anybody try'd this yet?Being almost 30in. tall tire and trying to push 4400lbs is not a performance gain with a 3.73 gear?

 

That would be at least 2600 RPM at 70 mph, so I doubt anyone is going to do it to a daily driver unless it has bigger than 30 inch tires.

 

well what about doing it to a lifted truck with 36" tires on it? when we are driving he will put it on cruise but at 70 or somewhere around that speed it keeps wanting to downshift. would that make his truck act like a truck with regular gears on it?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Phatchevy:
<strong> well what about doing it to a lifted truck with 36" tires on it? when we are driving he will put it on cruise but at 70 or somewhere around that speed it keeps wanting to downshift. would that make his truck act like a truck with regular gears on it? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You need to check out a gear ratio calculator.
www.dirtroad.com/gears
With 36 inch tires,4.56 gears and transmission final drive of .70(4th/overdrive)you would be running approx 2085 rpm's.....I would think it would feel about like it did with the stock tires on it,maybe a little better.

 

I don't think anyone around here is running that much gear. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />

I would look to a nice stall converter to get the truck off the line. That way you don't loose the benefits of 4th gear on the highway.

If you were running an all out drag setup then the 4.56's would be awesome if you could hook'm but, you'd have to be trapping pretty good to take full advantage of them at the end of third gear. I don't think they'd be the best choice for a bolt-on stock motored truck.IMO They're also going to be weaker then a lower(numerically) gear if your planning on putting alot of power threw them.

Try this calculator out. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

http://www.smokemup.com/auto_math/mph_range.php

John

 

i run 4.56s on a 27" tall tire. its not that bad, i am doin 70 at like 2500RPMs

the only times i do long travel freeway driving, i am towing, so i dont mind my RPMs where they are at. And the way the truck drives now is great. ill never go back <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Did you ever go back to the track to see how much quicker it was?

 

havent been to the track yet but i will be real soon, like in a week or 2. its a huge difference, my last run was a 15.3 and my truck feels like a 14.8 or 7 car now.

 

I've been thinking real hard about going from my stock 3.73 to either 4.56 and keep the stock tire height or 4.10's and run between a 27-28in. tire, works out almost the same gear ratio.I can deal with the extra 4-500rpm that would come from it. 2500+ rpm at 70mph would be better towing with,my gas mpg sucks when i pull any thing more than 800lbs? In realality if you compare the stock gear to tire ratio to say a vette or z28 etc,being that most of them run 25-26 in. tires we really have a 3.31- 3.42 gear!You just can't push 4400lbs down the road with any authority!!!

 

i have 4.10's and only turn about 2400rpm at 70-75mph. it isn't that big of a difference. i had 3.42's. 4.56's would be great if you are running the 1/4 all the time. i still have about 1500 or so rpm left going through the traps.