Based on experience, there’s no doubt in my mind that they do. They seem to roll much more freely. I’ve never understood why. It seems to me the important factor would be the friction between the axle ends and the pockets in the truck. I don’t know why that would be different if there are metal or plastic wheels on the axles.
Whenever I put a new piece of rolling stock on the layout, I do two things. I put KD 148 whisker couplers on and replace the plastic wheels with metal if they don’t already have them. The replacement wheels definitely make them roll better even if I don’t know why.
The overall construction of metal wheels makes them more rigid; allowing them to ride more consistently on top of the rails than flexible plastic wheels
Metal wheels add weight that aid in rolling inertia.
The major problem with derlin wheels is they pick up oil and dirt then spread it all over the layout. Nickle silver wheels usually do not do that the wheels and the layout keep clean, it is the reason our club bans plastic wheeled cars.
Scaled down, same reason the real railroads use metal wheels - Contact area. Smaller contact area means less friction.
And as Rick J mentions, the “crud” that plastic wheelsets gather (and spread) affects that contact area. More build-up of crud on the wheels makes a bigger contact area, making more friction. (And more crud on rails makes less power transmision ability.)
I agree 100% about the metal wheels usage. Also, I am learning metal wheels performance can decrease or increase based on the truck in which they are installed.
A lot of it is angular momentum. While total angular momentum isn’t much on scale wheels, the angular momentum of metal wheels is still much greater than plastic, because of the difference in density of the materials.
That gives metal wheels more ability to roll past a brief increase in friction that might be caused by dust in the bearings, and also a bit more ability to roll over irregularities in the track that might stop or significantly slow plastic wheels.
Also, many brands of metal wheels are turned rather than just cast, making them much more consistently round than their plastic counterparts, so the car’s linear momentum is dissipated much more evenly than is a car’s that has plastic wheelsets.
My guess is that the largest part of improvement (even with clean plastic wheels) is a much lower friction factor of the metal rim to rail vs. the plastic rim to rail. I believe that a push of a plastic wheeled truck along a straight piece of track will cause it to roll considerably less far than a similar truck with metal wheels in almost all cases.
The frictional force against movement is a combination of the friction factor and downward weight. If the steel wheeled truck goes farther, with the same initial push (on flat track) than the plastic wheeled truck, then the friction factor improvement is greater than the (potentially negative) effect of the additional downward weight on the wheel to rail friction force.
There is also the difference in the amount of axle tip friction in the axle cone, but my guess is that is a secondary effect, assuming the axle lengths are appropriate (in particular, not too long and tight) in both cases.
That’s my story but if missing something, I’ll be glad to not stick to it.
While I have some cars that came with metal wheels, I much prefer plastic, although in most cases, I don’t change-out the metal ones for plastic.
I would agree with the superior rolling qualities of many metal wheels, but not all of them.
As for plastic wheels, I have purchased pre-owned rolling stock with crud on the plastic wheels, but it’s easy enough to remove. As for crud on the wheel treads of my own rolling stock, I’ve yet to see any in the 30 years-or-so that my layout’s been in operation.
Rolling qualities aren’t much of a concern for me, as all of my locomotives have “tonnage ratings”, which allows me to assign the proper loco(s) to each train with consideration to the many grades they’re likely to encounter.
I generally don’t clean track, either, unless it’s just been ballasted, as excess glue does need to be removed from the rails.
I attribute the low maintenance to good housekeeping in the layout room.
I’m torn on plastic vs metal. Metal wheels oftentimes do perform better, but they make a lot of noise. Plastic wheels don’t make the noise, but they can and do warp, leading to poor performance. So the debate continues.
I guess for me, I don’t swap metal for that plastic, and I don’t swap plastic for metal. I will sometimes replace stock plastic wheelsets with a higher grade plastic version if they are warped. Accurail had a problem with warped wheelsets for a while. 3/4 sets would be fine, but the 4th was really nasty. [:^)]
So do the 1:1 wheels. [swg] I actually like the sound - especially the clickity-clack, as the metal wheel sets ride over the track joints. Makes it more real for me.
So, yea - I switch out all my plastic wheel sets for metal ones.
I agree that the metal wheels make a pleasing noise at low to mid speeds, but once you crank it up a bit the racket becomes unbearable for me, personally. I guess that point is when I can’t hear the loco sounds anymore.[#dots][(-D]
Smaller contact area does not result in less friction.
Steel on steel results in less rolling resistance because the steel distorts so little under the weight, as compared to the effect of a wheel on the ground, be it paved or not.
The distortion of the wheel and rail at the contact point is a rolling resistance factor in prototype but at our scale the weights are too small for that to matter.
If Delrin picks up crud more than metal then that’s your answer.
I havent had a layout since before this era of metal wheels came about in the hobby. Most of my rolling stock is all original. I do recognize the superior performance of the metal wheel sets over plastic and am still interested in reading the posts relaying experience with said wheelsets vs plastic.
What got me about this thread was Tom mentioning the ‘clickety-clack’. Now that i do remember and did like. Hadnt really thought about it when thinking of changing out to metal wheels, but now im looking forward to a louder than before rolling sound.
Put me down as a wheel changer - I will be going from plastic to metal. More for performance and look than sound. Thats the icing.
Athearn includes clickety lack in their sound files for locomotives. It doesn’t detect the welded rail we use…flex track…but keeps on clickety clacking over non existent joints.
The din of HO scale metal wheels is nowhere near similar to that of the wheels on a real train, and I’m not speaking of volume, but rather of the type of sounds generated.
If you don’t believe that, it’s time you got out for a little railfanning.
If you want the clickety-clack of wheels going over the rail joints (not all that common on the real ones nowadays), use a razor saw to make a slight cut every 39’ (HO), staggered, in the top of the rails.
As someone who is an outlier in this forum, I run 8 car trains slowly and switch the cars, free rolling cars hinder performance.
Also, locomotive pulling power is nearly irrelevant.
As long as the cars roll, the layout works. It works best when the cars do not roll well.
I’m concerned about free stopping, not free rolling.
As far as metal or plastic, it really doesn’t matter.
The noise I hear from metal wheels is not a clicky clack, more like a steady drone like ball bearings rolling on glass. Not realistic at all. I prefer the silence of plastic.
Most of my rolling stock is newer product that come with metal wheels. I’ll probably take the trucks off and treat the axle cone tips with somehting to make the cars more free stopping and enhance their sit-tightedness when being coupled.
Maybe it is due to my mild hearing loss but I have never noticed a clickety-clack or any other noise coming from the wheels of my rolling stock. Now that I have been made aware of it, it’ll probably drive me crazy.
There’s one other factor that has nothing to do with the wheels. I said earlier I put KD 148 couplers and metal wheels on all my rolling stock. If the trucks are plastic, I also use a reaming tool I bought from Micro-Mark that fits in the truck and ream out the pockets that the axle tips set in. This also helps improve the free rolling of the wheelsets. My layout has a 1.5% grade about 20 ft. long between two of my towns. To test the cars out, I give a gentle nudge from the top of the grade and the car should reach the depot in the next town which is on the flat. If the cars are really free rolling, they will go a yard or two past the depot but they need to at least reach the depot for me to be satisfied.
As another poster just pointed out, free rolling isn’t for everybody but I prefer it for my rolling stock.