Wheels & Trucks

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Please note:

I have an entire section on standards for track and wheels, please see this page: Track and Wheel Standards

Wheels, metal or plastic?

The short answer: Use metal wheels. Period.

You will find some basic data here. A years ago, there were still heated debates on plastic vs. metal wheels, but now, it's pretty much accepted that plastic wheels are just a cheap way out by the manufacturers. They have more negatives than positives. Cost can be the only reason to use them.

PLASTIC WHEELS

METAL WHEELS

Note: cast/molded wheels often have wobble as opposed to machined wheels.

All plastic wheels are cast. Some metal wheels are cast, some are machined, some are sintered (powdered metal pressed in a mold)

Standards:

Again, please check my page the Standards area under Track and Wheel Standards. You need to make some choices.

After choosing which standard you want to follow, for wheels, I suggest you first check your Back to Back spacing, it is the SINGLE most important aspect of your wheelset's measurements.

There have always been people who think that the check gauge of the wheel set is important. It's really not the most important. In scales where there is some standardization in the flange thickness, it's true, and it SHOULD be true in G scale. But it's NOT, there is EXTREME variation in flange thickness in G scale, so much that using the check gauge can give you a back to back setting that varies widely, and that causes derailments.

The most "dangerous" part of track work is switches, and the thing that guides wheels through switches is the guardrails.This is where over 90% of derailments occur.

The BACKS of the flanges/wheels are what ride against the guardrails, thus back to back measurements are vitally important.

To re-reinforce, in HO and other scales, the flange widths, and usually the entire wheel contour are the same in most cases. Then you could use check gauge, because it is "fixed" in relation to the back to back.

Not even close to being true in Large Scale. Flange widths are all over the place, from thick to thin.

So there are 2 reasons why you should measure and set the the back to back gauge. Your check gauge should be within specifications afterwards. If it is not, you need to consider other wheel sets.

Ball bearing wheels:

This is a bit of a tricky subject, since many people talk about ball bearing wheels, when there are really 3 different possibilities:

1. wheels fixed solidly to the axle, ball bearings in the truck journals to let the axle spin
2. wheels with ball bearings in them, so they both rotate independently of the axle
3. one wheel fixed to the axle, the other has a ball bearing (rarely seen now)

On a straight track types 1 and 2 will normally greatly reduce your rolling resistance.

Many people believe that a big advantage is on curves, since our curves are so tight, the differential action of types 2 and 3 will help (no independent wheel travel on type 1)

Well, in practice it does not help. Turns out that most of the rolling friction comes from a high attack angle of the flange to the rail head, due to our tight curves and sloppy tolerances.

Now, be aware, while you have lower rolling friction, ball bearings have no effect on grades. From the aspect of the laws of physics, you are still doing the same amount of work raising the weight of the cars in the air up a grade.

Overall, I don't use ball bearing wheel sets myself except to pick up power for lighted cars.

Now, if you have a completely flat layout, and cannot (or do not want to) add more locos for your train, you will gain a lot from ball bearings.

If you have grades on your layout, most likely you won't benefit.

Here's a couple of places that sell bearings inexpensively:

http://www.avidrc.com/product/8/metric-bearings/

http://www.bocabearings.com/default.aspx

Actual dimensions of commonly available metal wheel sets:

• These are actual measurements.
• When measuring diameter next to the flange, these measurements are taken as close to the flange as possible, but staying "off" any fillet that may exist between the flange and the wheel tread.
• I'm not comparing all plastic wheels, if you are replacing plastic wheels, keep in mind if you change the diameter, you may affect clearance issues and coupler height.
• You must pay attention to the diameter of the axle tip and the overall length of the axles. I'm updating the information below bit by bit.

Rolling stock wheels

Note that in 1:29 scale, very few wheels are the exact right size... and not all wheels from the same manufacturer are the same size!  For example, when you swap from Aristo plastic to Aristo metal wheels, your car height changes due to the differences in diameter! This will affect coupler height, so "finalize" any wheel changes first before doing coupler work.

Locomotive wheels

Aristo Motive power wheel information

Measurements of original Aristo Dash 9 wheels:

Overall diameter (including flange): 1.615
Tread diameter close to flange: 1.375-1.378
Difference (should be flange times 2):  0.24
Calculated flange depth: 0.12"
Flange thickness at base: 0.077 - 0.079

Background / comparison data, Limited run of Aristo SS wheels:

Overall diameter (including flange): 1.533"
Tread diameter close to flange:1.379"
Difference (should be flange times 2): 0.154"
Calculated flange depth: 0.077
Flange thickness at base:

Background / comparison data, Ted Doskaris' custom SS wheels:

Overall diameter (including flange):1.558
Tread diameter close to flange:1.393
Difference (should be flange times 2): 0.165
Calculated flange depth is 0.0825
Flange thickness at base: 0.065

Measurement of new Dash 9 wheels - RJ: (Feb 2012)

Overall diameter (including flange):1.573
Tread diameter close to flange:1.380
Difference (should be flange times 2): 0.193
Calculated flange depth: 0.0965
Flange thickness at base: 0.63

Measurement of new Dash 9 wheels - Greg:

Overall diameter (including flange):1.571
Tread diameter close to flange:1.379
Difference (should be flange times 2): 0.192
Calculated flange depth is:0.096
Flange thickness at base is 0.66

Wheel back to back for front truck starting at front leading wheel set.

1.580 L

1.586 M

1.583 T

Rear truck wheel set closest to fuel tank

1.566 L

1.593 M

1.581 T

Notes on various manufacturer's freight/passenger wheels

AML metal wheel-sets (sintered steel, stainless axles, blackened)

New in late 2008. Part G12-111. (about $6 per axle, great price) I have been buying more of these lately, they have a rough finish on the tread that leads to more rolling noise. I believe these are sintered steel, and no plating. The price is great.

Axle ends .112" in diameter, overall length about 2.84", axle protrudes about .35" from the wheel face, no outer shoulder.

Aristo Craft (machined, blackened, no bearings)

Item art-29111b These used to be an inexpensive alternative/upgrade, but the price is going out of control, I bought 4 axles for $16 a few years ago, now over double that. I think these are fine wheels, but they scale out at 35.7" and with the flanges look out of scale (which they are). High quality machined wheels. The plating is not great sometimes, and, like all Aristo plating, wears off more rapidly than their competitors. The wheels appear brass underneath. A very nice replacement wheel, but the price has shot out of sight. 

Bachmann (cast, no bearings)

Bachmann item number 92421. These wheels are cast, not machined like the others. They are priced very low, so do not expect extremely high quality. This is usually the cheapest way to change to metal wheels. For my money the Aristo or USAT or AML wheels are a better choice. I have found the overall quality poor, and many wheels wobble. I have had unacceptable quality from 10% to 50% depending on the "batch". You can buy cheaper at the same quality, or spend the same and get better quality.

LGB double BB wheel-sets:

Part number number 67403. Great quality, lowest drag way to do power pickup, clips attach to pins on axle, can be slid off easily to remove axle. Good appearance, shiny, appears to be nickle or chrome plated. Too large in most cases, but probably the best quality materials and machining. The LGB wheels have shiny plated wheel treads with a plastic center. They are very well made, but don't look too realistic. The ball bearing ones are very nice and have 2 small pins for power pickup. These are my choice if I only have a couple of wheels that can pick up power. They are much larger than others, so if you put 2 axles on a caboose, for example, you need to match the larger diameter with the matching non-ball bearing ones from LGB.

I swapped these onto my USAT wood-sided caboose. It had carbon brush pickups, and when my layout was in a rough stage, the drag from those pickups made long trains derail. The pickups needed some form of lubrication, and anything I tried made a mess. The LGB wheel-sets made all the difference, but at first I tried just swapping one axle on each truck. More derailments! The difference in wheel diameter caused the truck to hang up on the underframe. Replacing 2 more wheel-sets with standard, non-ball bearing wheels from LGB of equal diameter fixed the problem. They are shiny, which is something I'd like to fix some day.

Note that the standard flange depth of LGB wheels is 3.8 mm, way beyond the normal standards. This may cause problems in the frogs of many switches.

Dean Lowe:

I have heard he makes nice wheels, no web site, here's his email: This email address is being protected from spambots. You need JavaScript enabled to view it.

If you get a price list or info, let me know. I have a couple I purchased at a show, but have not used them.

I have an address from 1998, L&L Screw Machine Products, Inc, 9653 El Poche St, South El Monte, CA 626-444-0993

NWSL (NorthWest Short Lines) http://www.nwsl.com/

Sold to new owners in 2008 I believe.

In 2011 I ordered some (using the catalog part number) and 4 months later, nothing. When I called up, the nice woman on the phone had no idea what I needed, I asked for wheels for a Aristo RS3. She did not know which ones they were. She told me to pick, and I could not make heads or tails of their price list. I finally made a guess, she took my name, etc and my CC number. Nothing. A friend of mine called a few weeks later, and was told there were "problems" associated with the Aristo wheels that have the tapered center hole. A little more pressing, and "out of stock" turned into "probably will no longer be made".

In 2016, they apparently made some wheels for an Aristo GP-40 for Joe Mascitti. These wheels came in "bright nickel silver", but they indicated that they are going to SS only in the future. Too bad, NS on SS is good, SS on SS is too slippery. My friend R.J. DeBerg measured them and the back to back was 39.71, 39.66, 39.64, and 39.66 with a flange depth of 2.7mm. Now NMRA target is 40 plus .48, minus .13, so the wheels are under gauge. The flange depth of 2.7 is a bit high, 1.68mm recommended from NMRA, and 2.0 from G1MRA. BUT, this might be helpful on the 3 axle unsprung motor blocks from Aristo. It is UNNEEDED on the 2 axle blocks.

The tread diameter was 34.88 against the flange, the thickness of the flange was 2.45mm, and the total diameter was 40.28, the recommended flange thickness is 1.5 mm, plus or minus .5 mm, so again, a too thick flange means if the back to back is right, then the gauge is wrong and vice versa. In this case, the gauge is ok, and the back to back is too narrow, as is the effective "standard" from LGB, Aristo, USAT on as delivered stuff, which works with the sloppy turnouts as delivered.

In 2019, the company is closing and up for sale. Too bad.

Click here for their price list.

I have some old part numbers, since one of the problems is getting the right part from them:

They had 3 profiles, the 270 (pretty close to stock), the 236 (thinner tread and shallower flanges), and the 172 (basically scale flange and tread)... I believe the number is the tread width in thousandths. The 270's were fine, the 236's caused some problems, you need superior trackwork, and the 172 just won't work outside.

Looks like they are back, but some items still hard to find.

For USA, and the very early Aristo 2 axle motor blocks (the ones where the axle protrudes past the wheel.)

2521-6 36" / 236 NS

2522-6 40" / 236 NS

2529-6 36" / 270 NS

2562-6 40" / 172 NS

2548-6 36" /270 SS

2549-6 40"/270 SS

For the newer Aristo 2 axle blocks (screws hold wheels to axles)

2563-6 40" / 236 NS

2564-6 40" / 172 NS

2565-6 40" / 270 SS

If anyone has measurements of flange depth on any of the 3 types, I'd appreciate hearing from you.

Gary Raymond:

I have not tried his wheels (yet). Many people tell me his wheelsets are the highest quality. I may try to order some, I need some metal wheels for my old Lionel Atlantic. I would love to replace the crappy plated steel wheels on all my Aristo diesels, but Gary (as of now) does not make replacement wheels with the tapered hole in the center to fit Aristo. 

Note: I have heard "horror stories" by people who order smaller flanges and have trouble. These people think you can just run semi-scale wheels anywhere. You need really good trackwork to use smaller flanges, and 90% of all G scale layouts I see have bad trackwork. It's not right to blame the manufacturer when you try to run scale flanges on poor trackwork.

From Gary:

"I make 3 basic "Degrees of Fineness" (NMRA term) wheelsets. We have 60 models total at present which fall into these three basic categories. 

1).G & 1:29 Semiscale which will work in all worst case situations with really bad 332 track, as reliably as other deeper flange wheelsets in most cases.

2). F, 1:29 and #1 Finescale which are smaller flanges and will work on all 148 to 332 if the trackwork is reasonably well done

3). PROTO (Exact) in #1. Will work extremely reliably on all 125 to 250 rail, but require .059" flangeways (typical Semiscale flangeways used in most 197 to 332 trackwork are in the range of .118")."

Per Gary: "The flange heights vary based on scale also but basically, PROTO in 1:32 is .031"-.033, 1:20.32 .049"-.054", SS .062"-.068" and the deepest .090" approximately"

I did not know Gary was the Technical Chair for Large Scale in the NMRA. That's a good thing in my opinon! He's actively involved in the track and wheel standards.

Gary's contact info is: This email address is being protected from spambots. You need JavaScript enabled to view it., PO Box 1722-R, Thousand Oaks CA 91358, 805-492-5858  www.trainwheels.com

San-Val double BB wheelsets: (machined, steel, stainless axle, double ball bearings)

Several people have reported inconsistent dimensions and loose insulators. Since San-Val no longer exists, you only see this product as used, or sometimes from Ana Kramer, the ebay identity for what is left of San Val.

They are double ball bearings (each wheel) and roll well. they can be a lot less expensive than Aristo or LGB.

They come shiny steel or with a blackened finish. The shiny ones can be darkened somewhat with a magic marker.

The blackened ones are not nickle plated, and some people have commented about rust. Oil the bearings on regular intervals in humid climates.

You might have to trim the brake shoes on older Aristo cars using these wheels.

I have not tried these yet. Might order some, but they seem to be a lot smaller than other wheels. The advantage here is cost.

Sierra Valley Enterprises:

Have not researched yet, here is the web site: http://www.sierravalleyenterprises.com/index.html

USAT (machined, brass, blackened, stainless axle, no bearings)

I like these wheels and the AML the best, scale appearance, (work out to 31.9", with the larger flanges, look just like 33" wheels). They are heavy, with a solid metal axle, and are fixed to the axle more securely than the aristo wheels. This means they go out of gauge less. I have had very few problems, but I have had loose insulators on a few, when regauging, be sure that the insulator moves with the wheel. Blackened brass with stainless steel axles. They are heavy, track well, and the thin axle is a plus since it is less likely to hit the coupler draft gear box when using Kadees. They have a small plastic insulator in the center of each wheel. They always come slightly undergauge. Put them in a vise so that the wheel backside is supported by the vise, and a light tap with a soft mallet on the axle is all that is usually needed.

Trucks - sprung or not?

Well, at first you might think sprung trucks would follow the track better. But my initial experience was that USAT and AML cars (no springs or equalization) stayed on the tracks much better than Aristo (sprung trucks).

Why was this?

At first I had all truck mounted couplers. If you think about it, the coupler tang is a long lever arm on the truck. The springs allowed so much flexibility in the motion of the coupler tang, it led to couplers deflecting up or down. This caused all kinds of problems when there was a significant number of cars in the train. Couplers would climb over each other, uncouple, and in the case of Kadees, the trip pins would hit rails at switches, track magnets, etc.

OK, so I am all body mount now. I expected the problems with Aristo freight cars would go away, but I still had more derailments with the Aristo cars. I started buying AML cars, and I still had better luck with USAT and AML than the Aristo. 

From my experience, with reasonable trackwork or better (I cannot speak for bad trackwork), sprung trucks add nothing to operational reliability, and are actually a negative when there are truck mounted couplers and/or trains of significant length.

As an aside, I thought that the difference in weight between Aristo and USAT cars (comparing 40' box cars) was the factor, but my AML cars are closer in weight to the Aristo, so that does not appear to be a factor.

Bottom line, don't expect better performance from sprung trucks, and remember that the Aristo truck springs can rust outdoors.

What makes a good wheel?

 good wheel contour. http://www.croberts.com/railroad.htm

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