Re: COLUMBIA with 3.78 gears
 

so 38 Coupe - with your chart (thank you very much!) 2354rpm @ 65mph is indicated for a 4:11gear and Columbia in high with a 28" tire - so both Kahuna and I are in sync at the "guestimated" 2300 rpm at 65mph - although with my 30" tire I am probably a tad lower rpm at 65mph - nice to know.

Re: COLUMBIA with 3.78 gears
 

I apologize about the fuzziness of the chart. I can email a pdf copy to anyone interested, just send me a private message with your email address.

The chart is actually just a pdf print of a spreadsheet I put together out of curiosity. I can change the tire diameter and the calculations change. With a 4.11, Columbia, and a 28 inch tall tire you are spinning 2316.1 rpm at 65 miles per hour, plus or minus actual tire radius. 2300 was a really close guesstimate. With a 30 inch tall tire your rpms drop to 2161.7, plus or minus.

Re: COLUMBIA with 3.78 gears
 

Nice chart. You can also find calculators online but it is a fairly simple equation to figure by hand.

Re: COLUMBIA with 3.78 gears
 

Some time ago there was a chart on another forum that showed a relationship of tire size (diameter) to gear ratio change. I have never been able to find it again, but it was really informative, as you could factor a tire change and make a calculated guess as to speed changes, etc

Re: COLUMBIA with 3.78 gears
 

Chart is interesting! Can you attach the spreadsheet file instead of the image?

Thanks,
Glenn

Re: COLUMBIA with 3.78 gears
 

This is a great discussion, thanks for all your inputs!
So my 32 Vicky has a 4.11 Columbia. The tires are stock 18" Firestones, about 28+" tall. During a recent drive from Niagara to Maine along secondary roads it performed flawlessly. Especially through the hills of Vermont.
I have an acoustic tachometer app on my phone (RPM Gauge) that indicates 2220 RPM at 60 mph.
Driving locally,with mostly flat lands, my shift points are into 2nd at 15mph, 3rd gear at 25mph and OD at 40mph. Shift points are higher if I'm winding it through the gears obviously, but during normal leisurely driving I am in OD pretty soon.
The car pulls very well at low RPM even with a mild Winfield cam.
Prior to the Columbia install, I ran 3.54 gears with no problems except I wanted an extra gear on the highway.
So with you all have presented so far, I am leaning strongly toward a 3.78 Columbia in my coupe.
Now, where can I find an NOS ring and pinion? Ted

Re: COLUMBIA with 3.78 gears
 

Maybe! The image I posted is actually part of one tab on a larger spreadsheet. I originally created the spreadsheet to help me decide what main and auxiliary transmissions to run in my 1950 F-2 pickup. I added tabs for the Ford cars when my dad added a 46 tudor to his fleet and we wanted to decide what type of overdrive to install in his car (I like the 26% Mitchell with the 3.54 axle). Adding to the complications is I run Xubuntu (a version of Linux) on my home computer and the spreadsheet file type doesn't play nice with this website. I have tried to pull out just the two Early V8 related tabs out, convert them to older Excel .xls file types, and then compress them into a .zip file that this website will allow as an attachment. I have no idea if the resulting file will be usable once it is downloaded and uncompressed. I expect at the least the formatting will be different.

Kahuna, if the attached file doesn't work for you then you can do a little math with my previously posted table. Take the RPM and multiply:
With a 25 inch tall tire multiply the rpm by 1.120
With a 26 inch tall tire multiply the rpm by 1.077
With a 27 inch tall tire multiply the rpm by 1.037
With a 28 inch tall tire the chart is accurate
With a 29 inch tall tire multiply the rpm by 0.966
With a 30 inch tall tire multiply the rpm by 0.933
With a 31 inch tall tire multiply the rpm by 0.903

JSeery, true the math isn't too difficult, I just like the table with color bands for comparing options.

Re: COLUMBIA with 3.78 gears
 

My '36 Ford coupe is a DeLux 5 window with just about every accessory that Ford offered, and a few they did not offer, therefore it is a little bit on the heavy side.
The engine is a well built 59AB with a .060 overbore, trans is a 28 tooth column shift unit bolted to the original drive-line and 3.78 center section. The Columbia rear end is a '47-48 unit adapted to the '36 banjo, etc. using '37 radius bars.. A bolt together application.
During the 62 years I have owned the car I have driven it through out the eleven western states under ever road condition there is. I used the car as my everyday work car for over four years on the freeways of Southern California, then raced the car on the weekends at local drag strips and street racing.
The Columbia and the 3.78 gear ratio never presented a problem, in fact it was an advantage because I did not waste energy smoking my tires, in many races I never got out of 2nd over.

Re: COLUMBIA with 3.78 gears
 

I used to have two of them: '40 tudor and '47 tudor, worked wonderfully! I wish I had one in my '40 coupe.

fordman

Re: COLUMBIA with 3.78 gears
 

Columbia's are neat stuff IF you don't abuse them with a lot of horsepower in overdrive.
In original unmodified form, they won't stand up under the shock loads of drag racing or applying big horsepower.
Here is a company that knows what it takes to keep one together.
http://www.columbiatwospeedparts.com...tproofing.aspx

Re: COLUMBIA with 3.78 gears
 

Hi,

Just noticed that you replied to me ages ago! Yes, I had a little trouble with the files. I do run Ubuntu on a netbook I have so maybe you could just send me what you use for an application there.

Thanks,
Glenn

Re: COLUMBIA with 3.78 gears
 

I have a very stock 39 with 3:78 gears and a columbia. If you do a lot of driving this is an excellent combination that will handle hills, flats, city , country, whatever. This combination will serve you well.

Re: COLUMBIA with 3.78 gears
 

Good David, that's what I have in my 32 roadster with 59A motor. I hope to be driving it next Summer.

Re: COLUMBIA with 3.78 gears
 

I am building this combo for my 32 three window with a strong flathead. Having the 4.11 in a similar 32 Vicky, I am confident that 3.78's are an excellent choice for me. Appreciate your input! Ted

Re: COLUMBIA with 3.78 gears
 

have one in my 46 coupe with merc crank and 3.78 im happy with it.i wired in a bypass switch so it will stay in od if u want when u push in clutch.

Re: COLUMBIA with 3.78 gears
 

my first columbia was in a 34 w/17'' stock whls w/?cam, was gutless, needed more rpms to run good. next was a 1940 w/ mild eng ?cam, 25t linc gears 4.44 rear,28''tires, sold it man said ran great on hiway at 80mph. next[stii have] rdst pu w/8ba, 400jr cam, heads 3/2s, 26t linc grs, 4.44 grs 7:00/16 trs, was awful to drive w/400jr cam needed to be excelerating and more rpm's than i had the way i drive. pulled the 400 cam and put back in the stock 53 merc cam, a completely different car, great to drive. next, i'm still working on it, i'm out of linc gears so its a 8ba, stock cam, orig edlbrok blok ltr hds, slingshot int, 39 linc gearbox w/48 ford gears, columbia w/4.11 gears,31'' 7:50x16 trs. i like the 4.44 rear gears but you need 25 or 26 tooth trans gears to run them or you run out of rpm's quick. i like to lug around in hi gr at 35-40 hph. cam, trans grs, tire size, how you drive = rear gr ratio.. just my 2 cents

Re: COLUMBIA with 3.78 gears
 

This post is now 6 years old. Can people with 3.78 columbia comment any further. Lawrie Kyte is currently building a 4.11 columbia for my stock 35 powered convertible. But the roadster will have heaps of grunt (286 MCF) to run a 3.78 with columbia. I’d just like to hear peoples actual experience please before we purchase another crown and pinion as the rear axle I just stripped yesterday was cactus. Thanks.

Re: COLUMBIA with 3.78 gears
 

Hi Dan,


The 3:78 ratio is great with my roadster. Shown below is in my profile but just so you know that I have a great motor too.


Original 32 Ford steel roadster

- 268 CI 59A block
- 4" Merc crank
- 0.400 Offenhauser heads
- Isky Max 1 cam
- Dual Stromberg 97s
- 39 transmission with LZ 25 Tooth gear set
- Columbia 2-Speed rearend

Re: COLUMBIA with 3.78 gears
 

It’ll work ok. Got one in my 40 with the 3:78 which is a heavier car and it’s great. I drive it daily and has a stock 221 ci flathead.

Re: COLUMBIA with 3.78 gears
 

I have put many miles on my two cars, a '34 Cabriolet and '34 5w Coupe. They both have a 276 cu flat, 400jr cam in both. I've been very pleased with the 3:78 Columbia in both cars.