Rear end gears - Hot Rod Forum : Hotrodders Bulletin Board -- 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
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 12-05-2006, 10:20 PM
stoney 81ta's Avatar
Last photo:
Join Date: Dec 2003
Location: innisfil ontario
Posts: 328
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Rear end gears

what are the best rear end gearing for city and street driving for a sbc stroker in a 81 trans am auto.Currently have stock2.56 gearing non possi.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 12-05-2006, 10:40 PM's Avatar Moderator
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,455
Wiki Edits: 21

Thanks: 6
Thanked 45 Times in 33 Posts
Can't go wrong w/ gears in the 3.54 -3.73 range for gorcery getter/stoplight bandit service.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-06-2006, 04:18 AM
Last photo:
Join Date: Aug 2005
Location: Yackandandah.Australia.
Age: 55
Posts: 641
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If it sees 90% urban/10% highway aim for 3000 rpm at hwy cruise. Over 50% highway, go 2300 or lower cruise - assuming your engine is smooth at low rpm. All stoplight to stoplight who cares? set your gearing to suit your trap speed.
Tyre height is as important as rear end gearing when calculating cruise rpm.Much like prop dia or pitch in a boat.
Try this, loaded radius x 5.92 divided by overall gearing = mph per 1000rpm in direct gear. Assume a 30 inch slick then measure from the centre of the wheel to the ground- should be around 14 inches with a vehicle weight of 3400 - 60/40 distribution, then go 4spd direct top or auto with lock up converter. Multiply 14 x 5.92 = 82.88 then divide by final drive ratio say 4.10 (diff gears x top gear ratio), should be 20.21 mph.
Yep, 3 grand equals 60.63 mph at cruise.
With an auto make sure your cruise rpm is higher than your stall speed. With manuals make sure it doesn't 'pigroot' (surge on the cam) at cruise rpm,years ago - young n dumb - I ran a package that would pigroot at 55mph in top and smooth out at 60. Pull it back 2 gears and it would run like a dog shot in the rse - 93 in 2nd,129 in 3rd and big mph in top, but it was far from toey down low.

Last edited by IanRiordan; 12-06-2006 at 04:20 AM. Reason: forgot final drive ratio
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply

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:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


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
Change 4.11 to 3.08 rear end gears cares Transmission - Rearend 4 08-13-2006 01:46 PM
spinning the rear end gears.. onecoomofo Transmission - Rearend 4 06-21-2004 06:19 PM
anybody take a guess what my rear end gears might be? smlblcks10 Transmission - Rearend 7 04-22-2004 11:46 AM
65 Chevy Rear End Gears mweber Engine 3 01-03-2004 04:05 PM
Changing rear end gears... chevyelc81 Transmission - Rearend 1 07-23-2002 07:52 PM

All times are GMT -6. The time now is 08:22 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.