Widest Rear Tire With Factory 12 Bolt? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Spot1984 · 06-14-2012, 11:28 PM

I have the rear lowered 6 inches. I have the factory 1970 12 bolt (C Clip elminator) I am going to mini-tub the girl. What is the widest rear tire I can go with? Also what backspace would I need? I'm jammed up here on this boys! Some pics would be helpful too. Ooo factory springs and trailing arms. Thanks!

BR3W CITY · 06-15-2012, 10:56 AM

I asked this, and ended up having to just go and measure; are you asking for the widest tire on a normal rim, or the widest rim AND tire you can stuff in there?

If you want to go as wide as you can, you'll need to have custom wheels made or ordered.
I squeezed a 15x12 with a M/T drag radial in 325. Assuming the 12 bolt is stock width, that will be about the biggest you can go (a slightly larger diameter rim might get you a tiny bit more width inside, but not much)... it requires about an 8.5" backspacing, which is deeper than some companies will do, although you can get them. It makes rear brakes a pain though, depending on the rim size (I run 15s) you may have to modify your brakes.

ProStreet68SB · 06-15-2012, 01:48 PM

We run a 31x18.5" hoosier on a minitub and smaller diameter springs.

Spot1984 · 06-15-2012, 08:18 PM

Prostreet68 what backspace are you runnin? I was wondering if 15x12 with 7.5 backspace and 325 tire would fit?

1moretoy · 11-04-2012, 12:55 PM

Quote:

Originally Posted by ProStreet68SB

We run a 31x18.5" hoosier on a minitub and smaller diameter springs.

Did you have to narrow the frame?
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spill · 11-07-2012, 08:13 AM

Quote:

Originally Posted by 1moretoy

Did you have to narrow the frame?
Posted via Mobile Device

Where u get dose rear ralley wheels
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ProStreet68SB · 11-07-2012, 09:41 AM

Quote:

Originally Posted by 1moretoy

Did you have to narrow the frame?
Posted via Mobile Device

Nope. Cut the bed back to the frame and run straight spring instead of a factory style.beehive.

Quote:

Originally Posted by spill

Where u get dose rear ralley wheels
Posted via Mobile Device

Widened factory wheels.
Posted via Mobile Device

BR3W CITY · 06-15-2012, 10:16 PM

Not sure if your slightly newer fleetsides are wider or not. I've got eh trailing arm suspension w/ jeep springs which are a tad wider.

If I would have gone with a 7.5" bs, the tire would rub into the outside of the fender.

74 stepside · 06-15-2012, 10:40 PM

315/60/15 MT drag radial on 15x10 with 5" bs on stock width 12 bolt. No tubbing needed.

ProStreet68SB · 06-16-2012, 01:30 AM

Quote:

Originally Posted by Spot1984

Prostreet68 what backspace are you runnin? I was wondering if 15x12 with 7.5 backspace and 325 tire would fit?

Quote:

Originally Posted by BR3W CITY

Not sure if your slightly newer fleetsides are wider or not. I've got eh trailing arm suspension w/ jeep springs which are a tad wider.

If I would have gone with a 7.5" bs, the tire would rub into the outside of the fender.

We're running a non tapered, we've alway assumed they were Jeep springs.

And we're running 8.75inches of backspacing.

djracer · 06-16-2012, 10:15 AM

I had 12.5 wide sportsman pro's on this old 71 with an off the shelf Centerline Telestar wheel.

This truck was not that low you would need a little more back spacing but not a ton.

limitedstreetoutlaw · 06-16-2012, 04:16 PM

Here is link to a pic i posted last year for some one asking the same kind of question. I was lazy and didn't want to find the pic and upload again lol
14 or 14.5 wide wheels with 15 inch wide tires and all stock susp. and stock width rearend that is what it had when i bought it.
http://67-72chevytrucks.com/vboard/s...12&postcount=8

spill · 11-01-2012, 08:05 PM

I have a 15x12 6"back space will it work on a 1965 chevy truck ,what is the lest back space u can have with a15x12 wheel
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**Captainfab** · 11-01-2012, 11:05 PM

Is your truck a stepside or a fleetside?

Quote:

Originally Posted by spill

I have a 15x12 6"back space will it work on a 1965 chevy truck ,what is the lest back space u can have with a15x12 wheel
Posted via Mobile Device

spill · 11-02-2012, 05:59 PM

Quote:

Originally Posted by spill

I have a 15x12 6"back space will it work on a 1965 chevy truck ,what is the lest back space u can have with a15x12 wheel
Posted via Mobile Device

Posted via Mobile Device

spill · 11-01-2012, 11:46 PM

Fleetside
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hotrod 80 · 11-02-2012, 12:19 AM

Welcome to the forum

djracer · 11-02-2012, 12:27 AM

Quote:

Originally Posted by spill

Fleetside
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What Year?

68GMCCustom · 11-02-2012, 09:33 PM

My plan is replacing the 12 bolt with a stronger rear (Dana 60 or 9.5" 14 bolt) and narrow it by 1.5-2" per side w/mini tubs and 15x12's...then 315/60-15's will fit easily.

but for now...its factory 12 bolt with new Eaton posi and 3.73 gears
they're 15x10", 4.5"b.s., with MT ET Street radials in 315/60-15

**Captainfab** · 11-02-2012, 10:57 PM

Is your 12 bolt the original 62" wide or is it the wider '63.5" width used from late '70 on up? Are you willing to widen the inner wheel wells? What size tire are you wanting to run?

spill · 11-02-2012, 11:19 PM

15"29x15.5 , later 70&up
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bigboybodry · 11-08-2012, 09:26 AM

My rear tires are a 29/15.50 15 sportsman or a 31 10.5w on a custom Holeshot 16" rim with a 10" backspace. I ordered a new set of factoy rear wheel tubs and welded them to my old ones. My frame has not been moved and I ran the factory style spring with this setup.

sleeper69 · 03-14-2013, 09:03 PM

do you guys think ill be able to run 295/50/15 with a 5.5 bs, on a 69 short bed fleetside (factory tubs) and have everything clear?

spill · 03-14-2013, 11:04 PM

Posted via Mobile Device

sleeper69 · 03-15-2013, 06:33 PM

factory 12bolt and 15 by 10 rims with either a 5 or a 5.5 bs
i seem to remember that there is around 12 or 13 in the factory tubs. the truck is in the shop being painted right now and i dont have it here to measure

06-14-2012, 11:28 PM	#1
Spot1984 Registered User Join Date: Mar 2010 Location: Grand Island, Nebraska Posts: 106	Widest Rear Tire With Factory 12 Bolt? I have the rear lowered 6 inches. I have the factory 1970 12 bolt (C Clip elminator) I am going to mini-tub the girl. What is the widest rear tire I can go with? Also what backspace would I need? I'm jammed up here on this boys! Some pics would be helpful too. Ooo factory springs and trailing arms. Thanks! __________________ 1970 Chevy C10 shortbox- 454 1970 Chevy Nova- 383 1987 Grand National

06-15-2012, 10:56 AM	#2
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Widest Rear Tire With Factory 12 Bolt? I asked this, and ended up having to just go and measure; are you asking for the widest tire on a normal rim, or the widest rim AND tire you can stuff in there? If you want to go as wide as you can, you'll need to have custom wheels made or ordered. I squeezed a 15x12 with a M/T drag radial in 325. Assuming the 12 bolt is stock width, that will be about the biggest you can go (a slightly larger diameter rim might get you a tiny bit more width inside, but not much)... it requires about an 8.5" backspacing, which is deeper than some companies will do, although you can get them. It makes rear brakes a pain though, depending on the rim size (I run 15s) you may have to modify your brakes. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

06-15-2012, 01:48 PM	#3
ProStreet68SB The Engine Whisperer Join Date: Sep 2006 Location: Ohio Posts: 770	Re: Widest Rear Tire With Factory 12 Bolt? We run a 31x18.5" hoosier on a minitub and smaller diameter springs.

06-15-2012, 08:18 PM	#4
Spot1984 Registered User Join Date: Mar 2010 Location: Grand Island, Nebraska Posts: 106	Re: Widest Rear Tire With Factory 12 Bolt? Prostreet68 what backspace are you runnin? I was wondering if 15x12 with 7.5 backspace and 325 tire would fit? __________________ 1970 Chevy C10 shortbox- 454 1970 Chevy Nova- 383 1987 Grand National

06-15-2012, 10:16 PM	#8
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: Widest Rear Tire With Factory 12 Bolt? Not sure if your slightly newer fleetsides are wider or not. I've got eh trailing arm suspension w/ jeep springs which are a tad wider. If I would have gone with a 7.5" bs, the tire would rub into the outside of the fender. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

06-15-2012, 10:40 PM	#9
74 stepside Registered User Join Date: Oct 2009 Location: SoCal Posts: 815	Re: Widest Rear Tire With Factory 12 Bolt? 315/60/15 MT drag radial on 15x10 with 5" bs on stock width 12 bolt. No tubbing needed. Attached Images

06-16-2012, 10:15 AM	#11
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,892	Re: Widest Rear Tire With Factory 12 Bolt? I had 12.5 wide sportsman pro's on this old 71 with an off the shelf Centerline Telestar wheel. This truck was not that low you would need a little more back spacing but not a ton. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

06-16-2012, 04:16 PM	#12
limitedstreetoutlaw Registered User Join Date: Jun 2009 Location: Arkoma OK Posts: 134	Re: Widest Rear Tire With Factory 12 Bolt? Here is link to a pic i posted last year for some one asking the same kind of question. I was lazy and didn't want to find the pic and upload again lol 14 or 14.5 wide wheels with 15 inch wide tires and all stock susp. and stock width rearend that is what it had when i bought it. http://67-72chevytrucks.com/vboard/s...12&postcount=8 __________________ Brandon Street Car Mafia

11-01-2012, 08:05 PM	#13
spill Registered User Join Date: Apr 2011 Location: huntsville,texas Posts: 8	Re: Widest Rear Tire With Factory 12 Bolt? I have a 15x12 6"back space will it work on a 1965 chevy truck ,what is the lest back space u can have with a15x12 wheel Posted via Mobile Device

11-01-2012, 11:46 PM	#16
spill Registered User Join Date: Apr 2011 Location: huntsville,texas Posts: 8	Re: Widest Rear Tire With Factory 12 Bolt? Fleetside Posted via Mobile Device

11-02-2012, 12:19 AM	#17
hotrod 80 mini truck racer Join Date: Aug 2006 Location: Baytown , texas Posts: 3,010	Re: Widest Rear Tire With Factory 12 Bolt? Welcome to the forum __________________ 1949 5-window 1969 Camaro 1976 Chevy Luv yellow 1978 Chevy Luv Blue 1976 Chevy Luv Black 1979 Firebird Flooded in Harvey 1999 F350 Dually 2005 GMC Sierra 4.8 RCSB 2014 Explorer (wifes) My build :http://67-72chevytrucks.com/vboard/s...d.php?t=399148 Build #2: http://67-72chevytrucks.com/vboard/s...d.php?t=653583

11-02-2012, 09:33 PM	#19
68GMCCustom Truck and auto performance nut Join Date: Feb 2007 Location: McKinney,Texas Posts: 3,848	Re: Widest Rear Tire With Factory 12 Bolt? My plan is replacing the 12 bolt with a stronger rear (Dana 60 or 9.5" 14 bolt) and narrow it by 1.5-2" per side w/mini tubs and 15x12's...then 315/60-15's will fit easily. but for now...its factory 12 bolt with new Eaton posi and 3.73 gears they're 15x10", 4.5"b.s., with MT ET Street radials in 315/60-15 __________________ Kurt - '68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy '72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close '06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD '18 Kia Sorento - wife's econo-driver '95 Chevy S10 - reg cab shortbed, LS, 4.3, auto... my '68's powertrain and chassis build -links broken A surprise phase - carb to efi -links broken

11-02-2012, 10:57 PM	#20
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Widest Rear Tire With Factory 12 Bolt? Is your 12 bolt the original 62" wide or is it the wider '63.5" width used from late '70 on up? Are you willing to widen the inner wheel wells? What size tire are you wanting to run? __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

11-02-2012, 11:19 PM	#21
spill Registered User Join Date: Apr 2011 Location: huntsville,texas Posts: 8	Re: Widest Rear Tire With Factory 12 Bolt? 15"29x15.5 , later 70&up Posted via Mobile Device

11-08-2012, 09:26 AM	#22
bigboybodry Registered User Join Date: Jul 2009 Location: Florence,Mississippi Posts: 301	Re: Widest Rear Tire With Factory 12 Bolt? My rear tires are a 29/15.50 15 sportsman or a 31 10.5w on a custom Holeshot 16" rim with a 10" backspace. I ordered a new set of factoy rear wheel tubs and welded them to my old ones. My frame has not been moved and I ran the factory style spring with this setup. Attached Images __________________ first track pass with the new motor on motor http://youtu.be/YgrJaEF_TaQ



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03-14-2013, 09:03 PM	#23
sleeper69 Registered User Join Date: Feb 2013 Location: Arundel, Maine Posts: 11	Re: Widest Rear Tire With Factory 12 Bolt? do you guys think ill be able to run 295/50/15 with a 5.5 bs, on a 69 short bed fleetside (factory tubs) and have everything clear?

03-14-2013, 11:04 PM	#24
spill Registered User Join Date: Apr 2011 Location: huntsville,texas Posts: 8	Re: Widest Rear Tire With Factory 12 Bolt? Posted via Mobile Device

03-15-2013, 06:33 PM	#25
sleeper69 Registered User Join Date: Feb 2013 Location: Arundel, Maine Posts: 11	Re: Widest Rear Tire With Factory 12 Bolt? factory 12bolt and 15 by 10 rims with either a 5 or a 5.5 bs i seem to remember that there is around 12 or 13 in the factory tubs. the truck is in the shop being painted right now and i dont have it here to measure

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