To key or not to key ...

AlanTDickey · April 18, 2003

Okay, I thought that was the question. Now I realize there are many more.

My new 1500HD LT 4x4 is allegedly being delivered on April 29. I'm going to replace the itty bitty factory tires with larger (probably the Wrangler MT/Rs, but maybe the Revos). I just ordered the Ranch Hand Bull Nose replacement bumper. See Bumper. [ignore the icky Ford in the photo.]

By doing so, I open up the front half of the wheel well.

If anyone can answer any of the following questions, I will be indebted:

1. Would I still need to crank the torsion bars to fit 285s on 16x8 wheels?

In other words, what is the largest tire that does not rub on the back of the wheel well?

2. If I don't need to crank the T-bars, should I anyway?

3. Am I correct that installing the Ford keys will only increase the amount I can crank the T-bars? I.e. am I correct that there is no benefit of using the keys unless I want to crank the T-bars more than I could without the keys?

Or is there some benefit to the suspension by installing the keys even if I only intend to crank the T-bars less than an inch?

4. Does a post-T-bar-cranking front-end reallignment reduce any toe-in caused by the cranking?

5. Also, since I'm eliminating the front wheel well obstruction, can I go even bigger than the 285s - say a 305/70/16s (they actually have the same 33" outer diameter as the 285/75/16s)?

4. Also (if you've hung in this long), does anyone know why the 305/70/16s (at least in the Wrangler MT/Rs) have only a 2,910 lbs load rating, whereas the narrower 285/75/16s have a 3,305 lbs load rating? (More than 10% higher.)

Is it different rubber or thickness? Or is a wider tire of the same height weaker for some reason?

Eternal gratitude for any answers.

Shaners · April 18, 2003

In an earlier post you were concerned about the low range gearing not being enough for offroading in your new truck... The bigger the tire, the worse it will get, and I doubt you are going to want to go to an expensive gear swap.

I would think that 285's would change your 4.10 ratio down to around a 3.70 somewhere...

AlanTDickey · April 18, 2003

Shaners, thanks for the advice.

I know I'm a little greedy, but I want both bigger tires (nothing obscene, just 285s) and a good crawl ratio. I want the bigger tires for a little more clearance under the diffs and some mroe rubber on the ground. I also think that the taller 285s may let me air down a little more for increased traction in tricky spots.

The fact that the bigger tires will lower the ratio was one of the reasons I was concerned about reducing the low-range gear ratio frm the start. Your estimate is close: By my calculation, relative to the outer diameter of the 30.6" stock tires, putting 33" 285s will change the gear ration to 3.80:1. I think that this would effectively be a little lower though off road if I lowered the tire profile by lowering the tire pressure.

Maybe you're right though. Maybe I should just simplify and go with the 265s. Or maybe I should have ordered a 2500HD with the manual tranny, which would have a 5.61:1 1st gear ratio instead of my 2.48:1.

[Note: I would actually have a higher crawl ratio (lower number) with my 2.48 1st gear and a 4.00 low-range reduction than the stock 5-sp manual and the stock 2.72 low-range reduction.]

Nothing in life is simple.

I think I'm going with the 285s and I will see how it works. If I need to change the low-range, I'll do it later.

Either way, I'm getting excited about the impending arrival of my new 1500HD.

Cheers.

timk49 · April 19, 2003

Shaners, thanks for the advice.
I know I'm a little greedy, but I want both bigger tires (nothing obscene, just 285s) and a good crawl ratio. I want the bigger tires for a little more clearance under the diffs and some mroe rubber on the ground. I also think that the taller 285s may let me air down a little more for increased traction in tricky spots.

The fact that the bigger tires will lower the ratio was one of the reasons I was concerned about reducing the low-range gear ratio frm the start. Your estimate is close: By my calculation, relative to the outer diameter of the 30.6" stock tires, putting 33" 285s will change the gear ration to 3.80:1. I think that this would effectively be a little lower though off road if I lowered the tire profile by lowering the tire pressure.

Maybe you're right though. Maybe I should just simplify and go with the 265s. Or maybe I should have ordered a 2500HD with the manual tranny, which would have a 5.61:1 1st gear ratio instead of my 2.48:1.

[Note: I would actually have a higher crawl ratio (lower number) with my 2.48 1st gear and a 4.00 low-range reduction than the stock 5-sp manual and the stock 2.72 low-range reduction.]

Nothing in life is simple.

I think I'm going with the 285s and I will see how it works. If I need to change the low-range, I'll do it later.

Either way, I'm getting excited about the impending arrival of my new 1500HD.

Cheers.

Wow thats a mouthful. Take a breath dude.

AlanTDickey · April 19, 2003

Sh!t. When It saw the new response, I thought I had some more substantive input on my overly-long, breath-depleting questions.

Bob G. · April 19, 2003

Alan,

I'm not sure what kind of 4 wheeling you plan on doing, the 1500HD is a big truck for offroading. I don't do any true off-roading with mine due to its size. I live in the northeast and most trails are in the woods and there is very rarely a place to turn around. Most of the locals where I hunt use bone stock Jeeps and ride around the logging roads. I used to have a stock Jeep Grand Cherokee and that thing would go in and out of alot of places that my truck would never go without some sheetmetal damage. Either way, the 1500HD is a great truck. I hope it works out for ya!

Bob G.

lrymal · April 19, 2003

...I used to have a stock Jeep Grand Cherokee and that thing would go in and out of alot of places that my truck would never go without some sheetmetal damage. ...

I totally agree with this. I went with some pals to some trails in East Texas about a month back. Their rigs were a Toyota and Mazda---smallish 4WDs. Another rig was a ten year old Amigo.

The Amigo----STOCK!--- blew us all away due to its small size. In fact, it just boringly crawled all over the ruts and hills like a dog.

In my case, I had a real problem with the back end wanting to walk around, and in the smaller trucks, they were just too light, and kept spinning with no traction, in spite of their aggressive tires. I was lucky that my step bars held up and protected the rocker side rails. No damage or stress to the body---although I'm still finding red clay powder on the driveway. No matter how much cleaning you do underneathe, you'll still have embedded clay.

The Amigo, though a paper weight, just seemed to bounce better through the deep ruts and literally seemed to be built for this kind of stuff, in spite of the fact it was always bottoming out.

AlanTDickey · April 19, 2003

You guys know more than me, since you have already tested your trucks.

I know I cannot handle tight switchbacks in my truck, but I'm still planning on making it as capable off-road as possible. Maybe I'll have to lift it 4", etc. I won't mind if I scartch it up a little - it's a truck not a Volvo.

I do know that my uncle followed me up 2/3 of the way up the Blanca Peak trail in CO with only his piece of sh!t '94 ex-cab F-150. Also, I used to take 87"-wide, 7,000 lbs Hummers and massive 5-ton trucks thorugh #### in Camp Pendleton, 29-Palms, and Saudi Arabia. So size alone cannot be the only factor (as with other things).

AlanTDickey · April 19, 2003

E.G., check out these military trucks from GM and others:

http://www.trucktrend.com/roadtests/ultima...av2/index1.html

Tucson_02Silverado · April 19, 2003

The little one that amazes me is the Suzuki Samari. Just do an over the axle spring conversion, and engine stock will climb just about anything and still hold up.