Topic: ring and pinion


sarahcecelia    -- 05-09-2018 @ 5:30 PM
  Doesn't a 4:10 rear have 41 teeth on the ring gear and 10 teeth on the pinion and that is an original o'drive rear? How about it Tom? Or whomever??

Regards, Steve Lee


Kens 36    -- 05-10-2018 @ 8:35 AM
  Steve,

I'm not sure of the tooth count. Yes, 4.10 to 1 was the ratio on overdrive-equipped 1949-1951 Fords. 3.73 was standard with regular 3-speed trans. There were several other ratios for Station Wagons and Fordomatics.

If you don't have the 1949-1951 book published by the Club and available on this site's Online Store, you need it.

Ken


sarahcecelia    -- 05-10-2018 @ 9:12 AM
  I have a manual, but that doesn't tell the tooth count. You divide the number on the ring gear by the number on the pinion and that answer is 4.10. Overdrive rear.

Regards, Steve Lee


sarahcecelia    -- 05-10-2018 @ 4:00 PM
  Well 41 divided by 10 equals 4.10.

Regards, Steve Lee


kubes40    -- 05-10-2018 @ 6:36 PM
  The ratio does not necessarily equate to ACTUAL tooth count. A 3:78 has nine teeth on the pinion and 34 on the ring.

It's a RATIO. If the 4:10 has 41 teeth on the ring and ten on the pinion, that's coincidence.

Mike "Kube" Kubarth


BUCKAWHO    -- 05-11-2018 @ 4:43 AM
  Hi...Large numbers of teeth on the ring mean a large diameter gear, which in most cases is not desirable, calling for a huge pumpkin. Most I've heard of have a 37 ring and a 9 pinion, which results in a 4:11 ratio, not 4.10. My '51 has a 4:11 , standard with overdrive, and a rather normal sized differential housing. My Vette has 37 and 11 for a 3:36 ratio. BT


sarahcecelia    -- 05-11-2018 @ 7:53 AM
  34 divided by 8 = 377.7, which is 378

Regards, Steve Lee


sarahcecelia    -- 05-11-2018 @ 8:07 AM
  Something s wrong. I have a NOS ring and pinion in the original Ford box. It has 41 teeth on the ring gear, and 10 on the pinion. Its marked "410 to 1 Overdrive." You can't argue with Ford.

Regards, Steve Lee


kubes40    -- 05-12-2018 @ 8:12 AM
  quote:
34 divided by 8 = 377.7, which is 378
Regards, Steve Lee

Actually 377.7 is 377.7, not 378. And, even by your vastly incorrect calculation, 34 divided by eight is (according to you) 3.777, not 377.7.

Regardless, 34 divided by eight, at least the last time I checked, is 4.25.

Wow. All I can say is "wow".

Mike "Kube" Kubarth

This message was edited by kubes40 on 5-12-18 @ 8:18 AM


TomO    -- 05-12-2018 @ 10:35 AM
  I don't understand the whole point of this post.

Steve, you say that you have a ring and pinion in a Ford box and the ring gear has 41 teeth and the pinion has 10 teeth and the box is marked 4.10:1 ratio and then you ask the question of "Doesn't a 4:10 rear have 41 teeth on the ring gear and 10 teeth on the pinion and that is an original o'drive rear?".

You believe the box, because you say"Something s wrong. I have a NOS ring and pinion in the original Ford box. It has 41 teeth on the ring gear, and 10 on the pinion. Its marked "410 to 1 Overdrive." You can't argue with Ford."

So if you had the answer, why did you ask the question? Did you intend to start an argument? Are you trying to test the knowledge of people on the Forum? Or did you just want to waste some time?

Tom


gunner    -- 05-13-2018 @ 6:22 AM
  If you want to find out the gear ratio with out counting teeth.To check the ratio I block one wheel. I mark the drive shaft and the free wheel. On a 4:10 rear end the drive shaft should turn 4.1 times for the free wheel to turn 2 full turns. Am I wrong?

gunner


kubes40    -- 05-13-2018 @ 6:31 AM
  quote:
Hi...Large numbers of teeth on the ring mean a large diameter gear, which in most cases is not desirable, calling for a huge pumpkin. Most I've heard of have a 37 ring and a 9 pinion, which results in a 4:11 ratio, not 4.10. My '51 has a 4:11 , standard with overdrive, and a rather normal sized differential housing. My Vette has 37 and 11 for a 3:36 ratio. BT

I understand the theory you are expressing but with due respect, the number of teeth on ANY gear has very little to do with diameter.
Even narrowing this down to Ford ring gears of say, 1940... there were several different ratios (number of teeth) and yet the diameter was identical among them all.
Rest assured that as a tool maker, I made more gears than I care to recall. Some were very small in diameter yet had a tooth count over 100. Nope, tooth count has nothing to do with diameter.


Mike "Kube" Kubarth


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