# Tire size question



## tacovic (Sep 5, 2012)

Would a 285/70/17 be too big/wide of a tire to run for plowing on my 07 OBS duramax? Also, would they have any fitment issues. I am getting a leveling kit installed for the added weight of my new 8.2 boss V.


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## Plowtoy (Dec 15, 2001)

Is "fitment" really a word? Not sure of the tire question, but a leveling kit wont help with the weight of the plow, it will just make the truck ride level when the plows not on. If you need additional support in the front end, I would suggest Timbrens ( www.Timbren.com ). I wouldn't go with out them on IFS any more


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## Holland (Aug 18, 2010)

Might have to trim the front valence a bit to clear when your turning.


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## tacovic (Sep 5, 2012)

Plowtoy;1496310 said:


> Is "fitment" really a word? Not sure of the tire question, but a leveling kit wont help with the weight of the plow, it will just make the truck ride level when the plows not on. If you need additional support in the front end, I would suggest Timbrens ( www.Timbren.com ). I wouldn't go with out them on IFS any more


Not quite sure if it is a word or not, just threw it out there. My question was if that size of tires would be too wide/tall for effectively plowing snow.


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## oldbluehairhemi (Oct 22, 2011)

yes it is a word. there are plenty of guys out there plowing with 285's.


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## the05goat (Sep 28, 2012)

I have an 03 same body style, I put leveling kit in, and I'm clearing 315/70/17 with very minor trim on lower valance, to plow toy I disagree when you crank up the torsion keys you increase your spring rate (torsion bar is your spring) and reduce the amount of drop to the front end. However this does affect the ride cranked up the truck rides like an 80's p/u with leaf springs on all four corners. Timbrens are the right way to do it but this will work. You should be able to clear 285's with just cranking your stock keys.


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## Plowtoy (Dec 15, 2001)

the05goat;1496486 said:


> I have an 03 same body style, I put leveling kit in, and I'm clearing 315/70/17 with very minor trim on lower valance, to plow toy I disagree when you crank up the torsion keys you increase your spring rate (torsion bar is your spring) and reduce the amount of drop to the front end. However this does affect the ride cranked up the truck rides like an 80's p/u with leaf springs on all four corners. Timbrens are the right way to do it but this will work. You should be able to clear 285's with just cranking your stock keys.


I have done it both ways (although I didn't make any statement about torsion bars). It also changes your alignment angles when you crank up your bars. The added stress to your front suspension parts is also a factor when doing this. Also, I'm not sure of the 3/4 tons in 07, but I'm pretty sure the half tons didn't have torsion bars


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## crazyboy (Feb 3, 2009)

Plowtoy;1496602 said:


> I have done it both ways (although I didn't make any statement about torsion bars). It also changes your alignment angles when you crank up your bars. The added stress to your front suspension parts is also a factor when doing this. Also, I'm not sure of the 3/4 tons in 07, but I'm pretty sure the half tons didn't have torsion bars


A lot of people get crazy with cranking, and disregard their CV angles. Keep an eye on the CV angles and keep them low, and get an alignment and it should be fine.


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## brad96z28 (Aug 21, 2005)

oldbluehairhemi;1496403 said:


> yes it is a word. there are plenty of guys out there plowing with 285's.


I have been plowing with 285s for years stock keys I would never waste my money on aftermarket keys. A few turns do not affect the alignment that much you wont notice anymore tire wear then you do now.


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## bigthom (Oct 14, 2010)

dude i run 315 70 17 in the snow... loce em. they r old hummer h2 rims and tires btw they would boolt up to ur d max if its tall enough


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## oldbluehairhemi (Oct 22, 2011)

bigthom;1496670 said:


> dude i run 315 70 17 in the snow... loce em. they r old hummer h2 rims and tires btw they would boolt up to ur d max if its tall enough


that's right.... go big or go home:laughing:


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## tuney443 (Jun 25, 2006)

Plowtoy;1496602 said:


> I have done it both ways (although I didn't make any statement about torsion bars). It also changes your alignment angles when you crank up your bars. The added stress to your front suspension parts is also a factor when doing this. Also, I'm not sure of the 3/4 tons in 07, but I'm pretty sure the half tons didn't have torsion bars


You really don't want to go past 5 turns on your bars.All late model GM trucks--1500-3500's have IFS with torsion bars.


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## Plowtoy (Dec 15, 2001)

tuney443;1496794 said:


> You really don't want to go past 5 turns on your bars.All late model GM trucks--1500-3500's have IFS with torsion bars.


What year did they switch over to coil overs? I have one that I work on occasionally that always rides down hill, they wanted me to level it out by turning up the torsion bars and to my surprise, it didn't have any and it is 4wd. I did find a leveling kit (that would take care of their problem) but they (a government agency) didn't want to spend the money to do it.


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## brad96z28 (Aug 21, 2005)

Plowtoy;1497026 said:


> What year did they switch over to coil overs? I have one that I work on occasionally that always rides down hill, they wanted me to level it out by turning up the torsion bars and to my surprise, it didn't have any and it is 4wd. I did find a leveling kit (that would take care of their problem) but they (a government agency) didn't want to spend the money to do it.


You must be talking about a new body style half ton.


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## brad96z28 (Aug 21, 2005)

tuney443;1496794 said:


> You really don't want to go past 5 turns on your bars.All late model GM trucks--1500-3500's have IFS with torsion bars.


And why is that. There are lots of different spring rates bars on these trucks some take alot more tunrs then others. Ive done some 4 some 6 some even more If you have a long enough shock and ur angles are good what are you gona hurt? Some come from the factory in a major nose dive and could take 6 turns depending on the bars just to get them near level.


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## BigJ (Oct 17, 2008)

I have an 07 new body style and put a level kit right away when it was new. Now 5 yrs later the ride is horrible because the stock shocks get pulled too far and go to hell. In hindsight I should have left it stock and went timbrens. Oh, I run 235 75 and my tires rub when the plow is up as i still bdont have timbrens.


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## tuney443 (Jun 25, 2006)

brad96z28;1497192 said:


> And why is that. There are lots of different spring rates bars on these trucks some take alot more tunrs then others. Ive done some 4 some 6 some even more If you have a long enough shock and ur angles are good what are you gona hurt? Some come from the factory in a major nose dive and could take 6 turns depending on the bars just to get them near level.


Just being conservative that's all so as not to stress front end components and needing alignments more often.Only a true alignment mechanic knows FOR SURE what you really have done to your ride and after talking to a few,4-5 turns maximum,generally speaking,is considered OK.You want more--be my guest.


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## REAPER (Nov 23, 2004)

BigJ;1497244 said:


> I have an 07 new body style and put a level kit right away when it was new. Now 5 yrs later the ride is horrible because the stock shocks get pulled too far and go to hell. In hindsight I should have left it stock and went timbrens. Oh, I run 235 75 and my tires rub when the plow is up as i still bdont have timbrens.


When I got the Cognito leveling kit it came with 2" shock extenders replacements for the OEM 1" ones that came on the truck. They bolted right up to where the original ones were. Look around and you can get em I Believe for about $40 bucks separately.

http://www.cognitomotorsports.com/products/c548/Shock_Extenders.html


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## theholycow (Nov 29, 2002)

brad96z28;1497186 said:


> You must be talking about a new body style half ton.





BigJ;1497244 said:


> I have an 07 new body style and put a level kit right away when it was new. Now 5 yrs later the ride is horrible because the stock shocks get pulled too far and go to hell. In hindsight I should have left it stock and went timbrens.


The "new body style" terminology has become vague...on some forums the latest style is "new new body style", as "new body style" has been in use for ten years to describe what _used to be_ the new body style and changing that would make it difficult to search. Might I recommend using GM's series numbers? GMT800, GMT900, etc.



> Oh, I run 235 75 and my tires rub when the plow is up as i still bdont have timbrens.


When I see 235/75 I think of the ultra-common 235/75-15 tires used on compact pickups. What rim diameter are you using?


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## buddymanzpop (Nov 14, 2009)

Plowtoy;1496310 said:


> Is "fitment" really a word? Not sure of the tire question, but a leveling kit wont help with the weight of the plow, it will just make the truck ride level when the plows not on. If you need additional support in the front end, I would suggest Timbrens ( www.Timbren.com ). I wouldn't go with out them on IFS any more


"Fitment" is a word but it is a noun meaning equipment or furnishings. Has nothing to do with size or proper fit. Good question plowtoy, I had to look it up out of curiosity.


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## brad96z28 (Aug 21, 2005)

tuney443;1497265 said:


> Just being conservative that's all so as not to stress front end components and needing alignments more often.Only a true alignment mechanic knows FOR SURE what you really have done to your ride and after talking to a few,4-5 turns maximum,generally speaking,is considered OK.You want more--be my guest.


I worked at an alignment shop for 5 years. Before recently opening my own place.I Have gone more many a many times its not an issue. Like I said I have had to go more turns then that just to get a truck to sit level. But you do need to watch the angles, extreme angles will cause pre mature wear. I think I am between 4 and 6 turns now from stock on my own truck. Still have 3 out of the 4 original balljoints. Tie rods, I wont go there they all suck.Ive seem a few half tons with worn out bars that have been 10 turns and still wont sit level.


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## tuney443 (Jun 25, 2006)

brad96z28;1497421 said:


> I worked at an alignment shop for 5 years. Before recently opening my own place.I Have gone more many a many times its not an issue. Like I said I have had to go more turns then that just to get a truck to sit level. But you do need to watch the angles, extreme angles will cause pre mature wear. I think I am between 4 and 6 turns now from stock on my own truck. Still have 3 out of the 4 original balljoints. Tie rods, I wont go there they all suck.Ive seem a few half tons with worn out bars that have been 10 turns and still wont sit level.


Thanks,but I'll just stick to my own advice.Around my part of the world,a truck is supposed to sit slightly nose down.To each their own.


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## brad96z28 (Aug 21, 2005)

tuney443;1497585 said:


> Thanks,but I'll just stick to my own advice.Around my part of the world,a truck is supposed to sit slightly nose down.To each their own.


Must look great with a plow on it.


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## the05goat (Sep 28, 2012)

leveling keys minor crank and add a leaf in rear, with new bilstein 5100 series shocks so i dont need the extensions.


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## the05goat (Sep 28, 2012)

Oh sorry these are 305/70/17 nit to terra grapplers


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## tuney443 (Jun 25, 2006)

brad96z28;1497641 said:


> Must look great with a plow on it.


With my plow on,it does,but then again I'm not out to win any beauty contests.It's a working truck that makes me money and that's the bottom line.Thanks for asking though.


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