37" tires

[chris15706]

I had a 2008 sierra 1500 lifted with 35's and regeared to 4.56 with a trutrac and black bear tune. I know that's a different truck but in my opinion if you want 37's get a 2500. Even 35's are hard on everything for a half ton long term. People that don't put on a lot of miles or trade in their truck every year or two will disagree though.

If none of that matters to you regear for the fun factor.

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[L86 All Terrain]

If you have a 6.2L All Terrain you will have 3.23 gears, not the 3.42 gears. The 3.42 ratio is only available with the 6.2L, 8L90e and NHT (Max Towing) package, which you can't spec on the All Terrain trim. 

 

I noticed a huge loss just going to a new tire on mine, 2-3mpg loss on stock wheels going to a 33" tire. Power is noticeably down because each tire/wheel is now 25lbs heavier than the stock bologna skins. I think I would be considering a gear swap at the 35" mark, so I would definitely go to a 3.42 for a 37" tire. You don't need to gear too much as your transmission ratios are too close to justify something like a 4.10 gear. Most of the gearing now is done in the transmission so the driving attributes are less dependant on the FD ratio than they were with the old wide-spread 4 speeds. A small gear change will make a big difference in these new 8+ speed transmissions. I would say if you are set on a 37" mount them, drive it, then decide if you can live with the power and fuel economy loss before re-gearing but it would make the truck easier to live with. 

[Jacoby]

12 minutes ago, L86 All Terrain said:

If you have a 6.2L All Terrain you will have 3.23 gears, not the 3.42 gears. The 3.42 ratio is only available with the 6.2L, 8L90e and NHT (Max Towing) package, which you can't spec on the All Terrain trim. 

 

I noticed a huge loss just going to a new tire on mine, 2-3mpg loss on stock wheels going to a 33" tire. Power is noticeably down because each tire/wheel is now 25lbs heavier than the stock bologna skins. I think I would be considering a gear swap at the 35" mark, so I would definitely go to a 3.42 for a 37" tire. You don't need to gear too much as your transmission ratios are too close to justify something like a 4.10 gear. Most of the gearing now is done in the transmission so the driving attributes are less dependant on the FD ratio than they were with the old wide-spread 4 speeds. A small gear change will make a big difference in these new 8+ speed transmissions. I would say if you are set on a 37" mount them, drive it, then decide if you can live with the power and fuel economy loss before re-gearing but it would make the truck easier to live with. 

OP has 2014 so I doubt he has an 8 speed.  And going from a 3.23 to a 3.42 will make no difference at all.  A 4.10 would be a lot better and a 4.56 would be best. 

 

That's just my OPINION.  Just stating that so the cry babies wont have a fit

[country_09]

If you don’t drive it much then I wouldn’t worry about gearing. I’d be more worried about if they’ll fit or not 

[doozer78]

If you have a 6.2L All Terrain you will have 3.23 gears, not the 3.42 gears. The 3.42 ratio is only available with the 6.2L, 8L90e and NHT (Max Towing) package, which you can't spec on the All Terrain trim. 
 
I noticed a huge loss just going to a new tire on mine, 2-3mpg loss on stock wheels going to a 33" tire. Power is noticeably down because each tire/wheel is now 25lbs heavier than the stock bologna skins. I think I would be considering a gear swap at the 35" mark, so I would definitely go to a 3.42 for a 37" tire. You don't need to gear too much as your transmission ratios are too close to justify something like a 4.10 gear. Most of the gearing now is done in the transmission so the driving attributes are less dependant on the FD ratio than they were with the old wide-spread 4 speeds. A small gear change will make a big difference in these new 8+ speed transmissions. I would say if you are set on a 37" mount them, drive it, then decide if you can live with the power and fuel economy loss before re-gearing but it would make the truck easier to live with. 

Just checked I have the Gu6 code which = the 3.42 gears. Not sure where you got the above info from...

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[L86 All Terrain]

17 hours ago, doozer78 said:

Just checked I have the Gu6 code which = the 3.42 gears. Not sure where you got the above info from...

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I skimmed over or misread that the OP had a 2015+, not a 2014. The 2014's only had the 6L80e available for the 6.2L if I remember right. My info pertains to 8L90e equipped trucks only. My bad. 

[doozer78]

Gotcha yes mine is a 2014 model so it must of been available then

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[gearheadesw]

Put on those 37's, lets see this. With the amount of driving that you do, you'll only notice the difference in looks.

[doozer78]

It may be a while still but wanted some input first

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[gearheadesw]

You have 35's now, how does it go? If  you fit them, that's half the battle. You truly drive so little, that the extra wear won't effect you like a daily driver.

 

[Mike GMC]

What do you use the truck for?  Why do you want 37's?  If it's just looks, go for it as is without gears.  If you tow or use the truck off-road, re-gear and look to strengthen the drivetrain.  37's will break stuff off-road, particularly in the front axle.  Also remember that the higher numeric gear ratios are not as strong due to smaller pinion gears.

[doozer78]

I have no complaints with the 35s now and how it runs. I initially had a 14 Silverado which was a daily driver and the engine blew. So after the battle I had with that the dealer I bought it from basically gave me what I paid for it on trade in and that's when I took the 14 Allterrain. In between that time I also acquired a car to commute to and from work which I still use therefore I don't drive the truck on a daily basis. I drive it primarily in the nicer weather months and when I need to haul bigger items that i can put in the bed. I do some occasional Towing but it's very rare. The truck originally came from Canada so the less I have to drive it in the winter months and keep the salt off of it the better for me since i plan on keeping it for a while. I see no point driving it to work 7 miles one way and then driving it right back home and parking it on a daily basis. I like having a nicer vehicle that I can take out on the weekends and on nice days or evenings. I do think if I get 37s at some point it will give the truck a little beefier look. I'm not dead set on doing it it's just he thought I had in the back of my head for when the time comes

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[L86 All Terrain]

12 minutes ago, doozer78 said:

I have no complaints with the 35s now and how it runs. I initially had a 14 Silverado which was a daily driver and the engine blew. So after the battle I had with that the dealer I bought it from basically gave me what I paid for it on trade in and that's when I took the 14 Allterrain. In between that time I also acquired a car to commute to and from work which I still use therefore I don't drive the truck on a daily basis. I drive it primarily in the nicer weather months and when I need to haul bigger items that i can put in the bed. I do some occasional Towing but it's very rare. The truck originally came from Canada so the less I have to drive it in the winter months and keep the salt off of it the better for me since i plan on keeping it for a while. I see no point driving it to work 7 miles one way and then driving it right back home and parking it on a daily basis. I like having a nicer vehicle that I can take out on the weekends and on nice days or evenings. I do think if I get 37s at some point it will give the truck a little beefier look. I'm not dead set on doing it it's just he thought I had in the back of my head for when the time comes

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You sound like me. Mine is currently wintering in the garage as well. Got to love Ontario's magnesium chlorate. It will rot out parked to close to the stuff, never mind bathed in it daily. I should sell mine and buy a Corvette honestly for what I do with it. If I have a show pony it might as well be something special rather than my dubbed "Canadian Corvette" 6.2L truck. 

[doozer78]

You sound like me. Mine is currently wintering in the garage as well. Got to love Ontario's magnesium chlorate. It will rot out parked to close to the stuff, never mind bathed in it daily. I should sell mine and buy a Corvette honestly for what I do with it. If I have a show pony it might as well be something special rather than my dubbed "Canadian Corvette" 6.2L truck. 

Im from Pittsburgh pa area and we have our share of salt use in winter months so if I can keep it away I will

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