As most of us know, on the 6-speed trucks 1st gear is essentially never used except in extreme "creeping" situations. IN fact, I have yet to have a load heavy enough to even warrant it when towing. When I upgrade to the 22.5" wheels and 275/70/22.5 michelin tires, what kind of drop in overall ration can I expect and will the TST allow me to compensate for it. If not, what should I add to reconfigure the speedo?

I was just curious as to whether or not I will be starting out in 1st like a normal vehicle instead of 2nd with the new wheel & tire combo. I can imagine that since I do not pan to lift my vehicle, I will be able to cruise around 75mph at the same RPM that the stock truck would around 60-65mph. It will be nice to keep the MPG advantage of slower speeds with without slowing down! (I wouldn't think that these wheels and tires would add enough weight, or drag, especially since I am not lifting, to counteract the advantage of the lowered final drive ratio.) Any input would be greatly appreciated!

 

showing 65mph will be 79mph
here is a good link
http://www.net-comber.com/tirecalc1.html

 

Did you go with 4.10 rear end? that will help you out a little as far as the towing situation and loss of power due to the lowered ratio. You should be able to go to the dealership and have your computer reflashed for the speedo problem. If the gearing is still not good enough you may have to swap out to something more steep like a 4.55 but I am sure you will have plenty of power to compensate for the loss of gearing.

 

I think you are going to love the ratio change of that tire and wheel package. I need a manual which I got but I absolutly hate the g56. The 6 speed in my old 04 was geared way better. 80 mph at 2500 makes me mad just thinking about it. No wonder the milage on the newer trucks suck. If I could get my rpms in the 1800 range at 75 , I know that I would save fuel ,exhaust temps would be lower, engine would last longer The truck would pull better.

 

What is your gear ratio now (3.73 or 4.10?) and do you have the 265/70-17's? Assuming I have the correct tire size, with 3.73's you will effectively lower the ratio to 3.04:1. With the 4.10's it will go down to 3.35:1. In my opinion you need a gear change to 4.56 bare minimum (that'll bring you back to 3.72:1), but if available I'd go a bit lower, say 4.88:1. The 4.88's will bring you to 3.98:1.

And I think you're are gravely mistaken by assuming you won't be adding much weight with those tires. That combois going to be very heavy, and will require a lot of force to start and stop rolling. You can try without regearing but I don't think you'll be happy.

How are you going to stuff 38" tires under the front of your truck with a lift? I sure would like to see pics when your done!

 

I do have the 3.73 gears with the 6-speed. I had an '03 with what I think was the same gear ratio (it was NOT the 4.10 I know that) and it still was too high with the RPMs at 75mph. I would like it to be in the 1700-1800 RPM range at 75. I figure that dropping the ratio to either 3.04:1 or 3:35:1 would be a much better drive making all 6 gears longer.

When you think about it, 1st is useless, 3rd doesn't do much unless towing VERY heavy stuff, and 6th is too short.

As for the weight, you are right, I am sure that it will add like 30 lbs. per corner of unsprung weight, which is bad; however, the increased traction (especially in bad weather) mileage, and lack of wear, not to mention the increased MPG should be substantial. When you think about the added weight, it really is only going to affect the starting and stopping, not the highway stuff. Once you get the weight moving, it's inertia will actually help keep it moving. I will just be curious to see if a brake upgrade is in order. I know that the '06s have great brakes with stock wheels. I am curious to see if that will still be true with the 22.5s.

As far as the lift goes, I MAY do the leveling kit depending on how the truck looks. I am from the school of thought that says, "I will do whatever it takes to make it work." If that means, cutting ot plastic or grinding away some corners, no problem. The American force website clearly shows completely stock trucks running these wheels and tires so I doubt that it will be much of a problem. I got 38x15.50 Nitto Mud Grapplers on my H2 to fit with NO RUBBING AT ALL on anything but offroad before I put my lift on so I will make it work !

 

I'd like to be in the same RPM range also. I like to cruise the highway at 80 mph, and with the 4-speed auto I'm well over 2000 rpm at that speed.

Yeah, once you get them moving you'll be fine, but I'm sure you'll notice a difference trying to get them moving! But if your not drag racing, who cares?

I come from the same school. I had a slick suspension setup on the Titan I sold to get my MegaCab. It wasn't really tall (4" lift) but I could still fit 35's and the ride was awesome, both on- and off-road, degrees better than any of the commercial lift kits available.

Do you have a link to that website for the rims? I'd like to get a set of 19.5" rims for mine. Do you know if they make a set in that size?

When all is said and done, be sure to post some pics. I'd love to see the finished product!

 

www.americanforcewheels.com is the website and they DO offer a 19.5" upgrade as well.

I agree with you completely about the "who cares unless you are drag racing" comment. I bought my truck to haul and pull anything and everything, not to race; that's what my Lambo is for !

I will be sure to post a LOT of pictures when I am done, and I am sure that not much modification will be needed; at least not much more than a DeWalt angle grinder!