One more reason why I went with the 3.90's. Theroetically, I figured they would be stronger than the 4.10's. Like I said though, I will find out when I get them in the car. I will be spraying it too so I really don't want to run out of gear in the 1/4 mile.

 

I don't understand why anyone thinks one gear is stronger than another.....

Most people don't like the 3.90 gear sets b/c they are noisy...

Also a 3.90 is not going to make much of a diff. from a 4.10 anyway....maybe on a timesheet a few thou or less, deff. nothing you would ever feel

I don't think most people could tell the diff. from a 3.73 from a 4.10 unless you have alot of seat time in the car

 

The reason is because the smaller the number of teeth on the ring gear the bigger the teeth actually are. For example there are 4.10's that are 41 tooth ring gears and 10 teeth on the pinion. Thats a lot of small teeth to cover the circumference of the gear. There are also sets of 4.11's that are 37 tooth ring gears and 9 tooth pinion gears. Now you have less teeth covering the same circumference so in theory the teeth are bigger and probably stronger.
I also disagree that a person probably wouldn't notice a difference from 3.73 to 4.10's. Thats a fair jump.

 

how many teeth are on the 3.90 ring gear?
I don't see the teth being smaller or more teeth making the grear set weakers in any way The size of the tooth should not matter if it is a high quality gear set.....

I have driven many cars...with all types of gears, I went from a 4.11 to a 4.57 and did not feel a thing...felt the same to me, I guess it depends on the car.
Mine left hard before and feels the same now....Even tho its a tad faster its not enough for me to feel.

 

[QUOTE=mdacton;4467199]how many teeth are on the 3.90 ring gear?
I don't see the teth being smaller or more teeth making the grear set weakers in any way The size of the tooth should not matter if it is a high quality gear set.....
QUOTE]

The ring gear is the weak link in a 10 bolt and most people knock the teeth off the 4.10's. So bigger stronger teeth might help the setup live.

 

Exactly. I think the 3.90 gear is a 11/39 tooth instead of the 41/10 ( I may be wrong), so you would have stronger, thicker teeth on the ring gear, which is the weakest link on the 10 bolt.

I agree that you would not be able to FEEL a difference between a 3.90 or a 4.10. I couldn't tell between my friends two cars that have those gears (they were two mustangs) but, if you do the calculations, a 3.90 gear will have an extra 4-5 mph in the quarter before running out of gear in 4th. Right now shifting at 6000 in 4th gear you will run out at about 114 MPH. After I put in the cam (hotcam), with the gears, and spraying it I will be right at the limit and will most likely run out of gear right before crossing the line. If I would step up to a 28" in tall tire then 4.10's would have been perfect. But since I am staying with a ~26" tall tire the 3.90's will be perfect.

Gears should not be picked out by which ones rev faster, which ones will get you down the track faster, or which ones feel the best. You need to take into calculation many other things when trying to figure out what gears would do you best.