I’ve had a Bachmann Spectrum Mogul for a while. It was binding a little in the curves and riding up the rail with the front driver. I finally pulled it apart today and found the front driver about 1/16" inward. I haven’t pulled the driver yet. Question is can you spread these and how would you do it?

Binding and riding up on the rails suggests over gauge more then under gauge. I would try measuring with a dial caliper to see what the gauge really is, and to see if it is indeed under-gauge, like you gauge shows in the picture. Not all gauges are accurate.

100% agree, buy a cheap set of calipers, and adjust the back to back to nmra spec.

The Kadee gauge is a bit sloppy in many cases, depends too much on the flange contour.

Greg

I’ll check the so called standards.

I already own an expensive Starrett caliper.

Are these wheels adjustable?. If not, then I’ll just toss the loco into the parts bin.

The wheels check out (within tolerances) in gauge.

When turning they are a little wobbly. And when turning under power, the front wheel rides all the way to the right, but doesn’t rub the frame. Both in forward or reverse.

OH well. It’s been lubed and put back together.

On to the next project.

I would think they could be adjusted. The question is, how hard is it to adjust them?

The wobble would explain its bad behavior.

They looked pretty solid to me. That’s why I didn’t want to try to widen them a little. With my luck…

Widen them? You would want to fix the wobble, or send it back to Bachmann to have them fix it.

What does the back to back actually measure?

Greg

“Believe it or not”, in spite of the fact that Aristo was not overly famous for maintaining any standard of gauge in their products (Wheel sets, or track), they did produce a rather accurate wheel and track gauge. At least, it was/is accurate to NMRA standards, although many in Large scale seem to find fault with the NMRA, for all sorts of reasons, many bordering on religion or politics.!!

Those gauges are rather hard to find these days, but if you do find one; it is a very handy tool for your work bench.

As was mentioned, the pictured Kadee wheel/coupler gauge, is another fine tool, but the wheel gauge part is not the best of wheel gauges to depend on. The other measuring tools are much more dependable, and the "Back-to-Back wheel spacing is the important measurement.

The B’mann driving wheels are usually held to the axles, by a screw in the centre, most times covered by a plastic plug (If I’m not mistaken). To alter the spacing, especially if the gauge is narrow, would only involve pulling a wheel and inserting a small washer, of the appropriate thickness.If, however the problem is a wobbly wheel; the wobble might be caused by the wheel not being properly mounted. Removal and a cleaning, while observing the wheel, might show some obstruction, or burr, easily fixed with a small file, then replacement might show the problem to be fixed.

Or…as a last resort, contact B’mann, and ask for instructions, or just return it for repairs, as suggested.