Speedometer Information. - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Closed Thread
 
LinkBack Thread Tools
  #1 (permalink)  
Old 04-03-2005, 08:47 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
Speedometer Information.


This thread is meant to answer as many questions as to:
How do I correct my speedometer?
Why does my speedometer needle wobble?
I just changed my rear-end gears why is my speedometer so far off?
What gears do I need to correct my speedometer?

JUST REMEMBER THIS:
(Q) I got an instrument cluster from a wrecking yard. Can I use it in my project vehicle? Can it be reset to the mileage I want?
(A) It is a felony in most states to tamper with odometer readings, honest people in the business or repairing such mechanisms are NOT willing to risk it for the sake of providing you with a counterfeit "low mileage" car -- no matter how nice you are.

This has been a project that I wanted to work on for quite a while, I was going to hold off until I got things worked out the way I wanted, and to make it as easy as possible, BUT here we are with little to go on.

However, you are allowed to repair the speedometer mechanicals to allow the reading to be as correct as possible, the ODOMETER is the "rolling" number counter that tells the vehicle operator how many miles the vehicle has been driven, the odometer is a PART of the speedometer.

The speedometer is a mechanical calculator comprised of a drive gear, a driven gear, at least one cable and the speedometer head. The drive and driven gears can be changed to allow correct readings in tire and axle gear changes, but to a certain extent without an additional gear ratio adapter.

Newer computer controlled vehicles speedometers are electronic units that use specific parameters, signals, and calculations for that specific vehicle to show the correct speed, I WILL NOT COVER THESE AT THIS TIME- UNLESS SOMEONE WANTS TO HELP.

Mathematical equations related to gearing:

Ratio = (rpm x tire diameter) divided by (mph x 336)
RPM = (mph x gear ratio x 336) divided by (tire diameter)
MPH = (rpm x tire diameter) divided by (gear ratio x 336)
Tire Diameter = (mph x gear ratio x 336) divided by (rpm)

Online calculators:

This one tells you the size and MPH differences when switching tire sizes.
Corvetteactioncenter.com's Speedo Calibrator

I have used this link frequently in the past.
This is a tire size comparison calculator.

This link does the math for finding out MPH with many parameters you can change.
A MPH Calculator from RPM and Gearing

This link gives some ratios with referenced tire sizes, and part numbers for correcting speedometers in a Jaguar/Chevy V-8 swap.
Chevy TH-350/400/700R4 in a Jaguar.

A freeware RPM calculation program I found this morning.

This tells what gears are needed for correct speedometer readings, but DOES NOT cover all transmissions.
Bowtie Overdrive's Speedo Calculator.

This link also lists gears available.
TCI's Calculator, this requires you to already know what drive gear you have.

This link shows available speedo gears, gearing reducers and recommended combinations for correct readings.
Speedometer parts and calculations.

Try the search link above (it has a small dropdown arrow immediately next to it and search for what you need through the 14 pages of results. Just type in "speedometer". This subject has most likely had your particular question covered in the past. I will eventually have links to the most important and relevant information for almost anyone to find what they need.


I will have A LOT OF INFORMATION when I get this done, however long that may be.
Attached Thumbnails
Click image for larger version

Name:	Speedometers.jpg
Views:	5405
Size:	16.4 KB
ID:	4521  

    Advertisement

Last edited by M&M CUSTOM; 07-15-2005 at 06:15 PM. Reason: Just updating, again.
Quick reply to this message
Closed Thread

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
speedometer with its own mind???? Old School Nut General Rodding Tech 15 06-06-2008 04:10 PM
Axle Information. M&M CUSTOM Transmission - Rearend 1 02-21-2005 01:37 PM
Speedometer Problem - Not sure where to put this? Fragzem Transmission - Rearend 6 02-04-2005 02:09 PM
Transmission Information. M&M CUSTOM Transmission - Rearend 1 08-24-2004 03:15 PM
700R4 - Speedometer chev38 Transmission - Rearend 10 05-06-2004 08:00 PM


All times are GMT -6. The time now is 03:30 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.