3/4" scale riding car are needle roller bearings worth it?

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pat1027
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by pat1027 »

Needle bearing are worth it if you want to use needle bearings for the sake of doing it. Otherwise there are simpler to implement options.. I have cars running on shielded lawn mower wheel bearings, sealed ball bearings and one (the oldest) with oilite bushings in wood journal boxes. The lawn mower bearing and oilite bushings need a touch of oil now and then. On the track you can't tell which is which.

They are pulled by a locomotive riding on ball bearing in the lead truck, oilite bushings on the driver's and bronze plain bearings on the trailing truck.
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LVRR2095
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by LVRR2095 »

apm wrote: Fri Sep 30, 2022 7:34 pm

Keith, my current riding car is plain bearings and the drivers can spin quite a bit starting just me. If my numbers are right that 200lb me creates 20lb friction I think that explains a lot.
Adam…I weigh in at over 200 lbs and while I have had drivers spin too….it is more a factor of the locomotive not weighing enough! Or…guys that over oil their locomotives and lubricating the rails. Just as personal experience, I also have riding cars with needle bearings and I don’t notice any difference in the ability to start while hauling me around.
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by FKreider »

The trucks that Jim Abrams sells now and were previously sold by Don Ritchie are Bill Van Brocklin pattern trucks, they are not "based on Van Brocklin" they literally are direct copies of the original VB patterns.

The patterns/drawings were originally designed by Bill for "plain bearings" (bronze bushings) and for this reason there is not a lot of room in the casting to fit roller bearings.

That being said many of us are using 5/8" OD x 3/8" ID x 5/32" Wide bearings in these trucks - we are using these doubled up, meaning each axle end rides on two bearings and not one.

https://www.avidrc.com/product/1/bearin ... rings.html

While there is nothing wrong with the plain bearing version (I have these trucks with plain bearings under my tender) any future trucks that I machine will all have roller bearings because its that much less machining to get the trucks completed, simply mill pockets and pop in the roller bearings and you are done. No need to machine the bushings and drill oil holes, etc.
-Frank K.
apm
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by apm »

Frank, thanks for the link I think we found a winner. At that price on those bearings I think I may even buy some spares. I had searched quite a bit at the usual vendors and couldn't find ball bearings with a bore that large on a 5/8 OD.

I am still surprised though that no one else seems to be able to corroborate my back of the envelope numbers that show 20x reduction in friction between roller bearings vs bronze sleeve bushings. I guess when all is said and done I will have trucks equipped with both types of bearings I think a fish scale test may be worth while to see if the numbers are as bad for plain bearings as I suspect.
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Dick_Morris
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by Dick_Morris »

I can't give numbers, but I've read that in full-sized rail cars the rolling friction of a bronze bearing and roller bearing aren't that much different. Starting friction is higher on bronze. A big advantage is the decreased maintenance of rollers. In our sizes, I see a big advantage of rollers is that we don't have to take the time and effort to oil the bearings. And for many of us, getting back up from our hands and knees to oil them is something we would rather not do.

One internal report I found in the Alaska Railroad archives from the ear1930s was that on cars parked near a skating pond the kids would steal the oily waste from the journals to build fires to keep warm, leaving the bearings vulnerable to failure when the cars were moved.
pat1027
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by pat1027 »

apm wrote: Sun Oct 02, 2022 9:55 am I am still surprised though that no one else seems to be able to corroborate my back of the envelope numbers that show 20x reduction in friction between roller bearings vs bronze sleeve bushings.
As Bill Shields was describing with plain or friction bearings oil is pulled by the axle to to top side forming a film between the axle and the bearing. In the prototype once the car was moving rolling resistance of friction bearings was said to be similar. Lower starting resistance of roller bearings was an early selling point for Timken. In a 1949 ad they claimed an 88% reduction in starting resistance.
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LVRR2095
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by LVRR2095 »

Dick_Morris wrote: Sun Oct 02, 2022 11:42 am And for many of us, getting back up from our hands and knees to oil them is something we would rather not do.
Dick…that is not an issue with 3/4” scale on elevated tracks. No getting down on your knees to oil, or stoke the fire, clean the ashes etc. Everything is up in the air on the elevated trestles.
And I can tell you from personal experience on the Lehigh Valley RR and later on Conrail…..I never saw ANY difference in rolling resistance on trains with plain bearings, roller bearings or a mix of that two. Railroads went to roller bearings to cut the car knocker staff. You didn’t have to re-pack and oil roller bearing. However, that said, I DID see just as many journals burnt off and causing derailments with roller bearing cars.
Keith Taylor
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Re: 3/4" scale riding car are needle roller bearings worth it?

Post by Bill Shields »

However...in the world of live steam....when was the last time that the riding car sat PERFECTLY STILL until the oil film was pushed out and we had metal to metal contact on starting and the roller bearing reduction effect came into play?

In our world, the riding car is almost always in motion, hence a film can be expected. Every time I move on the riding car, the car also rolls a little.

The statements about dry start rolling friction are absolutely true...the question is -> how often does it apply?

Even on my riding car with ball bearings, there are frequent cases where "needs a nudge to get going" apply -> but is it because of riding car axle bearing stiction or other factors like crud under the loco drivers, or a low spot on the track or (fill in the blanks). :mrgreen:
Too many things going on to bother listing them.
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