What is a spool??
01-18-2005, 01:15 AM
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There are 2 major types of spools, but their function remains the same. All they do is lock the axles too the ring gear and consequently each other. This allows absolutely no difference in tire speed from one side to the other.
The two types are a conventional (full) spool and a mini spool.
The full spool, which for simplification we will say is a solid chunk of metal, has the ring gear is bolted two it and replaces the original differential. It gets spun around by the pinion gear which is attached to the drive shaft. The spool is splined at each end (perpendicular to the ring gear) to allow the axles to slide in basically attaching them directly to the ring gear.
The mini spool does basically the same thing, but retains the original differential (usually has to be a non-posi type unit) that the ring gear attaches to. You just pull out the guts and insert the mini spool, this in turns locks the axles to the differential which is bolted to the ring gear.
One thing that has also been done in the past but is not recommended, is to weld the spider gears that the axles slide into, to the differential itself which will accomplish the same thing but not even close to as strong.
Spools are desirable in drag racing because it forces the tires to turn at exactly the same speed. They are less desirable on the street because when you turn, one tire needs to turn faster than the other (the outside tire has a farther distance to travel so it must spin faster). If that can not happen, one or both tires must slip to stay even with the other. This results in tire screeching, popping, hopping, or some other action as the tires try to stay even with each other. As a side note, it also makes it almost impossible to push a car by hand while you are trying to turn.
Hope this clears it up for you.
The two types are a conventional (full) spool and a mini spool.
The full spool, which for simplification we will say is a solid chunk of metal, has the ring gear is bolted two it and replaces the original differential. It gets spun around by the pinion gear which is attached to the drive shaft. The spool is splined at each end (perpendicular to the ring gear) to allow the axles to slide in basically attaching them directly to the ring gear.
The mini spool does basically the same thing, but retains the original differential (usually has to be a non-posi type unit) that the ring gear attaches to. You just pull out the guts and insert the mini spool, this in turns locks the axles to the differential which is bolted to the ring gear.
One thing that has also been done in the past but is not recommended, is to weld the spider gears that the axles slide into, to the differential itself which will accomplish the same thing but not even close to as strong.
Spools are desirable in drag racing because it forces the tires to turn at exactly the same speed. They are less desirable on the street because when you turn, one tire needs to turn faster than the other (the outside tire has a farther distance to travel so it must spin faster). If that can not happen, one or both tires must slip to stay even with the other. This results in tire screeching, popping, hopping, or some other action as the tires try to stay even with each other. As a side note, it also makes it almost impossible to push a car by hand while you are trying to turn.
Hope this clears it up for you.
Last edited by ACW; 09-05-2005 at 10:19 PM. Reason: add paragraph breaks for readability
01-18-2005, 01:18 AM
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Originally Posted by BOWTIE
There are 2 major types of spools, but their function remains the same. all they do is lock the axles too the ring gear and consequently each other. This allows absolutely no difference in tire speed from one side to the other. The two types are a conventional (full) spool and a mini spool. The full spool, which for simplification we will say is a solid chunk of metal, has the ring gear is bolted two it which gets spun around by the pinion gear which is attached to the drive shaft and it is splined at each end (perpendicular to the ring gear) to allow the axles to slide in basically attaching them directly to the ring gear. The mini spool does basically the same thing, but retains the original differential Usually has to be a non-posi type unit) that the ring gear attaches to. You just pull out the guts and insert the mini spool, this in turns locks the axles to the differential which is bolted to the ring gear. Spools are desirable in drag racing because it forces the tires to turn at exactly the same speed. They are less desirable on the street because when you turn one tire needs to turn faster than the other (the outside tire has a farther distance to travel so it must spin faster), if that can not happen one or both tires must slip to stay even with the other. This results in tire screeching, popping, hopping, or some other action as the tires try to stay even with each other. As a side note, it also makes it almost impossible to push a car by hand while you are trying to turn. Hope this clears it up for you.
