Nash Model T Speedometer Setup

[Manitouc]

I have a Nash setup on my car. Works ok but the speed registers low. Suspect I have the wrong gears in it. Does anybody have setup information or spare parts on these?

[ewdysar]

Do you have any idea about the tire size for the Nash car that the speedometer set up came from ?

That will give you an idea of how much of a correction that you will need. The only thing that a speedometer cares about is the tire circumference and therefore, the number of rotations per mile. If the tires were close in size, that may point towards getting the speedo adjusted back to spec, rather than a change in gearing.

Here on the forum, Russ Furstnow is the guy that can answer almost any question about period speedometers.

Keep crankin',
Eric

[Shannon_in_Texas]

Grant, are you referring to the speedometer drive that is incorporated into the transmission door?

If so, these threads may have some useful information:

https://www.mtfca.com/discus/messages/1 ... 1288740654

https://www.mtfca.com/discus/messages/5 ... 1439205405

https://www.mtfca.com/discus/messages/5 ... 1431056113

[ModelTWoods]

Yes, there was a speedometer drive offered under the brand name of NASH, NOT to be confused with NASH, the brand of automobile. The NASH speedometer drive added a gear inside the main drive of the transmission, and another gear held against it by the transmission inspection cover. They are probably rarer than most, if not all, Stewart speedometer drives.

[Manitouc]

No idea what this came off of but my car has 30-3-1/2 tires on it. Some literature on this would greatly help me. Russ Furstnow has nothing.

[ewdysar]

In one of the threads that Shannon posted, the Patterson version of the transmission drive speedometer had various combinations of gearing to suit different Ford configurations as noted here:

In the same thread, the original Patterson documentation shows what speedometer gears match up to which Ford tires and rear-end gear ratios:

The Nash speedometer set-ups might have similar parts. So, I think that you need to figure out which speedometer gears (drive and pinion) that you have compared to what tires and rear-end gear ratio that you are using. From that, you can start backing into what different speedometer drive or pinion gear that you might need based on how far off your odometer reads.

I say odometer, because that is a geared connection in the speedometer head and it will more accurately indicate whether your speedometer cable is turning slower, faster or just right for your speedometer head with your current speedometer drive and pinion, tires, and rear-end gearing. And given the age of our cars, we can't assume that things are as they one were. You might not be running with the stock Ford gear ratio, but at least it's easy to tell the tire size.

If you determine that you need to change the speedometer drive gear and or pinion, then at least you will know what you're going to be asking for.

As you learn more specifics about your installation, report back here and someone might pop up with just what you need.

Keep crankin',
Eric