what dose gear and axel ratio mean. and how do u read it.

__________________
2001 sort box reg cab 2WD 3.0L with five speed
MBRP bell dump exhaust

whos alex?

__________________
2008 F250 Super Duty KEM tuned

differant gear ratios help some with bottem end power or top end driveability. the lower the gear ratio number, (like 3.55) will make the truck run at lower RPM's on the highway at 60-70+ MPH, and get better fuel economy at higher speeds. a higher number (like 4.10's) will make the truck accelerate quicker, and typically pull a trailer or heavy load better, but you loose some of your top end power and the truck will run at higher RPM's when you're at highway speeds, resulting in lower highway fuel mileage.

the other benifit of a higher gear # is that it allows you to run larger (taller) tires. bigger tires can actually drop the gear ratio to a lower #. so if you had 4.10 gears, and decided to run 31" tires, you would wind up with closer to 3.73 gearing, which can help improve highway fuel mileage as long as they arn't super wide.

__________________
2000 XLT 4X4, 3.0, Auto, regular cab - throttle cable mod, K&N drop in filter, taylor thundervolt 8.2 plug wires, autolite sparkplugs, Accel coil pack, AVS Ventshades, Rampage LED tailgate light bar, BFGoodrich All Terrain T/A tires, Trail F/X toolbox, cruse control pod light fix, Cobra 19 ultra II CB, lil wil antenna, pioneer door speakers, expo woodgrain radio bezal, 06+ mirrors & tails, powerdome hood

2000 XLT 4X4 Offroad, 4.0 / auto, supercab - the project truck!

I always thought that the RPM's measured the revolutions of the crank shaft and had nothing to do with the axle ratio. How does changing the ratio of the rear axle affect the revolutions of the crankshaft? You may be correct. It may just have to be explained to me how this works. Can someone explain? I do understand that changing gear ratio can help or hurt in acceleration and towing power.

----------

I got it.
http://www.hotrodders.com/forum/effe...pm-140898.html

__________________

RPM is crank shaft & is measured in the old days by a flexible shaft off a distributor drive fitting. Today its measure electronically off the ignition & has nothing to do with anything past the transmission input shaft.

The Ratio is read pinion gear rotation verses wheel rotation 3.00 to 1 is three pinion gear rotation to 1 rear wheel rotation.

If you lost the differential tag or can't convert the factory casting code; jack the rear wheels up off the ground & make a chalk mark on it.

Then make a chalk mark on the drive shaft. Rotated the drive shaft & count the revolutions to get one full wheel rotation. On a 3.00 to 1 you will turn the drive shaft three times for the wheel to turn once.

__________________
Kevin
1998 3.0 4X4 5MT Splash Box- 2014 435iM-Sport - 2013 BMW 135is convt - 2009 Ford Expedition 4X4 EL - 1965 FFR Cobra - 2016 Genesis R-Spec coupe - 2017 Mazda CX5GT AWD .

It's common sense bud.

__________________

What skylark is saying is when you put a bigger or smaller tire size on it essentially changes the final drive ratio. It will take less or more rpm's (depending on what you do) to do 60 mph than if you were to have left the tire size alone.

__________________
2011 Ranger XLT 4.0 extended cab 4X4
3.73 diff limited slip
Snowdogg MD 68
Readylift 2.5" torsion keys
Air Shocks in the rear
2009 F250 XL 4X4 7'6" Western plow

An even more general way to read the ratio is input: output Gear ratios are everywhere and not just on a vehicle. Understanding the numbers in general will help you understand how things work and why more so than just knowing what ratio works where. Lower gearing, which means higher numerical value, offers more mechanical advantage or leverage. That's why you can accelerate better from a stop in first than second. First is a lower gear.

__________________
Trey

Looking to get an 01-03 4x4 supercab. I do have a Ducati and a couple GM vehicles if you want to know about them.

my best friend?

__________________

Why does everyone think prerunners just jump stuff?

Please click HERE to watch this video!

repeat after me: A-X-L-E

__________________
1987 2.3/TK5, 125K.

Alex Ratio sounds like a detective series

__________________
2001 Ranger Edge 4x4 (sold)
2006 F150 Lariat 4x4 (sold)
2007 Explorer XLT (Destroyed by Deer on highway)
2014 Explorer XLT (inherited from parents)

He on fb?

Sent from my VS910 4G using FRF App

__________________
2008 F250 Super Duty KEM tuned

ok guys i get it i cant spell. i legit have a problem with letters. lol if u read my signature im new and not all knowing. but to thos who legitly helped thanks alot i understand now and this info will help alot.

__________________
2001 sort box reg cab 2WD 3.0L with five speed
MBRP bell dump exhaust