M200A1 Wheel Bearings

[Gypsyman]

I'm slowly accumulating spare parts for my trailers and I've hit a wall on the wheel bearings for the M200A1 under my MEP-004A generator. The inner seal, spindle nuts and lock are the same as the M105A2 trailers. Unfortunately the wheel bearings are a different part number. The M200A1 TM lists the bearings as p/n MS19081-112. I've searched high and low for an NSN or cross reference with zero results. That number comes up as no record on both WB Parts and Part Target. I'm at a loss on this one.

Upon further research the race 7411377 also matches the M105A2.

Would it be safe to assume that the bearing would be the same? Hopefully the Timken SET408 will work for both the M200A1 and the M105A2.

Any help or guidance would be greatly appreciated.

Richard

 

[Guyfang]

The number in red below is a Timken part #. All of the part numbers listed below will fit on the M200A1. My contact said the M105A3 has the same parts as the M200Al. Cost to the gov was 30 bucks.

3110001005951	SCY13
3651552	24617
3920/2984	38655
3984-3920	60038
3984-3920	0LTL1
3984-3920	51588
3984-3920	61220
3984-3920	01212
M2196	61208
PL5167418	25130
X18D15	79500
X18D15	65054

 

[Gypsyman]

I don't understand why the correct p/n MS19081-112 never had an NSN assigned or why it is so hard to locate. It's not like they only built a handful of M200A1 trailers. Looks like I'll have to tear down a hub to get a number.

 

[Guyfang]

Why? Plug in M2196 and Timken in your search engine.

 

[gringeltaube]

Guy: 3rd row in your table (3920/2984) is a mistake. Should be 3920/3984.

 

[Guyfang]

That table came from FEDLOG.

 

[Gypsyman]

The M2196 is actually a Twin Disc Inc. number and not Timken. That's why I was seeing no results. I'm digging around on Timken sight right now.

 

[gringeltaube]

That table came from FEDLOG.

Well, it's still wrong...

The correct cup for the M200A1 is #3920 (Ø 4-7/16" x 15/16" width) and the correct cone for it is #3984 (Ø 2-9/16").
Both inner and outer hub bearing sets are identical. So it takes (4) 3920 and (4) 3984 for a complete axle rebuild.

And yes, the M105A3 trailer has the very same bearing numbers.



BTW, WB-parts also shows the same wrong number........

 

[Gypsyman]

I saw that too and assumed it was a typo.

 

[gringeltaube]

I don't understand why the correct p/n MS19081-112 never had an NSN assigned or why it is so hard to locate.

Richard, you do have the PDF TM9-2330-205-14&P downloaded, right? If you use the find-function for that P/N MS19081-112, it gives you the corresponding NSN, in the cross-reference indexes, at the end of the book, SECTION IV.

 

[Gypsyman]

I do but I sure missed that in Section IV. Thanks G!

 

[Gypsyman]

Armed with the NSN finally thanks to Gerhard I went back to WB Parts and compared the M200A1 bearing set to the M105A2 bearing set. It appears that the M105A2 set is a mere .0045" thicker than the M200A1 set. All other dimensions appear to be identical. With this information I see no reason that the Timken 39590-39520 set used on the M105A2 couldn't be used on the M200A1. Here are the NSN's that I used.

M105A2 NSN 3110-00-198-1757 Timken 39590-39520

M200A1 NSN 3110-00-100-5951 Timken 3984-3920

Oddly enough the 39590 bearing used in the M105A2 application has a higher C1 dynamic radial rating (65300 lbf) than the 3984 bearing (54300 lbf).

 

[gringeltaube]

Oddly enough the 39590 bearing used in the M105A2 application has a higher C1 dynamic radial rating.... .......

The angle "a" is smaller for the 39590/39520 (meaning the rollers are less conical, thus increasing the radial load capacity while reducing the max. axial load.)

It appears that the M105A2 set is a mere .0045" thicker than the M200A1 set.

Dimension "T" is the same for both sets: 1.1875"

 

[Gypsyman]

Gerhard,

Your understanding of all of this is well beyond mine. I was going by dimension B from the Timken CAD drawings.



Dimension B of the 39590-39520 shows 1.1875" while dimension B for the 3984-3920 shows 1.1830". Maybe I'm reading the drawings incorrectly.

39590-39520

3984-3920

If I'm off base please step in and correct me.

Richard

 

[gringeltaube]

Yeah, usually those CAD drawings you find in the Timken catalogs (and others too) aren't very precise. "B" is just the bare cone width; not considering the cage.
"B" may-or may not be identical to "T", depending each bearing(set) design-and number. And in our particular case, only "T" is relevant.

I just edited your drawing a bit, to avoid any confusion....

 

[Gypsyman]

So, let's recap...

The correct bearings for each application are as follows:

M105A2 NSN 3110-00-198-1757 Timken 39590-39520
M200A1 NSN 3110-00-100-5951 Timken 3984-3920

If that's all you came to see you can stop right here.

A few few thoughts and observations of my own...

1. It would appear that dimensionally these bearings can be interchanged. Radial and Axial load ratings are slightly different between the two as noted a few posts back. The M105A2 bearing set has a slightly higher radial load rating while the M200A1 set has a slightly higher axial load rating. In my mind this makes sense since the M105A2 is a single tire configuration and the M200A1 is a dual tire config.

2. The listed part number in the M200A1 parts TM for the bearing race must be incorrect. It shows that it's the same as used on the M105A2 but, as you can see from above, the races (and bearings) are actually different part numbers. 39520 vs 3920.

3. The bearing assembly (p/n MS19081-112) shown in the M200A1 parts TM shows that no NSN was ever assigned when entered into the WB Parts site. But, in Section IV of the parts TM there actually IS an NSN listed. This NSN when checked through WB Parts does not list the p/n that the book shows it to correspond to. Very confusing to say the least. I'm assuming that at some point something was changed or the parts list with the drawing was incorrect all along.

In my mind, for no more use than my trailers see, I would be comfortable running either bearing set in either application. Since the Timken 3984-3920 has a slightly higher axial load rating it might be a small upgrade if you want to run dual tires on an M105A2. This is a project that I have on the list for my trailer and I think that I may just use the M200A1 bearing for this application.

Richard

 

[gringeltaube]

2. The listed part number in the M200A1 parts TM for the bearing race must be incorrect. It shows that it's the same as used on the M105A2 but, as you can see from above, the races (and bearings) are actually different part numbers. 39520 vs 3920.

I which TM did you find that info...?
I know it's a bit confusing, but following has already been confirmed to be correct:

• TM 9-2330-205-14&P , for the M200A1 & A2, lists the P/N MS19081-112 - (4) sets per trailer, which we know is 3984/3920 in the civi bearing world. And that same P/N MS19081-112 also appears in the TM 9-2330-324-14&P, for the M105A3.
• TM 9-2320-213-14&P (for the M105 & M105A1 and M105A2 trailers) tells us that the early versions 105 and 105A1 still have the same hub and bearings as the M35, where the outer bearing set is a 392/3920 and the inner, 3994/3920. (see this post, also....) Then the later M105A2 and -A2C versions take the 39590/39520 set; also (4) sets per axle.

...... if you want to run dual tires on an M105A2. This is a project that I have on the list for my trailer and I think that I may just use the M200A1 bearing for this application.

Just keep in mind: dual tires on a M105A2 axle is doable, but not street-legal, because of the resulting over-width. The -A2 hubs can't be flipped (not without a lot of work, at least) so you may be better off swapping the entire axle for one out of the M200A1 or M149.

 

[Guyfang]

BTW, WB-parts also shows the same wrong number........
Thats because they take their data from FEDLOG.

Your understanding of all of this is well beyond mine.
Mine also. I am but a poor Ground Power Diesel Duck.

But, in Section IV of the parts TM there actually IS an NSN listed. ( 3110-00-100-5951) This NSN when checked through WB Parts does not list the p/n that the book shows it to correspond to. (But in FEDLG, it shows up with that part number.) Very confusing to say the least. I'm assuming that at some point something was changed or the parts list with the drawing was incorrect all along.

One of the part numbers in that list I posted, marked in red, was the first Supplier for the part, in 1961, and it was given the NSN.

3110001005951	SCY13
3651552	24617
3920/2984	38655
3984-3920	60038
3984-3920	0LTL1
3984-3920	51588
3984-3920	61220
3984-3920	01212
M2196	61208
PL5167418	25130
X18D15	79500
X18D15	65054

Guy: 3rd row in your table (3920/2984) is a mistake. (Now we know it. But FEDLOG still shows it in association with the NSN: 3110-00-100-5951. And someone I know in TACOM looked it all up, and told me that this has been incorrectly listed for 30-40 years! The Gentleman in TACOM told me there will be an "annotation" made in FEDLOG.)

3. The bearing assembly (p/n MS19081-112) shown in the M200A1 parts TM shows that no NSN was ever assigned when entered into the WB Parts site. But, in Section IV of the parts TM there actually IS an NSN listed. The NSN is correct. The part number was wrong, and the reason it was all this time wrong is simple.The Army only uses NSN's. The only time we used a Part Number was when there was NO NSN.

This has been a very interesting parts search!

 

[Gypsyman]

I which TM did you find that info...?
I know it's a bit confusing, but following has already been confirmed to be correct:

• TM 9-2330-205-14&P , for the M200A1 & A2, lists the P/N MS19081-112 - (4) sets per trailer, which we know is 3984/3920 in the civi bearing world. And that same P/N MS19081-112 also appears in the TM 9-2330-324-14&P, for the M105A3.
• TM 9-2320-213-14&P (for the M105 & M105A1 and M105A2 trailers) tells us that the early versions 105 and 105A1 still have the same hub and bearings as the M35, where the outer bearing set is a 392/3920 and the inner, 3994/3920. (see this post, also....) Then the later M105A2 and -A2C versions take the 39590/39520 set; also (4) sets per axle.

Just keep in mind: dual tires on a M105A2 axle is doable, but not street-legal, because of the resulting over-width. The -A2 hubs can't be flipped (not without a lot of work, at least) so you may be better off swapping the entire axle for one out of the M200A1 or M149.

This has been interesting for sure. Here's what started my questioning.

TM 9-2330-205-14&P for the M200A1 lists the race separately as 7411377 which is the same race (Timken 39520) that is part of the bearing assembly used in the M105A2. As stated above we know that the race used for the bearing assembly on the M200A1 is actually the Timken 3920. When I noticed that the bearing assembly number was different even though they showed the same race I knew that something was off. That discrepancy is how I ended down this path with questions.

I've read that the dual tires on an M105A2 will be over width but I have never found an actual outside to outside dimension posted with dual tires installed. If anyone has seen this posted somewhere I would love to know what that dimension is. I sure can't find it. We are allowed 102" overall width. Unfortunately my trailer is not here right now so I can't verify any measurements. Push come to shove I will pick up a junk M200A1 as a parts donor and take it from there.

Richard

 

[gringeltaube]

I've read that the dual tires on an M105A2 will be over width but I have never found an actual outside to outside dimension posted with dual tires installed. If anyone has seen this posted somewhere I would love to know what that dimension is.

That's an easy one, since we know the width of each component:

A) The axle measures 78.9" between wheel mounting surfaces. (same as the M35 front axle, BTW)
B) Each center disc has a thickness of 0.48".
C) The stock 20x7.5" wheel backspace is 10.53".
D) Stock 9.00-20 tires protrude from the rim about 0.7" (not counting the bulge towards the ground.)


So the total WOA, dualed would be: A + (4x B) + (2x C) + (2x D) = 103.3"