Author Topic: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks  (Read 764 times)

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peteski

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The original wheelsets in those trucks have huge (by today's standards) flanges, and scale out to about 32" (should be 36").  Fortunately, FVM makes modern 36" replacement wheels for those trucks. Part # FVM 3602. It is almost a drop-in installation.

The center axle is a drop-in installation, but the outside axles require slight modification to the truck.


RivarossiWheelReplacement01.jpg
The outside wheelsets do drop in, and even the brake shoes have ample clearance.  Actually the brake shoes seem to be designed to work with 36" wheels.  But a piece of the side frame molding binds against the FVM wheel's thread (see the arrow), preventing it from spinning freely.




RivarossiWheelReplacement02.jpg
Here is a photo showing it from another angle, with the wheelset removed.




RivarossiWheelReplacement03.jpg
Fortunately, that piece of the truck can be easily trimmed. This photo shows it after trimming.




RivarossiWheelReplacement04.jpg
I found it easiest to trim the protrusion from the topside of the truck. Hold the truck upside down and trim it as shown in the photo. That old plastic can be brittle - take couple of light cuts instead of single deep cut.  It is also not necessary to trim it as much as I did. I did that to clearly show what needs to be done.




RivarossiWheelReplacement05.jpg
This photo shows the original (left) wheel, and on the right the truck with FVM whee sets installed.  This photo also shows that the FVM axles are quite a bit thicker than the original axles.   Also the original axles measure 0.551" long, while the FVM axles measure 0.556" (supposed to be 0.553").  That can cause slight binding in the cup bearings.  In the trucks I converted only one FVM axle has a very slight bind. Using my thumb and index finger squeezed the side frames tightly against the axle, and using the index finger of my other hand I turned the wheels of that binding wheel set.  I did that several times and that loosened up the axle cups enough for the wheel set to spin freely.




RivarossiWheelReplacement06.jpg
Another photo shows how much better the truck looks like with the FVM 36" wheels.
« Last Edit: June 24, 2020, 11:15:22 AM by peteski »
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bobthebear

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #1 on: June 24, 2020, 05:16:23 AM »
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Thanks peteski, just what I wanted. The only difficulty now is finding Fox Valley #3602 wheels!
Cheers, Bob.

Simon D.

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #2 on: June 24, 2020, 05:57:51 AM »
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One thing I've found hacking into these very old plastic mouldings is that they can be brittle, and bits can snap off!

Lemosteam

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« Last Edit: June 24, 2020, 06:37:26 AM by Lemosteam »

altohorn25

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #4 on: June 24, 2020, 07:43:03 AM »
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The Atlas/Riv trucks aren't designed for a 36" wheel which is why you're having to modify it.  It's designed for a 33" wheel.  Yes, since it's a heavyweight passenger truck it SHOULD have a 36" wheel, I'm just saying that old design is for a 33" wheel (from back in the day when none of the manufatures cared about what the wheel diameter was...).  The original MT heavyweight passenger trucks (the ones with the moveable coupler) are also like that.

The newer MT heavyweight passenger trucks ARE designed to use a 36" wheel.

Nate Pierce
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peteski

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #5 on: June 24, 2020, 11:14:14 AM »
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One thing I've found hacking into these very old plastic mouldings is that they can be brittle, and bits can snap off!

True Simon, that is why I stated "Take couple of light cuts instead of single deep cut.  It is not necessary to trim it as much as I did. I did that to clearly show what needs to be done."  I'll add a better warning.
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peteski

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #6 on: June 24, 2020, 11:20:08 AM »
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The Atlas/Riv trucks aren't designed for a 36" wheel which is why you're having to modify it.  It's designed for a 33" wheel.  Yes, since it's a heavyweight passenger truck it SHOULD have a 36" wheel, I'm just saying that old design is for a 33" wheel (from back in the day when none of the manufatures cared about what the wheel diameter was...).  The original MT heavyweight passenger trucks (the ones with the moveable coupler) are also like that.

The newer MT heavyweight passenger trucks ARE designed to use a 36" wheel.

Yes, back in the day these were made N scale was still a toy-train scale, and pretty much all rolling stock used those small metal wheels with large flanges.  I think that the Atlas/Roco freight car trucks used wheels which were even slightly smaller!  The flange diameter more than made up for the undersized tread diameter, but looking back, they looked really funny that way.  However luckily for us, the brake shoes were molded far enough from the 32" wheels to still clear the 36" wheels. 
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nickelplate759

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #7 on: June 24, 2020, 11:48:57 AM »
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It's worth noting that the Rivarossi trucks have a short wheelbase as well as undersized wheels.   For best appearance the entire truck must be replaced with something like the newer Micro-Trains Pullman trucks (not the one with the truck-mounted coupler - that's the same size as the Rivarossi truck), but that's not a straightforward swap.
George
NKPH&TS #3628

I'm sorry Dave, I'm afraid I can't do that.

mmagliaro

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #8 on: June 24, 2020, 05:51:42 PM »
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Peteski is quite correct about having to trim out that plastic as he shows.  But there is an additional trouble spot that I've had with these.  I commandeered Peteski's photo to circle the location.  It's not a close-up, but you can see how close the brake shoe gets to the tread here.  Just make sure that shoe doesn't touch.  I sometimes have to pull the brake shoe away a smidge.  Softening/fatiguing the plastic with some liquid cement on it usually works so that it doesn't drift back in onto the wheel later.


peteski

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #9 on: June 24, 2020, 06:23:54 PM »
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Interesting.
In the trucks I converted there seem to be ample clearance between the brake shoe and the wheel tread.  FVM axles are fairly tight in the axle cups (since those axles are bit longer than the original axles), so the wheelsets don't have much slop.  But I guess in some instances, the brake shoe could be a trouble area, however in my example the plastic part of the side frame I trimmed was basically stopping the wheel from turning.


RivarossiWheelReplacement07.jpg
As you can see in this example, there is plenty of clearance between the brake shoes and the wheel trad/flange.
« Last Edit: June 24, 2020, 06:44:14 PM by peteski »
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Mike Madonna

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Re: Installing FVM 36" wheelsets in Rivarossi 3-axle heavyweight trucks
« Reply #10 on: June 24, 2020, 10:14:48 PM »
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All good information gentlemen, thank you!!
Mike
SOUTHERN PACIFIC Coast Division 1953
Santa Margarita Sub