 |
|
09-17-2021, 05:31 PM
|
#1
|
|
Senior Member
Fleetwood Owners Club
Join Date: Sep 2015
Posts: 439
|
What's Your Speed
I'm running across I-64 this afternoon and I looked at the speedo and the needle was covering the 65 MPH line. GPS on Google Maps says I doing 66. I got the 5 Star tune SCT programmer mounted on the dash and plugged in for kicks. (Yeah, I'm kinda geeky that way) Anyway, the data on the SCT programmers bouncing between 63.5 and 64. So GPS is 66, Speedo is 65, and SCT under 64ish.
Which one is the most accurate?
__________________
Steve n' Tammy in a 2003 Fleetwood Bounder 32' on a Ford F53 Chassis and a V-10 gasser pulling a 2020 Pacifica on a EZE Tow Dolly
|
|
|
 |
Join the #1 RV Forum Today - It's Totally Free!
iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!
You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
|
|
09-17-2021, 05:40 PM
|
#2
|
|
Member
Newmar Owners Club Spartan Chassis
Join Date: Jun 2016
Posts: 87
|
A man with one watch knows what time it is. A man with two is never sure.
__________________
Bill and Brenda
2003 Newmar Mountain Aire 4097
|
|
|
|
|
09-17-2021, 05:41 PM
|
#3
|
|
Senior Member
Alpine Owners Club
Join Date: Nov 2015
Location: Lake Havasu City, AZ
Posts: 3,015
|
__________________
Paul & Jean
2001 Alpine 36FDDS (74291)-3900W Solar, 13,440Wh (525Ah @24V) LiFePO4
2019 Jeep Grand Cherokee Trailhawk (Hemi)
2006 Alpenlite 32RL - Sold
|
|
|
|
|
09-17-2021, 05:45 PM
|
#4
|
|
Senior Member
Join Date: Jul 2005
Posts: 5,996
|
One could argue you are a distracted driver. Maybe.
__________________
TandW
|
|
|
|
|
09-17-2021, 05:47 PM
|
#5
|
|
Senior Member
Join Date: Nov 2013
Location: Elko, Nv
Posts: 2,464
|
Average them and call it good.
|
|
|
|
|
09-17-2021, 05:55 PM
|
#6
|
|
Senior Member
Join Date: Jan 2021
Posts: 281
|
You have WAY too much time on your hands…
|
|
|
|
|
09-17-2021, 06:03 PM
|
#7
|
|
Senior Member
Join Date: Aug 2020
Location: Ohio
Posts: 2,353
|
You forgot to add or subtract for 26,000 plus miles per hour the planet is going... did you every study significant difference ? So I believe there is no significant difference..
__________________
2000 southwind storm, workhorse custom chassis with 7.4l vortec
|
|
|
|
|
09-17-2021, 06:07 PM
|
#8
|
|
Senior Member
Join Date: Dec 1969
Posts: 2,668
|
Quote:
Originally Posted by c92vette
......
Which one is the most accurate?
|
What is the accuracy of your judgement for estimating your stopping distance?
I was a slide rule engineer who started out as an operator reading an analog gauge.
All three of your speed reading are accurate enough to get the job done. If the needle is over 65 and the ground is flying by, ignore the computer generated number that says you are stopped.
I also ignore the computer voice telling me to make a u-turn on a bridge.
__________________
Kit & Rita (in memory)
37 foot ‘98 HolidayRambler Endeavor diesel pusher
|
|
|
|
|
09-17-2021, 06:28 PM
|
#9
|
|
Senior Member
Join Date: May 2021
Location: Houston
Posts: 541
|
The way I check a speedo is to drive at 60mph indicated on the speedo. Preferably on level ground to make it easy to maintain a steady speed. Wait for a mile marker, when you pass it, start a stop watch. Keep the speed at 60 indicated, til the next mile marker(one mile later) stop the watch. It should read 60 seconds if the speedo is accurate. If it’s more than 60 seconds the speedo reads faster than you are going. Most read fast by 2 or 3 mph. Well it’s really a percentage.
Maybe have your co-driver do the stop watch, and watch GPS, and 5Star.
|
|
|
|
|
09-17-2021, 06:28 PM
|
#10
|
|
Senior Member
Join Date: Jul 2005
Posts: 5,996
|
Quote:
Originally Posted by donr103
You forgot to add or subtract for 26,000 plus miles per hour the planet is going... did you every study significant difference ? So I believe there is no significant difference..
|
Did you ever study Statistical Difference?
__________________
TandW
|
|
|
|
|
09-17-2021, 06:33 PM
|
#11
|
|
Senior Member
Join Date: Jul 2005
Posts: 5,996
|
Quote:
Originally Posted by SergioP
The way I check a speedo is to drive at 60mph indicated on the speedo. Preferably on level ground to make it easy to maintain a steady speed. Wait for a mile marker, when you pass it, start a stop watch. Keep the speed at 60 indicated, til the next mile marker(one mile later) stop the watch. It should read 60 seconds if the speedo is accurate. If it’s more than 60 seconds the speedo reads faster than you are going. Most read fast by 2 or 3 mph. Well it’s really a percentage.
Maybe have your co-driver do the stop watch, and watch GPS, and 5Star.
|
Might be good for checking odometer error.
__________________
TandW
|
|
|
|
|
09-17-2021, 07:06 PM
|
#12
|
|
Senior Member
Newmar Owners Club Freightliner Owners Club RV Trip Wizard
Join Date: Jun 2021
Location: Nashville, TN, USA
Posts: 118
|
Quote:
Originally Posted by c92vette
I'm running across I-64 this afternoon and I looked at the speedo and the needle was covering the 65 MPH line. GPS on Google Maps says I doing 66. I got the 5 Star tune SCT programmer mounted on the dash and plugged in for kicks. (Yeah, I'm kinda geeky that way) Anyway, the data on the SCT programmers bouncing between 63.5 and 64. So GPS is 66, Speedo is 65, and SCT under 64ish.
Which one is the most accurate?
|
GPS is the least accurate of them because it's not a constant sample, but an average of the sample points.
__________________
____________
David C. Baker (Nashville): author | speaker | advisor | airplanes | helicopters | motorcycles | photography | woodworking | rving
|
|
|
|
|
09-17-2021, 07:56 PM
|
#13
|
|
Senior Member
Join Date: Apr 2012
Location: Louisville, KY
Posts: 1,417
|
Folks.. be nice. I have seen this difference myself. Yes, it might not be “significant”, but it is still noticeable. I did the stopwatch thing with mile markers, and turned out the gps appeared more accurate. Whether I go with the gps or the dash reading, in practice, depends on how much of a hurry I am in (or am not)...
__________________
- 2017 Newmar London Aire -
|
|
|
|
|
09-17-2021, 07:59 PM
|
#14
|
|
Senior Member
Tiffin Owners Club
Join Date: Jul 2016
Location: Where we park it!
Posts: 13,145
|
__________________
momdoc
2018 Tiffin Allegro RED 37PA
2020 JEEP Trailhawk
|
|
|
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Linear Mode
