VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1931 Differential Highway gears

Hi everyone,
Having been in the club since the 60's I've heard tell from time to time of someone in the club who made highway cruising differential gears for a '31, or possibly that even fits other years.
I would either like to obtain a gear set or locate the person who designed and had them made and get the spec's and drawings so I can do the same.
Does anyone know who this was by chance?

Larry Jackson was the member who made the 3:50 gear sets. They have not been made for many years and I do not have contact info for him.

Near the end of production the gear sets were selling for around $1,000 per set. The gear sets were advertised in the G&D for several decades.

Thanks Steve!

i went through this 3:55 business some time ago now, maybe last year i scored a set. the "wanted" notice i placed in the g & d paid off. i previously had spoken with larry jackson for the back story and also our fine club reference folks, placed wanted notice in our tappet & clatter and etc. i got two responses through the g & d. paid $550. wonderful change. '30 through '32 will work. check out the "search" function here going back a few years. good hunting. jim

you dont know where i could get a set of 3;50 for my 31 i would be happy to find a set

1931 coupe, the best way i know left is to take out a "parts wanted" ad in the g & d. i tried my local "tappet and clatter" and "wanted" notice board here. no deal. you might place an ad in each of our regional club's newsletter. good hunting. jim

I have what is perhaps the last set of highway gears that Larry Jackson made, still wrapped up and still in the box that he shipped them in. I will sell them for what I paid for them plus shipping.

Consider them sold to me!!!!

Hi all, I know the 3.55 gears are all gone now but look what just happened here, long shot but if someone out there has a set that may be for sale please contact me here, I have a friend who has a set in his 31 roadster and it goes sooo much easier than my 31 5 window, as I said a long shot but one never knows.

Thanks
Brian

I am also looking for a set of the Jackson differential gears for my 32 Sedan

bobl,
I contacted you with a private message. I would like to complete the transaction for the highway gears.
Dave

If someone does get a set of these in their hands, it would be nice to see if they could be copied by someone to produce future sets. You might end up with your set for "free" by doing the legwork to get additional sets made and collecting names and some deposits to make it happen.

There always seems to be people looking so while having a fresh set in hand it might be worthwhile to ask around to feel out the demand.

I'm sure there are others that my not even belong to this forum that would like to have a set of highway gears. Copying those gears with today's technology would be pretty easy to do.

i would be interested in a set as long as the fit the 1929

main thing is to get them reproduced. once all the leg work is done the rest is cake walk. we do some gears at work, but not these type, but we work with machine shops that only do gears. your stock material is also KEY, need a good strong quality base to start with or you may loose a few teeth.

I might be interested in a 1929 set but as they only fit that years might be an issue. Already 1929 gears have a more favorable ratio then 1930 and later. I believe 29 is 3.84 and 1930 (plus several years after) are 4.11. I thought I read somewhere this was done to give Chevs more pep from the start as Ford's were just a little quicker off the line.

The 4:11 gears are just to slow for today's traffic. Besides myself I know of at east one other owner of a 32 that would like to have a set.

If someone takes on this project of producing a rear gear set (higher 3.55 or so), I would also be interested in buying a set. Thanks.

So I did a quick calculation for 1929 with 3.84 gears. With tire diameter at about 30.5" engine rpm should be 2540 at 60 MPH. Changing to 3.55 gears would only reduce engine speed by about 190 rpm. I believe top rpm for a 1920 was 2600 so if the bearings are good and oil system is clean and flowing properly 60 mph should not be an issue for a 1929. So the expense of making gears for a one year model may not be reasonable. Taller tires would slow down the engine as well. For later years with 4.11 gears changing to 3.55 makes a bigger difference and as there are more years covered the cost could make it worth while.

yeah larger tires, lower engine rpm, faster speed

if i had a set in hand i would be talking to gear shops on reproduction and cost per each and base load ?!? sure hte initial set up and cost would be high, but would have them available if needed... (no chipper not THAT Guy, lol)

I would be willing to bet there are other owners of these cars out there that don't belong to this forum that would want a set as well.

I wonder if Larry Jackson still has the technical data to build these gears?

That brings up another issue, if you change gears or use larger diameter tires your speedometer will be off. Anyway I do have a NOS set of 1929 gears. Maybe to make it more worth while for 1929 the ratio could be 3.23 or so? That would bring engine speed down to about 2140 at 60 mph or almost 70 mph at 2500 rpm. Might be sluggish at the start though. Now you would be approaching a speed where wheel balance and braking efficiency might start to become issues.

not sure i would want to do 60 let alone 70 in my 1929
cruising all day at 45 would be nice at lower rpm, maybe 50

Well at 45 your engine should be at about 1900 RPM which should be quite comfortable for it.

I totally agree, that would be a crazy experience 60-70 mph in a '31 leave me out of that, you still have to corner and stop, they were never designed to do much more than 40 mph, I want to travel at 40-45 a little easier than now