Wheels, metal or plastic?

Wheels: Metal or Plastic?

Q) I'd like to ask about whether to use plastic or metal wheels and I can't find much in the magazines, etc. I was hoping someone here would be able to help.
A) There is a little more to that question than just metal or plastic. All wheels are not created equal whether in plastic or metal. Some of the older rolling stock has plastic wheels where the wheels and axles are all molded as one piece. Many times the wheel flange is very deep and sharp like a 'cookie cutter'. This is not good. The NMRA developed a Recommended Practice several years ago (RP-25) showing what a good wheel should look like whether metal or plastic. It is the quality of manufacturer and following the RP-25 contour that makes a better wheel.

Q) What are the parts of the 'wheel' and what do they do?
A) When you look at a train wheel, you will see that the inside of the wheel is deeper. That is the flange. Then there is the wide portion that rides on the rail. That is the tread. The overall depth of the wheel including flange and tread is the width. The better wheels are mounted on an axle and can be adjusted slightly by rotating the wheel on the axle and pulling or pushing at the time you rotate it. This allows you to adjust the 'gauge' (distance apart) of the wheelset. Most people tend to think of the wheels and axles as 'wheels'. They are really wheelsets.

Q) What problems do we have with wheels and wheelsets?
A) They may be out-of-gauge too wide or too narrow. They may also not be centered correctly on the axle leading to a wobble (if crooked) or an up and down pumping action if mounted off-center. This can happen with both plastic and metal. Wheels will also pick up dirt from the track and form a build up on the tread. This makes the flange grow smaller until derailments occur. Simply clean the buildup off. It is harder to see this buildup on plastic.

Q) Why isn't a deeper flange better then?
A) Deeper flanges may appear to run well on higher track such as code 100 in HO, but will begin to bottom out in turnouts and even hit the ties and spike heads on lower, more nearly prototypical track such as code 85 or even 70 in HO. There is nothing like taking your cars to another layout and watching them bounce down the track and derail. This is where the RP-25 wheel contour comes in. It has a wheel shape that is more like the real thing and will run well on a large variety of track sizes. In fact many clubs require wheels with the RP-25 contour.

Q) OK, but what about metal wheels?
A) As we get more deeply into metal versus plastic, I want to say that I use plastic wheelsets primarily from Athearn and MDC/Roundhouse. I replaced most of my poorer wheels and axles a long time ago and completely replaced many of the older truck assemblies themselves when necessary. I didn't consider metal an option then. That said, I still use good plastic wheels and have had very few problems that cleaning didn't fix.

However, I can say that metal wheels have come a long way in the last few years. Kadee has had metal HO wheelsets for many years and a number of newer manufacturers have brought out some great wheelsets. Some of the new metal wheelsets are nothing short of fantastic. Some are even 'blackened' to take away the metal shine. Reboxx, for example, has some with axles that match specific model manufacturer's wheelsets to facilitate 'drop in' conversion. They look and (apparently) run great. The only downside with the Reboxx is that they are the newer .088 width, but that seems to be working well with the NMRA track standards.

Q) Whoa! Newer narrower width! Aren't all treads the same?
A) No. Many modelers are looking for a better looking wheels saying that the 'standard' wheel is too fat and some manufacturers have responded with a narrower tread. For example, the NMRA S4 Wheel Standard calls for .108 inch width in HO. I guess that means that you might have some problems with some track turnouts for example, but if everything else is up to spec, the .088 should work well.

In other words, the choice of metal or plastic is really up to you. I have a couple of Life-Like Proto2000 cars with metal wheels that seem to be working well for me. Now with that, I want to share an answer that one of our volunteers gave in answer to the metal versus plastic question.

Take it away, Eric

I have several different brands in use. I really like the Jay-Bee wheelsets, but price and availability in my area can limit my purchases. Kadee are the dominant style, and the Proto2000 wheels are okay. Sometimes you will find a Proto set that isn't quite up to snuff. Here's how the pricing has worked out, from cheapest to most expensive

I have not tried the Intermountain sets.

Of course, you probably are wondering why I change out the wheels. Here are a few reasons:

  • metal wheelsets add a bit more mass
  • metal wheelsets seem to run through rough track easier
  • I like that clickty-clack
  • using metal wheelsets seems to cut down on dirty track

This last reason has little scientific merit. On several discussion lists, the metal vs. plastic argument erupts every few months. Several modelers have noticed a distinct improvement in track cleanliness once all rolling stock is switched to metal wheelsets. I have seen arguments noting that plastic wheelsets leave an oily residue on the rails that builds up to the 'black crud' that needs to be cleaned off of the rails to make things roll again. Some have noted no difference on their layouts. I think much of this comes down to two other factors in our layout rooms.

Humidity and dust control.

Keeping dust under control and humidity at a constant percentage may do more to keep track clean than changing wheelsets. I am unable to control either aspect at this time in my layout room.

I hope this helps you out.