Athearn gear ratios


T

trainman78

Member
Does the Atheran SD45 and SD50 have the same gear ratio i would like to use them as a pair but i dont know if they have the same gear ratio and if not would working them as a pair cause damage to one or both? and if they dont have the same gear ratio could one be changed/modified to match the other?

Thanks in advance

Chris
 
Would think Athearn would use the same gears since both are 6 axles. The only difference might be the plastic side frames which has nothing to do w/ the gears. Theirs no reason for Athearn much less EMD to "reinvent the wheel" for gears in the trucks. But there still could be differences in all the mechanisms involved that they wont run at the same speeds. Make sure that both are broken in good. Then run them on the same track but not connected to see which one runs faster & by how much. If you don't have DCC run the faster one in front if the speed differences aren't too horrific. That's one of the advantages of DCC, loco speeds can more easily be matched.
 
are we talking older Athearn vs new? or both are of the same years of MFG?

I know Proto 2000 went back and forth with ratios on some of their locomotives. Not sure about Athearn. If you can run them both on a section of track it should be obvious if one is alot faster than the other. if they are both about the same speed I put the faster one up front and let it pull on the slightly slower loco. Regardless if both run about the same and the faster one is not slipping or dragging the slower loco you will be all good.
 
I don't think Athearn have changed their ratios at all over the years, the spare gears you can get for them are a 1 set fits all type of thing. Proto's seem now to be closer to Athearn's, my P2K SD45 from the runs with factory Tsunami sound in them, match the similarly equipped Genesis locos very well, The earlier P2K's are slower, but very smooth, especially take off and stopping in DC, they can be controlled to an absolute crawl.
 
Athearn has pretty much kept to the same gear ratios for years. It was never an issue with their stuff. Life Like, Proto, on the other hand, varied by release/ unit modeled.

The only way to truly find out if two units are compatible, is to put them together and see what they do. If you are using DCC, you can speed match them if they are not quite right.
 
Are you going to run DCC? If you are it shouldn't be too big of an issue since you can fiddle with the various values in registers to make them behave the same.
 
Athearn's Flexicoil 3 axle truck is the same gear ratio as their HTC truck.
In English, that means the SD45 and SD50 have the same gear ratio. There may be differences in motor windings, mechanical resistance, and other drive train components that might make a difference. Also, the really old metal sideframe trucks will have a different rolling resistance than the newer, plastic-sideframe trucks.
 
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