gearing question
Thread Starter
|
Senior User
Joined: Oct 2003
Posts: 124
Likes: 0
From: SoCal
gearing question
If you were to take a stock f-250 and lift it to fit 37's I know the speed/odo/etc would not read the correct speed. However when you go and re-gear the diffs to similar rpm's of a stock vehicle, shouldn't the speedometer now read close??
I lifted my f-250 put in 37's, re-geared to 4.33's and am still reading slow by 8 mph's according to my gps.
Should I have gone with the 4.56's
F-250 CC 6.0
I lifted my f-250 put in 37's, re-geared to 4.33's and am still reading slow by 8 mph's according to my gps.
Should I have gone with the 4.56's
F-250 CC 6.0
Senior User
Joined: Mar 2004
Posts: 324
Likes: 0
I went with 38" tires and 4.88 gears. Using radar I found 20 on the speedo is actually 22...30 on the speedo is actually 35...and 55 on the speedo is actually 65.
My plan at this point is to install one of the speed correction "chips". I've been looking at the Jet Performance "Accu-Speed" which is $150.00.
My plan at this point is to install one of the speed correction "chips". I've been looking at the Jet Performance "Accu-Speed" which is $150.00.
Junior User
Joined: Mar 2004
Posts: 57
Likes: 2
Originally Posted by 4mil
If you were to take a stock f-250 and lift it to fit 37's I know the speed/odo/etc would not read the correct speed. However when you go and re-gear the diffs to similar rpm's of a stock vehicle, shouldn't the speedometer now read close??
I lifted my f-250 put in 37's, re-geared to 4.33's and am still reading slow by 8 mph's according to my gps.
I lifted my f-250 put in 37's, re-geared to 4.33's and am still reading slow by 8 mph's according to my gps.
If for some reason SDs measured wheel revolutions, a gear change would have no effect.
I'm not sure where signal comes from, just thinking out loud.
Last edited by 03SD; Jan 6, 2005 at 06:55 AM.
Post Fiend
Joined: Dec 2002
Posts: 6,245
Likes: 1
From: IL, USA
Gears won't effect the speedo reading.
The VSS is mounted on the rear diff and gets the reading off of the tone ring that is mounted on the carrier with the ring gear. So, the only thing that's going to effect how fast the tone ring rotates at a given speed is the tire size.
I have the Superlift Truspeed module on my SD for the speedo.
The VSS is mounted on the rear diff and gets the reading off of the tone ring that is mounted on the carrier with the ring gear. So, the only thing that's going to effect how fast the tone ring rotates at a given speed is the tire size.
I have the Superlift Truspeed module on my SD for the speedo.
