Tonight on the way home from dinner with the fam, I had my dad do 65 right next to me on the freeway. I did the same (according to my speedo) but I was pulling on him at about 4-5mph faster. I decided to do this because it seems like I'm flying by everyone when my gauge says I'm doing the speed limit. I have the stock 15" rim and tire on the car so it's not that. How do I go about fixing this?

1992 Si - Swapped H22a w/H23 5spd

 

What wheel/tire combo does your dad have? Also, there will be a slight variation between cars from tire wear and factory accuract tollerences (readings between x and y are considered correct)

 

find a cool cop (if possible) and just ask him to radar you.

 

He has whatever came with the '06 Base Civic. I seriously pass ppl left and right when I'm on the freeway. I do think that my tires are a bit....high profile for my car though. Will the "profile" make a diff?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ludeing1 &raquo;</TD></TR><TR><TD CLASS="quote">find a cool cop (if possible) and just ask him to radar you.</TD></TR></TABLE>

I'd rather just go get it checked out by an honest shop. If anyone is around KC, post one up

 

yea, i have way to large of tires on my lude right now, and i run about 3-5 miles an hour faster when at 60+.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMgareth &raquo;</TD></TR><TR><TD CLASS="quote">yea, i have way to large of tires on my lude right now, and i run about 3-5 miles an hour faster when at 60+.

</TD></TR></TABLE>

hmmm. sounds like my problem then. But when I do put 17's on this, how do I get the speedo to read right? Just wanting to know for future reference

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NtheWorks &raquo;</TD></TR><TR><TD CLASS="quote">

hmmm. sounds like my problem then. But when I do put 17's on this, how do I get the speedo to read right? Just wanting to know for future reference</TD></TR></TABLE>

It's driven by a gear in the tranny and a gear in the VSS (vehicle speed sensor), you can't adjust it. Get the right sized tires if you want the speedo to read properly.

 

get a gps to see if your speedometer is accurate

mine isn't. when my speedo is at 62 my gps read my speed at 65. i have 205/50/16 tires

my 97 accord is opposite when my speedo read 65mph it is really going 63mph

 

use this.

http://www.miata.net/garage/tirecalc.html

you want to keep overall diameter the same if not as close as you can.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hawkze_2.3 &raquo;</TD></TR><TR><TD CLASS="quote">

It's driven by a gear in the tranny and a gear in the VSS (vehicle speed sensor), you can't adjust it. Get the right sized tires if you want the speedo to read properly.</TD></TR></TABLE>

 

you can't just get the thing recalibrated or something?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NtheWorks &raquo;</TD></TR><TR><TD CLASS="quote">you can't just get the thing recalibrated or something? </TD></TR></TABLE>

<U>It is driven by gears as already stated. </U>

How would you suggest calibrating some metal gears?....

 

by throwing a monkey wrench into it maybe?

 

you can use a speedo healer like on a street bike. Just get a fully adjustable one.

http://www.speedohealer.com/