Mixing wheel set sizes

[kasskaboose]

I model the early 1980s and have different freight cars of varying lengths.  I'm soon going to replace some plastic wheels on centerflow hoppers (w/ build dates from the 1960s or 1970s).  Most of them have 33" wheels but I do have other freight cars with 36" wheels. Should I make all the freight car wheels the same size?  As a test, I've not encountered any derailment issues when running consists with one car having 33" wheels next to another with 36" wheels.

Thanks all!

[DSchmitt]

kasskaboose

Most of them have 33" wheels but I do have other freight cars with 36" wheels. Should I make all the freight car wheels the same size? 

/

 

No. On an reasonably accurate model the wheel size a model manufacturer puts on a model is deternined by the wheel size on the prototype. 

Although the difference is slight changing the wheel size could result in problems with the vertical alignment of couplers.  (assuming the alignment is good to begin with).   

[maxman]

kasskaboose

I'm soon going to replace some plastic wheels on centerflow hoppers (w/ build dates from the 1960s or 1970s). Most of them have 33" wheels but I do have other freight cars with 36" wheels.

There's what came with and what the car should have.  If they are centerflow hoppers and have 100 ton weight limits, then they theoretically should have 36 inch diameter wheels.  On the other hand, if the manufacturer designed the car around 33 inch wheels then installing 36 inch wheels may cause rubbing on the underframe and other issues.

[slammin]

In HO scale a 36" wheel is .034" taller than a 33" wheel, roughly 1/32 inch When you figure from the center line, .017"  20 pound printer paper is .004 thick, so your looking at about the thickness of 4 sheets of paper. 

[Bundy74]

maxman

 

 

kasskaboose

I'm soon going to replace some plastic wheels on centerflow hoppers (w/ build dates from the 1960s or 1970s). Most of them have 33" wheels but I do have other freight cars with 36" wheels.

 

 

There's what came with and what the car should have.  If they are centerflow hoppers and have 100 ton weight limits, then they theoretically should have 36 inch diameter wheels.  On the other hand, if the manufacturer designed the car around 33 inch wheels then installing 36 inch wheels may cause rubbing on the underframe and other issues.

 

Depending on who made your cars, adding the correct wheelsets should result in a correct height according to an NMRA guage.  As an example, all of my Accurail ACF 4600s and PS4750's have 36" wheels, and did not require any adjustment.  

 

My Athearn PS4740's on the other hand are all different, and have required adjustment and shims to get the couplers to the right height.  I still use 36" wheels on them though.

 

Generally, 100 ton cars have 36" wheels, while 50 and 70 ton cars have 33" wheels.  You can deduce this based on the capacity on the car side (assuming that is correct).