why wouldnt taller gear ratios always be better?

[madwilly240]

if i understand correctly, if one gear spins one time, and that makes the other gear spin 2 times, you have a 1:2 gear ratio.

I think that on the differential ratios, the 2 gears are the input gear from the driveshaft, and then the output gears to the halfshafts. so if you have a 1:4.06 final drive ratio, that would mean that the driveshaft has to spin 4.06 times to spin the output shafts (and wheels) one full turn. Now if you have a 1:3.86 final drive ratio, wouldnt the driveshaft only have to spin 3.86 times to spin the wheel one revolution? it seems like, if you could have a 1:1 gear ratio, that would be the way to go, but people say that the 3.86 diff. will slow down the car a lot.

where am i making my mistake, and what is the real way that it works?

thanks

[RanciD]

Because the taller the gearing the higher your top speed in that gear will be, but the slower you'll accelerate in that gear. Since the engine spins fewer times per rotation of the half shafts it has to work harder to turn them.

[240Dave]

IIRC, 4th gear has about a 1:1 ratio with the wheels if that gives any indication of what 1:1 feels like.

Can't go too short either or you'll be way too high in the rpm's on the highway...great for a real racer though.

[mbmbmb23]

Originally posted by RanciD
Because the taller the gearing the higher your top speed in that gear will be, but the slower you'll accelerate in that gear. Since the engine spins fewer times per rotation of the half shafts it has to work harder to turn them.

And thats not always a bad thing.....like if you have a KA-T that gets NO traction in first gear with the 4.08 gears....the 3.96 (or whatever) gears would be a definate upgrade, increasing the top speed by like %7 (I think I heard 7 percent) and slightly decreasing spin-out torque in lower gears.



-m