proper gearing

[yukonjohn]

Acouple of years ago I purchased a 1950 club coupe. Highway speed was slow (cruise about 45). I pulled the rear end and found 4.10 gearing. I got on the (now defunct) Shoebox Central forum and was told the proper gearing for the 8BA with standard transmission. I failed to write down what it was. Anyway, I changed it and my highway speed only increased about 5 MPH. The number 3.73 stands out in my old memory. Does that sound right? It has 15" wheels and the speedo reads too fast. Could this car have had an overdrive tranny that was switched out? I need to cruise faster than 50 on state roads or get run over. Is there a recommended ratio from anyone? Thanks, John

[JSeery]

If you establish what rpm you want to run at a given mph and tire diameter there are formulas that will give you the rear axle ratio.

[tubman]

My '51 club coupe (W/O overdrive) was very original when I got it. When I pulled the rear end apart to replace bearings and seals, etc. it had a 3.55 ratio rear end. The car was assembled at the St. Paul, MN plant in late June 1951. It will easily cruise at 60-65, but I will admit, it seems to want another gear up there.

[paul2748]

I think that the 52-56 automatic rears rears had a 3.31 ratio. I don't know if the center sections fit in the 50 rear, but it's something to check out.


If not, look into a O/D trans

[Black Fifty]

I have a 1950 Custom Deluxe. I recall reading that non-OD cars came with 3.73 and OD cars came with 4.10. My two cents!

[40 Deluxe]

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Originally Posted by yukonjohn

Acouple of years ago I purchased a 1950 club coupe. Highway speed was slow (cruise about 45). I pulled the rear end and found 4.10 gearing. I got on the (now defunct) Shoebox Central forum and was told the proper gearing for the 8BA with standard transmission. I failed to write down what it was. Anyway, I changed it and my highway speed only increased about 5 MPH. The number 3.73 stands out in my old memory. Does that sound right? It has 15" wheels and the speedo reads too fast. Could this car have had an overdrive tranny that was switched out? I need to cruise faster than 50 on state roads or get run over. Is there a recommended ratio from anyone? Thanks, John

Something is terribly wrong if your highway speed is only 50 MPH! Does it lack power? Simply find and fix the cause. When the car was new (or when owned by a high school kid 10 years later) it easily ran 70 MPH or better. Is the engine too noisy (knocks, rattles, etc.) over 50? Time for an overhaul. Does it simply sound like it's revving too fast? That's only because we're used to new cars that are sound-proofed and slower revving.

[yukonjohn]

It is being torn down already for an overhaul. It did not use any oil, didn't smoke and had plenty of power with no knocks or noises but I'm installing Offy heads and duel 94's and a 3/4 cam. Thought this would be a good time to rethink the rear ratio. The 3.31 ratio sounds interesting. Probably be the old needle in a haystack trying to find one.Never heard of the formula to determine a ratio. Thanks to you all.

[tubman]

From my experience, these cars can greatly benefit from the addition of an overdrive, whether it be the stock set up or replacing the transmission with something like a T5, which has an overdrive in top gear.

[Bored&Stroked]

One of the challenges is that it is hard to have it both ways ---> nice acceleration from stop signs, up hills, etc -- and good highway cruising speeds. I just went through this with my 32 Cab. It has a 284 cubic inch engine with plenty of power. With the stock 4.11 gears, I just didn't like the higher RPMs it required to cruise at 70 - 75 mph. So, I decided to do what everybody else does - put a set of 3.54 gears in it. Well, now it is not nearly as fun to drive around the back country roads - but it is nice on the open highway.

So, what to do??? Well, I don't want to cut the car up (floorpan, open drive, etc) and install a T5 overdrive trans, so the only option for this car is a Columbia rear. I will have fun 4.44 gears in it (for around my country roads) and when it goes into OD, it will be 3.15 - great for the highway.

I'd highly recommend putting an OD transmission into your car while you have it all apart! You'll then not have to change the rear gears and you'll have good highway gears.

[40cpe]

We have gotten used to modern cars and low RPM cruising. My '55 has a 3.25 8" rear. At 60 in direct drive it sounds like it needs another gear and it is only turning 2500 RPM. With a 3.73 rear your car should cruise 60 easily. Maybe if you have an aggressive cooling fan it is creating the abnormal sound. I agree with others above, the only way to get comfortable freeway speeds is with an overdrive or an abnormally high rear gear.

[petehoovie]

I replaced the 4.11's in my '34 with 3.54's.... But I now think 3.78's would have been a better choice....It's the hills....

[flatford8]

http://www.advanced-ev.com/Calculators/TireSize/
Try this site to help with your gearing. It’s one of many online..... Mark