gear ratio

[Club Coupe]

An acquaintance is trying to give me a differential for my 1950 Ford. It has 15 teeth on the pinion and 42 on the ring gear.
By my calculations that is a 2.80 ratio. Obviously I can't use it but I have never heard of that ratio.
What the heck is it?

 

[supereal]

According to the numbers 2.80 is indicated. That ratio varies according to the engine type and transmission used. It can also vary as to the location, as hilly places require additional power. This is true to both cars and trucks.

 

[tubman]

You didn't say specifically, but is it even for an early '50's Ford? They never offered that ratio or even anything close to it. I can't believe that the after-market offered that ratio either, but never say never.

 

[40cpe]

A ratio in that range is not unusual for later automatic transmission cars. I had a 2.79 ratio 9" rear axle/302/c4 in my '40. I put many miles on it going all over the southeast.

 

[Sid]

Sounds like your friend is trying to offer you a later model 8" rear end. Is it just the 3'rd member or the axle assy.? Numerically most of the early 50's Fords had 4.11's or somewhere around 3.89's. I do know first hand that nothing numerically 3.55 down will not replace a housing that occupied the 4.11 or 3.89 gears in the 1950 housing. If you are going to retain the 49-56 axle housing you would need to use a 54-56 housing that had 3.55 gears or lower number. Reason being the ring gear hits the rear of the housing when trying to install the later highway gears. You will also find that the axle splines changed somewhere around 54-55. IMO you may be better off looking for a complete 8" from an early Mustang,Maverick or Fairlane. Your housing should measure close to 53" axle flange to flange. Same as 57-59 Ford car or wagon.

 

[37 Cab]

The maverick rear was narrower then the mustang and Fairlane. Much desired 8" rear in my opinion. Back in the 80s I built several che** luv trucks with small blocks and the maverick was a perfect fit. Just had to move the perches but width was spot on. Made a great little sleeper..

 

[paul2748]

I agree with Sid. 50's Ford rear axles had a much lower ratio (higher numerically) . The ratio you mentioned didn't come out until later with the 8 inch rear of the 60's and the center section (and gears) are not compatible with the earlier housings..


If you are looking for a better ratio, the 52 to 56 automatic rears had around a 3.31 ratio. Not sure if the 52-56 center sections fit in the 50 housing.

 

[50fordcoupeman]

Sounds like your friend is trying to offer you a later model 8" rear end. Is it just the 3'rd member or the axle assy.? Numerically most of the early 50's Fords had 4.11's or somewhere around 3.89's. I do know first hand that nothing numerically 3.55 down will not replace a housing that occupied the 4.11 or 3.89 gears in the 1950 housing. If you are going to retain the 49-56 axle housing you would need to use a 54-56 housing that had 3.55 gears or lower number. Reason being the ring gear hits the rear of the housing when trying to install the later highway gears. You will also find that the axle splines changed somewhere around 54-55. IMO you may be better off looking for a complete 8" from an early Mustang,Maverick or Fairlane. Your housing should measure close to 53" axle flange to flange. Same as 57-59 Ford car or wagon.[/QUOT

Referring to the work you did on my '50 Sid? Still working good! Thank you my friend............

 

[Sid]

I agree with Sid. 50's Ford rear axles had a much lower ratio (higher numerically) . The ratio you mentioned didn't come out until later with the 8 inch rear of the 60's and the center section (and gears) are not compatible with the earlier housings..


If you are looking for a better ratio, the 52 to 56 automatic rears had around a 3.31 ratio. Not sure if the 52-56 center sections fit in the 50 housing.

3'rd members are the same 49-56. The axle spline count changed somewhere around 55'ish. But trying to install 3.31 ratio in the 50 housing the ring gear will hit the rear of the housing. I have heard of guys heating the case and pounding where the ring gear hits. A housing from the 55-56 will fit in a 50. The only difference is it will lower the rear of the car about 1/2 inch because of the design of the perch. You would need to use the housing that had the more desirable gear ratio such as 3.23 or 3.31.

 

[tubman]

I have heard that 3.31 gears were available in Fordomatic cars in 1951. There is a gentleman on here occasionally who claims to have one and to have seen another. My '51 no O/D V8 came originally with 3.54's, so it may be possible.

Take it for what it's worth.

 

[Bored&Stroked]

Your housing should measure close to 53" axle flange to flange. Same as 57-59 Ford car or wagon.

If you're talking about outside axle flange to outside axle flange (where the brake drum sits against - a 57 Ford should be close to about 57" wide.

 

[Sid]

If you're talking about outside axle flange to outside axle flange (where the brake drum sits against - a 57 Ford should be close to about 57" wide.

I am talking about the naked housing. No drums or axles. Measuring the housing flange to flange. I do know 50-59 are the same width measuring just the housing but the perches on the 57-57 are just a tad wider by about 1/2". I think that overall width they should be very close. I wasn't clear on that earlier.

 

[Club Coupe]

Thanks, friends. I'm sure this will not work in my '50. I just wondered what car had a gearing that high. I would have to get a push to take off even if it did fit. But I will tell the owner of the rear end that it is for a much later 8" Ford. I appreciate all your responses.

 

[Sid]

I'm a little confused though. As I remember 2.79 ford 8" was a 14-39 ring pinion. I just don't recall a 2.80 ratio in a ford car in a 8" or a 9". Unless it might be from a Pinto or a Bobcat or some other compact.

 

[JSeery]

Thanks, friends. I'm sure this will not work in my '50. I just wondered what car had a gearing that high. I would have to get a push to take off even if it did fit. But I will tell the owner of the rear end that it is for a much later 8" Ford. I appreciate all your responses.

Automatics can use the higher gear ratios.