differential terminology explanations
#1
differential terminology explanations
so, i'm sure a lot of people are confused about what the differences are between different types of differentials... i know i have questions, so i figure it is time to start a thread that outlines the details and differences in them... and i'll edit this post to add in new information when people add it
Open Differentials: these are the basic differentials almost every rear wheel drive or 4x4 have, the differential puts power to which ever wheel has the least amount of traction, aka "one tire fire" on fords, it tends to be rear right tire. can be most easily identified by lifting the rear end, and spinning one tire, the other tire will turn in reverse of your direction, upside: cheap, can find them virtually anywhere. Downside: almost everything else, give the lowest possible traction in any situation where tires may spin
Limited Slip: AKA Posi, Positrac, Positraction, Positivetraction (all of which are GM terms for their brand of l/s) tracloc/traction lock (ford's brand) or anti spin (mopar) these usually use a series of clutches, that does not allow the 2 wheels to spin at different speeds, until there is a difference of a set amount of torque, on my mustang i believe it was 13lbs. upside: far superior traction over the open differential, as you have all drive wheels turning, so you will have double the traction. allows the wheels to spin at different speeds when driving on the road (for going around corners) downsides: clutches wear out, and eventually it will loose it's grab, and act like an open diff. not a full locker, and can cause 1 tire to not have power if the difference in traction between the wheels is great (ice on 1 tire, pavement on another)
Spool: quite possibly the best differential for racing or off roading, this diff uses no moving parts (spider gears, clutches, ect) so will not wear out, the only "consumable" parts are the ring and pinion gears, which will wear no more than on any other differential. this differential works as a solid unit between the 2 axle half shafts, and makes the 2 tires spin the EXACT same speed no matter what. Upsides: tires spin the exact same speeds, which will give you superior traction in all situations. there is no moving parts, so it will perform the same from day 1 till the day it completely breaks (which is unlikely) downsides: does not allow the diff to slip when turning, which causes you to have 1 tire that has a tendency to hop around corners, or slide around corners. when making turns, 1 tire is already at a loss of traction due to the previous downside, and if considerable power is added to the wheels, it has a higher likely hood of slipping out with the other wheel (as 1 tire is all that is gripping) causes a very high amount of stress on the axle shafts.
Lincoln Locker: very similar to the spool, in all of it's abilities and performances, although, it is a home made spool, made out of an open differential, by welding the spider gears together to not allow them to turn, and let 1 wheel spin. upsides: all of the same as the spool. Cheaper than a spool (not by a considerable amount) downsides: all of the same as the spool, plus has a larger likely hood of breaking, due to the parts weakening due to welding in the diff. if the weld were to break off, due to poor penitration, it causes slag to be in the fluid which works as an abraisive and can destroy meshing gears
other types i don't know enough about to do a full write up about are air lockers, and other types of lockers
other names:
open diff: one tire fire, standard diff,
limited slip: posi, positrac, positraction, positive traction, tracloc, traction lock, torsen, anti spin,
spool: spool
lincoln locker: welded diff, home made spool,
aditional resources that you may find helpful:
Diffs for Dummies @ TRS
http://www.therangerstation.com/tech...erComparo.html
Open Differentials: these are the basic differentials almost every rear wheel drive or 4x4 have, the differential puts power to which ever wheel has the least amount of traction, aka "one tire fire" on fords, it tends to be rear right tire. can be most easily identified by lifting the rear end, and spinning one tire, the other tire will turn in reverse of your direction, upside: cheap, can find them virtually anywhere. Downside: almost everything else, give the lowest possible traction in any situation where tires may spin
Limited Slip: AKA Posi, Positrac, Positraction, Positivetraction (all of which are GM terms for their brand of l/s) tracloc/traction lock (ford's brand) or anti spin (mopar) these usually use a series of clutches, that does not allow the 2 wheels to spin at different speeds, until there is a difference of a set amount of torque, on my mustang i believe it was 13lbs. upside: far superior traction over the open differential, as you have all drive wheels turning, so you will have double the traction. allows the wheels to spin at different speeds when driving on the road (for going around corners) downsides: clutches wear out, and eventually it will loose it's grab, and act like an open diff. not a full locker, and can cause 1 tire to not have power if the difference in traction between the wheels is great (ice on 1 tire, pavement on another)
Spool: quite possibly the best differential for racing or off roading, this diff uses no moving parts (spider gears, clutches, ect) so will not wear out, the only "consumable" parts are the ring and pinion gears, which will wear no more than on any other differential. this differential works as a solid unit between the 2 axle half shafts, and makes the 2 tires spin the EXACT same speed no matter what. Upsides: tires spin the exact same speeds, which will give you superior traction in all situations. there is no moving parts, so it will perform the same from day 1 till the day it completely breaks (which is unlikely) downsides: does not allow the diff to slip when turning, which causes you to have 1 tire that has a tendency to hop around corners, or slide around corners. when making turns, 1 tire is already at a loss of traction due to the previous downside, and if considerable power is added to the wheels, it has a higher likely hood of slipping out with the other wheel (as 1 tire is all that is gripping) causes a very high amount of stress on the axle shafts.
Lincoln Locker: very similar to the spool, in all of it's abilities and performances, although, it is a home made spool, made out of an open differential, by welding the spider gears together to not allow them to turn, and let 1 wheel spin. upsides: all of the same as the spool. Cheaper than a spool (not by a considerable amount) downsides: all of the same as the spool, plus has a larger likely hood of breaking, due to the parts weakening due to welding in the diff. if the weld were to break off, due to poor penitration, it causes slag to be in the fluid which works as an abraisive and can destroy meshing gears
other types i don't know enough about to do a full write up about are air lockers, and other types of lockers
other names:
open diff: one tire fire, standard diff,
limited slip: posi, positrac, positraction, positive traction, tracloc, traction lock, torsen, anti spin,
spool: spool
lincoln locker: welded diff, home made spool,
aditional resources that you may find helpful:
Diffs for Dummies @ TRS
http://www.therangerstation.com/tech...erComparo.html
Last edited by --weezl--; 12-24-2009 at 11:25 PM. Reason: add more information
#3
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#8
thanks man! even if that other one is there, and obviously better, with descriptions on how it all works, including animations (which is wicked) most people on this site wouldn't go to that forum to look for answers... so i think this thread will be well used in the future, as it is r-f.com searchable
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