anyone rolling on 37s???

duster89 · September 29, 2014

just looking for input on running 37s. im getting a 2014 Silverado 1500 with the 5.3 this week. have been looking into the mcgaughys 7"-9" lift and set at 9 it will fit 37s. im wondering if anyone has 37s on their truck now and how bad the power/fuel economy gets running that big of tire. I think the truck only has the 3.08 gears unfortunately which definitely concerns me trying to move that heavy of a tire. I run 95% highway and an thinking of getting into the mud the odd time. I sold my 08 duramax with a 6" and 35s, and I know moving to a 1500 will not be near the power but just curious how bad it is with that sort of setup! thanks for your input

and post up some pics if you got them!

kstruckcountry · September 29, 2014

I haven't seen any 37's on a 2014 yet. But if you even go to 35's you MUST get lower gears. With 37's and 3.08's it'll be dangerously slow..

Spurshot · September 29, 2014

37s and 3.08s is a really bad idea. You're gonna want like 4.88s or 5 sumpin. Otherwise you're gonna feel like a 20% decrease in power. So, swaggin that your 355 hp 5.3L is probably putting like 300 hp at the rear wheels from what I could find on the net, you're going feel like you lost 60 hp.

KMGZ400 · September 29, 2014

^^ this.. No way you can turn 37's with 308's.. You NEED to regear

blackout07 · September 29, 2014

You do not have to regear. You should, but it's not like your truck will be incapable of operating. Ideally you will want to do so to maintain driveability and take the stress off the transmission though. But it's definately something you could wait to do. 4.88 will put you close to stock. Either way expect a serious hit to MPG. If I drive conservatively I can get 12 in town. Typically I'm in the 10-11 range. I have 37s on 20x10 wheels with 4.88s.

Big Whiskey · September 29, 2014

Agreed. That thing is gonna be a turd with 37's and 3:08's. 6th gear will be basically useless....maybe even 5th. You'll probably need 4:88's to get the driving manners back where you want it. And for tire clearance, I think you'll be ok if you're at 8-9" lift. Guys are running 35's with a 6" all day, so 37's will actually only be 1" closer to your fenders than a 35".

KMGZ400 · September 29, 2014

I have a truck with 3.08's and I know the way it drives...you'd toast the trans in 10k

fuse36 · September 30, 2014

I wouldn't even put a lift or 35's with 3.08. Dude that truck will down shift all day especially driving over 65

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Kent2500 · September 30, 2014

A interesting video titled "FUBAR BIG TIRES KILLS TRANSMISSIONS" related to big tires and replacing transmissions. The guy presenting is pretty cool if you haven't seen the powerstrokehelp videos on youtube.

Obviously this is not an exact match to the OP scenario, but close and worth a watch (even if for fun).

blackout07 · September 30, 2014

I ran 33s and 35s for like 3 or 4 years with 3.42s before going to 4.88s. Without doing any math, I'd say thats comparable to .08s and a 6spd. These trucks won't grenade right away...I promise. I have seen many a truck run 37s with 3.42s with the 4spd tranny as well. Was it a dog? Yes. Should they regear? Yes. Shoukd they stay the hell away from the mud? Absolutely!

duster89 · October 1, 2014

haha funny how everyone gave the exact same response as I was expecting. I wouldn't have a problem regearing, except everywhere I seem to research its showing the carriers on the 2014 1500s only will fit up to a 3.42.. so in order to regear it would involve a LOT more then just jamming a new set in there. I have a set of 35's currently off the my old truck, so guess ill be sticking to those instead of the 37's. anyone first hand regeared a 14 yet?

CAtaylor · October 1, 2014

haha funny how everyone gave the exact same response as I was expecting. I wouldn't have a problem regearing, except everywhere I seem to research its showing the carriers on the 2014 1500s only will fit up to a 3.42.. so in order to regear it would involve a LOT more then just jamming a new set in there. I have a set of 35's currently off the my old truck, so guess ill be sticking to those instead of the 37's. anyone first hand regeared a 14 yet?

Yep, see the link below. As far as I know only me and one other guy have done it and I haven't seen him on here in a while. Find a good shop.

http://www.gm-trucks.com/forums/topic/158167-gear-change-95-12-bolt/

SouthernSilveradoGuy85 · October 1, 2014

Ya regear. To roughly equal the performance of the 3.08s then you'd need 3.42 for 35s and 3.73 for 37s. But, being that 3.08 is too high of a gear anyways then get in 4s, at least 4.11s. Mine has 3.08s and I plan to regear them to 3.73 or at least 3.42 and I don't even plan on a lift.