Club Cobra Gas - N Exhaust  

Go Back   Club Cobra > Manufacturers, Engine Builders, tools, and parts. > Antique & Collectibles

Welcome to Club Cobra!  The World's largest non biased Shelby Cobra related site!

  •  » Representation from nearly all Cobra/Daytona/GT40 manufacturers
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and nearly 1 million posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

Nevada Classics
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
MMG Superformance
Advertise at CC
Banner Ad Rates
MMG Superformance
MMG Superformance
November 2022
    1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30      
  #1 (permalink)  
Old 06-04-2007, 08:09 AM
CC Member
Visit my Photo Gallery

Join Date: Aug 2006
Cobra Make, Engine: A&C
Posts: 379
Not Ranked     
Default Is it offset or backspace?

Before I call Sonny at A&C the manual says "offset" for tire rim selection. I think this might be a misprint. It doesn't say negative or positive offset.

On a 10" rim it says to have a 4" offset. That would make 9" of back spacing?

I found this Yokoham explanation.

Wheel offset
The wheel's offset is the distance from its hub mounting surface to the centerline of the wheel. To determine wheel offset:
Position the wheel on a flat surface and measure its overall width.
Divide the overall width by two, then subtract this result from the backspace value.

Offset = Backspace - (Rim Width 2)

The offset of a wheel can be one of the following three settings:

Zero offset:
The hub mounting surface is even with the centerline of the wheel.

Positive offset:
The hub mounting surface is toward the front or wheel side of the wheel. Positive offset wheels are generally found on front-wheel drive cars.

Negative offset:
The hub mounting surface is toward the back or brake side of the wheel's centerline. "Deep dish" wheels are typically negative offset.

Reply With Quote
Sponsored Links
Sponsored Links
  #2 (permalink)  
Old 06-04-2007, 08:55 AM
Roscoe's Avatar
CC Member
Visit my Photo Gallery

Join Date: Mar 2000
Location: Fairfield, NJ, USA, NJ
Cobra Make, Engine: A & C, 351W, Tremec 3550. Exiled Member: Club Cranky
Posts: 5,897
Send a message via ICQ to Roscoe
Not Ranked     

First off, while Sonny is a great guy, talk to Joe about tech issues.

My A&C wheel setup is as follows:

Front: 4.5" on 8"
Rear: 4" on 10"


Front: 245/60
Rear: 295/50

"Crisis occurs when women and cattle get excited!"....James Thurber
Reply With Quote
  #3 (permalink)  
Old 06-04-2007, 10:50 AM
CC Member
Visit my Photo Gallery

Join Date: Sep 2006
Cobra Make, Engine:
Posts: 242
Not Ranked     

I used the offsets that were in the manual and gave the information to the Tire and rim dealer when i ordered my rims. They turned out perfect. Went with exactly what the manual said both with the offsets and tire size.

Reply With Quote
  #4 (permalink)  
Old 06-04-2007, 11:31 AM
pmfranke's Avatar
CC Member
Visit my Photo Gallery

Join Date: Feb 2005
Location: Truckee and Kailua, Ca
Cobra Make, Engine: B&B 351/402 Fi roller everything
Posts: 527
Not Ranked     

backset is measured from the mounting surface to the inside edge of the rim(or back edge). So place rim face down put strait edge across rim then measure down to the mounting face of the hub. Thats back space.What I don't get is when there is a back space and an offset together. IE.4.5 bs and 6mm offfset I just don't understand.
the older i get the faster i was.
Reply With Quote

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not 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

All times are GMT -7. The time now is 10:29 PM.

Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink