Speedo adjusting?

Reply Subscribe

Thread Tools

Search this Thread

Feb 27, 2005 | 05:27 PM

#16

Haulin_in_Dixie

Registered User

Joined: Nov 2001

Posts: 4,199

Likes: 1

From: Branchville, Alabama

Get the truspeed sensor and set it with your gps. Any future changes, just change it again. They work great. The ECM has nothing to do with the speedo.

Another thing, tire size does not dictate the diameter. A goodyear 235/85 is 30 inches, while a Michelen rib in 235/85 is 32 inches. You can look on the net at the specs for the tires you have and get the rpm per mile.

Feb 27, 2005 | 05:58 PM

#17

crobtex

Chapter President

Joined: Oct 2002

Posts: 4,983

Likes: 1

From: Sedalia, Texas

Quote:

Originally posted by crobtex
The charts I looked at showed about 10% difference? How do you figure 3%.

I went from 245's to 285's.

Feb 27, 2005 | 08:51 PM

#18

high country

Registered User

Joined: Feb 2005

Posts: 735

Likes: 0

From: spokane/N. ID

Quote:

Originally posted by ArcticWolf
I'd like to know where he came up with the 3% also....

I was running 285's on my 99 and was stopped by CHP for going 14 mph over what I showed on the speedometer - and my dealer even told me that it wasn't more than 3 or 4 mph off.. WRONG! LOL

Luckily the CHP officer was decent, he let me go with a butt chewing - he also had a truck with over sized tires and understood when I told him what the dealer told me - I had just put the tires on the truck a few days before.

I recently switched to 295's and had the rev's per mile with me when I went to the dealer and they FINALLY got my speedo setup right! At least now I can try to get a good check on my MPG...

Did you find anything wrong with your truck? if you were going 60mph by the speedo and got a 14 over ticket your speedo would have been off more than 23.5% something is wrong with that picture