Those with 20's, I need help! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

REPO1 · 10-24-2004, 10:39 PM

I have been searching the net for some rims for my '70 shortbox fleetside project. I see there are all kinds of offsets out there. From -30mm, -5mm, +10mm, +14mm, etc. etc. etc.

And they also show a BSM number. Now is this backspacing?

Please post what size of rims you have, and what your offset and backspacing is please.

I am totally confused. Please help!

Here is a link for example: http://www.aewheel.com/wheels_detail.cfm?id=11

TheFabShop · 10-24-2004, 11:12 PM

Look to the left under BSM that is the b/s.

REPO1 · 10-24-2004, 11:44 PM

That is kind of what I figured. But what BSM and Offset am I looking at for my truck? I was hoping for either a 20x8 or 20x9.5 in the rear and either 20x8 or 18x8 in the front.

Truckhead · 10-26-2004, 02:20 PM

I can say a 20x9 off an escalade will fit F&R with 1/2inch spacers out back and alittle grinding of the hub up front. I ended up having to install longer studs for the spacers,then i had to cut about 3/4 of an inch off the studs to make the chrome closed lugs to fit just right. But, to fit the longer studs i had to have the stud holes machined out alittle to fit the studs as they were alittle bigger. It's all good now and everything looks and works fine.

turmoline · 10-26-2004, 06:21 PM

I have 20x9.5 out back w/ 0 offset and a 5.25 backspacing. 20x8 up front w/ 0 offset and a 4.5 backspacing. backspacing is a measurement from the mounting point of the rim to the outside edge. Offset is a measurement from the center for and aft. for instance a negative offset(large backspacing) will give you a shallow looking rim. hope this helps.

grnddwn · 11-03-2004, 06:45 PM

BSM is backspace my 20s have a 4 3/4 " back space

10-24-2004, 10:39 PM	#1
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	Those with 20's, I need help! I have been searching the net for some rims for my '70 shortbox fleetside project. I see there are all kinds of offsets out there. From -30mm, -5mm, +10mm, +14mm, etc. etc. etc. And they also show a BSM number. Now is this backspacing? Please post what size of rims you have, and what your offset and backspacing is please. I am totally confused. Please help! Here is a link for example: http://www.aewheel.com/wheels_detail.cfm?id=11 __________________ 1970 Chevy C20 Custom Camper 402BB Turbo 400 trans. (Slowly becoming a '70 shortbox 1/2 ton) '71 Camaro SS 402/T400 resto '97 Z28 (11.41@127MPH) Last edited by REPO1; 10-24-2004 at 10:41 PM.

10-24-2004, 11:44 PM	#3
REPO1 Shortbox wanna-be. Join Date: Mar 2002 Location: Fort St.John, British Columbia, Canada Posts: 773	That is kind of what I figured. But what BSM and Offset am I looking at for my truck? I was hoping for either a 20x8 or 20x9.5 in the rear and either 20x8 or 18x8 in the front. __________________ 1970 Chevy C20 Custom Camper 402BB Turbo 400 trans. (Slowly becoming a '70 shortbox 1/2 ton) '71 Camaro SS 402/T400 resto '97 Z28 (11.41@127MPH)

10-24-2004, 11:12 PM	#2
TheFabShop Registered User Join Date: Oct 2004 Posts: 67	Look to the left under BSM that is the b/s.

10-26-2004, 02:20 PM	#4
Truckhead 18436572 Join Date: Aug 2003 Location: Waynesboro, Va. Posts: 488	I can say a 20x9 off an escalade will fit F&R with 1/2inch spacers out back and alittle grinding of the hub up front. I ended up having to install longer studs for the spacers,then i had to cut about 3/4 of an inch off the studs to make the chrome closed lugs to fit just right. But, to fit the longer studs i had to have the stud holes machined out alittle to fit the studs as they were alittle bigger. It's all good now and everything looks and works fine.

10-26-2004, 06:21 PM	#5
turmoline Registered User Join Date: Jul 2001 Location: santa cruz, Calif. U.S. Posts: 166	I have 20x9.5 out back w/ 0 offset and a 5.25 backspacing. 20x8 up front w/ 0 offset and a 4.5 backspacing. backspacing is a measurement from the mounting point of the rim to the outside edge. Offset is a measurement from the center for and aft. for instance a negative offset(large backspacing) will give you a shallow looking rim. hope this helps.

11-03-2004, 06:45 PM	#6
grnddwn belly dragger Join Date: Feb 2002 Location: sherwood park AB. Canada Posts: 694	BSM is backspace my 20s have a 4 3/4 " back space



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