Still have that trani lag.

[Jackpine]

Your point is well taken, and I'm possibly wasting everyone's time - you could even be writing tunes! (But, you need a break from work now and then).

Good observation about the spin up time using a balancing machine. That DOES clearly show the effect of getting the greater mass into motion. I grant that there IS that effect, but as a percentage of the total power delivered by the truck's engine, I think the tire mass effect is greatly overshadowed by the loss in mechanical advantage due to the greater distance between the axle and the road. And, that was what I thought I was saying.

Doesn't an aggressive, wider tread contribute more to "rolling resistance" than anything else? That's certainly the effect I feel between a mountain bike and a road bike when pedaling or coasting.

There clearly IS some optimum gear ratio and tire size combination for each of the following though:

1. Acceleration (0 - 60)
2. 1/4 mile speed
3. Fuel economy at cruise
4. Max top end speed (accelerator floored)

And, unless I'm totally out to lunch here, I think each one of these goals requires a somewhat different combination.

I suppose I'm reacting to the "one size fits all" mentality I've observed by some posters in other forums where they seem to think they can mod their trucks in such a way as to get all four of the goals I cited above at once. I'm especially amused when they complain about economy after putting in mods to improve acceleration.

- Jack

[SinCityFX4]

Well, I guess the increased surface area and type (MT/AT) would have a huge impact on the co efficient of friction as well...hmmmm. Food for thought as I ponder tire choices...

[Jackpine]

Originally Posted by SinCityFX4

Well, I guess the increased surface area and type (MT/AT) would have a huge impact on the co efficient of friction as well...hmmmm. Food for thought as I ponder tier choices...

There's a reason racing cars run "slicks", isn't there? The tread is for improved traction on wet, slick or "loose" surfaces, but it hurts you on dry pavement. And, if you never had to turn corners, like running on the salt flats, you'd want the narrowest tires you could mount.

- Jack

[pullmeoverred]

Andddd now I'm going to totally ruin the quality of the coversation here...

I've got a 06' 5.4L 4x4 with the 3.55LS, and now it's got 275/60/20R cooper zeons to deal with (32.99") which has robbed it of a decent amount of performance. I've been searching for a few days now on this forum and other f150 forums for what my best option would be. So far the vast majority of responses I've gotten have reccomended I buy a grypon (which I've been considering already) and rolling the dice on my extended warranty of 5 yrs 75k (I'm at 25k). Only two people have suggested regearing and my Ford dealer basically thought I was a mental case for asking them if they could install them for me. I've accepted the fact that my knowledge on this subject is severely lacking. I'm not a total lead foot, but I do enjoy performance. I work with one of your customers (glockwinger) and he giggled like a school kid when he got his custom tunes. I'm intrigued...

Is your Gryphon the answer? Or should I be looking at new gears? Or both?

Thanks, Aaron

[Chris74]

I'd say just go with Gryphon first. That may completely satisfy you........but if not, then I'd throw some deeper gears in it.

With your new tires you now have an effective ratio of 3.34. You would technically need a 3.76 ratio just to get back to the feel of stock. So purchasing 3.73's won't even quite get you there. You would want 4.10's or 4.56's if you decide to do gears as well. That's my opinion anyway
BTW - Don't worry about the Ford dealer looking at you funny!