turbo dreams

i would like to hear from some people who have actually towed a decent bit with 315 tires. preferably with an auto and 3:55 gears. i've ran the 315's before but didn't hardly tow that much with them. just looking for opinions on 315's with stock auto and 3:55 gears. i tow about 2K to 5K tops. so it is very light towing. just looking for other in put. did a search and didn't find all i was after. thanks

blown32

I have been towing 8K box (very bad air flow) with 3.73s and 315s. It does alright but 4.10 would be better (if I had it to do again). With only 2 - 5k towing you should have no problems unless you are towing a sail.

BEHRMAN

3.55 are not good for towing, much less adding 315's to it. Should do fine with a couple thousand lbs. but may run a little warm if you run a pressure box due to the gearing/load.

Homestead

I run 3:55's and 315's and tow just fine. Anywhere from 1000 lbs to 10,000lbs. Truck most of the time doesn't even know the trailer is there. I'm a 6spd not an auto but just watch your temps, keep your tire pressures up and go for it.

Your not driving a race car in the first place, so keep your weights and pressures inside the trucks parameters and just drive it.

Buckshotmckee

Before I started BOMBing the truck, it was real a dog, especially in 5th on any sort of hill or incline. With the BOMBs you have started on your truck you will have no problems.

ddestruel

315'sn and 3.54's are fine with a 12v i towed upwards of 20k lbs regularly with em and liked the gearing that way.

i could pull 7-8% grade hills in direct at 65 mph no problems temp wise nor power wise and then wing down the highway at 65-75 mph loaded and pull 1800+/- rpms or at 55-60 mph im pulling 2100 rpm in direct so it gave me a nice medium for highway cruising/towing. When i wanted to pass someone instead of being tached out whe i would downshift to pass someone at 2400-2600 rpm at 60mph in direct with the smaller tires and/or my 4.10's, with the 3.54's and 315's i had rpms left to playwith and could wind the truck right up and get around the pokey 1.

I had 4.10's with the 315's and with 285's before swapping to the 3.54's and aside from the engine winding up faster and cruising at a higher rpm i noticed very little change in towability nor loss power. my fuel consumption was down with the taller tires also.

FYI i have the fuel records for the last 130k miles of that trucks service life pulling the 20k+ lbs gooseneck trailer 75% of the time all over montana, idaho, nevada washington, wyoming and colorado, alot of high moutain passes in there and i really liked the package

DanTana

I run BFG 315s x 4.10s and they do great.

turbo dreams

i am mainly worried about my tranny. i've heard the 315's with the 3:55 rear isn't too good. i know 4:10's would be better but like ddestruel said is there really a big difference? there is alot of hype about the 47re but i think it is a good tranny. i would like to make it bulletproof so i don't have to worry about towing problems. would like to keep the ez and get some mild injectors with a bigger compressor housing. something good for towing and daily driving. no interest in racing. i tow lighty and it is mostly during hunting season. how would the tranny do?

J BODY

IMHO that tire and gear is a really bad towing combo. I KNOW that I wouldn't be happy with the results. My boat is approx 5k and the race rig 8000-8500. My truck had 4.10's, but I installed 3.55 gears. It was either keep the 4.10's and go with big tires to get the rpms down, or stay with a 245/265 series tire and change the gears. I opted for the gear change as I'm not comfortable with towing heavy in extreme heat with large tires. Even with the factory 265 I have to run pretty fast to keep a decent rpm in od while towing. For my application a 3.7 gear would have been perfect. I was trying to get as close to that fine line "towing power vs highway mpg not towing" as I could for my application.

turbo dreams

so what size tire do you run now? was there a big difference to you from 4:10 to 3:55 in the same tire size?

J BODY

I run the factory equip 265 tires. Empty I can run 75 at around 2K rpm which will still get me 19 mpg. Towing it still does pretty good, but with the grades down here I could still use a couple hundred more rpm. 245 tires would probably put it in a sweet spot, but I'm not sure I could deal with the "pizza cutter" tires (little show pony in all of us I guess). When the truck had the 4.10's I would end up going up our local pass at 40-45mph with the od locked out. With the 3.55 I can get the job done at 55 mph od locked out at around 2300 rpm. I also didn't like the drivability with the 4.10 gears. Driving 75-80 it was really buzzing (2400 rpm). With the same tire I dropped 400 rpm (od/lockup) by going to the 3.55. Doesn't sound like much, but 400 rpm is alot with the Cummins. I also spent alot of time throwing gear/tire combo's at a couple of web sites that had calculators for this purpose.

Crimedog

I've got the 315s and 3.55 gear ratio. Before I got the 315s I had 245s and 33s. For my current needs it does just fine. EGTs are up because there is less gear working for you, but power wise it is just fine. Like ddestrul says, it is perfect for the freeway, and with 2-5K behind you, you won't feel uncomfortable cruising at speeds tomake the 315s work for you. When cruising at 55 you can lock OD out and run at an ideal RPM. Then when you get on the freeway, in 4th gear you can run at the ideal RPM again. I just finished a little road trip and at 7000 lbs (empty truck) I got 19 MPG. A similar trip last year and I got about 18-18.25 with the little 245s. The 33's were the perfect size for towing IMO, but the 315s do just fine.

turbo dreams

the smallest i would want to go is 285's. i think with the 265's and my 2" over stock the fender wells would tower over the tires. if i went below 285 i'd have to take my spacer and aal out. the smaller tires are alot cheaper though. i know alot of people have pics of leveling kits with 285's but what about with a smaller 265 or something?

Rambob45

Keep in mind that your MPG goes down with 315s, but you need to understand something here, your economy actually goes up, not down. The odometer has to be calibrated with the tiresize to be accurate. With 315s, your tires actually cover the same distance with FEWER rotations because of the longer tire diameter and circumference. The odometer settings in the computer can only be adjusted to a 265/75R16 as the largest tire. You need a 3rd party odometer meter upgrade that will recognize the larger tire circumference to get an accurate reading.