School me on gear ratios

[OHEARN.2012]

ok so i dont rely know to much about how gear ratios work with bigger tires smaller tires all the lil factors but school me on the ratios lower then 410s and up to rockwells massive 672s i know anything higher then 410s are street whimpy gears but right now i run either 410s or 373s in a gm 14 bolt ff and corp 10 front 35 inch cut boggers 327/350th/203 soon to be upgraded to a 208. but would a higher gear ratio lets say 513s would they give me a real high increase in tire speed? idk just SCHOOL me on gears dunno much bout them 

[betterbeaters]

going from 4.10 to 5.13 will lose wheel speed.  the higher the number (5.13) the slower the wheels can spin... it may get the motor to rev faster but rpm to rpm the lower numbers (4.10) will spin the tires faster.. just like changing from a 203 to a 208 the 208 has more gear so the tires spin slower... hope this helps some

[mudbillyredneck]

Also 5.13 has a smaller pinion head tooth count Than a 4.10 ....so some say it is a weaker gear set

Really depends on what your going to do with it ,(street use.....Boggs....truck pulls ...ect )  I suppose ?

[Blazin40s]

4.10s should be good for 35s. 5.13s would be better for 38s on up to 42s or 44s

[Hammerlane]

don't mean to hi-jack your thread..
how to tell what gears you have in your axle..
I grenaded the pinion carrier on the Cheep (9" Ford).. pinion gear is spent
ring gear shows signs of significant wear..
both the pinion and ring gear have "1940" on them.. (don't believe thats the year they were born.. )
do I divide the first 2 digits by the second two?? (.475) or the other way around (2.15.. nah!)
to find the ratio

[dirtydog]

divide the number of ring gear teeth by the pinion gear teeht 11 41 is 3.727272727 so u round it to a 3.73

[Blazin40s]

  What he said

divide the number of ring gear teeth by the pinion gear teeht 11 41 is 3.727272727 so u round it to a 3.73

[ProGrade]

ok so i dont rely know to much about how gear ratios work with bigger tires smaller tires all the lil factors but school me on the ratios lower then 410s and up to rockwells massive 672s i know anything higher then 410s are street whimpy gears but right now i run either 410s or 373s in a gm 14 bolt ff and corp 10 front 35 inch cut boggers 327/350th/203 soon to be upgraded to a 208. but would a higher gear ratio lets say 513s would they give me a real high increase in tire speed? idk just SCHOOL me on gears dunno much bout them  

a gear ratio is the number of times the driveshaft revolves to one revolution of the axle shaft.  so for a 4.10:1 the driveshaft turns 4.1 times to turn the axle 1 time.  (this is in a posi or locked state)  so a higher ratio means lower wheel speed, it also means higher torque.  if your torque at the rear output shaft of the t-case is 300ft-lb (its probably much higher)  if you are in 2wd, a 4:10:1 will give you 1230 ft-lb through the axle where as a 3.73:1 will give you 1119ft-lb through the axle.  if you are in 4wd the torque from the t-case is cut in half because half is sent up front.  With 35" tires Blazin40s is right, 4:10's are plenty for a trail/mud rig.  Since a higher ratio results in more torque in the axle shaft and at the wheel, there is a greater chance of snapping an axle when gassing the truck.  If you are going from a 203 to a 208 case, you will lower your wheel speed an increase your torque in low range.  hi range will remain constant.  hope this helps.

[85cHeavyMetalBogger]

is your 10 bolt beefed up with any goodies.. cut boggers even 35's will tear it up if ur not carefull. try to keep front tires on ground, if they happen to leave dnt stay in throttle to much when u come dwn

[OHEARN.2012]

no just stock i do believe

[Blazin40s]

Boggers will snap those shafts.....may wanna trade someone with tsls 2 of yer tires and run tsl up front and bogger in rear

[85cHeavyMetalBogger]

just dnt cut the fronts, u should be ok. i got a corp 10 front 410 gears new lockouts and calipers shaved to fit 15 in rims was told its beefed up a lil what ever that means if u need it for a spare i want to sell it. i ran it last year with 35 boggers and had no problems. i upgraded to a d60.

[OHEARN.2012]

i want a 60s and some 40+ tires
but finds are tight

[ProGrade]

i want a 60s and some 40+ tires
but finds are tight

10 bolt front will be fine, usually when you break up front its cuz you are in it and turn, or have a bad u-joint.  if you are really worried about it beef up your u-joints, thats probably what 85 heavymetalbogger is referring to.  I know a lot of guys with big power that run 10 bolt fronts without a problem.

[Blazin40s]

I kept breaking my 10 bolt shafts, and I babied it with the 10 bolt.  But I was runnin 39.5s........dang u joints snapped and broke both shafts

[OHEARN.2012]

so im thinking about upgrading to a 39.5 tire this winter wat would you guys suggest for a step up in gears?

[Blazin40s]

4.88s or 5.13s

[OHEARN.2012]

well with running a 208 wat would match better with its gearing?

[85cHeavyMetalBogger]

how much power u gonna have to turn em? I like my 410's

[OHEARN.2012]

idk yet decision on an engine is up in air leaning towards smc but if price is good on a running bbc prolly go with it.
still got that axle?