How much air to run in my 33x12.5 tires - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Destructo · 02-18-2004, 08:20 PM

I currently have 28 in the front and 25 in the back. The front tires look like their sitting all the way down on the pavement, but the rears still look like they are not sitting all the way flat even with 25 psi in them. If I get down on my knees I can see that part of the tire is still off the pavement. Should I let the air down until it starts to bulge a little bit and sits all the way down? Their on 15x8 wheels BTW.

BladeX · 02-18-2004, 11:07 PM

35psi is standard in all tires i thought.

Destructo · 02-19-2004, 01:04 AM

Yeah, for most tires that works. But with 8" wheels and 35 psi and the bigger tires it causes the middle to be raised up and not ride flat on the tread and will cause the middle to wear out fast. I think I got my front tires running pretty flat with 28 psi. But with 25 psi my rear tires don't seem to be completely on the pavement. I can still see that the edges are still off the pavement some.

Mudder · 02-19-2004, 05:06 AM

The full width of the tread should be in contact with the pavement.

smokekiki · 02-19-2004, 12:43 PM

You are on the right track.The guy I buy all my tires from set my first 4x4 up when I was 16.He filled the tires up and let air out till the tread was making contact the way it should.The psi on the side wall is max pressure.I got 53000 out of my bfg at's.WhenI took them off still had enough tread to pass pa inspection.I ran 28psi in all four on a heavy 4x4 van.

Destructo · 02-19-2004, 03:46 PM

I let it down to 21 in the rear and it looks like it still need to go down some. 28 in the front seems to be good right now, I guess the light backend on my truck and the tires being on 8" wheels their gonna have to run pretty low PSI.

Mudder · 02-19-2004, 04:06 PM

Mine are 15.50 wide and I am aired down to 20 or less in the rear. I wouldn't be doing dounuts with it that low.

Destructo · 02-19-2004, 04:17 PM

I have them at 18 now, seems low but the full tread seems to be sitting on the pavement now. Have 28 in the front though. I guess its just because of how light my backend is with 1/2 ton axles and only a spare and a tool box in the bed.

Mudder · 02-20-2004, 04:48 AM

How does it ride?

Destructo · 02-20-2004, 06:14 PM

Seems to ride good right now, seems like its a little more bouncy though.

Mudder · 02-20-2004, 06:34 PM

Remember that the lbs will change with the temp outside. I have always played around with mine to get them the way I like.

Destructo · 02-21-2004, 01:11 AM

Yeah, i'll have to remember to air them up when I load it down also. I don't suspect i'll need to worry about temp changes too much until it gets to where its going to stay warm.

4t5acp · 02-29-2004, 06:16 PM

I ran into the same problem for years with my 8" rally wheels, then finally I tried some 33x 10.5 x15" BFG A/T this last set of tires I bought and I can actually air them up to a decent level. Believe it or not they still look great too, even though they are narrower.

Mike

Destructo · 02-29-2004, 06:18 PM

I may end up going with some 15x10's when I put new tires on it, they seem like they will do a lot better on the street. I will probably end up putting some shiny wheels on it rather than the black ones and thats when i'll go to 15x10's. I got a good set of 10 inch wheels but they don't look that great.

02-18-2004, 08:20 PM	#1
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	How much air to run in my 33x12.5 tires I currently have 28 in the front and 25 in the back. The front tires look like their sitting all the way down on the pavement, but the rears still look like they are not sitting all the way flat even with 25 psi in them. If I get down on my knees I can see that part of the tire is still off the pavement. Should I let the air down until it starts to bulge a little bit and sits all the way down? Their on 15x8 wheels BTW. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-19-2004, 01:04 AM	#3
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	Yeah, for most tires that works. But with 8" wheels and 35 psi and the bigger tires it causes the middle to be raised up and not ride flat on the tread and will cause the middle to wear out fast. I think I got my front tires running pretty flat with 28 psi. But with 25 psi my rear tires don't seem to be completely on the pavement. I can still see that the edges are still off the pavement some. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-19-2004, 12:43 PM	#5
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	You are on the right track.The guy I buy all my tires from set my first 4x4 up when I was 16.He filled the tires up and let air out till the tread was making contact the way it should.The psi on the side wall is max pressure.I got 53000 out of my bfg at's.WhenI took them off still had enough tread to pass pa inspection.I ran 28psi in all four on a heavy 4x4 van. __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

02-19-2004, 03:46 PM	#6
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	I let it down to 21 in the rear and it looks like it still need to go down some. 28 in the front seems to be good right now, I guess the light backend on my truck and the tires being on 8" wheels their gonna have to run pretty low PSI. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-19-2004, 04:17 PM	#8
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	I have them at 18 now, seems low but the full tread seems to be sitting on the pavement now. Have 28 in the front though. I guess its just because of how light my backend is with 1/2 ton axles and only a spare and a tool box in the bed. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-18-2004, 11:07 PM	#2
BladeX Registered User Join Date: Dec 2003 Location: Kentucky, Ft. Campbell Posts: 287	35psi is standard in all tires i thought.

02-19-2004, 05:06 AM	#4
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	The full width of the tread should be in contact with the pavement.

02-19-2004, 04:06 PM	#7
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Mine are 15.50 wide and I am aired down to 20 or less in the rear. I wouldn't be doing dounuts with it that low.

02-20-2004, 04:48 AM	#9
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	How does it ride?

02-20-2004, 06:14 PM	#10
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	Seems to ride good right now, seems like its a little more bouncy though. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-20-2004, 06:34 PM	#11
Mudder Registered User Join Date: Feb 2001 Location: East Central, MO Posts: 11,336	Remember that the lbs will change with the temp outside. I have always played around with mine to get them the way I like.

02-21-2004, 01:11 AM	#12
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	Yeah, i'll have to remember to air them up when I load it down also. I don't suspect i'll need to worry about temp changes too much until it gets to where its going to stay warm. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

02-29-2004, 06:16 PM	#13
4t5acp Registered User Join Date: May 2003 Location: NC Posts: 66	I ran into the same problem for years with my 8" rally wheels, then finally I tried some 33x 10.5 x15" BFG A/T this last set of tires I bought and I can actually air them up to a decent level. Believe it or not they still look great too, even though they are narrower. Mike __________________ Romans 10:9-10

02-29-2004, 06:18 PM	#14
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	I may end up going with some 15x10's when I put new tires on it, they seem like they will do a lot better on the street. I will probably end up putting some shiny wheels on it rather than the black ones and thats when i'll go to 15x10's. I got a good set of 10 inch wheels but they don't look that great. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.



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