Hi,

I sometimes purchase non-Marklin rolling stock to add variety. Because I like to make them compatible with the Marklin 3 rail system, I change the wheelsets to non-insulated AC type. To assist me I use a table, which shows brandname and various dimensions. I can measure the original DC wheels, and choose an appropriate replacement.

The axle length is the measurement across the tip of the axle. (I have listed only pin-point type wheel sets, there are shoulder or stepped type axle ends in some Marklin and Trix models).
The back-to-back (b to b) measurement is between the inside faces of the wheels along the axle.
Diameter of tread is self-explanatory, but it is the outer edge, not the diameter against the flange.

So the table is brandname (and catalogue # if known), axle length in mm, b to b in mm, tread diam. in mm. The following Types are not rigid examples.
Type A are typical general Marklin stock for era 1, II, III and IV.
Type B are a smaller diameter wheel, presumably used in more modern era V and era VI, and also in US freight rolling stock.
Type C are a longer axle used in some models.

These were one-off measurements on a sample, and may vary across production by 0.1 or 0.2mm. The repetitive accuracy of modern quantity machining is remarkable, although we don't know what percentage of production is discarded under quality checks.
The table is comma delimited, so you can use it in a spreadsheet.
I show proven workable replacements in compatible sets.

Type A AC Disc wheels (Marklin DC equivalent wheel set catalogue #700580).
Marklin 700150,24.5,14.0,10.0
Fleischmann 6560,23.85,13.85,10.5
Brawa 2181,23.8,13.9,10.6
(Spoked wheel set is Marklin 700230)

Type B AC Disc wheels - (also use for US freight rolling stock)
Marklin,320551,24.5,14.25,9.0
Roco 40195,24.7,14.0,9.0

Type C AC nominal axle length of 25mm
Fleischmann 6561,24.95,13.95,10.3

Original DC wheelsets as follows:
Type A DC
Older Fleischmann 1950/1960/1970,23.85,14.35.10.5
Newer Trix,24.5,14.1,10.0
Newer Liliput,24.6,14.25,10.3

Type C DC nominal axle length of 25mm
Older Fleischmann 1950/1960/1970,24.8,14.35,10.5
Roco,24.8,14.0,10.5

Sometimes trial and error is required to ensure that wheels spin freely. For example, I recently replaced a standard Liliput wheel set, but had to use the Type B AC, because the height/depth of the flanges on Type A AC fouled the under-frame of the wagon. I have not included flange depth in the table, because it is not usually an issue.

Flange width is another measurement that is not usually an issue. However, with the Marklin puko being as close as 14.0 mm to an opposite rail in curve points and crossovers, the b to b measurement is important. I have on occasion had both Marklin and non-Marklin wheel flanges on long-wheelbase stock touch the puko and cause a momentary short. In these cases, I check the b to b, and if OK I focus attention on the track. I file the puko thinner, usually by about 0.1 to 0.2mm, and this makes all the difference.

Rolling stock sold for the US market in HO, such as Atlas, Athearn, Bachmann, BLI, Red Caboose, Accurail, Model Power, Mantua etc have a wheel set (RP25 standard, nominally 9mm in diameter at the outside of the tread) that does not run well on Marklin track.

Marklin have an exact equivalent for these wheels (type B AC in the table above), and I tried them on one of my Athearn freight cars. They are perfect, and work fine on my C track.

The numbers are 320 552 NEM DC wheel set (for 2 rail), and 320 551 (Märklin) AC wheel set for your 3 rail track.
These could be Marklin or Trix numbers, their databases are very unspecific.
The wheels are basically the same. Do not use the Marklin AC wheels on your 2 rail layout, as it will create a short circuit.
The following thanks to member Foumaro from Greece:
1.320552 NEM 2rail DC
2.320551 3 rail AC
3.320389 RP25 2rail DC

You should try your dealer to get these wheels for you.
I am unable to find them online or in the Marklin or Trix catalogues.

I hope the table is of use to some. I take no responsibility for the accuracy or for the application of this data.

regards
Kimball

Edited by user 30 May 2014 08:50:46(UTC)  | Reason: added information for US rolling stock

Hello,

What wheels have you used with Walthers HO rolling stock? I want to include some walthers and athearn cars to be used with a Big Boy.
I tried the wheels included with the 45656-02 tank (NEM 320552) and the wheel "touches" the car structure. The wheel it's too big. :-(

Thanks in advance.

You could try re-gauging the existing wheels, twist and pull slowly. (good tip from Jacques)

-Brandon

I can confirm that i bought the 24902 trix set with 20 USA cars and the cars have the rp25 wheels.I have to change them because i have problems,they do not run well,i have relailments on the 24611-24612 turnouts.I orders 80 wheels with part number 700150 to change them.

One question regaarding the axel it self, do you know the mesurment?