Kato diesel locomotive wheel question.

[Vaderta]

I bought a used Kato F7A unit and realized that it had a bad gear in the wheel truck. I thought no problem I will just switch it out With an F7P truck I have apart already to put a decoder in. It was at that point I realized that Kato at some point changed the diameter of their geared wheels to a small diameter wheel. I looked at Kato USA parts website and saw that they don't list a large diameter geared wheel.My question is does anyone know if another manufacturer sells large diameter wheels that would work in the Kato axle? Second question is does anyone know what year Kato made the switch to the low profile geared wheel? If I can't find a suitable replacement wheel I would likely have to shop for a beat up locomotive on ebay for parts. Thanks

[Sdynamo]

My guess is Kato went to Low Profile Wheels when they updated the mechanisms to be DCC friendly.  You might be able to use a good axle and gear with the larger wheels from the used unit.  The wheels can be pulled out of the plastic axle, which is easy enough to test.

JW

[Vaderta]

I wonder if they used HO scale wheels on the older units when they produced more HO scale stuff. I haven't looked at HO stuff in a long time. But I would say the wheel size is about double the diameter of the newer low profile geared wheel sets.

[Vaderta]

Nope definitely not HO. Looked at some of my HO stiff and realized just how big HO is compared to N scale. That was an interesting refresher lol

[peteski]

Edited the post after finding additional info:

Geared wheels? I'm not sure what you mean. Kato's diesel loco wheels were always ~40" scale diameter, and the same holds true for other manufacturers.  Maybe you meant "gears"?

There were multiple iterations of Kato F3 chassis/trucks.

First was the truck with inside bearings and metal gear case:


Next was all new truck using low-friction outside bearings and plastic gear case.


The appear to use different size idler gears.

Latest (current) iteration uses a typical Kato low-friction Kato design they use on other models Here is the chassis photo.


These photos were taken from http://spookshow.net/loco/katof.html (excellent N scale locos reference website).

[Vaderta]

Edited the post after finding additional info:

Geared wheels? I'm not sure what you mean. Kato's diesel loco wheels were always ~40" scale diameter, and the same holds true for other manufacturers.  Maybe you meant "gears"?

There were multiple iterations of Kato F3 chassis/trucks.

First was the truck with inside bearings and metal gear case:


Next was all new truck using low-friction outside bearings and plastic gear case.


The appear to use different size idler gears.

Latest (current) iteration uses a typical Kato low-friction Kato design they use on other models Here is the chassis photo.


These photos were taken from http://spookshow.net/loco/katof.html (excellent N scale locos reference website).

  Thanks Pete. I guess I meant to say geared wheelset as that is how they have them listed on the Kato website. https://store.katousa.com/product/low-profile-geared-wheelset-pointed-axle-w-offset-gear-n-scale/  It appears from the article you posted my F7 is around the 2006 redesign.  The locomotive I borrowed the wheels from has the low profile wheels on. When I went to snap the wheels into the 2006 F7s truck the wheels were smaller and I had to pull the wheels out of the geared axle and replace them with the larger wheels from the 2006 to match the rear truck. Maybe I can use low profile wheels in the 2006 style F7A without issue. I don't know but will have to try it next time I have the shell off

[peteski]

Hmm, I don't believe the actual tread diameter has changed on any iteration of Kato's wheelsets with offset gear. Compared to the older wheelsets the currently available wheelsets have lower flanges and narrower tread, but I believe the tread diameter is the same.  They look larger because of the low profile flange. The tread diameter should still be IIRC 42 scale inches.  To be 100% sure I would have to find an older wheelset and measure it with my calipers.

[Lackawannae8]

send me pics of what you all have there I probaly have what your looking for here in my Hoard of parts

[Vaderta]

 Pete you may be right. Without pulling the shell and trucks off and just eyeballing the diameter looks similar. The flange that contacts the rail is definitely wider and gives the illusion of a bigger wheel. I have to go to Kato maybe tomorrow to buy a couple of new trucks. I might ask one of the guys there if there was a different diameter wheel in the earlier runs of the F7s. Sometimes you get lucky and get a guy that has been there a while. Other times I have encountered people that are new and they are not familiar with the older runs. But my guess is you are correct and the way they machined the flanges on the older wheels make them appear as a larger wheel.

[peteski]

I dug out my Kato U30C, which is the first model Kato used the low-friction trucks and those wheelsets were used in all their future models (until they changed the wheelsets to the current lo-profile ones available on Kato's parts site).

Both the U30C wheelset and the new version have 0.255" tread diameter. 
The old wheelset's overall (flange) diameter is 0.309" while the low-profile wheel diameter is 0.293" (as expected).
The axle length on both old and new is 0.561".

That verifies that the new wheel sets should be fully compatible with the older wheelsets (well except for visual appearance).  Here are some photos of both wheelsets. Actually the "old" wheelset in the photos is Atlas wheelset, but those were clones of Kato early wheelsets, so it is just like the Kato U30C wheelset I measured.  The old wheelset appears smaller, but the tread is the same diameter. The large flange likely causes the optical illusion.





You're almost up to the 25 post count at which you will be able to upload photos to the forum, to maybe show us what your wheelsets look like.

[Vaderta]

I dug out my Kato U30C, which is the first model Kato used the low-friction trucks and those wheelsets were used in all their future models (until they changed the wheelsets to the current lo-profile ones available on Kato's parts site).

Both the U30C wheelset and the new version have 0.255" tread diameter. 
The old wheelset's overall (flange) diameter is 0.309" while the low-profile wheel diameter is 0.293" (as expected).
The axle length on both old and new is 0.561".

That verifies that the new wheel sets should be fully compatible with the older wheelsets (well except for visual appearance).  Here are some photos of both wheelsets. Actually the "old" wheelset in the photos is Atlas wheelset, but those were clones of Kato early wheelsets, so it is just like the Kato U30C wheelset I measured.  The old wheelset appears smaller, but the tread is the same diameter. The large flange likely causes the optical illusion.





You're almost up to the 25 post count at which you will be able to upload photos to the forum, to maybe show us what your wheelsets look like.

Thanks Pete, you were posting the same time I was. You are correct. I appreciate you checking for me. In my haste I assumed the wheel was larger from appearance.  It definitely does give an optical illusion. I appreciate the help

[GM50 4164]

I dug out my Kato U30C, which is the first model Kato used the low-friction trucks and those wheelsets were used in all their future models (until they changed the wheelsets to the current lo-profile ones available on Kato's parts site).

Both the U30C wheelset and the new version have 0.255" tread diameter. 
The old wheelset's overall (flange) diameter is 0.309" while the low-profile wheel diameter is 0.293" (as expected).
The axle length on both old and new is 0.561".

That verifies that the new wheel sets should be fully compatible with the older wheelsets (well except for visual appearance).  Here are some photos of both wheelsets. Actually the "old" wheelset in the photos is Atlas wheelset, but those were clones of Kato early wheelsets, so it is just like the Kato U30C wheelset I measured.  The old wheelset appears smaller, but the tread is the same diameter. The large flange likely causes the optical illusion.






You're almost up to the 25 post count at which you will be able to upload photos to the forum, to maybe show us what your wheelsets look like.

Hey Peteski, what thickness is the styrene you used for the spacer washer on your axle?

[nkalanaga]

It wouldn't make any operational difference, but the large-flange wheel also has a wider tread.

[peteski]

Hey Peteski, what thickness is the styrene you used for the spacer washer on your axle?

The photos I reused here were for a thread about adapting Kato Wheels to Atlas trucks.  For more info about the washers see https://www.therailwire.net/forum/index.php?topic=33107.msg596466#msg596466 .

[Freight Train]

If Kato still has the old parts diagram on their website before they made the change you maybe be able to find the old part number for the wheel set in question ? Could contact Kato and see if they may have any of these old wheel sets still left in stock ? If not could always search eBay as theirs always someone selling replacement parts.