Biggest tires on my 72, K-20? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Daubs** · 08-25-2005, 08:13 PM

She's running 265's right now and looking like 285's will fit with no problem (16" rims). How much larger can I go without getting in to a lift or any body mods (cutting sheet metal)?

**hilljob26** · 08-25-2005, 08:38 PM

You Might Be Able To Fit A 305/70r16,they Are About The Same As 33's And They Usually Fit

Sooner1970_K10 · 08-25-2005, 08:56 PM

Quote:

Originally Posted by Daubs

She's running 265's right now and looking like 285's will fit with no problem (16" rims). How much larger can I go without getting in to a lift or any body mods (cutting sheet metal)?

I was able to put 33 x 12.50 x 15 with 8 inch rims on my 1970 k10

**JIMs70GMC** · 08-25-2005, 09:30 PM

I'd agree what hurts is the width of the rim. If you can stay with an 7-8" rim you should have no problems with a 33" tire. meaning a 33-9.5 on 7" rim or as wide as a 33-12.5 on an 8" wide rim.

al's71gmc · 08-26-2005, 02:47 AM

I wouldn't put the 305/70/16's (same as a 33/12.50/16), on without a lift unless you don't plan on doing much wheeling. You won't have much clearance when turning and if you hit much of a bump at the same time they will hit the wheel wells. My .02
Al

**special-K** · 08-26-2005, 07:57 AM

I have 285/75 Swampers on 8" rims on a truck that sits up a bit.Either add-a-leafs or spring shop job.These tires are nubby on the side and they`ll rub (no damage) a bit in certain turns like going into an uphill driveway.But,the shocks are way past shot.They are just things with bolts at each end.I have a lift/shocks to go on it.

earl87gta · 08-26-2005, 12:25 PM

I would get a set of ord zero rates they will give you 1in of lift and then run the 33 12.50. if they still end up a little to big never know how much your springs have sedled you can get exstended spring shackles for the front that will give you a little more lift and use an air shock in the rear or mabe a helper spring.

72 Cheyenne K20 · 08-26-2005, 03:58 PM

I've been looking for the same answer. I have a 72 Cheyenne 3/4 ton 4x4 that has 305/70/16's on it now, but has a 4" lift right now, I hope it won't rub when I take the lift out, I think the 3/4 spring will keep it high enough. I also have a 72 CST Blazer that I just got factory rally's for (15x8's). I think I'm going to run 32/11.50's on them. I shouldn't have to worry about rubbing.

Scott

08-25-2005, 08:13 PM	#1
Daubs Registered User Join Date: Jan 2005 Location: Eastern Nebraska Posts: 613	Biggest tires on my 72, K-20? She's running 265's right now and looking like 285's will fit with no problem (16" rims). How much larger can I go without getting in to a lift or any body mods (cutting sheet metal)? __________________ '72 Chevy K-20 Crate 350, SM465, 4.10's

08-25-2005, 08:38 PM	#2
hilljob26 Registered User Join Date: Dec 2004 Location: Gypsum Kansas 67448 Posts: 1,681	You Might Be Able To Fit A 305/70r16,they Are About The Same As 33's And They Usually Fit __________________ 21 2500hd duramax 58 apache HILLJOB GRAPHIX--for all your graphic needs My build thread http://67-72chevytrucks.com/vboard/s...d.php?t=542497 LS ENGINE SWAP INFORMATION THREAD http://67-72chevytrucks.com/vboard/s...d.php?t=377348 4l60 to an NP205 http://67-72chevytrucks.com/vboard/s...43#post3697343

08-25-2005, 09:30 PM	#4
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I'd agree what hurts is the width of the rim. If you can stay with an 7-8" rim you should have no problems with a 33" tire. meaning a 33-9.5 on 7" rim or as wide as a 33-12.5 on an 8" wide rim. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm Last edited by JIMs70GMC; 08-25-2005 at 09:32 PM.

08-26-2005, 02:47 AM	#5
al's71gmc 4 eyed fever Join Date: Jul 2005 Location: Eureka, Nevada Posts: 500	I wouldn't put the 305/70/16's (same as a 33/12.50/16), on without a lift unless you don't plan on doing much wheeling. You won't have much clearance when turning and if you hit much of a bump at the same time they will hit the wheel wells. My .02 Al __________________ 1971 GMC 2500 4x4 1972 GMC Sierra Grande 1/2 t 4x4-#1 son's truck. Recently completed resto. 4 YO daughter," Daddy, I like your truck better than Mom's." (2000 F350-ranch truck) Smart kid!!

08-26-2005, 07:57 AM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	I have 285/75 Swampers on 8" rims on a truck that sits up a bit.Either add-a-leafs or spring shop job.These tires are nubby on the side and they`ll rub (no damage) a bit in certain turns like going into an uphill driveway.But,the shocks are way past shot.They are just things with bolts at each end.I have a lift/shocks to go on it. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

08-26-2005, 12:25 PM	#7
earl87gta Senior Member Join Date: Dec 2003 Location: Kingsport TN Posts: 4,641	I would get a set of ord zero rates they will give you 1in of lift and then run the 33 12.50. if they still end up a little to big never know how much your springs have sedled you can get exstended spring shackles for the front that will give you a little more lift and use an air shock in the rear or mabe a helper spring. __________________ Earl 68 2500 4x4 GMC Burb

08-26-2005, 03:58 PM	#8
72 Cheyenne K20 Registered User Join Date: Feb 2003 Location: Staunton, Virginia Posts: 554	I've been looking for the same answer. I have a 72 Cheyenne 3/4 ton 4x4 that has 305/70/16's on it now, but has a 4" lift right now, I hope it won't rub when I take the lift out, I think the 3/4 spring will keep it high enough. I also have a 72 CST Blazer that I just got factory rally's for (15x8's). I think I'm going to run 32/11.50's on them. I shouldn't have to worry about rubbing. Scott



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