Hi all-
Novice question but how can I tell which size wheel to use to replace current stock?
Thanks in advance,
Hi!
Last year I replaced a large number of wheelsets on my 1950s era HO rolling stock. Passenger cars got 36 inch, and freight 33 inch wheels. Intermountain was my choice, and I’m happy with them.
You can place the two different wheelsets together side by side to tell one from the other, or use a micrometer.
ENJOY,
Mobilman44
Intermountain was also my choice. They seem to roll very well. The rule of thumb I uses was out of the Model Railroading “Getting statred in the Hobby”.
They recommend 33’ for all freight cars with 70-ton (140,000 lbs) capacity or less. The 36" are for passenger cars and all freight cars of 100-ton capacity. (Greater than 140,000 lbs.) Anything above 210,000 lbs should use 38" wheels.
Check the (“CAPY”) line in the car’s data listed on the side of the cars.
Good Morning,
The size of the wheel is an indicator of the weight it must carry. The size of the axle and the bearing are the main items, but the wheel diameter is something ‘visual’ the modeler can see. Basically the following should be a rough guide:
28" - Some intermodal flat cars that cars that carry truck trailers, and auto racks(reduce overall height).
33" - Up to 77 tons capacity. This would include most box cars and just about all freight cars in the 50’s transition era.
36" - Passenger cars, and any freight car over 77 tons capacity, up to about 112 tons capacity. Modern coal hoppers and grain hoppers fall into this area.
38" - 112 to 125 ton capacity. Some high capacity hoppers fall into this area(check your prototype).
The larger the diameter of the wheel, the larger the ‘contact patch’ is on the rail. There are exceptions to the above guide, but as a general rule this information should work. Note that many model train manufacturers use 33" wheels on everything they make(lower production cost).
Jim
If you are not sure what size you have, purchase a dial caliper. The calipers come with US and metric marks. I have a inexpensive plastic one I purchased a number of years ago and just purchased a digital caliper from Micro Mark. The digital gives you a direct reading. Less chance of error. Take the reading and multiply by 87 for HO scale. You can find decent calipers for about $25.00. A truck tuner from Micro Mark is a good tool to have. Some wheel sets are a little longer than others and the tuner helps a lot in this case. I usually measure the length of the original wheel set and order the appropriate one from Reboxx who sells wheel sets of different lengths. Make sure you get a wheel set with metal wheels.
Rich
Hi!
I too bought a digital micrometer last year when I was replacing wheelsets. I never thought I would have a use for one, and now find I use it for all sorts of stuff. Also picked up Micromart wheel tuner, and found that my BB old Athearn cars almost never needed any “truck work”, while most of the others did. As one who has been in HO since 1960, I can’t say enough about those Athearn kits!
Mobilman44