Lighten 9 inch gear

[cheaterleaddog]

Our rules say no lightened gears. I know quick performance offers a carrier that is star shaped and only uses half the ring gear bolts. What I was thinking of doing was grinding away metal on every other bolt hole on back side of ring gear so that carrier blocks the view of ground off material. How thin can I go any ideas.

[Egoracing]

Our rules say no lightened gears. I know quick performance offers a carrier that is star shaped and only uses half the ring gear bolts. What I was thinking of doing was grinding away metal on every other bolt hole on back side of ring gear so that carrier blocks the view of ground off material. How thin can I go any ideas.

If you get it out of ballance it will not matter as it will come apart.
A lightened gear is back cut on the outside diameter as will as around and it is thined from inside to outside. To determine somethings moment of inertia you have to do a little math, weight X (diamter squared) 9 inch ring gear that weighs in at 7 lbs would have a MOI of 567 If you cut it to 5.5 which would be huge, it would be at 405 which you will never notice. SO unless you remove over 1/2 of th weight you will not see a noticable difference and it will let go. The factory lightened gears for example are cut down in diameter so lets say they get 1/2 inch off each side that would be 1 inch total so if that cut 1 lb off the MOI is 384 if they got it at 8 inches and kept it 7lbs the MOI is 448. You are better off getting a smaller diameter drive shaft that is not too small.

[stockcar5]

try these

http://www.dansracingsupply.com/contents/en-us/p1312.html

[cheaterleaddog]

If you get it out of ballance it will not matter as it will come apart.
A lightened gear is back cut on the outside diameter as will as around and it is thined from inside to outside. To determine somethings moment of inertia you have to do a little math, weight X (diamter squared) 9 inch ring gear that weighs in at 7 lbs would have a MOI of 567 If you cut it to 5.5 which would be huge, it would be at 405 which you will never notice. SO unless you remove over 1/2 of th weight you will not see a noticable difference and it will let go. The factory lightened gears for example are cut down in diameter so lets say they get 1/2 inch off each side that would be 1 inch total so if that cut 1 lb off the MOI is 384 if they got it at 8 inches and kept it 7lbs the MOI is 448. You are better off getting a smaller diameter drive shaft that is not too small.

what is the moment of inertia on a drive shaft that is 52" long and save even three pounds on. I bet at that diameter, it isn't much but maybe I am wrong. If I took a pound off the crankshaft somebody would pay $$$ for that. Anything behind flywheel can't be claimed.

[Egoracing]

Length has no place other than it makes it heavier. You need to look at it as stated above. Weight X (diameter squared).
If your DS is a 4 inch one that is 20 lbs the the MOI is (4 x 4) X 20 = 320, if you get a 3 inch DS at the same weight it is(3 x 3) X 20 = 180, which is a big enough change to see and more than you will gain on the gear. The little 2.5 inch shaft that some were using several years ago would be at 125.
NOW if that 3 inch was only 2lbs lighter (3 x 3) X 18 then you would be at 162 which will accelerate almost 2 times faster with an equal input compaired to the original DS.

[Hurst390]

I had a buddy break his spool...It wasn't the star spool but had a straight "Hub" instead of a tapered one...snapped in 2 right at the 90...3200# car...I installed a new mitler bros spool...much stronger..