# Wheel change on Bachmann MDT switcher



## cabledawg (Nov 30, 2010)

So I bought a Bachmann MDT 2 axle switcher that was in very good shape except one thing, one of the drive wheels was worn bad. After installing a decoder and cleaning up the wheels I was able to get it running pretty good, but it still couldnt pull anything due to the bum wheel.










I swapped the front and rear wheels so at least the drive axle has two wheels the same size. With a few ounces of weight, it'll at least pull a few cars now. This is what it looks like in caomparision to the other wheel.


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## gunrunnerjohn (Nov 10, 2010)

That wheel almost looks like it used to have a traction tire on it! Are you sure you don't just need the traction tire?

This is the picture that talks to me.


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## cabledawg (Nov 30, 2010)

Since Bachmann made this switcher in 1988 only, it might be easier to find the Holy Grail before I find parts for this thing. Here are a few shots of the wheels and axle with measurements. The wheel flange is 0.56" and the smaller part is 0.47". SO roughly a 49" and 41" scale size. The axle diameter where it enters the back of the wheel is 0.11".


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## gunrunnerjohn (Nov 10, 2010)

I really think all you're missing is a traction tire. That groove is much too regular for wear. I think the fix awaits you at the spare parts counter.


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## cabledawg (Nov 30, 2010)

gunrunnerjohn said:


> That wheel almost looks like it used to have a traction tire on it! Are you sure you don't just need the traction tire?
> 
> This is the picture that talks to me.
> 
> ...


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## cabledawg (Nov 30, 2010)

gunrunnerjohn said:


> I really think all you're missing is a traction tire. That groove is much too regular for wear. I think the fix awaits you at the spare parts counter.


Hopefully. Unfortunately, my local shop doesnt have any  But Spokane has a big train shop so when we head over there I'll bring this little guy and get him sized up for new shoes


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## gunrunnerjohn (Nov 10, 2010)

Traction tires are frequently on one side only. I have several engines that have a single traction tire, it all depends on how many driving wheels they have. Remember, they have to have track contact with some wheels to power the engine. 

I can't imagine that neat groove being wear, that would be a LOT of wear all on one side, that just doesn't happen that way.

You may be able to find a compatible traction tire, I've run across the same issue.


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## cabledawg (Nov 30, 2010)

Well GRJ, I thank you for your help as it seems this might be a very simple fix. SInce I have you here though, how do you measure wheel diameter? On the flange or the flat spot that sits on top of the rail? I have a few small cars that need wheels cahnged out but arent the standard rolling stock truck setup.


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## T-Man (May 16, 2008)

John is right about the tire groove.

For old Tycos I use dental elastics. One size fits all. I have added two at times.

Here is a reference thread.

The LHS sells packages with different sizes. they are available.


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## gunrunnerjohn (Nov 10, 2010)

I think the T-Man has come through with the solution.

I'm not entirely sure how to measure wheel diameter, I always thought it was the rolling surface (tread) and not including the flange. Of course, with the traction tire groove, I'm not sure if you measure in the groove, or the edge that's larger than the groove. Obviously, if you were trying to determine car height, you'd have to measure with the traction tire in place.

When you get the traction tire fitted, I'd move these back to the driving wheels, since I think you'll notice a big difference in pulling power.


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## NIMT (Jan 6, 2011)

Dang I hate when I come to the party late! Yep traction tire grove. Why only one side you ask, It's kind of like why a differential in a car so it can turn, Otherwise on a short loco like that they will crawl off the rails.
I think I have some really good traction tires that will fit that!


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## cabledawg (Nov 30, 2010)

Will do! I'll check the LHS in Spokane for the traction tires and if I cant find them there, I'll ask the kids' dentist for some bands.

Thanks guys for all your help! :thumbsup:


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## gunrunnerjohn (Nov 10, 2010)

Or you can take Sean up on his offer. 

Even with engines with multiple traction tires, they are only on one side for a given axle. I have one that has 8 wheel drive and 4 traction tires, two on a truck on one side, and two on the other truck on the other side.


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## cabledawg (Nov 30, 2010)

Makes sense. I didnt see Sean's post until after I wrote mine. 

Sean, I'll bring my switcher up and we'll see if we can find something that works. :thumbsup:


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## gunrunnerjohn (Nov 10, 2010)

You guys must live close.


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## cabledawg (Nov 30, 2010)

Nope, I have family over there and I'm headed that way for vacation next week.


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## NIMT (Jan 6, 2011)

That's cool, I'll bring the goodies with me!


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## whurd (Mar 17, 2011)

Who sells these things online?? I have a Bachmann that needs these, or I would LOVE to replace with steel wheels if possible. Can I get them factory direct????


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## gc53dfgc (Apr 13, 2010)

whurd said:


> Who sells these things online?? I have a Bachmann that needs these, or I would LOVE to replace with steel wheels if possible. Can I get them factory direct????


It's a bad idea to change out a traction tire wheels with a non one. You will loose traction and the train was not ment to run that way. LHS's or dental elastics are where to get them.

Cable in response to your question.

The wheel diameter is measured on the real prototype in to spots center point to outside of the flange and center point to where the wheels runs on top of the rail you would use the second for wheels in this case.


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## shaygetz (Sep 23, 2007)

Relocate them as well...I did it on mine by moving the traction tired one off of the power pickup to an axle without pickups. This improves electrical contact while retaining the traction ability...


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## gc53dfgc (Apr 13, 2010)

shaygetz said:


> Relocate them as well...I did it on mine by moving the traction tired one off of the power pickup to an axle without pickups. This improves electrical contact while retaining the traction ability...


I would also like to add that by flip flopping the axles with the traction tires you are giving it more tractive capabilitys on curves of both directions than if all the traction tires were on one side.


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## gunrunnerjohn (Nov 10, 2010)

Good point. On one 12 wheel drive locomotive, I have two on one truck on one side and two on the other truck on the other side.


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## cabledawg (Nov 30, 2010)

Good advice, but in my case I only have one drive axle while both have pickups. So I'd end up moving the traction tire back to the drive axle. I'll probably leave the weight in the back.


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## gc53dfgc (Apr 13, 2010)

gunrunnerjohn said:


> Good point. On one 12 wheel drive locomotive, I have two on one truck on one side and two on the other truck on the other side.


What diesel engine do you have that has 12 powered axles? That thing must pull like a boss.:laugh:


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## gunrunnerjohn (Nov 10, 2010)

I have several. I have an Lionel SD-40 with magnatraction that has 12 driving wheels, magnatraction on 8 of them. I also have a Williams GG-1 with 12 driving wheels. However, the one I thought was 12 wheeled is only 8 wheeled. In addition to that, one pair of driving wheels on each truck has the traction tires. The only part of my recall that was correct was the four traction tires! 

FWIW, it is a pulling fool, I had a temporary track in my office and strung 40 O-gauge cars behind it, it had no problem hauling them around. The SD-40 also handled them with ease. The GG-1 has no magnatraction or traction tires, but it does weigh over 6 pounds. It wasn't complete when I did this test, so I didn't see how many it can pull. It seems like it'll be a decent puller, it's two motors are huge in comparison to other DC motors, and just holding a car back when it cranked up it has a nice amount of force before it'll start spinning the wheels. Since I have cruise control on that one, it'll sit there and slowly spin it's wheels if you break it free. You can sure feel the "want to go" when you're holding it back, pretty decent traction. That one might get Bullfrog Snot if it has a problem pulling. All metal gears indicates to me that it's going to take a bit to break one. I'm also not intending to abuse the ability to pull


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