I am planning on replacing the plastic wheelsets on my rolling stock with metal wheelsets. Can anyone tell me what the difference is between the various sizes? How do I know if I need 33", 36", 28", etc? Thanks in advance for any help!
Hi,
I replaced all of mine with Intermountain a few years ago. If you can do it, buy in bulk (see Ebay) as there is a major cost savings.
For most all freight cars before 1960 (or thereabouts), 33 inches was the norm. For passenger cars, 36 inches was used.
To tell the size you can use a scale ruler for your scale and measure the diameter. You can also use digital calipers for taking the measurements and do the scale conversion on a calculator.
As you get into this, you may find items such as the following useful:
a) a nice MR article on freight car trucks you can download
b) a couple of listings on the Reboxx site that show info on stock axle length, etc so you can help choose a compatible length with your replacement
http://www.reboxx.com/wheelsets.htm
Many folks advise to always use a MicroMart “truck tuner” or similar tool to ream the cone within plastic truck frames to remove burrs, etc to ensure a good axle nesting point. I also found it helpful to buy a moderate price (about $25) digital caliper to ascertain stock axle length when I was substituting. For freight cars I settled on 33" Intermountain primarily, Proto 2000 backup. Some folks like other brands (e.g., Kadee, Reboxx) alot also. The P2K I can get in either smooth back or ribbed back 33" wheels, the latter for older freight cars. Suggest you can do a roll test on a slope with rollout and easily see big differences as you work on this.
There are a number of older threads on metal wheelsets but I have limited luck with the search feature. An example follows.
Although there are exceptions, typically a 30, 50 or 70 ton freight car would have 33" wheelsets, while a car of greater capacity would have 36". Cars that may have 28" wheels include tri-level auto racks and spine cars.
What difference does it make?
You will find out when you try to line up the couplers, and so what is prototypically correct might be wrong for your model. IIRC the old Riverossi / IHC cars had undersized wheels when new, and replacement wheel sets could cause parting especially at the crest of a hill.
I would of course put the correct size wheels on and then correct the couplers as needed.
ROAR