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post #1 of (permalink) Old 05-25-2005, 05:15 PM Thread Starter
 
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Tire size and towing ability

Hi everyone, I'm a recent Chevy owner--'04 2500HD Crew Cab 4x4, 6.0L, 4.10's--and I have a couple questions so far...

First off, why do they put these little dinky tires on such a big truck??? Well, I want to increase my tire size, but I don't want a huge decrease in towing ability. I've been told I could fit 33's on it, if I crank the torsion bars, or rekey it, and trim the plastic on the front bumper a little, or I could fit 32's on it without any modifications. My real question is how much power loss regarding towing ability will I notice if I go to 33's?

Would there be a big difference in power between the 32's & 33's?

How much would replacing the exhaust system help overcome this power loss?

We tow a 7500lb travel trailer, and will eventually tow the CJ7.

Thanks!
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post #2 of (permalink) Old 05-25-2005, 08:48 PM
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Re: Tire size and towing ability

[ QUOTE ]
First off, why do they put these little dinky tires on such a big truck???

[/ QUOTE ]

To save them money. The first thing owners do when they get truck is replace them with the ones they want anyway. The 245s are also easier to tow with. Smaller narrower tires offer less resistance than larger wider ones.

As for upgrading tires, measure the ones you want. Don't completely rely on what's written on the sidewall.

There is a difference between 32s and 33s. At least I felt a difference when going from 265s to 33x12.5. The truck feels it. It changes the way the tranny shifts.

Out of all this though, you have 4.10 gears. That is what makes up for tire diameter changes. Going to 33s with 410s should be fine. I do recommend you calibrate your speedo and make sure your computer is reading your speed and distance correctly.

Replacing the exhaust will help the truck breath better. I also think you should get the truck breathing in better as well. So look into intake upgrades.
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post #3 of (permalink) Old 05-26-2005, 02:20 PM Thread Starter
 
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Re: Tire size and towing ability

Yeah, when I went from 31's to 32's in my CJ7 I noticed quite a bit of difference, but then again my gears are only 3.73's there, and the power difference between the two vehicles is huge. I was hoping the difference would not be as noticable in the Siverado. Thanks!
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post #4 of (permalink) Old 05-26-2005, 02:45 PM
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Re: Tire size and towing ability

Well.. you should have bought the duramax engine if you wanted to tow that much. Granted the gasoline engine will do just fine with little modifications, all you really should need is a dualed out three inch exsaust. That should give you adequet power. If that doesn't I'd look into chipping it or as was stated above an intake. I wouldn't really go the route of headers unless you want to spend about 500 for a set. Also they wouldn't give you as much gain as a intake can.
post #5 of (permalink) Old 05-27-2005, 11:25 AM Thread Starter
 
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Re: Tire size and towing ability

Well, I opted for gas since it's still rated to pull 10,000lbs with the 6.0L. I didn't want to spend the extra 7k when I knew I wouldn't be towing anywhere near the rated 12500lbs. I will probably end up replacing the exhaust and intake at some point. Thanks for eveyone's input!
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post #6 of (permalink) Old 05-29-2005, 07:25 PM
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Re: Tire size and towing ability

Get a computer program for tuning .....Dyno 2000 or something like it. It will help with those choices.
I put a FIPK kit on my 96 3500 w/454, and all I got was a lot of noise, pulling 8000# didn't feel any different. I changed tires from the 215/85's to 235/85's and didn't notice any difference in towing performance or gas mileage. I have 4.11 gears.

I have put a Dynomax cat back system on my 95 350 sub. and a high flow cat converter, and didn't notice any difference either. Being it has the CFI I flipped the lid on the air cleaner, and actually noticed a difference.
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post #7 of (permalink) Old 05-29-2005, 07:28 PM
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Re: Tire size and towing ability

actualy bout the best exhaust is 3" single with a good muffler and cat(if your truck has to have it)

dualed 3" is horrible. just no need for it and it sounds bad. 2.5" is as big as youd want to go running duals. 2" might even be better. the smaller pipe is better for the power and sound.

tire size. id love to run my truck with the 245s or 225s just to see what it would feel like compared to 35s. if i haD a true tow rig i think id keep the tire size 33" and smaller.

if its just the acasional boat or camper puller then 35s to 37s would be just fine. but youd want to be gears or hope its all flat interstate miles your towing.

with 33s i wouldnt jump all over changen gears but 35s i would and would run 410s or 456's depending on the tranny. 37"s would definalty want 456

i have towed quite a bit with 35x12.5x16s. truck is reg ld 2500 its seen quite a few miles in front of the horse trailer(4horse), bobcat trailer, car trailer, and the acasional boat. 35s never botherd me untill i was pulling pretty good grade. this was running 342 gears,
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post #8 of (permalink) Old 06-11-2005, 01:49 AM
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Re: Tire size and towing ability

Gears,gears,gears.....I run 38's with a mainly stock 350. I can pull some serious payload with this truck, but I also run 4.88 gears. If you want to tow, gear for the tire size you want to run. In my opinion, gearing is better and cheaper than hp mods for towing.
post #9 of (permalink) Old 06-11-2005, 02:14 AM
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Re: Tire size and towing ability

i agree to the fulleest. 35s and and an auto tranny almost require 456 gears at the minumum to drive and town decent.
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