I’ve heard of ball bearing wheels in HO, but I just can’t imagine ball bearings small enough to be a reality. Can someone clear this up for me? I’ve seen ball bearings as small as 1/4" outside diameter, but can’t imagine anything smaller than that. To me it’s like puting a ball bearing inside a watch mechanism instead of a jewel bearing.
Trucks_Brass-Intermountain by Edmund, on Flickr
Trucks_Brass-Intermountain1 by Edmund, on Flickr
Regards, Ed
So the wheels on each axle rotate independently?
Sounds like it might be a good thing on curves, but also sounds like it might be a little rough on the wallet.
Wayne
Is that a ball bearing with inner and outer race?
No, they are more akin to the “quill drive” of a GG1 locomotive. The pointed axle shaft passes through a tube in one piece. The wheels are pressed on to the tube with one end being insulated so if you have a power pickup wiper it can rub on the tube and pick up power from one wheel. There is no continuity from either wheel to the axle.
I’ve only used them on a few brass cabooses and passenger cars that have unique trucks that are poorly designed as far as rolling qualities. The Ball bearing wheelsets improve rolling quality immensely.
$20 worth of wheelsets on a $800 passenger car, in order to make it road-worthy, seemed like an OK investment for me. I recall I bought some from a train show dealer at one time and the cost was something closer to $2.25 (US) per wheelset.
I’ve never pried one open but there certainly is a pair of low-friction bearings in there. The “inner race” may be the axle shaft itself and the “outer race” might be the hub machined into the back of the wheel.
There is a little bit of play (slop in technical terms) between the axle shaft and the wheel/tube assembly. In operation this slop has no bearing in their operation.
YMMV
Cheers, Ed
Doesn’t sound like its truly a ball bearing. The balls would have to be less than .031" diameter. I still can’t imagine it. I may have to contact the manufacturer and ask them.
I would get in touch with the good folks at Intermountain and ask for their explanation, then.
intermountain@intermountain-railway.com
When I spin the wheels in my fingers while holding the axle points it sure spins nicely. Maybe that’s where the idea of those spinners the kids are into these days came from.
They are NOT a “precision” bearing by any means. I doubt they would hold up too well in a 420,000 rpm dental drill but for an HO railroad car, IF you need them for a car that is otherwise a “lead sled” they CAN be an option.
I don’t think anyone out there has outfitted their five-hundred car roster with them.
Regards, Ed
Here you can find balls at .026" dia:
https://www.mcmaster.com/steel-balls/hard-wear-resistant-52100-alloy-steel-balls-7/
To further astound and amaze you, Rivarossi used to use motors in their HO models with ball bearings on the shaft.
Ed
I did a search on McMaster Carr and came up with a ball bearing, .040" ID, .125" OD and 3/64" wide, cost: $11.43 each. I guess it’s possible to have a true ball bearing wheel in HO, but not not practical at that cost.
I believe the Intermountain items ARE true ball bearings. But I don’t think they are as “wonderful” as the $11.43 ones.
Ed
There was a (relatively) enormous market in these as early as the 1950s – the early makers of precision ‘micro’ bearings being largely in New England at the time. A quick way to appreciate the history is to Google ball bearings for clock applications, or to look at one of the ‘missiles and space’ handbooks of the Cold War era.
If you look at the final post in this thread there’s a bit of rolling resistance testing of these wheelsets and from what I read I could see why folk who want to run a full length passenger consist with a steam locomotive would go for them.
They’re expensive, but I bought enough for three of my tri-level auto racks. These particular freight cars have loads of 15 or 18 of the “Fresh Cherries” (or some such) brand of HO vehicles. Each of the vehicles weighs a lot (by HO standards) and they made these auto racks quite heavy. But with the Intermountain BB wheelsets, the cars roll beautifully.
What’s the conclusion to be drawn by us non-users of ball bearing wheelsets? Should we transfer out our non-ball bearing wheelsets for ball bearing wheelsets if we can afford to on all of our rolling stock?
Rich
Not in my opinion. A good setup with coned-end-on-proper-surface will very often “beat” a microbearing for sufficiently light equipment, and have much easier setup and alignment. I suspect it will also be easier to maintain as the years go by.
I mentioned my reasoning in an earlier reply:
The ball bearing wheelsets are a possible solution to getting better operation from equipment that may otherwise not perform well with stock wheelsets.
Strictly optional and indeed NOT the only solution available. Choices and options.
My first choice is to find Kadee or Central Valley or another good quality replacement truck but if nothing is readily available, as is often the case for a specific prototype particularly for a road like Pennsylvania which designed many of their own trucks, then the ball bearing wheelsets can be an economical solution.
Regards, Ed
So, I use the standard Intermountain wheelsets on all of my rolling stock. Good enough?
Rich
Only you can answer that.
Cheers, Ed
Good enough!
Rich