gear ratios

I was wondering if anyone out there that's done a conversion to steam could tell me what sort of gear ratio they used. I've been researching ring and pinion ratios. The ratio that I think would be closest to what you would want with steam that i can find is 2.14:1. It came in gm products. Anyone know of anything more suitable. As always open to any suggestions criticism whatever.

Hi Joe,

As phrased, I don't think the question is answerable. It's going to depend on the engine torque curve, rpm, vehicle weight, designers expectations for cruise and acceleration, gearing of transmission (if any). 'Fer example, when you say 'conversion to steam', that is covering a whole lot of variables. A 2 cylinder, 1200 rpm, DA simple engine like a Stanley fits the bill. So does a 4 cylinder bash valve running 5,000 rpm. The torque curves are wildly different, in meaningful terms the traditional engine can't even reach cutoffs as short as the bash valve and likewise the bash valve is never going to work with the kinds of long cutoff the other can see. Like I said, expectations count for a lot, too. If you are looking for long distance, efficient cruising the gearing will be different than if you want fast acceleration --- even if everything else is held constant.

Regards,

Ken

Ken,
I realize and understand that there are many variables I certainly could have worded it better. I'm just interested in other peoples experiences wondering what they used and how well it worked for them. I'm sure my car may be entirely different. I'm going to use a transmission with 2 speeds, have even considered whether a third overdrive gear would work better under certain conditions like cruising on the highway. As always open to any and all suggestions critisicm what have you. Thanks.
Joe

Joe, Give us some idea of what your design estimates are and we will see if we can give you some ideas of what gear ratios have worked in the past for us. What is the vehicle's expected weight? What is the evaporation rate of your boiler? What is the expected hp and torque from your engine? At what RPM does your engine's power curve really start to diminish? What will be the outside diameter of your drive tires?

With our 1909 to 1916 Stanley steam cars, their rear axle ratios vary from: engine/axle 2 to 1, to: 1 to 1 using 36" outside diameter diameter tires. These same cars' curb side weights vary from 1,500 pounds to 5,500 pounds. Their horse power ratings vary from 10 hp to 30 hp. Their comfortable higher cruising speeds vary from 45 mph to 60 mph. Their kerosene/gasoline consumption varies from 5 miles to the gallon to 10 miles to the gallon. Without condensers, their water mileage varies from 1/2 mile to the gallon to 1.25 miles to the gallon. And they all are good hill climbers. A modern steam car should easily improve on these 100+ year old statistics. It is my guess that there are easily eight more vintage steam cars being assembled each year from parts new and old. I have personally scratch built two Stanleys from about nothing but an engine. It is a lot of fun creating a steam car.

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