OK, I'm new to this site and I have a question. I have a 2003 Chevy 1500 Z71, Ext. Cab 5.3L w/Auto tranny. It is completely stock except for 33" Firestone Destination M/T's on the factory wheels. I am currently in Iraq and plan on getting some 38"s when I get back to the states. I want to get Pro-Comp X-Terrains, but I don't know how they will do (most of the places I ride in are mud). So, my question is how will they perform in mud, and is there a better tire for the price?

Also, how much will I need to lift it to clear 38"s? The 33"s I have scrub the wheel wells in rough terrains but are fine for the road. And will I need to upgrade my drivetrain for them?

Thanks  

I do not mean to rain of your parade but you have picked the wrong horse to put those new shoes on. There is several of good reasons too. First, the chassis is not that strong and the front end (ball joints, tie rods, control arm bushings, steering knuckle wheel bearings and maybe steering box) will have a much shorter life span. Next, axles are too small for those tires and axle shafts could break if you horse it some. Your front drive axle is a 8.25 IFS and too light for those tires and it is not possible to swap the stronger 9.25 IFS axle used in 2500 and 3500 models (it will not bolt in or fit) and rear axle is a 10 bolt and way over classed with 38's (actually anything over 33's is pushing it with that rear axle if you play hard ad factory govloc will grenade with 38's if you push it.) Next there is the brakes, they are going too have greatly reduced capacity and fade quicker due to increased leverage and weight of bigger tires. Then there is the axle ratio's They are not right now for 33's and they will really be wrong for 38's You need like 5.13's because 4.10 or even 4.56's are not enough and nor is a 4.88 really. Failure to do this would GREATLY shorten tranny life and performance will be poor and MPG too. Your truck is not as sturdy as the old 67 to 87 1500's with basically used same frame as 2500 and same front drive axle except for wheel hub due to lug pattern. Even the 88 to 99 1500 had a stronger front end in that they offer after market kits to support a solid axle swap which Silverado 1500 does not support due to chassis limitations. Sorry to be a downer but I am telling you like it is. If you have your heart set on 38's you need a 2500 truck with deeper axle gears is you want it to last a bit longer and and be able to get out of its own way have some brakes too. BTW, the new 07 1500 have even a lighter chassis yet. Sure they boxed it but they had to because there is even less total metal when cross sectioned even before normal rust sets in and the bad thing about a boxed frame that while it appears stiffer with less metal, it is far less forgiving than old C channel frame when push to limit and beyond because when it does yield, it is weakened a lot for life.  

If you have your heart set on 38's toss an 8" lift on there, trim your bumpers, gear your axles, and run it until you break something... which will happen... Then you can either upgrade or just replace... Autozone has a great lifetime warranty on CV's and Tie Rods... lol  

Thanks for the advice, sounds like I need a different truck.  

Or you can just swap the rear axle and do a SAS up front. That would be cheaper than a new truck, and you can go as strong as you like.  

Dirty_Dog:
Or you can just swap the rear axle and do a SAS up front. That would be cheaper than a new truck, and you can go as strong as you like.

Bad advise because that model chassis is not a good platform for a SAS up front because it is not very stout. This is not just my opinion but the after markets as well.  

OK, well if I DO decide to go the 38" route, who makes good parts for Z71s? It seems that there is little aftermarket for them, aside from 'pretty parts'. I love the truck and don't want to get crazy with mods, so all I planned on was the 38"s b/c my 33"s don't hold up for long in mud.

And if I do go for a new truck, what is a good platform? I thought about a Tacoma since a lot of my friends back in AL have them and they seem to take a beating fine.

Sorry for the 'newbie' questions but this is the first truck I've had. The last thing I drove was a Mitsubishi Evolution.  

There is not after market parts to make it 38 worthy. If you really want 38's you need a 2500 series 2001 or newer Silverado and a SAS swap for front axle (there are kits for this) Also 99 and older chevy truck (non silverados) also have kits for SAS swaps for them (1/2 and 3/4 ton) but your model does not. Sure you could make something and modify/beef up frame and make brackets but this would be very expensive to do and you would still need to change rear axle too. If you start with a 3/4 ton, the only thing you are going to need to change back there is gears for 38's not whole axle too.  

Any SAS requires some extra work to stiffen the front of the chassis. If you've got the fabrication skills to do a SAS, then you won't have any difficulty bracing things. The rear axle is a bolt in.  

Dirty_Dog:
Any SAS requires some extra work to stiffen the front of the chassis. If you've got the fabrication skills to do a SAS, then you won't have any difficulty bracing things. The rear axle is a bolt in.

If you can find a 9.5 ind 6 lug 14 bolt semi floater it is a bolt in otherwise it is not because wheel lugs will not match if you use a 10.5 FF. You will need a 9.5 with disc brakes too making it harder to find a bolt in 9.5 and more expensive to convert a older 9.5 to discs. Also, you should beef up rear frame too if you go this route as it is not very stout either. It is simpler and cheaper to start this with a 01 or newer 2500 chassis for that body style. GM is not generous with frames on 1500 anymore and they are really more of a 4 wheel drive car with a truck body than a real truck.  

what a joke.............lift your z-71 chevy how you want it and run the crap out of it it will last longer than you will probably keep it anyway.

snoman has some valid points, however they are a bit extreme and...  

mudb8-.:
what a joke.............lift your z-71 chevy how you want it and run the crap out of it it will last longer than you will probably keep it anyway.

snoman has some valid points, however they are a bit extreme and...

The joke will not be kind on owner. It will break quickly and at great expense that he will bare and not you. Those drive axle are not strong and nor is the front suspension ball joints and bushings. You have to line up the major model year changes from early 80's to newest model to fully appreciate and understand just how much modern 1/2 tons have been lighted up from frames to even less springs too. Up thru 87, the 1/2 was still a pretty tuff cookie frame wise  but in 88 the lightened the frame in them and even more 99 when Sliverados came out and yet again in 07. I take no pleasure it telling the guy to get another truck but I would be far less than honest if I was to tell to go for it and run it till it breaks because it will break and he will pay for it not you.  

speculation  

I would have to agree that it would be better to start with a 2500 chassis for the least expensive route.  If stuck on the current 1500, the EXTREME would be a full tube chassis with the 1500 body on it, that would be major dollars.  That is going to the extreme.  I have avoided the 1988 and newer body styles because of the IFS and chassis not being as good for severe use (other reasons also).  But like snoman stated, the 1988-98 are stronger than 99 and newer.  Sure you could reinforce the frame of the 2003 1500, but you would need to compare that cost against just starting with a 2500.  

USMC...u don't say. What is ur MOS and where are you at? I'm headin there shortly.