If you are looking for a more protypical wheel for more accuracy, then Gary Raymond also has ball bearing metal wheel sets which have the correct prfile and are protypical.
ball-bearing metal wheel sets Ball-bearing metal wheel sets are the only way to go. And I have tried every metal wheel out there. I have even done tests with the different metal wheels. But the ball-bearing wheel sets ride much nicer, and there is no drag around the curves whatsoever! And that's where the difference is, the curves. On the straights, most any wheel will basically do. Each wheel is traveling at the same rate of speed. But once you hit the curves, physics come into play. With any wheel (plastic or metal) the outside wheel can't keep up with the inside wheel. And the sharper the curve, the worse the drag is. But with ball-bearing wheels, each wheel moves independant of the other wheel. So there is absolutely no drag at all! The reason; because the outside wheel is traveling at it's rate of speed and the inside wheel is traveling at it's rate of speed. Neither wheel fights each other. Thus a nice smooth ride around the curves without one wheel fighting the other. I would have never been able to pull those 152 cars with the Big Boy around that curve without the ball-bearing wheel sets that I use. In fact, everysingle piece of rolling stock that I have (and I have alot) has ball-bearing wheel sets on them. The only things I don't do is the passenger cars. The reason; passenger trains are rather short, so the curves don't really come into play. And USA Train passenger cars are some of the smoothest riding cars I have ever use. Wow! They just glide along the rails. I purchase all of my ball-bearing wheel sets from Al Krammer who use to own San-Val Trains out of Van Nuys, Ca. before he shut down several years ago. He is still selling USA Train items and metal wheel sets on eBay. He has the cheapest and best made ball-bearing wheel sets out there. And out of the 8,000 plus wheel sets that I have bought from him over the years, I have only had 3 sets (6 axles) that were bad. How's that for a percentage? Dennis Sirrine Palo Verde & Southwestern Railroad
Hi Dennis Sirrine, I'm glad you came to visit Train Board. Everyone, please welcome aboard dennissirrine, Route 66 posted a you tube video that fatures his huge collection and layout. So while I was there, I decided to give him a invite to the board to come and see the USA Trains registry threead. Yep is the same one and only who made the famous pull, congradualtions.
I just came across this thread because it was referenced in another thread I was reading and I would like to make some observations: 1. In the posts, when "roller"-bearing wheels are mentioned you should substitute "ball"-bearing wheels. There are both roller bearings and ball bearings, they are not the same, but all G-scale wheels with bearings have ball-bearings, not roller-bearings. Minor point. 2. All ball-bearing wheels are not the same. We tested quite a number a few years ago and not only did they differ mechanically, but the rolling resistance was also quite different between the different brands. Some rolled much easier than others. But that's not necessarily a good thing - makes it difficult to park a car if the track isn't absolutely level. 3. The basic assumption is that metal wheels are always better than plastic. Well, depends on the plastic wheels of course. Some leave a residue on the track when it is very hot - that of course is not good. Metal wheels also sound nicer than plastic wheels when the train is running but with sound engines that may be a moot point. Metal wheels lower the center of gravity of the cars which makes them more stable and less prone to derailment, all good. But metal wheels also increase the weight of the car which adds to the effort required to pull a train up an incline. What we always wanted to test but never got around to it, is to find out if the lower rolling resistance of metal wheels more than compensates for the extra weight the has to be pulled up an incline. 4. And here is something to think about. On the real trains, the wheels and axle are permanently connected, essentially one solid piece. So why does one of those wheels not drag when the train goes around a curve? And after you figured that out, why does the same principle not apply to G-scale trains? Or does it?
Because real railroads won't run a 55ft freight car on a 8ft diameter curve or even a 10ft diameter curve or a 16ft diameter curve. This is why wheel drag in G scale is so common and over other scales our G scale freight cars are heavier per ratio of train than smaller scales. Someone once told me if you tried to run a real SD-70MAC on a 8ft curve it would fall off, it's not realistic, but we do it anyway because we want the train. We do alot of things in G scale that are not realistic because of space limitations. Don't quote me on this, but don't most railroads here in the US have 20ft curve minimum diameter curves?
Sorry Trainman - think again. The tightness of the curve would make the situation worse, but for any curvature, no matter how gentle, the outer wheel will always have to travel a larger distance than the inner wheel. Real railroads have solved this problem in a rather simple but ingenious way.
I believe this page will illustrate why this problem does not happen, but in simple terms - its because the flanges of the wheels are not exactly touching the rails, there is space between the flange and wheel. Wheels and Bogies As for radius, I know most G-Scale livesteamers like to have a 10-14ft minimum radius, but the bigger the radius the more realistic the train will look. As for real life, minimum radius varies A LOT, it really depends what you are doing. For instance, the minimum radius for high speed trains in Europe is 2.8-5.6 miles, depending on how fast that specific section of track is meant for. And for US mainline, anything less than a 1000ft minimum radius is considered extremely tight (Horse Shoe Curve is 900ft)
Very nice web site. It's true that the flanges of the wheels are normally not touching the wheels, but the reason there is no slippage (or very little depending on the radius) is just a bit firther down that page: The wheels we use in Large Scale also have the coning of the wheel treads, so the same principle applies. I assume it's not as effective as on the prototype because our radii are scale-wise quite a bit tighter, but to compensate for that, the coning angle of the LS wheel sets is steeper and the well treads are quite a bit wider. I always wanted to measure the coning angle and tread width of a number of typical LS wheel sets and calculate the minimum curve that wheel set (without bearings) can handle without slipping - would be a nice tidbit of information to have.
Its going to be far sharper than what any steam engine can go around (assuming the correct drivers are actually flanged and not blind). I know the accucraft livesteam narrow guage has a minimum radius of 48", but their standard gauge is up around 100-120". And that's the absolute minimum the engines can negotiate, how well they will is another story.
Well, if you need a 100 - 120 inch radius curve to accomodate a standard gauge Accucraft live-steam engine, couldn't that throw the argument that one always needs ball-bearing wheel sets on the cars to avoid slippage on curves out the window? I don't see why the principle used by the prototype does not apply to Large scale - the question is - to what degree.
Well you also must remember that even cars built to scale are still not exactly like the real prototype, simply because some things don't scale down, and as said above - how many g-scalers do you know would have enough space to lay out an accurate minimum radius to the scale. 100-120" radius sounds like a lot, but is nothing if you actually scaled it down. I would assume that if you built a 100% accurate scale model of a car, it would need the same requirements as other cars. A more important fact to note is that you should really be looking at your engines, because engines are going to be the tightest factor in curve radius. If you have steam engines, that factor is even large, because of the long rigid wheel base. Even a four axle diesel is going to need a larger radius than a four axle car. I think the biggest reason you do not NEED the metal wheel and bearings is the over coning of the wheels EDIT: Another factor to consider is that you are also not loading your cars (to scale of course) with the same weight as that car would be loading with in real life. The wheel bearing is not needed for the car to be able to move, but it makes the number of cars an engine can pull much larger. The time of maintenance is also much less, imagine in the old days when every single bearing had to be greased at regular intervals, and if you forgot - you would need to replace the wheel or axle.
I was only looking at the coning of the wheels and how that affects slippage (or not) when going around a curve, nothing else. All the other points you mentioned are valid of course, but I wanted to focus only on that one aspect because of the assertion towards the beginning of this thread. I know when I run trains with normal metal wheels, not ball bearing metal wheels, I don't really notice a substantial amount of slippage going around a curve. I say "substantial" since there might be a little bit of slippage that is not noticable, so I don't want to claim there is none. I also have a large number of the Roll EZ wheel sets with ball-bearings as well as regular metal wheel sets and ball-bearing wheel sets with power pick ups from other manufacturers, so any theoretical calculation could be supplemented with some practical tests.
Well another problem I can think of as to why wheels drag into a curve is because many G scale manufacturers make thier wheels with deep over flanges which is not prototypical as we know, but they make it that way for reliability. With a over deep wheel flange there is more friction area on the side on the wheel in a curve which a Ball Bearing metal axle would just allow a wheel to spin faster when a drag sitaution started since they operate independently on a axle. But as you pointed out this is not realistic either. Roll EZ ball bearing sets are also over flanged So I guess another fix drag into a curve would be to install correct profile wheel sets. This would also probably solve the problem of drag into a curve since how the wheel flange area would be less and there would be a reduction of friction and be more realistic for those who have to run trains as "Real" as possible
I hope you are having a good time and are not getting frustrated. I know I am - having a great time I mean; more activity in this forum recently that for quite a while. :tb-biggrin::tb-biggrin:
Oh, of course I am having fun, no frustration here. I like it when I'm kept on my toes. I noticed alot of activity also in the G scale section and I'm glad it picked up. Glad you are having fun here and hopefully others will follow again. You wouldn't believe how many people joined the G scale section but more times than not they either don't post, don't get involved with other posts or limit the amount of activity they have here. This is a fun place to be in all reality. I encourage ALL new G scalers to get more invovled, you never know what fun you might have.
