How do you measure backspacing on a wheel?
Thread Starter
Registered User
Joined: Jun 1999
Posts: 609
From: Pensacola Florida
How do you measure backspacing on a wheel?
How do you measure backspacing on a wheel?
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1980 Camaro Z28 Sikkens 3 Stage Blue and Purple
1994 Camaro Z28 Teal M6
Ported Heads, LT4 Hot Cam and Springs, 1.6 RR's, Mac Headers and Offroad Y Pipe, Flowmaster Catback, Resonators, Flowtech Cutout, NX 150 Horsepower Shot of Nitrous, NX Bottle Heater, NX Remote Bottle Opener, NOS Purge, KB DD SFCs, BMR STB, Hypertech 160 Thermostat, Redline Water Wetter and Synthetic Diff. Fluid, McLeod Dual Performance Clutch, K&N FIPK, LT4 KM, 1LE Bellow, Holley 58mm Throttle Body, TB Coolant Bypass, Metco Valve Cover Breather, LPW Rearend Support Cover, Strange 3.73s, Eaton Posi, TA Stud Kit, Lakewood LCAs and Adjustable Panhard Rod, LS1 Driveshaft, March Underdrive Pullies, MSD 6AL, MSD Window Switch, MSD Blaster Coil, NGK TR6's, Mobil 1 Synthetic, Pro 5.0 Shifter, Intrax Lowering Springs, BFGoodRich Comp TAs 255/50/16, Nitto Drag Radials 245/50/16, AVS Blackouts on the back.
339 RWHP Corrected with two broke rings
465 RWHP Corrected on the nitrous with the clutch slipping bad and two broke rings
www.geocities.com/speeds8erm1
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1980 Camaro Z28 Sikkens 3 Stage Blue and Purple
1994 Camaro Z28 Teal M6
Ported Heads, LT4 Hot Cam and Springs, 1.6 RR's, Mac Headers and Offroad Y Pipe, Flowmaster Catback, Resonators, Flowtech Cutout, NX 150 Horsepower Shot of Nitrous, NX Bottle Heater, NX Remote Bottle Opener, NOS Purge, KB DD SFCs, BMR STB, Hypertech 160 Thermostat, Redline Water Wetter and Synthetic Diff. Fluid, McLeod Dual Performance Clutch, K&N FIPK, LT4 KM, 1LE Bellow, Holley 58mm Throttle Body, TB Coolant Bypass, Metco Valve Cover Breather, LPW Rearend Support Cover, Strange 3.73s, Eaton Posi, TA Stud Kit, Lakewood LCAs and Adjustable Panhard Rod, LS1 Driveshaft, March Underdrive Pullies, MSD 6AL, MSD Window Switch, MSD Blaster Coil, NGK TR6's, Mobil 1 Synthetic, Pro 5.0 Shifter, Intrax Lowering Springs, BFGoodRich Comp TAs 255/50/16, Nitto Drag Radials 245/50/16, AVS Blackouts on the back.
339 RWHP Corrected with two broke rings
465 RWHP Corrected on the nitrous with the clutch slipping bad and two broke rings
www.geocities.com/speeds8erm1
Registered User
Joined: Dec 1969
Posts: 472
From: Mobile, Alabama
read this: http://www.tirerack.com/wheels/tech/offset.htm
backspacing is basically: offset + 1/2 of wheel width.
For reference, if you want to run an 8" wide wheel, you would want 5-5.5" backspacing, if you want to run a 10" wide wheel, you'll want approximately 7.5" backspacing. If you run these wheels, the tires won't stick out of the fenderwells.
in a nutshell
....Brady
backspacing is basically: offset + 1/2 of wheel width.
For reference, if you want to run an 8" wide wheel, you would want 5-5.5" backspacing, if you want to run a 10" wide wheel, you'll want approximately 7.5" backspacing. If you run these wheels, the tires won't stick out of the fenderwells.
in a nutshell
....Brady
Thread Starter
Registered User
Joined: Jun 1999
Posts: 609
From: Pensacola Florida
Thanks! I was wanting to know because I have two Cragar Superlites for sale and somebody wanted to know what the backspacing is. I took one of my Weld Draglites that is 7.5 backspacing and measured until I figured out what they were measuring to get 7.5, then I did it on my Cragar Superlites, they are 4.5. I am going to check the thing on Tirerack and make sure I did it right. 
Administrator
Joined: Nov 1998
Posts: 71,097
From: Hell was full so they sent me to NJ
Backspace is a little more complicated than that, because it also includes the width of the flange that retains the tire bead. The stated wheel width is measured between the bead seats, inside the retaining flanges. The backspace would then include 1/2 the wheel width + offset + approx 1/2" for the flange. This could be measured by putting a straightedge across the back of the rim, and measuring the distance from the straightedge to the hub mounting surface.
If you look carefully at the details of the Tire Rack sketch, you will see what I am talking about.
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Fred
94 Formula A3+1: 381/TH400+OD/N2O
Advanced Tech Posting Guidelines
Detailed Mod's List
11.513@115.59 on motor; 11.162@127.67, 1.643 60' on a 125-shot. Going with a 275-shot this year
[This message has been edited by Injuneer 94FormM6 (edited August 13, 2002).]
If you look carefully at the details of the Tire Rack sketch, you will see what I am talking about.
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Fred
94 Formula A3+1: 381/TH400+OD/N2O
Advanced Tech Posting Guidelines
Detailed Mod's List
11.513@115.59 on motor; 11.162@127.67, 1.643 60' on a 125-shot. Going with a 275-shot this year
[This message has been edited by Injuneer 94FormM6 (edited August 13, 2002).]
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