________ Doug THANK YOU to our American Soldiers & Veterans - POW MIA "You will NEVER be forgotten". The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson

03-26-2009, 12:54 PM	#11
Critter Future TOTM Winner Join Date: Aug 2006 Location: Bulverde, TX Posts: 2,692	Re: It was nice of the local cops to help calibrate my speedo I have had pleanty of cops be so kind as too actually flag me down and give me a little paper "ticket" that tells me exactly what my speedometer should be reading. I have even taken this paper to the court room and had it confirmed that I was actually going as fast as they said. Seriously though, the handheld GPS works great in my opinion. Assuming that a speedo unit is physically working properly (aka not gummed up or something) but simply off in accuracy, they will be off by a %, not a set amount. I have heard way too many guys say "my speedo says 70 when I am actually going 60 so it is 10mph off." In reality, it is about 15% fast. Anyway, the GPS allows you to take reading at 30mph, 55mph, 70mph, etc and get an idea of the % variance. The trailers work nice also though. __________________ 72 Chevy CST K5 HIGHLANDER BLAZER Getting a 6.0,NV4500,NP205,14BFF (Currently laying all over the place in little pieces) 72 Chevy swb step-side "LS" 6.0 Here's a build thread of sorts 2002 HD2500 Crew Cab, 8.1L Allison 4x4 Daily Driver Check it out www.lsdyno.com

03-26-2009, 03:03 PM	#12
old Chevy guy Registered User Join Date: Apr 2007 Location: Foster Rhode Island Posts: 1,176	Re: It was nice of the local cops to help calibrate my speedo If you check your odometer on a measured mile ,like you see places along the hiway,you figure how many 10ths its off + or - and figure 10% for every 10th. So that means every 10th eqauls 1 mile off for every 10 miles of speed on your speedometer 1mph at 10,2at 20 ,3 at 30 and so on. If you have less than 1 mile on you odometer in a measured mile your speedo is slow,and if it reads more than a mile it reads to fast. Hope you got all that there may be a quiz latter.LOL



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