Tires with 3.08 gears?

jerseygti337 · November 16, 2015

Hi everyone, I'm ready to put new tires on my 14 Silverado and was wondering if 275/70/18 will be to much for the 3.08 gears. I don't do any towing with this truck and there's no mountains in south NJ.

HondaHawkGT · November 17, 2015

I run 33's with the 3.08 gears. The transmission has low enough gearing that you won't have a problem. The shift points are terrible though. You'll want to get the shift points changed with a tune or get good at shifting manually.

After my BB tune, my truck feels faster with 10-ply 33's than it did with the stock tune and street tires.

jerseygti337 · November 17, 2015

Thanks, anyone else?

black00ta · November 17, 2015

I use LT285/65R18 (32.6") 10 ply's with 3.08's - I've had them on since 300 miles and can't say I have any complaints...14,xxx miles now. the recent transfer case software update made it much more pleasant to drive overall.

jerseygti337 · November 17, 2015

I use LT285/65R18 (32.6") 10 ply's with 3.08's - I've had them on since 300 miles and can't say I have any complaints...14,xxx miles now. the recent transfer case software update made it much more pleasant to drive overall.

Do you have a tune and do you run in m5 or just drive?

black00ta · November 17, 2015

No tune, I occasionally drive around in M5 but its not necessary.

TheTunaHunter · November 17, 2015

LT275/70/18 E-Rated(10ply) DuraTracs on my CCSB w/ 3.08 - The only time I've ever really regretted the 3.08/33 combo was on a 700mile weekend up to Vermont(severe grades) The truck definitely was on a gear hunt, but driving in M5 and/or engaging tow mode both helped. Even on the beach (very soft/deep sand) hauling firewood/people/coolers and a full tool box, the truck seems fine. I do a fair amount of highway driving and consistently average 20mpg with winter blend. I've seen as high as a 26.8 avg during summer and running 93. I came from the a modded v8 Audi wagon and knew nothing about trucks coming, if i had to do it again, I'd certainly go for 3.42's.

royrjs · November 17, 2015

My truck came with 255/70/17 and 3.08; I recently upgraded to 35"s, and went to the dealer to have them change the tire setting to the max setting from the stock list, which was near a 33".

I towed these past weekend a trailer with a race vehicle for 200 miles approx, and it was kinda fine. I'm definitely changing the gear ratio to 3.73, but again I'm running 35x12.50 All Terrains with occasional towing.

I think you'll be fine having the dealer to set the new tire size (if you don't wanna mess with external tunes, that is) as you'll be rolling on something around 33" tires.

jerseygti337 · November 17, 2015

Awesome thanks a lot. Everything I read online makes you believe the truck will self destruct with anything over stock size, I'm glad it will be fine.

HondaHawkGT · November 18, 2015

My truck came with 255/70/17 and 3.08; I recently upgraded to 35"s, and went to the dealer to have them change the tire setting to the max setting from the stock list, which was near a 33".

I towed these past weekend a trailer with a race vehicle for 200 miles approx, and it was kinda fine. I'm definitely changing the gear ratio to 3.73, but again I'm running 35x12.50 All Terrains with occasional towing.

I think you'll be fine having the dealer to set the new tire size (if you don't wanna mess with external tunes, that is) as you'll be rolling on something around 33" tires.

Impressive you towed with 35's and 3.08s lol. Did you look at your trans temperature while you pulled that?

Dealers can't change the configuration for oversized tires (33's on up). GM will only allow changes between OE tire sizes. The biggest tire available is approximatelty 32".

royrjs · November 18, 2015

Impressive you towed with 35's and 3.08s lol. Did you look at your trans temperature while you pulled that?

Dealers can't change the configuration for oversized tires (33's on up). GM will only allow changes between OE tire sizes. The biggest tire available is approximatelty 32".

I actually didn't check that temp, shame on me; didn't recall one of the options from the central display is that one; engine was usually spinning at 2.5k when pulling, 3,3.5 when engine breaking, but I was shifting between tow mode and regular, I did notice in regular straights, engine would turn at 2k, with the trans probably 1 gear below what it shifted if I turned the tow mode off, engine spinning at 1.3k, pulling fine at 55mph. It was a two lane road, I couldn't go faster like going on a US Highway.

I'm not sure which tire size the guys at the dealer set, but he told me he'd go with the biggest the computer would allow him to. Speedo is still off by 10%, against the GPS from my phone

HondaHawkGT · November 18, 2015

The transmission temp is towards the bottom of the list, just after engine hours.

VinnyZ17 · November 18, 2015

I have 3.08 gears running 265/70/18 Hankook Dynapro ATMs. They are 32.6x10.7 P-rated tire. The only time I notice any difference is when the tranny is cold. Once it warms up and has cycled through the gears a time or two, it shifts pretty seamlessly. I do hate when driving in town (20-30mph) it shifts to v4 and back to v8 it has a jerk sometimes associated with it. I occasionally pull a small utility trailer and 4wheeler or now that its hunting season, a truck full of buddies to and from the duck blind, and I think it drives better with a little extra weight added. I drove 12k with factory tires and about 7k with the Hankooks with no adjustment to the computer. From the day I pulled off the lot, it says I'm at 16.9mpg. I've been looking at 275/60/20 (33x11) but just not sure.

crushNchowda · November 18, 2015

LT275/70/18 E-Rated(10ply) DuraTracs on my CCSB w/ 3.08 - The only time I've ever really regretted the 3.08/33 combo was on a 700mile weekend up to Vermont(severe grades) The truck definitely was on a gear hunt, but driving in M5 and/or engaging tow mode both helped. Even on the beach (very soft/deep sand) hauling firewood/people/coolers and a full tool box, the truck seems fine. I do a fair amount of highway driving and consistently average 20mpg with winter blend. I've seen as high as a 26.8 avg during summer and running 93. I came from the a modded v8 Audi wagon and knew nothing about trucks coming, if i had to do it again, I'd certainly go for 3.42's.

I had to respond to this because when I first bought a new truck I got a '14 Sierra 5.3 w/ 3.08 brand new one of the first on the lot, I thought (and so did the dealer) that it had 3.42 gears at first because of the weird way they list the options on the sticker. I took the truck up to Franconia notch in NH for a hiking weekend w/ my wife and literally called the dealer while I was up in the mountains there and wAs like - there's no way I can keep this truck. I ended up swapping it for a 14 5.3 3.42 and was much happier w/ that one..,,I ended up totaling it and now have a 6.2 w/ 8 speed

Truthfully if I could custom order a truck exactly how I want it would be crew cab, LONG bed, 4x4 6.2 w/ the 6 speed and 3.73 gears- not the 8 speed..,,and if we could really custom order I wish we could get the Allison 6 speed as an option in the 1/2 tons paired w/ the 6.2

TheTunaHunter · November 18, 2015

I had to respond to this because when I first bought a new truck I got a '14 Sierra 5.3 w/ 3.08 brand new one of the first on the lot, I thought (and so did the dealer) that it had 3.42 gears at first because of the weird way they list the options on the sticker. I took the truck up to Franconia notch in NH for a hiking weekend w/ my wife and literally called the dealer while I was up in the mountains there and wAs like - there's no way I can keep this truck. I ended up swapping it for a 14 5.3 3.42 and was much happier w/ that one..,,I ended up totaling it and now have a 6.2 w/ 8 speed

Truthfully if I could custom order a truck exactly how I want it would be crew cab, LONG bed, 4x4 6.2 w/ the 6 speed and 3.73 gears- not the 8 speed..,,and if we could really custom order I wish we could get the Allison 6 speed as an option in the 1/2 tons paired w/ the 6.2

I should have done my homework a little bit more, no question. That said, I have zero complaints about my truck. While I've got zero complaints, that doesn't mean I'm not always on the fence about getting a 6.2 or a 2500. Coming from a highly tuned V8/420hp+ performance car, my desires to for power/weight ratios are a bit biased.