speed_demon24

iTrader: (6)

I've seen different opinions on the 37/9 4.11's and 41/10 4.10's. I'll take every bit of strength I can get since I'm still on a 10 bolt. Or should I just throw in another set of 3.73's?

guppymech

iTrader: (7)

I have heard of people getting the 37/9 4.11 as a substitute when they ordered 41/10 4.10s. I just checked Motive's and Richmond's online catalogs for the 7.5/7.625 10 bolts and neither lists the 37/9 4.11. Also checked Strange Eng. and Summit Racing....still no luck. Have you actually found the 4.11 ratio for sale?

01ssreda4

iTrader: (96)

They don't make a 4.11 for our rear end. We have 4.10. There will be a slight strength advantage on Richmond's side simply because of the way they cut their gears. Their cut is more aggressive yielding higher strength on the gear's tooth, but can lead to a noisy rear end. Motive's are kind of in the middle. They tend to be better (stronger) then a stock cut gear like GM/SLP/AAM, but have the potential to be noisier. Richmond does seem to get the nod for having the noisiest gearset around.....and I've had very good luck running Motive's stuff. I think you will find that you will snap a posi unit before you break the gears, or at least in my experience that seems like the more common failure point.

speed_demon24

iTrader: (6)

Pretty sure motives are 4.11's even though they list them as 4.10's. At least the motive performance line.

Isolde

iTrader: (4)

Seems to me that a 4.11 would have the same problem as the 4.56:1, with the small pinion, and the thick ring gear intruding on the cross shaft. That means weakening the shaft, the ring gear, or both, to get everything assembled. Now, in a stronger axle design that was intended to take 4.56:1s without issues, I have no idea of the 4.11 would offer any inherent advantage, or disadvantage, in ultimate strength.
There must be good reason that GM hasn't chosen 4.11 over 4.10 in the last 40 years.

HioSSilver

iTrader: (8)

Yes there is a difference. The 10/41 gears tend to break the teeth off the ring gear. The 9/37 (4.11) the ring gear teeth are thicker and don't break as easy.

Isolde

iTrader: (4)

But with more teeth, you always have more engagement, spreading the load out over more teeth at any given time.

HioSSilver

iTrader: (8)

Not when the pinion is so small it can only contact a couple teeth anyway. I busted 2 sets of 10/41. I didn't bust the 9/37, I removed them to put 3.90 in my car. I would actually recommend the 3.90 over both of them, the pinoin is much larger to spread the load like you say.

speed_demon24

iTrader: (6)

Just wanted up update this thread. My orange box motives came in today and they are indeed 4.10's. Oh well I haven't had a drag radial on my car in 3 years so I'm hoping they last.