Hate to do this... 20" wheel question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

randomhero472 · 06-12-2007, 07:38 PM

I know.. i know, another f'n wheel question, and i really hate to do this but i FINALLY found the perfect wheels for my project, but am slightly confused of what some of this means, and want to be 120% sure these will fit before i order. Specs of the truck will be bolt-in bag setup, bolt in c-notch, and i'll be keeping the stock inner fenders, and keeping the stock bed tubs.
Now for the wheel specs:
front will be 20x8.5" and wheels come in different configurartions
What is the "offset" these wheels are offered in either 15mm or 40mm offset, what exactly is this? Backspacing offered is either 5.3" or 6.3"

Now for the rear.. wheels will be 22x9.5" and are offered in 15mm or 42mm, backspacing 5.3" or 6.4"

SO... WHAT WILL FIT AND WORK BEST??

I've searched for over an hour, and i am sorry to post up one of these threads.. just looking for info

, thanks guys!!

EDIT: dont know if this matters or not, but it also lists "hub bore" as 72.6

MrShelley · 06-12-2007, 07:59 PM

I'd go with the 5.3" backspacing for front and rear. I think the 6.3"-6.4" backspacing is quite a bit too much. Of course, I don't have my wheels yet (less than a month!) but I almost 100% sure.

7T2 · 06-12-2007, 08:07 PM

You're probably going to be more concerned with the backspacing number than the offset number.

Backspacing is the measurement from the mounting surface of the wheel to the inside lip. Backspacing is measured by putting something with a straight edge, like a piece of 2 x 4, across the back of the rim, then measuring to the surface that meets the brake drum or rotor.

Offset is the distance that the mounting surface of the wheel is from the exact center of the wheel. On a wheel with 0 offset, the mounting surface of the wheel is exactly in the center of the wheel. a wheel that has 45mm positive offset would have the mounting surface of the wheel 45mm towards the front of the wheel from the center.

Here's a good page that explains it all with pictures:

https://www.rsracing.com/tech-wheel.html

randomhero472 · 06-12-2007, 08:33 PM

thanks for the page... that is helpful! either one of you recomend a certain offset and backspacing, im thinking the 15mm offset & 5.3" backspacing.. but want to be 1000% sure

SCOTI · 06-12-2007, 11:23 PM

First off..... We must know exactly what wheel you plan to use to offer correct info

.......

5.3"BS for the fronts.

The rears are going to depend on what rear end you now have: Is it a 67-70 w/5-lug axles or a true 71-72 5-lug? The 71-72 rear is .75" wider on each side & will effect BS requirements.

More than likely you will also need the 5.3"BS but if you have the shorter rear housing, it may allow the tires to rub on the inner tubs.

randomhero472 · 06-12-2007, 11:38 PM

i didnt mention, i could and probably will just go w/an 22x8.5" rear wheel to keep things a little narrorer back there, would that solve the rubbing issue if there was any scoti? also how do i tell what year rear end i have?

skunkwerx · 06-13-2007, 09:36 AM

is your rear 5 or 6 lug,if it a 5 lug it should be a 71 or 72,if its a 6 than a 67-70.

CUSTOM 72 · 06-13-2007, 10:22 AM

I JUST FINISHED INSTALLING MY BOLT ON AIR RIDE SYSTEM ( VERY VERY COOL ) I'M RUNNING FRONTS 265/40 20" -- 285/35/22" ALL RIMS HAVE A 14mm BACK SPACE, I'M ALSO RUNNING A 1" SPACER ON THE REARS. WHEN I SLAM THE TRUCK THE REAR FRAME STITS ON THE DIF AND THE TIRES JUST TOUCH THE INNER WHEEL WELL -- I HAVE NOT INSTALLED MY FT INNERS YET BUT IT LOOKS LIKE IT JUST MIGHT FIT. I HOPE THIS HELPS.

72 Cheyenne402 · 06-13-2007, 10:36 AM

Quote:

Originally Posted by CUSTOM 72

I JUST FINISHED INSTALLING MY BOLT ON AIR RIDE SYSTEM ( VERY VERY COOL ) I'M RUNNING FRONTS 265/40 20" -- 285/35/22" ALL RIMS HAVE A 14mm BACK SPACE, I'M ALSO RUNNING A 1" SPACER ON THE REARS. WHEN I SLAM THE TRUCK THE REAR FRAME STITS ON THE DIF AND THE TIRES JUST TOUCH THE INNER WHEEL WELL -- I HAVE NOT INSTALLED MY FT INNERS YET BUT IT LOOKS LIKE IT JUST MIGHT FIT. I HOPE THIS HELPS.

Where did you get the spacer? I'm doing 18x8 5.0 bs and 20x8.5 5.4 bs I just might need 1" in the rear

randomhero472 · 06-13-2007, 02:18 PM

custom.. what width rims are you running, and you think if i went with a 22x9.5 in the rear i could get away w/o using a spacer?

CUSTOM 72 · 06-13-2007, 02:26 PM

Randomhero472

I'm Running A 22" X 9.5 Rear -- With Out The Spacer The Tire Rides Very Close To The Inside Tub - I Recomend The Spacer

72 Cheyenne402 · 06-13-2007, 02:37 PM

I'm going to try these guys for a 5-5 to 5-5, 1" wheel adaptor. These guys use 6061-T6 billet aluminum and are made here in the USA. here is the link

http://www.wheeladapter.com/home.asp

itsmike2k · 06-13-2007, 02:43 PM

Tire size has alot to do with it also, a 285 tire has almost 11.5" section width, so that another 1" on each side of a 9.5" wheel.. But a 5.5" is alot of back spacing on a 9.5" wheel.. It seems like to me a zero offset works best which would be 4.75" on a 9.5" wheel..

72 Cheyenne402 · 06-13-2007, 05:41 PM

What size tire to run on 18x8 & 20x8.5 any advice?

06-12-2007, 07:38 PM	#1
randomhero472 Registered User Join Date: Feb 2006 Location: oklahoma Posts: 516	Hate to do this... 20" wheel question I know.. i know, another f'n wheel question, and i really hate to do this but i FINALLY found the perfect wheels for my project, but am slightly confused of what some of this means, and want to be 120% sure these will fit before i order. Specs of the truck will be bolt-in bag setup, bolt in c-notch, and i'll be keeping the stock inner fenders, and keeping the stock bed tubs. Now for the wheel specs: front will be 20x8.5" and wheels come in different configurartions What is the "offset" these wheels are offered in either 15mm or 40mm offset, what exactly is this? Backspacing offered is either 5.3" or 6.3" Now for the rear.. wheels will be 22x9.5" and are offered in 15mm or 42mm, backspacing 5.3" or 6.4" SO... WHAT WILL FIT AND WORK BEST?? I've searched for over an hour, and i am sorry to post up one of these threads.. just looking for info , thanks guys!! EDIT: dont know if this matters or not, but it also lists "hub bore" as 72.6 __________________ 67' in the "build" process.. soon to be bagged, big wheels ect, finally got it back home!! Last edited by randomhero472; 06-12-2007 at 07:57 PM.

06-12-2007, 07:59 PM	#2
MrShelley Too Many Clubs Club Join Date: Jul 2003 Location: Kilgore, Texas Posts: 443	Re: Hate to do this... 20" wheel question I'd go with the 5.3" backspacing for front and rear. I think the 6.3"-6.4" backspacing is quite a bit too much. Of course, I don't have my wheels yet (less than a month!) but I almost 100% sure. __________________ How I installed my air bags...

06-12-2007, 08:07 PM	#3
7T2 Active Member Join Date: Dec 2004 Location: Marysville, OH Posts: 667	Re: Hate to do this... 20" wheel question You're probably going to be more concerned with the backspacing number than the offset number. Backspacing is the measurement from the mounting surface of the wheel to the inside lip. Backspacing is measured by putting something with a straight edge, like a piece of 2 x 4, across the back of the rim, then measuring to the surface that meets the brake drum or rotor. Offset is the distance that the mounting surface of the wheel is from the exact center of the wheel. On a wheel with 0 offset, the mounting surface of the wheel is exactly in the center of the wheel. a wheel that has 45mm positive offset would have the mounting surface of the wheel 45mm towards the front of the wheel from the center. Here's a good page that explains it all with pictures: https://www.rsracing.com/tech-wheel.html __________________ 1957 GMC Ambulance 1962 Belair Wagon 1963 C80 Truck Cab FOR SALE 1969 Chevy C10 Short Bed 1972 Chevy C10 Long Bed SOLD 1996 C3500 Dually SOLD

06-12-2007, 08:33 PM	#4
randomhero472 Registered User Join Date: Feb 2006 Location: oklahoma Posts: 516	Re: Hate to do this... 20" wheel question thanks for the page... that is helpful! either one of you recomend a certain offset and backspacing, im thinking the 15mm offset & 5.3" backspacing.. but want to be 1000% sure __________________ 67' in the "build" process.. soon to be bagged, big wheels ect, finally got it back home!!

06-12-2007, 11:23 PM	#5
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 21,949	Re: Hate to do this... 20" wheel question First off..... We must know exactly what wheel you plan to use to offer correct info ....... 5.3"BS for the fronts. The rears are going to depend on what rear end you now have: Is it a 67-70 w/5-lug axles or a true 71-72 5-lug? The 71-72 rear is .75" wider on each side & will effect BS requirements. More than likely you will also need the 5.3"BS but if you have the shorter rear housing, it may allow the tires to rub on the inner tubs. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.* Last edited by SCOTI; 06-12-2007 at 11:25 PM.

06-12-2007, 11:38 PM	#6
randomhero472 Registered User Join Date: Feb 2006 Location: oklahoma Posts: 516	Re: Hate to do this... 20" wheel question i didnt mention, i could and probably will just go w/an 22x8.5" rear wheel to keep things a little narrorer back there, would that solve the rubbing issue if there was any scoti? also how do i tell what year rear end i have? __________________ 67' in the "build" process.. soon to be bagged, big wheels ect, finally got it back home!!

06-13-2007, 09:36 AM	#7
skunkwerx Registered User Join Date: Oct 2006 Location: oklahoma Posts: 238	Re: Hate to do this... 20" wheel question is your rear 5 or 6 lug,if it a 5 lug it should be a 71 or 72,if its a 6 than a 67-70.

06-13-2007, 10:22 AM	#8
CUSTOM 72 Registered User Join Date: Feb 2007 Location: winfield bc Posts: 54	Re: Hate to do this... 20" wheel question I JUST FINISHED INSTALLING MY BOLT ON AIR RIDE SYSTEM ( VERY VERY COOL ) I'M RUNNING FRONTS 265/40 20" -- 285/35/22" ALL RIMS HAVE A 14mm BACK SPACE, I'M ALSO RUNNING A 1" SPACER ON THE REARS. WHEN I SLAM THE TRUCK THE REAR FRAME STITS ON THE DIF AND THE TIRES JUST TOUCH THE INNER WHEEL WELL -- I HAVE NOT INSTALLED MY FT INNERS YET BUT IT LOOKS LIKE IT JUST MIGHT FIT. I HOPE THIS HELPS. __________________ 1972 c/10 Custom, Long Box, 350 Small Block, Auto 3 Speed, Custom Wood box, Full Air Ride, 3" C-Notch, 20" Front & 22" Rear Tires, Snow White Paint, PT Crusher Handles,

06-13-2007, 02:18 PM	#10
randomhero472 Registered User Join Date: Feb 2006 Location: oklahoma Posts: 516	Re: Hate to do this... 20" wheel question custom.. what width rims are you running, and you think if i went with a 22x9.5 in the rear i could get away w/o using a spacer? __________________ 67' in the "build" process.. soon to be bagged, big wheels ect, finally got it back home!!

06-13-2007, 02:26 PM	#11
CUSTOM 72 Registered User Join Date: Feb 2007 Location: winfield bc Posts: 54	Re: Hate to do this... 20" wheel question Randomhero472 I'm Running A 22" X 9.5 Rear -- With Out The Spacer The Tire Rides Very Close To The Inside Tub - I Recomend The Spacer __________________ 1972 c/10 Custom, Long Box, 350 Small Block, Auto 3 Speed, Custom Wood box, Full Air Ride, 3" C-Notch, 20" Front & 22" Rear Tires, Snow White Paint, PT Crusher Handles,

06-13-2007, 02:37 PM	#12
72 Cheyenne402 Registered User Join Date: Feb 2005 Location: Texas Posts: 581	Re: Hate to do this... 20" wheel question I'm going to try these guys for a 5-5 to 5-5, 1" wheel adaptor. These guys use 6061-T6 billet aluminum and are made here in the USA. here is the link http://www.wheeladapter.com/home.asp __________________ 1972 Cheyenne 402 LWB 2005 Silverado X-Cab 5.3L 2004 John Deere L120 20HP B&S Last edited by 72 Cheyenne402; 06-13-2007 at 02:38 PM.

06-13-2007, 02:43 PM	#13
itsmike2k Registered User Join Date: Apr 2007 Location: Vegas Posts: 225	Re: Hate to do this... 20" wheel question Tire size has alot to do with it also, a 285 tire has almost 11.5" section width, so that another 1" on each side of a 9.5" wheel.. But a 5.5" is alot of back spacing on a 9.5" wheel.. It seems like to me a zero offset works best which would be 4.75" on a 9.5" wheel.. __________________ Mike 1972 LT1/4l60e Short Bed ART Front and Rear Strong Arms http://www.67-72chevytrucks.com/vboa...50#post2151750

06-13-2007, 05:41 PM	#14
72 Cheyenne402 Registered User Join Date: Feb 2005 Location: Texas Posts: 581	Re: Hate to do this... 20" wheel question What size tire to run on 18x8 & 20x8.5 any advice? __________________ 1972 Cheyenne 402 LWB 2005 Silverado X-Cab 5.3L 2004 John Deere L120 20HP B&S



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