G Scale Model Train Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
230 Posts
Discussion Starter #1
I have two metal wheel solutions on my layout at present:

1. USA Trains all-metal wheelsets, which are nice & heavy, with plain brass bearings (although they model roller bearing wheels, which I find amusing)

2. Roll-EZ axles with a ball bearing hub on each wheel, but a plain knob on the axle ends - Not prototypical looking at all - they are fit into USA Trains, Bachman, and Aristo plastic trucks of various types, some sprung, some solid-pieces.

In all cases I have lubricated the pin -> frame connection with one of those new, high-speed lubricants, like white lithium grease.

Putting each wheel type to the test by spooling it up to 12,000RPM using a Dremel tool (I was cleaning grime off the road surfaces) produced some contradictory results:

The solid USA Trains axles with plain brass bearings spun like a gyroscope, and held their speed for a ridiculous amount of time.

The Roll-EZ wheels, in contrast, took longer to spool up, and lost momentum within seconds of removing power. Each axle lost the least amount of momentum at the connection to the frame, when both wheels and the axle spun as a unit. If I held the axle and spun one wheel, the wheel lost momentum immediately - presumably because the ball bearings were dragging.

I actually find that the Roll-EZ ball bearings are really sluggish - I'm considering tearing them down and replacing their stock lubricant to try and improve performance, but the axles do so well on the lithium grease, I'm not sure it's worth the effort.

In either case, rolling resistance in my rolling stock appears to be as minimal as I can make it - I have taken all but 1/32 of lateral play out of all the axles. I"m even using body-mounted couplers. My turns are 8ft minimum radius.

When people talk about the magic of ball bearing wheelsets, are they talking about the Roll-EZ setup, or some sort of bearing in the journal box?

I"m considering buying a set of Kadee trucks - Anyone have experience with them?
 

·
Premium Member
Joined
·
1,062 Posts
First I do not think you will ever get your train wheels spinning 12000 rpm. All of my rolling stock have the roll-ez wheels. The wheels do have too much grease in them or they are pressed together to tight. I put a drop of smoke fluid on each side of the wheels wear the seal is located. That helped to free up the wheel. Pete
 

·
Premium Member
Joined
·
1,796 Posts
The benefit of the ballbearing wheels comes into play on curves. No drag like conventional axles. Why test at 12000rpm when in service we are only talking a few rpm?
 

·
Registered
Joined
·
230 Posts
Discussion Starter #5
The benefit of the ballbearing wheels comes into play on curves. No drag like conventional axles. Why test at 12000rpm when in service we are only talking a few rpm?
I actually had a question about that, since separating the two wheels means you don't get the hunting/auto centering effect caused by the coned wheels operating together. Wouldn't that mean the flanges are more likely to hit the outside rail and cause drag?
 

·
Super Moderator
Joined
·
4,960 Posts
If the wheel has a suitable fillet between tread and flange, that "should" keep the flange away from the side of the railhead. Not all wheels have a suitable fillet, though.

Personally, I think with your 8' radius (16' diameter) curves, you're not going to see much--if any--difference between using wheelsets where the wheels themselves are on ball bearings vs. using ball bearings in the axle journals. I think if you're that particular about drag and such, your money is better spent retrofitting your trucks with Sierra Valley wheels (known for their smooth rolling characteristics) and ball-bearing journal bearings. Sierra Valley wheels have a very nice profile with a good fillet and good-looking (semi-scale) flange. Cost - $4.25/axle for unplated steel wheels.

I'm personally not a huge fan of wheelsets where the wheels themselves are on ball bearings. I've had some where the bearings were loose enough where the wheel could wobble on the axle. This has the net effect of changing the gauge of the wheelset, which could introduce more operational issues than the bearings would solve. Not all are like this; it could be dependent on the quality of the bearings used in that batch of the wheels. I just don't think you gain anything--especially on the wider radius curves. If you're running 2' - 3' radius curves, I can see where it would be advantageous to have the wheels able to freely spin independent of one another.

One caveat to using ball bearings in your wheels. For many, reduced drag and smooth-rolling equipment is a primary goal. If you're running long trains, etc., making the trains as easy to pull as possible is a good thing. However, if you do prototypical operations where you're switching cars around, having cars that will start rolling with the slightest provocation is not necessarily a good thing. It's almost impossible to couple to a car with ball-bearing wheelsets. Most couplers require a certain amount of force to get them to close properly. If you're trying to couple to a car with ball bearing wheels, you'll succeed in pushing it further and further down the track, but you're not going to close the coupler unless you physically restrict the car from moving. That, and if you've got a car sitting on a siding, it doesn't take much of a breeze at all to start it rolling down the track unattended (to say nothing of needing to make sure your sidings are dead level).

Later,

K
 

·
Super Modulator
Joined
·
20,517 Posts
Spinning up the wheels and see how long they go is a time-honored test.

I think the Roll-ez might have sealed bearings, i.e. a rubber seal, which keeps out grit and dirt, but adds friction.

Greg
 
1 - 7 of 7 Posts
Top