The guy whose car is too fast with a new idea.
 

I'm the guy who is trying to slow down a model A project because it goes too fast to crawl around car and tractor shows. It has a standard A three speed and rear axle.
Recently ran across a "dual high underdrive". Looks like it would bolt up to the back of the three speed without much problem (or would it?) but would need some fabricating and machining to attach to the drive shaft.
My other question is, does anyone know how much it underdrives? As near as I can find it is 1;1.57. Which I think means if my low speed is now 9 it would be 6 with this added.

Re: The guy whose car is too fast with a new idea.
 

You better talk to some other A owners to see what is going on with your car. In low gear at a cackle, it is slower than a walking person.

Re: The guy whose car is too fast with a new idea.
 

I am building a speedster using a combination of Ford A and tractor parts. The tractor engine does not have a real wide range of RPMs. I need the thing to drive slow, like four or five MPH, for tractor shows.

Re: The guy whose car is too fast with a new idea.
 

Dual high requires an AA crossmember and special holder/mount for it. Be much easier to install a 4 speed.

Re: The guy whose car is too fast with a new idea.
 

Will a four speed slip into place where a three speed used to be or will it also take modifcations?
And, so far the cheapest AA four speed I've found is $1800.

Re: The guy whose car is too fast with a new idea.
 

Here is a link to Vince's site on putting a AA 4-speed in a Model A.
http://www.fordgarage.com/pages/aafourspeedachassis.htm


Bob

Re: The guy whose car is too fast with a new idea.
 

Truck bell housing, but the U-joint is the big hurdle.

Re: The guy whose car is too fast with a new idea.
 

How did you mate the engine to the trans? Is there a way to run a jackshaft or a gear reducer there? Is it a Dubuque two cylinder?

Re: The guy whose car is too fast with a new idea.
 

It is an L engine. The front transmission shaft was adapted to fit the L clutch splines.

Re: The guy whose car is too fast with a new idea.
 

Could you move the engine forward enough to put a gear reduction in there? Are you using the clutch on the engine? That is a Hercules engine. Higher RPM than Dubuque.

Re: The guy whose car is too fast with a new idea.
 

Install the AA truck 1929-1931 4 speed trans . It has a granny gear, and bolts right in. If you need any of the pieces Bert's Model A Center in Colorado has all the parts you need. It is an easy install. Not pricy

Re: The guy whose car is too fast with a new idea.
 

It’s a later L so it is a Deere engine

Re: The guy whose car is too fast with a new idea.
 

Doesn't that L engine idle as slow or even slower than an A engine?

Re: The guy whose car is too fast with a new idea.
 

No. And since it is significantly less horsepower than an A engine, you need to keep it wrapped up a bit.

Re: The guy whose car is too fast with a new idea.
 

https://www.fordbarn.com/forum/showthread.php?t=250962
You could keep it really simple and install a chain drive reduction between the transmission and final drive. Also the size of your rear wheels will change ground speed. How were you planing to install the rear axle?

Re: The guy whose car is too fast with a new idea.
 

Maybe doing a little math before choosing parts will help. Find out the gear ratios of your current trans and rear axle, tire diameter (or circumference), the RPM your engine needs to run at, and plug these numbers into a formula that will give ground speed. Or, switch the formula around to find the ratios needed to attain desired ground speed. Then look for trannies and/or axles that give that ratio. Maybe both an AA four speed and a "dual high" under drive will get 'er slowed down.

Re: The guy whose car is too fast with a new idea.
 

Yeah, unfortunately that ship has already left the dock. I think if I can find and install a four speed I will be good.

Re: The guy whose car is too fast with a new idea.
 

Put a second Model A transmission in it. When you put them both in reverse it will go forward so slow you can walk next to it.